CN106848998B - A kind of power output protection circuit and device - Google Patents
A kind of power output protection circuit and device Download PDFInfo
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- CN106848998B CN106848998B CN201710112319.7A CN201710112319A CN106848998B CN 106848998 B CN106848998 B CN 106848998B CN 201710112319 A CN201710112319 A CN 201710112319A CN 106848998 B CN106848998 B CN 106848998B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for DC applications
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Abstract
The invention discloses a kind of power output protection circuit and devices, comprising: sampling module, switch control module and processing and control module；Wherein, received supply voltage is converted to sampled voltage by sampling module in proportion; processing and control module confirmation load short circuits or overcurrent when judging that sampled voltage is not more than default overcurrent voltage; cut-off control signal is sent to switch control module; control switch control module stops transmitting received supply voltage to sampling module, realizes overcurrent protection.Processing and control module sends conductivity control signal to switch control module when judging that sampled voltage is greater than default overcurrent voltage, control switch control module constant conduction is with to the received supply voltage of sampling module continuous transmission, it is transferred to power output end after dividing again by sampling module to received supply voltage, to power to the load.It can thus be avoided the problem of being damaged when load short circuits or overcurrent to the power supply of power input connection.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a power output protection circuit and a power output protection device.
Background
In the alarm device, a low-voltage direct-current power supply (generally 12V) is often required to be externally provided to supply power to external devices such as a detector, an alarm and a configuration keyboard. Since the current consumed by these external devices is not large and in order to reduce the design cost, a low-voltage dc power supply and a power supply for supplying power to the alarm device are commonly used as a power supply. However, when the external device is abnormal or damaged by human, such as short circuit or overcurrent, the low-voltage dc power supply or even the power supply may be adversely affected, so as to affect the normal operation of the alarm device, such as abnormal reset, false alarm, etc.
The existing low-voltage direct-current power supply output protection circuit mainly aims at realizing overcurrent protection. Generally, the overcurrent protection is implemented by using a series PTC (Positive Temperature Coefficient thermistor), a fuse, or an electronic circuit protection method based on current loop detection. When the series PTC protection mode is adopted, although the PTC has the advantages of high reliability, low maintenance cost and the like, the action response time of overcurrent protection is long, and the overcurrent protection point is not accurate enough. When the fuse protection mode is adopted, the fuse has the advantages of high reliability, short action response time and the like, but the fuse cannot be recovered after being fused, so that the maintenance cost is high. When the electronic circuit protection mode based on current loop detection is adopted, the overcurrent protection point is relatively accurate, the protection action is timely, but the current loop detection is generally carried out in a mode of serially connecting a sampling resistor, the sampling resistor can cause certain influence on the normal work of a load, and the abnormal large current fault response is not timely enough, so that the reliability of the electronic circuit protection mode is relatively low.
Disclosure of Invention
The embodiment of the invention provides a power output protection circuit and a power output protection device, which are used for improving reliability, reducing action response time of protection and reducing maintenance cost.
Therefore, an embodiment of the present invention provides a power output protection circuit, including: the device comprises a sampling module, a switch control module and a processing control module; wherein,
the sampling module is used for receiving the power supply voltage transmitted by the switch control module, dividing the received power supply voltage, transmitting the divided power supply voltage to a power supply output end, converting the received power supply voltage into sampling voltage in proportion, and transmitting the sampling voltage to the processing control module;
the processing control module is used for receiving the sampling voltage, sending a cut-off control signal to the switch control module when judging that the received sampling voltage is not greater than a preset overcurrent voltage, and continuously sending a conduction control signal to the switch control module when judging that the received sampling voltage is greater than the preset overcurrent voltage;
the switch control module is used for receiving the power supply voltage of a power supply input end, the conduction control signal and the cut-off control signal, transmitting the received power supply voltage to the sampling module when receiving the conduction control signal, and stopping transmitting the received power supply voltage to the sampling module when receiving the cut-off control signal.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the power output protection circuit further includes: a logic control module; the processing control module sends a cut-off control signal and a turn-on control signal to the switch control module through the logic control module;
the logic control module is used for receiving the sampling voltage and the cut-off control signal sent by the processing control module, transmitting the received cut-off control signal to the switch control module, receiving the sampling voltage and the conduction control signal sent by the processing control module, and transmitting the received conduction control signal to the switch control module.
Preferably, in the above power output protection circuit provided in the embodiment of the present invention, the logic control module includes: an AND gate; wherein,
the first input end of the AND gate is used for receiving the sampling voltage, the second input end of the AND gate is used for receiving the cut-off control signal and the conduction control signal sent by the processing control module, and the output end of the AND gate is used for outputting the received cut-off control signal and the received conduction control signal to the switch control module.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the sampling module includes: the circuit comprises a diode, a first transistor, a first resistor, a second resistor, a third resistor and a fourth resistor; wherein,
the anode of the diode is used for receiving the power supply voltage transmitted by the switch control module, and the cathode of the diode is connected with the power supply output end and used for transmitting the divided power supply voltage to the power supply output end;
the first end of the first resistor and the source electrode of the first transistor are connected with the anode of the diode, and the second end of the first resistor and the drain electrode of the first transistor are connected with the first end of the second resistor;
the second end of the second resistor is connected with the first end of the third resistor, and the second end of the second resistor is used for outputting the sampling voltage;
the second end of the third resistor is connected with a grounding end;
the first end of the fourth resistor is connected with the cathode of the diode, and the second end of the fourth resistor is connected with the grid electrode of the first transistor;
the preset over-current voltage V0Satisfies the formula:wherein, UDRepresents the conduction voltage drop of the diode, r1A resistance value, r, representing said first resistance2Representing the resistance value, r, of said second resistor3Represents saidThe resistance value of the third resistor.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the switch control module includes: a second transistor, a third transistor, a fifth resistor, and a sixth resistor; wherein,
a source of the second transistor is connected to the power input terminal for receiving a power supply voltage of the power input terminal, a drain of the second transistor is used for transmitting the received power supply voltage, and a gate of the second transistor is connected to the first terminal of the fifth resistor and the source of the third transistor;
a second end of the fifth resistor is connected with a source electrode of the second transistor;
the grid electrode of the third transistor is connected with the first end of the sixth resistor, and the drain electrode of the third transistor is connected with a grounding end;
the second end of the sixth resistor is used for receiving the on control signal and the off control signal.
Preferably, in the above power output protection circuit provided in the embodiment of the present invention, the switch control module further includes: a seventh resistor and capacitor; wherein
The seventh resistor is connected between the gate of the second transistor and the source of the third transistor;
the capacitor is connected between the first end of the fifth resistor and the second end of the fifth resistor.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the power output protection circuit further includes: a driving control module connected between the source of the third transistor and the ground terminal; wherein,
the processing control module is further used for continuously sending a conducting pulse driving signal to the driving control module when the received sampling voltage is judged to be greater than a preset overcurrent voltage, and sending a stopping pulse driving signal to the driving control module when the received sampling voltage is judged to be not greater than the preset overcurrent voltage;
the driving control module is configured to receive the on-pulse driving signal and the off-pulse driving signal, turn on the source of the third transistor and the ground terminal when receiving the on-pulse driving signal, and turn off the source of the third transistor and the ground terminal when receiving the off-pulse driving signal.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the driving control module includes: a fourth transistor and an eighth resistor; wherein,
the first end of the eighth resistor is used for receiving the on-pulse driving signal and the off-pulse driving signal, and the second end of the eighth resistor is connected with the grid electrode of the fourth transistor;
and the source electrode of the fourth transistor is connected with the source electrode of the third transistor, and the drain electrode of the fourth transistor is connected with the grounding terminal.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the power output protection circuit further includes: a surge suppression module; the input end of the surge suppression module is connected with the power supply output end; the surge suppression module is used for preventing surge voltage at the power supply output end from being input into the sampling module; and/or the presence of a gas in the gas,
the power output protection circuit further includes: a status indication module; the processing control module is further used for sending an alarm control signal to the state indicating module when the received sampling voltage is judged to be not greater than the preset overcurrent voltage;
and the state indicating module is used for sending alarm information after receiving the alarm control signal.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, when the power output protection circuit further includes a surge suppression module, the surge suppression module includes: a transient voltage suppression diode; the negative electrode of the transient voltage suppression diode is the input end of the surge suppression module, and the positive electrode of the transient voltage suppression diode is connected with the ground end;
when the power output protection circuit further comprises a status indication module, the status indication module comprises: a ninth resistor and a light emitting diode; the first end of the ninth resistor is used for receiving the alarm control signal, the second end of the ninth resistor is connected with the anode of the light emitting diode, and the cathode of the light emitting diode is connected with the grounding end.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the processing control module includes: a microcontroller; wherein,
and a receiving port of the microcontroller is used for receiving the sampling voltage, and a first output port is used for outputting the on-state control signal and the off-state control signal.
Preferably, in the above power output protection circuit provided in the embodiment of the present invention, when the power output protection circuit further includes a driving control module, the microcontroller further includes: a second output port for outputting the off pulse driving signal and the on pulse driving signal;
when the power output protection circuit further comprises a status indication module, the microcontroller further comprises: and the third output port is used for outputting the alarm control signal.
Preferably, in the above power output protection circuit provided in an embodiment of the present invention, the power output protection circuit further includes: a positive temperature coefficient thermistor; the switch control module transmits the received power supply voltage to the sampling module through the positive temperature coefficient thermistor.
Correspondingly, the embodiment of the invention also provides a power output protection device which comprises any one of the power output protection circuits provided by the embodiment of the invention.
The invention has the following beneficial effects:
the embodiment of the invention provides a power output protection circuit and a device, comprising: the device comprises a sampling module, a switch control module and a processing control module; the received power supply voltage is converted into sampling voltage in proportion through the sampling module, whether the received sampling voltage is larger than preset overcurrent voltage or not is judged through the processing control module, when the sampling voltage is judged to be not larger than the preset overcurrent voltage, the load short circuit or overcurrent connected with the power supply output end can be confirmed, a cut-off control signal is sent to the switch control module, the switch control module is controlled to stop transmitting the received power supply voltage to the sampling module, the power supply input end and the sampling module are disconnected so as to avoid the damage of the load short circuit or overcurrent to the power supply connected with the power supply input end, and overcurrent protection is achieved. When the processing control module judges that the sampling voltage is greater than the preset overcurrent voltage, the processing control module sends a conduction control signal to the switch control module, the switch control module is controlled to be continuously conducted so as to continuously transmit the received power supply voltage to the sampling module, and then the sampling module divides the received power supply voltage and transmits the divided voltage to the power supply output end so as to supply power to the load. Therefore, through the mutual matching of the three modules, the problem that the power supply connected with the power input end is damaged when the load is in short circuit or overcurrent can be avoided, and the circuit is more stable and reliable.
Drawings
Fig. 1 is a schematic structural diagram of a power output protection circuit according to an embodiment of the present invention;
fig. 2 is a second schematic structural diagram of a power output protection circuit according to an embodiment of the invention;
FIG. 3a is a schematic diagram of a specific structure of the power output protection circuit shown in FIG. 1;
FIG. 3b is a schematic diagram of a specific structure of the power output protection circuit shown in FIG. 2;
fig. 3c is a third schematic structural diagram of a power output protection circuit according to an embodiment of the invention;
fig. 3d is a schematic structural diagram of the power output protection circuit shown in fig. 3 c.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, specific embodiments of a power output protection circuit and a device provided by an embodiment of the present invention are described in detail below with reference to the accompanying drawings. It should be understood that the preferred embodiments described below are only for illustrating and explaining the present invention and are not to be used for limiting the present invention. And the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
An embodiment of the present invention provides a power output protection circuit, as shown in fig. 1, including: the device comprises a sampling module 1, a switch control module 2 and a processing control module 3; wherein,
the sampling module 1 is used for receiving the power supply voltage transmitted by the switch control module 2, dividing the received power supply voltage, transmitting the divided power supply voltage to the power supply output end VOUT, converting the received power supply voltage into sampling voltage in proportion and transmitting the sampling voltage to the processing control module 3;
the processing control module 3 is used for receiving the sampling voltage, sending a cut-off control signal to the switch control module 2 when judging that the received sampling voltage is not greater than the preset overcurrent voltage, and continuously sending a turn-on control signal to the switch control module 2 when judging that the received sampling voltage is greater than the preset overcurrent voltage;
the switch control module 2 is configured to receive a power supply voltage of the power supply input terminal VIN, a turn-on control signal, and a turn-off control signal, transmit the received power supply voltage to the sampling module 1 when the turn-on control signal is received, and stop transmitting the received power supply voltage to the sampling module when the turn-off control signal is received.
The power output protection circuit provided by the embodiment of the invention comprises: the device comprises a sampling module, a switch control module and a processing control module; the received power supply voltage is converted into sampling voltage in proportion through the sampling module, whether the received sampling voltage is larger than preset overcurrent voltage or not is judged through the processing control module, when the sampling voltage is judged to be not larger than the preset overcurrent voltage, the load short circuit or overcurrent connected with the power supply output end can be confirmed, a cut-off control signal is sent to the switch control module, the switch control module is controlled to stop transmitting the received power supply voltage to the sampling module, the power supply input end and the sampling module are disconnected so as to avoid the damage of the load short circuit or overcurrent to the power supply connected with the power supply input end, and overcurrent protection is achieved. When the processing control module judges that the sampling voltage is greater than the preset overcurrent voltage, the processing control module sends a conduction control signal to the switch control module, the switch control module is controlled to be continuously conducted so as to continuously transmit the received power supply voltage to the sampling module, and then the sampling module divides the received power supply voltage and transmits the divided voltage to the power supply output end so as to supply power to the load. Therefore, the power output protection circuit provided by the embodiment of the invention can avoid the problem that a power supply connected with the power input end is damaged when a load is in a short circuit or an overcurrent through the mutual matching of the three modules, so that the circuit is more stable and reliable.
Further, when the circuit is in a stable output state, and when a load has a short circuit or an overcurrent fault, in order to quickly disconnect the power input terminal VIN from the sampling module 1 and reduce an influence on the power input terminal VIN, in a specific implementation, in the power output protection circuit provided in an embodiment of the present invention, as shown in fig. 2, the power output protection circuit may further include: a logic control module 4; the processing control module 3 sends a cut-off control signal and a cut-on control signal to the switch control module 2 through the logic control module 4; wherein,
the logic control module 4 is configured to receive the cut-off control signal sent by the sampling voltage and processing control module 3, transmit the received cut-off control signal to the switch control module 2, receive the turn-on control signal sent by the sampling voltage and processing control module 3, and transmit the received turn-on control signal to the switch control module 2.
Further, in order to prevent the influence of the abnormal surge voltage generated when the load is connected or disconnected on the power output protection circuit, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 2, the power output protection circuit may further include: a surge suppression module 5; wherein,
the input end of the surge suppression module 5 is connected with the power output end VOUT; the surge suppression module 5 is used for preventing the surge voltage of the power output terminal VOUT from being input into the sampling module 1.
Further, in order to timely notify when the load is short-circuited or overcurrent, in a specific implementation, in the power output protection circuit provided in an embodiment of the present invention, as shown in fig. 2, the power output protection circuit further includes: a status indication module 6; wherein,
the processing control module 3 is further configured to send an alarm control signal to the state indicating module 6 when it is determined that the received sampling voltage is not greater than the preset overcurrent voltage;
and the state indicating module 6 is used for sending alarm information after receiving the alarm control signal.
The present invention will be described in detail with reference to specific examples. It should be noted that the present embodiment is intended to better explain the present invention, but not to limit the present invention.
Specifically, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3a to 3d, the sampling module 1 may specifically include: the diode D, the first transistor M1, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4; wherein,
the anode of the diode D is used for receiving the power supply voltage transmitted by the switch control module 2, and the cathode of the diode D is connected with the power supply output end VOUT and used for transmitting the divided power supply voltage to the power supply output end VOUT;
a first end of the first resistor R1 and a source of the first transistor M1 are both connected to an anode of the diode D, and a second end of the first resistor R1 and a drain of the first transistor M1 are both connected to a first end of the second resistor R2;
a second end of the second resistor R2 is connected to a first end of the third resistor R3, and a second end of the second resistor R2 is used for outputting a sampling voltage;
a second end of the third resistor R3 is connected to the ground GND;
a first end of the fourth resistor R4 is connected to the cathode of the diode D, and a second end is connected to the gate of the first transistor M1;
preset over-current voltage V0Satisfies the formula:wherein, UDRepresenting the conduction voltage drop of the diode, r1Representing the resistance value of the first resistor, r2Representing the resistance value of the second resistor, r3Representing the resistance of the third resistor.
In a specific implementation, as shown in fig. 3a, in the power output protection circuit provided in the embodiment of the invention, the first transistor M1 may be a PNP transistor, where a base of the PNP transistor is a gate of the first transistor M1, a collector of the PNP transistor is a source of the first transistor M1, and an emitter of the PNP transistor is a source of the first transistor M1. Of course, the first transistor M1 may also be a Metal Oxide semiconductor field effect transistor (MOS). In practical applications, the specific structure of the first transistor M1 needs to be designed according to practical application environments, and is not limited herein.
In the concrete implementation, the invention providesIn the power output protection circuit, when the power output end is connected with a load and supplies power to the load, current exists between the anode of the diode and the cathode of the diode, and the diode has stable voltage drop, namely conduction voltage drop. Due to the presence of the conducting voltage drop, the voltage difference V between the grid electrode of the first transistor and the source electrode thereof can be enabledgsThe relationship between (M1) and its threshold voltage Vth (M1) satisfies the formula: i Vgs(M1)|＞|Vth(M1) |, thereby turning on the first transistor. And, the conduction voltage drop of the general diode is in the range of 0.6V-0.7V. Threshold voltage V of the first transistorth(M1) is generally in the range of 0.5V to 0.6V. In addition, the diode also has the function of reverse cut-off, so that the influence of external current backflow on the power output protection circuit can be prevented. In practical applications, the conduction voltage drop of the diode and the threshold voltage of the first transistor need to be designed and determined according to practical application environments, and are not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the diode is a silicon diode. This allows a relatively constant conduction voltage drop between the anode and the cathode of the diode. Of course, the diode may also be a germanium diode. In practical applications, the specific structure of the diode needs to be designed according to practical application environments, and is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, resistance values of the first resistor, the second resistor, the third resistor, and the fourth resistor need to be designed and determined according to an actual application environment, which is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, when the first transistor is a P-type MOS transistor, a resistance value of the fourth resistor may be 0.
The above is only an example of the specific structure of the sampling module in the power output protection circuit, and in the specific implementation, the specific structure of the sampling module is not limited to the above structure provided by the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Specifically, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3a, the switch control module 2 may specifically include: a second transistor M2, a third transistor M3, a fifth resistor R5, and a sixth resistor R6; wherein,
a source of the second transistor M2 is connected to the power input terminal VIN for receiving a power voltage of the power input terminal VIN, a drain is used for transmitting the received power voltage, and a gate is connected to the first terminal of the fifth resistor R5 and the source of the third transistor M3;
a second end of the fifth resistor R5 is connected to the source of the second transistor M2;
the gate of the third transistor M3 is connected to the first end of the sixth resistor R6, and the drain is connected to the ground GND;
the second end of the sixth resistor R6 is used for receiving the on control signal and the off control signal.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3a, the second transistor M2 may be a Metal Oxide semiconductor field effect transistor (MOS). Of course, the second transistor M2 may also be a P-type transistor, in which case the base of the P-type transistor is the gate of the second transistor M2, the collector of the P-type transistor is the source of the second transistor M2, and the emitter of the P-type transistor is the drain of the second transistor M2. In practical applications, the specific structure of the second transistor M2 needs to be designed according to practical application environments, and is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the second transistor is turned on when the gate of the second transistor has a low-level voltage signal, so that the power input terminal and the input terminal of the sampling module can be turned on, and the power voltage at the power input terminal is transmitted to the input terminal of the sampling module. In practical application, the second transistor is arranged at the grid electrode thereofVoltage difference V between it and its sourcegs(M2) and its threshold voltage Vth(M2) the relationship between satisfies the formula: i Vgs(M2)|＞|Vth(M2) | is on. After the second transistor is turned on, the resistance value of the equivalent resistor is small, and when the current flowing through the second transistor is small, the voltage drop between the two ends of the equivalent resistor can be ignored, so that the voltage loss is reduced.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, as shown in fig. 3a, the third transistor M3 may be an NPN transistor, where a base of the NPN transistor is a gate of the third transistor M3, a collector of the NPN transistor is a source of the third transistor M3, and an emitter of the NPN transistor is a drain of the third transistor M3. Of course, the third transistor M3 may also be an N-type MOS transistor. In practical applications, the specific structure of the third transistor M3 needs to be designed according to practical application environments, and is not limited herein.
In a specific implementation manner, in the power output protection circuit provided in the embodiment of the invention, the third transistor is turned on when the gate of the third transistor has a high-level voltage signal, so that a path may be formed between the second end of the fifth resistor and the ground terminal. In practical application, the voltage difference V between the gate and the source of the third transistorgs(M3) and its threshold voltage Vth(M3) the relationship between satisfies the formula: i Vgs(M3)|＞|Vth(M3) | is on. And after the third transistor is turned on, the resistance value of the equivalent resistor is small, and when the current flowing through the third transistor is small, the voltage drop between the two ends of the equivalent resistor can be ignored, so that the voltage loss is reduced.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, when the third transistor is an N-type MOS transistor, a resistance value of the sixth resistor may be 0. In practical applications, the resistance values of the fifth resistor and the sixth resistor need to be designed and determined according to practical application environments, and are not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the on control signal is a voltage signal having a high level, and the off control signal is a voltage signal having a low level.
Further, for filtering, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3b to 3d, the switch control module 2 may further include: a seventh resistor R7 and a capacitor C; wherein
The seventh resistor R7 is connected between the gate of the second transistor M2 and the source of the third transistor M3;
the capacitor C is connected between the first end and the second end of the fifth resistor R5.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, a resistance value of the seventh resistor needs to be designed and determined according to an actual application environment, which is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, a capacitance value of the capacitor needs to be designed and determined according to an actual application environment, which is not limited herein.
The above is only an example of the specific structure of the switch control module in the power output protection circuit, and in the specific implementation, the specific structure of the switch control module is not limited to the above structure provided in the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Specifically, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3b to 3d, the logic control module 4 may specifically include: and gate &; wherein,
the first input end a of the and gate & is used for receiving the sampling voltage, the second input end B of the and gate & is used for receiving the cut-off control signal and the turn-on control signal sent by the processing control module 3, and the output end F of the and gate & is used for outputting the received cut-off control signal and the received turn-on control signal to the switch control module 2.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the output terminal of the and gate outputs the voltage signal with the high level only when the first input terminal and the second input terminal of the and gate both have the voltage signal with the high level, and otherwise, the output terminal of the and gate outputs the voltage signal with the low level. Therefore, the sampling voltage can be converted into a voltage signal for controlling the on and off of the third transistor in the switch control module by adopting the AND gate, so that the on and off of the third transistor in the switch control module can be controlled quickly, and the response time is reduced. And may also mask the sampled voltage under control of the process control module.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, when the sampling voltage is greater than the preset overcurrent voltage, the sampling voltage is a voltage signal having a high level with respect to the and gate. And when the sampling voltage is not greater than the preset overcurrent voltage, aiming at the AND gate, the sampling voltage is a voltage signal with low level. In practical application, the specific structure of the and gate needs to be designed and determined according to the practical application environment, and is not limited herein.
The above is only an example of the specific structure of the logic control module in the power output protection circuit, and in the specific implementation, the specific structure of the logic control module is not limited to the above structure provided in the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Further, in order to ensure that when the power output protection circuit is turned on from off, the load overcurrent affects the circuit, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3c, the power output protection circuit may further include: the driving control module 7 connected between the source of the third transistor M3 and the ground GND; wherein,
the processing control module 3 is further configured to continuously send a conduction pulse driving signal to the driving control module 7 when judging that the received sampling voltage is greater than the preset overcurrent voltage, and send a cutoff pulse driving signal to the driving control module 7 when judging that the received sampling voltage is not greater than the preset overcurrent voltage;
the driving control module 7 is configured to receive the on-pulse driving signal and the off-pulse driving signal, turn on the source of the third transistor M3 and the ground GND when receiving the on-pulse driving signal, and turn off the source of the third transistor M3 and the ground GND when receiving the off-pulse driving signal.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3d, the driving control module 7 may specifically include: a fourth transistor M4 and an eighth resistor R8; wherein,
the first end of the eighth resistor R8 is used for receiving the on-pulse driving signal and the off-pulse driving signal, and the second end is connected to the gate of the fourth transistor M4;
the source of the fourth transistor M4 is connected to the source of the third transistor M3, and the drain of the fourth transistor M4 is connected to the ground GND.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, as shown in fig. 3d, the fourth transistor M4 may be an NPN transistor, where a base of the NPN transistor is a gate of the fourth transistor M4, a collector of the NPN transistor is a source of the fourth transistor M4, and an emitter of the NPN transistor is a drain of the fourth transistor M4. Of course, the fourth transistor M4 may also be an N-type MOS transistor. In practical applications, the specific structure of the fourth transistor M4 needs to be designed according to practical application environments, and is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, the fourth transistor is turned on when the gate of the fourth transistor has a high-level voltage signal, so that a path may be formed between the second end of the fifth resistor and the ground. In practical application, the voltage difference V between the gate and the source of the fourth transistorgs(M4) And its threshold voltage Vth(M4) the relationship between satisfies the formula: i Vgs(M4)|＞|Vth(M4) | is on. After the fourth transistor is turned on, the resistance value of the equivalent resistor is small, and when the current flowing through the fourth transistor is small, the voltage drop between the two ends of the fourth transistor can be ignored, so that the voltage loss is reduced.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the on Pulse driving signal is a voltage signal having a high level, the off Pulse driving signal is a voltage signal having a low level, and the on Pulse driving signal and the off Pulse driving signal are controlled by a PWM (Pulse Width Modulation) technique.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, a resistance value of the eighth resistor needs to be designed and determined according to an actual application environment, and is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the invention, when the fourth transistor M4 is an N-type MOS transistor, a resistance value of the eighth resistor may be 0.
Specifically, in the foregoing power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3a to 3d, the processing control module 3 may include: a microcontroller MCU; wherein,
the receiving port AI of the microcontroller MCU is configured to receive the sampling voltage, and the first output port IO1 is configured to output a turn-on control signal and a turn-off control signal. Therefore, the sampling voltage output by the sampling module can be detected in real time through the microcontroller, and the switch control module is controlled in a time mode.
Further, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3c and 3d, when the power output protection circuit further includes a driving control module 7, the microcontroller MCU further includes: and a second output port IO2 for outputting an off pulse driving signal and an on pulse driving signal.
Further, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3b to 3d, when the power output protection circuit further includes a status indication module 6, the microcontroller MCU further includes: and a third output port IO3 for outputting an alarm control signal.
In specific implementation, in the above power output protection circuit provided in the embodiment of the present invention, the specific structure of the microcontroller is the same as that in the prior art, and it should be understood by those skilled in the art that the specific structure is not described in detail herein, and should not be taken as a limitation to the present invention.
The above is only an example of the specific structure of the processing control module in the power output protection circuit, and in the specific implementation, the specific structure of the processing control module is not limited to the above structure provided in the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Specifically, in the foregoing power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3b to 3d, the surge suppressing module 5 may specifically include: a transient voltage suppression diode TVS; wherein,
the cathode of the transient voltage suppression diode TVS is the input terminal 5a of the surge suppression module 5, and the anode of the transient voltage suppression diode TVS is connected to the ground GND.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the transient voltage suppression diode may be a unidirectional transient voltage suppression diode, or the transient voltage suppression diode may also be a bidirectional transient voltage suppression diode. The specific type of the transient voltage suppression diode needs to be designed according to the actual application environment, and is not limited herein.
The above is merely an example of the specific structure of the surge suppression module in the power output protection circuit, and in the specific implementation, the specific structure of the surge suppression module is not limited to the above structure provided in the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Specifically, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3b to 3d, the state indicating module 6 may specifically include: a ninth resistor R9 and a light emitting diode L; wherein,
the first end of the ninth resistor R9 is used for receiving the alarm control signal, the second end is connected with the anode of the light emitting diode L, and the cathode of the light emitting diode L is connected with the ground end GND.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, when the state indication module receives the alarm control signal, the light emitting diode is in a flash state. Of course, when the power input end is disconnected from the power output end and power is not supplied, the microcontroller in the processing control module controls the light emitting diode to be in a closed state. When the power input end and the power output end are conducted and are in a normal state of supplying power to the load, the microcontroller in the processing control module controls the light-emitting diode to be in a normally-on state. When the load is disconnected or not connected, the microcontroller in the processing control module controls the light-emitting diode to be in a slow flashing state.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, a resistance value of the ninth resistor needs to be designed and determined according to an actual application environment, and is not limited herein.
In a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, the state indication module may further include an element having an alarm prompting function, such as a buzzer.
The above is only an example of the specific structure of the status indication module in the power output protection circuit, and in the specific implementation, the specific structure of the status indication module is not limited to the above structure provided in the embodiment of the present invention, and may be other structures known to those skilled in the art, and is not limited herein.
Further, in a specific implementation, in the power output protection circuit provided in the embodiment of the present invention, as shown in fig. 3c and 3d, the power output protection circuit may further include: a positive temperature coefficient thermistor PTC; wherein,
the switch control module 2 transmits the received power supply voltage to the sampling module 1 through the positive temperature coefficient thermistor PTC.
The following describes the operation of the power output protection circuit provided by the present invention by taking the specific structure shown in fig. 3a and 3d as an example. Wherein, the power voltage of the power input end VIN is VinPresetting an over-current voltage V0Satisfies the formula:
the first embodiment,
As shown in fig. 3a, the first transistor is a PNP transistor, the second transistor is a P-type MOS transistor, and the third transistor is an NPN transistor.
(1) When the load connected to the power output terminal VOUT operates normally without short circuit, i.e., when the power input terminal VIN is conducted with the power output terminal VOUT, the diode D has a stable conduction voltage drop, so that the voltage V of the first transistor M1gs(M1)>Vth(M1) is turned on, and the equivalent resistance of the first transistor M1 after being turned on is small and negligible. Therefore, the first resistor R1 is short-circuited, and the source of the first transistor M1, the second resistor R2 and the third resistor R3 form a path, so that the voltage V at the second end of the second resistor R21Namely, the sampling voltage satisfies the formula:wherein, U1For this purpose, the voltage of the anode of the diode D, r2Is the resistance value, R, of the second resistor R23Is the resistance value of the third resistor R3. Due to the loadThe current required for normal operation is small, so the voltage drop of the second transistor M2 is negligible, making U1≈Vin. Thus, it is possible to provideThereby satisfying the formula: v1>V0The microcontroller MCU continuously outputs a turn-on control signal to the third transistor M3 to control the third transistor M3 to be continuously turned on, so that the gate of the second transistor M2 is continuously turned on to the ground GND, thereby controlling the power input terminal VIN and the anode of the diode D to be continuously turned on to transmit the power voltage V to the anode of the diode Din。
(2) When the power output terminal VOUT is disconnected from the load or the connected load is disconnected, i.e., the power input terminal VIN is disconnected from the power output terminal VOUT, the diode D is not turned on, so that there is no conduction voltage drop across the diode D, and therefore the first transistor M1 is turned off, and the first resistor R1, the second resistor R2 and the third resistor R3 form a path, so that the voltage V at the second terminal of the second resistor R2 is connected to the second terminal of the second resistor R32Namely, the sampling voltage satisfies the formula:wherein, U2For this purpose, the voltage of the anode of the diode D, r1Is the resistance value of the first resistor R1. The voltage U of the anode of the diode D at this time2≈Vin. Thus, it is possible to provideThereby satisfying the formula: v2>V0The microcontroller MCU outputs a turn-on control signal to the third transistor M3 to control the third transistor M3 to turn on, so that the gate of the second transistor M2 is turned on to the ground GND, thereby controlling the power input terminal VIN and the anode of the diode D to turn on.
(3) When the load connected to the power output terminal VOUT is short-circuited, that is, the cathode of the diode D is directly grounded, so that the voltage of the anode of the diode D is the conduction voltage drop of the diode, and since the cathode of the diode D is grounded, the first transistor M1 is turned off, and the first resistor R1 and the second resistor R are turned offThe resistor R2 and the third resistor R3 form a path, so that the voltage V of the second end of the second resistor R23Namely, the sampling voltage satisfies the formula:thereby satisfying the formula: v3＝V0The microcontroller MCU outputs a cut-off control signal to the third transistor M3 to control the third transistor M3 to be cut off, and disconnect the gate of the second transistor M2 from the ground GND, thereby controlling the power input terminal VIN to be disconnected from the anode of the diode D, so as to open the circuit between the power input terminal VIN and the power output terminal VOUT, thereby implementing overcurrent protection.
Example II,
As shown in fig. 3d, the first transistor is a PNP transistor, the second transistor is a P-type MOS transistor, and the third transistor is an NPN transistor.
(1) When the load connected to the power output terminal VOUT operates normally without short circuit, i.e., when the power input terminal VIN is conducted with the power output terminal VOUT, the diode D has a stable conduction voltage drop, so that the voltage V of the first transistor M1gs(M1)>Vth(M1) is turned on, and the equivalent resistance of the first transistor M1 after being turned on is small and negligible. Therefore, the first resistor R1 is short-circuited, and the source of the first transistor M1, the second resistor R2 and the third resistor R3 form a path, so that the voltage V at the second end of the second resistor R21Namely, the sampling voltage satisfies the formula:wherein, U1For this purpose, the voltage of the anode of the diode D, r2Is the resistance value, R, of the second resistor R23Is the resistance value of the third resistor R3. Because the current required by the load in normal operation is small, the voltage drop of the second transistor M2 is negligible, so that U is enabled1≈Vin. Thus, it is possible to provideThereby being full ofFoot formula: v1>V0MCU continuous direction AND gate&Sends a turn-on control signal with a high level due to the AND gate&Has a high level voltage signal, and therefore an AND gate&The output terminal F outputs a voltage signal with a high level, so that the on-control signal with a high level received by the first input terminal a is transmitted to the third transistor M3 to control the third transistor M3 to be turned on continuously, so as to turn on the gate of the second transistor M2 and the ground terminal GND, thereby controlling the power input terminal VIN and the anode of the diode D to be turned on continuously. And the microcontroller MCU controls the light emitting diode L in the status indication module 6 to be in a normally on status for prompting.
(2) When the power output terminal VOUT is disconnected from the load or the connected load is disconnected, i.e., the power input terminal VIN is disconnected from the power output terminal VOUT, the diode D is not turned on, so that there is no conduction voltage drop across the diode D, and therefore the first transistor M1 is turned off, and the first resistor R1, the second resistor R2 and the third resistor R3 form a path, so that the voltage V at the second terminal of the second resistor R2 is connected to the second terminal of the second resistor R32That is, the voltage of the sampling voltage satisfies the formula:wherein, U2For this purpose, the voltage of the anode of the diode D, r1Is the resistance value of the first resistor R1. The voltage U of the anode of the diode D at this time2≈Vin. Thus, it is possible to provideThereby satisfying the formula: v2>V0MCU directional AND gate&Sends a turn-on control signal with a high level due to the AND gate&Has a high level voltage signal, and therefore an AND gate&The output terminal F outputs a voltage signal with a high level, so that the on-control signal with a high level received by the first input terminal a is transmitted to the third transistor M3 to control the third transistor M3 to be turned on, and the gate of the second transistor M2 and the ground terminal GND are turned on, so as to control the power input terminal VIN and the anode of the diode D to be turned on.And the microcontroller MCU controls the light emitting diode L in the indication module 6 to be in a slow flashing state so as to give an alarm for prompting.
(3) When the load connected to the power output terminal VOUT is short-circuited, that is, the cathode of the diode D is directly grounded, so that the voltage of the anode of the diode D is the conduction voltage drop of the diode, because the cathode of the diode D is grounded, the first transistor M1 is turned off, and the first resistor R1, the second resistor R2 and the third resistor R3 form a path, so that the voltage V at the second end of the second resistor R2 is reduced3That is, the voltage of the sampling voltage satisfies the formula:thereby satisfying the formula: v3＝V0So that the AND gate&The second input terminal B inputs a low-level voltage signal, so that the AND gate&The output terminal F of (b) can rapidly output the voltage signal having the low level, so that the third transistor M3 can be timely controlled to be turned off. Wherein, the MCU is used for judging V3Not more than V0Then to the AND gate&A low-level cut-off control signal is sent to the first input end A of the first transistor to enable the AND gate&Outputs a voltage signal having a low level. Therefore, the MCU has a processing and judging process for the sampling voltage, and the AND gate&As long as the voltage signal of low level is received at the first input terminal a or the second input terminal B, the voltage signal of low level is immediately output through the output terminal F to control the third transistor M3 to be turned off, so that the and gate is adopted&The gate of the second transistor M2 can be quickly disconnected from the ground GND, so that the power input terminal VIN can be quickly disconnected from the anode of the diode D, and the power input terminal VIN and the power output terminal VOUT are disconnected, thereby realizing overcurrent protection. And the microcontroller MCU sends an alarm control signal to the state indicating module 6, and the state indicating module 6 controls the light emitting diode L to be in a flash state after receiving the alarm control signal so as to give an alarm prompt. And due to the action of the transient voltage suppression diode TVS, the influence of abnormal voltage caused by abnormal load on the power output protection circuit can be further prevented. And is heat-sensitive due to positive temperature coefficientThe effect of resistance can further guarantee to lead to the influence of overflowing to the power input when the load short circuit.
(4) When the power input end VIN and the power output end VOUT are changed from disconnection to opening state, the microcontroller MCU turns to the AND gate&Sends a disable control signal having a low level, and thus an and gate&Outputs a voltage signal having a low level, thereby transmitting a turn-off control signal having a low level received at the first input terminal a thereof to the third transistor M3 to control the third transistor M3 to be turned off. The microcontroller MCU outputs a high-level on-pulse driving signal to the fourth transistor M4 to control the fourth transistor M4 to be turned on, so that the gate of the second transistor M2 is turned on to the ground GND, thereby controlling the power input terminal VIN to be turned on to the anode of the diode D. When the load is short-circuited, the voltage of the anode of the diode D is the conduction voltage drop of the diode, so that the voltage V at the second end of the second resistor R2 is obtained3That is, the voltage of the sampling voltage satisfies the formula:namely, the formula is satisfied: v3＝V0. The microcontroller MCU outputs a low-level cut-off pulse driving signal to the fourth transistor M4 to control the cut-off of the fourth transistor M4, so that the gate of the second transistor M2 is disconnected from the ground GND, thereby controlling the disconnection of the power input terminal VIN from the anode of the diode D, and implementing overcurrent protection. Otherwise, the microcontroller MCU controls the duty ratio of the conduction pulse driving signal to be the full duty ratio by adopting the PWM technology to control the fourth transistor M4 to be continuously conducted, and after the duty ratio of the conduction pulse driving signal is the full duty ratio, the microcontroller MCU controls the AND gate to be conducted&Sends a turn-on control signal with a high level due to the AND gate&Has a high level voltage signal, and therefore an AND gate&The output terminal F outputs a voltage signal with a high level, so that the on-control signal with a high level received by the first input terminal a is transmitted to the third transistor M3 to control the third transistor M3 to be turned on, so that the gate of the second transistor M2 is turned on with the ground terminal GND, thereby controlling the power input terminal VIN and the anode of the diode D to be turned on. At and gate&After stable output, the microcontroller MCU outputs a low-level cut-off pulse driving signal to the fourth transistor M4 to control the fourth transistor M4 to cut off, so that the gate of the second transistor M2 is disconnected from the ground GND, thereby controlling the power input terminal VIN to be disconnected from the anode of the diode D, and the microprocessor MCU and the and gate are connected to each other&The combined action realizes overcurrent protection. When the load is short-circuited, the voltage of the anode of the diode D is the conduction voltage drop of the diode, so that the voltage V at the second end of the second resistor R2 is obtained3That is, the voltage of the sampling voltage satisfies the formula:namely, the formula is satisfied: v3＝V0. Thus making the AND gate&The second input terminal B inputs a low-level voltage signal, so that the AND gate&The output terminal F of (b) can rapidly output the voltage signal having the low level, so that the third transistor M3 can be timely controlled to be turned off. Wherein, the MCU is used for judging V3Not more than V0Then to the AND gate&A low-level cut-off control signal is sent to the first input end A of the first transistor to enable the AND gate&Outputs a voltage signal having a low level. Therefore, the MCU has a processing and judging process for the sampling voltage, and the AND gate&As long as the voltage signal of low level is received at the first input terminal a or the second input terminal B, the voltage signal of low level is immediately output through the output terminal F to control the third transistor M3 to be turned off, so that the and gate is adopted&The gate of the second transistor M2 can be quickly disconnected from the ground GND, so that the power input terminal VIN can be quickly disconnected from the anode of the diode D, and the power input terminal VIN and the power output terminal VOUT are disconnected, thereby realizing overcurrent protection.
Based on the same inventive concept, the embodiment of the invention also provides a power output protection device, which comprises any one of the power output protection circuits provided by the embodiment of the invention. The principle of the power output protection device for solving the problems is similar to that of the power output protection circuit, so the implementation of the power output protection device can be referred to the implementation of the power output protection circuit, and repeated parts are not described herein again. The power output protection device can be any product or component with a power output function, such as alarm equipment. Other essential components of the power output protection device are understood by those skilled in the art, and are not described herein nor should they be construed as limiting the present invention.
The embodiment of the invention provides a power output protection circuit and a device, comprising: the device comprises a sampling module, a switch control module and a processing control module; the received power supply voltage is converted into sampling voltage in proportion through the sampling module, whether the received sampling voltage is larger than preset overcurrent voltage or not is judged through the processing control module, when the sampling voltage is judged to be not larger than the preset overcurrent voltage, the load short circuit or overcurrent connected with the power supply output end can be confirmed, a cut-off control signal is sent to the switch control module, the switch control module is controlled to stop transmitting the received power supply voltage to the sampling module, the power supply input end and the sampling module are disconnected so as to avoid the damage of the load short circuit or overcurrent to the power supply connected with the power supply input end, and overcurrent protection is achieved. When the processing control module judges that the sampling voltage is greater than the preset overcurrent voltage, the processing control module sends a conduction control signal to the switch control module, the switch control module is controlled to be continuously conducted so as to continuously transmit the received power supply voltage to the sampling module, and then the sampling module divides the received power supply voltage and transmits the divided voltage to the power supply output end so as to supply power to the load. Therefore, through the mutual matching of the three modules, the problem that the power supply connected with the power input end is damaged when the load is in short circuit or overcurrent can be avoided, and the circuit is more stable and reliable.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (13)
1. A power output protection circuit, comprising: the device comprises a sampling module, a switch control module and a processing control module; wherein,
the sampling module is used for receiving the power supply voltage transmitted by the switch control module, dividing the received power supply voltage, transmitting the divided power supply voltage to a power supply output end, converting the received power supply voltage into sampling voltage in proportion, and transmitting the sampling voltage to the processing control module; the sampling module comprises: a diode, a first transistor, a first resistor, a second resistor, a third resistor anda fourth resistor; the anode of the diode is used for receiving the power supply voltage transmitted by the switch control module, and the cathode of the diode is connected with the power supply output end and used for transmitting the divided power supply voltage to the power supply output end; the first end of the first resistor and the source electrode of the first transistor are connected with the anode of the diode, and the second end of the first resistor and the drain electrode of the first transistor are connected with the first end of the second resistor; the second end of the second resistor is connected with the first end of the third resistor, and the second end of the second resistor is used for outputting the sampling voltage; the second end of the third resistor is connected with a grounding end; the first end of the fourth resistor is connected with the cathode of the diode, and the second end of the fourth resistor is connected with the grid electrode of the first transistor; preset over-current voltage V0Satisfies the formula:wherein, UDRepresents the conduction voltage drop of the diode, r1A resistance value, r, representing said first resistance2Representing the resistance value, r, of said second resistor3A resistance value representing the third resistance;
the processing control module is used for receiving the sampling voltage, sending a cut-off control signal to the switch control module when judging that the received sampling voltage is not greater than a preset overcurrent voltage, and continuously sending a conduction control signal to the switch control module when judging that the received sampling voltage is greater than the preset overcurrent voltage;
the switch control module is used for receiving the power supply voltage of a power supply input end, the conduction control signal and the cut-off control signal, transmitting the power supply voltage received by the switch control module to the sampling module when receiving the conduction control signal, and stopping transmitting the power supply voltage received by the switch control module to the sampling module when receiving the cut-off control signal.
2. The power output protection circuit of claim 1, wherein the power output protection circuit further comprises: a logic control module; the processing control module sends a cut-off control signal and a turn-on control signal to the switch control module through the logic control module;
the logic control module is used for receiving the sampling voltage and the cut-off control signal sent by the processing control module, transmitting the received cut-off control signal to the switch control module, receiving the sampling voltage and the conduction control signal sent by the processing control module, and transmitting the received conduction control signal to the switch control module.
3. The power output protection circuit of claim 2, wherein the logic control module comprises: an AND gate; wherein,
the first input end of the AND gate is used for receiving the sampling voltage, the second input end of the AND gate is used for receiving the cut-off control signal and the conduction control signal sent by the processing control module, and the output end of the AND gate is used for outputting the received cut-off control signal and the received conduction control signal to the switch control module.
4. The power output protection circuit of claim 1, wherein the switch control module comprises: a second transistor, a third transistor, a fifth resistor, and a sixth resistor; wherein,
a source of the second transistor is connected to the power input terminal for receiving a power supply voltage of the power input terminal, a drain of the second transistor is used for transmitting the received power supply voltage, and a gate of the second transistor is connected to the first terminal of the fifth resistor and the source of the third transistor;
a second end of the fifth resistor is connected with a source electrode of the second transistor;
the grid electrode of the third transistor is connected with the first end of the sixth resistor, and the drain electrode of the third transistor is connected with a grounding end;
the second end of the sixth resistor is used for receiving the on control signal and the off control signal.
5. The power output protection circuit of claim 4, wherein the switch control module further comprises: a seventh resistor and capacitor; wherein
The seventh resistor is connected between the gate of the second transistor and the source of the third transistor;
the capacitor is connected between the first end of the fifth resistor and the second end of the fifth resistor.
6. The power output protection circuit of claim 4, wherein the power output protection circuit further comprises: a driving control module connected between the source of the third transistor and the ground terminal; wherein,
the processing control module is further used for continuously sending a conducting pulse driving signal to the driving control module when the received sampling voltage is judged to be greater than a preset overcurrent voltage, and sending a stopping pulse driving signal to the driving control module when the received sampling voltage is judged to be not greater than the preset overcurrent voltage;
the driving control module is configured to receive the on-pulse driving signal and the off-pulse driving signal, turn on the source of the third transistor and the ground terminal when receiving the on-pulse driving signal, and turn off the source of the third transistor and the ground terminal when receiving the off-pulse driving signal.
7. The power output protection circuit of claim 6, wherein the drive control module comprises: a fourth transistor and an eighth resistor; wherein,
the first end of the eighth resistor is used for receiving the on-pulse driving signal and the off-pulse driving signal, and the second end of the eighth resistor is connected with the grid electrode of the fourth transistor;
and the source electrode of the fourth transistor is connected with the source electrode of the third transistor, and the drain electrode of the fourth transistor is connected with the grounding terminal.
8. The power output protection circuit of claim 1, wherein the power output protection circuit further comprises: a surge suppression module; the input end of the surge suppression module is connected with the power supply output end; the surge suppression module is used for preventing surge voltage at the power supply output end from being input into the sampling module; and/or the presence of a gas in the gas,
the power output protection circuit further includes: a status indication module; the processing control module is further used for sending an alarm control signal to the state indicating module when the received sampling voltage is judged to be not greater than the preset overcurrent voltage;
and the state indicating module is used for sending alarm information after receiving the alarm control signal.
9. The power output protection circuit of claim 8, wherein when the power output protection circuit further comprises a surge suppression module, the surge suppression module comprises: a transient voltage suppression diode; the negative electrode of the transient voltage suppression diode is the input end of the surge suppression module, and the positive electrode of the transient voltage suppression diode is connected with the ground end;
when the power output protection circuit further comprises a status indication module, the status indication module comprises: a ninth resistor and a light emitting diode; the first end of the ninth resistor is used for receiving the alarm control signal, the second end of the ninth resistor is connected with the anode of the light emitting diode, and the cathode of the light emitting diode is connected with the grounding end.
10. The power output protection circuit according to any one of claims 1 to 9, wherein the processing control module includes: a microcontroller; wherein,
and a receiving port of the microcontroller is used for receiving the sampling voltage, and a first output port is used for outputting the on-state control signal and the off-state control signal.
11. The power output protection circuit of claim 10, wherein when the power output protection circuit further comprises a drive control module, the microcontroller further comprises: a second output port for outputting the off pulse driving signal and the on pulse driving signal;
when the power output protection circuit further comprises a status indication module, the microcontroller further comprises: and the third output port is used for outputting an alarm control signal.
12. The power supply output protection circuit according to any one of claims 1 to 7, wherein the power supply output protection circuit further comprises: a positive temperature coefficient thermistor; the switch control module transmits the received power supply voltage to the sampling module through the positive temperature coefficient thermistor.
13. A power output protection device comprising a power output protection circuit as claimed in any one of claims 1 to 12.
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| CN110275058A (en) * | 2019-06-20 | 2019-09-24 | 华立科技股份有限公司 | The communication module overload identification protection circuit and method of intelligent electric energy meter |
| CN111337735B (en) * | 2020-02-17 | 2022-09-13 | 上海艾为电子技术股份有限公司 | Chip and current sampling circuit |
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| CN106848998A (en) | 2017-06-13 |
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