CN118199584A - Switch protection circuit and electronic equipment - Google Patents
Switch protection circuit and electronic equipment Download PDFInfo
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- CN118199584A CN118199584A CN202410478180.8A CN202410478180A CN118199584A CN 118199584 A CN118199584 A CN 118199584A CN 202410478180 A CN202410478180 A CN 202410478180A CN 118199584 A CN118199584 A CN 118199584A
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- electronic switch
- protection circuit
- surge
- control module
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
- H03K17/08104—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in field-effect transistor switches
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
- H03K17/08112—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in bipolar transistor switches
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/081—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit
- H03K17/08116—Modifications for protecting switching circuit against overcurrent or overvoltage without feedback from the output circuit to the control circuit in composite switches
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/12—Modifications for increasing the maximum permissible switched current
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Abstract
The embodiment of the invention discloses a switch protection circuit and electronic equipment, relates to the technical field of electronic circuits, and can effectively prevent an electronic switch from being damaged by surge current. The circuit comprises: the electronic switch is arranged between the power supply access end and the load access end; the surge limiting control module is configured to perform integral operation according to a target current signal flowing through the electronic switch in a first mode of the switch protection circuit to obtain an integral voltage signal, and determine whether to limit and protect the surge current according to the integral voltage signal; the logic control module is connected with the surge limiting control module and is configured to: in the first mode, the electronic switch is controlled to be turned off in response to the surge limiting control module determining to limit protection for the surge current, or the electronic switch is controlled to be turned on in response to the surge limiting control module determining to de-limit protection for the surge current.
Description
Technical Field
The present invention relates to the field of electronic circuits, and in particular, to a switch protection circuit and an electronic device.
Background
Semiconductor switches are widely used in a variety of applications (e.g., in automotive applications or industrial applications). However, in a specific application, if a large capacitive load exists in the circuit, the load capacitor charges at the moment of power supply access or when the circuit is abnormal, so that the circuit generates peak current which is far greater than steady-state current, namely surge current. The surge current is easy to damage the switching element, so how to make the load safely pass the transient surge phase of the surge current to smoothly enter the steady-state working state is a problem to be solved in the field.
Disclosure of Invention
Therefore, the embodiment of the invention provides a switch protection circuit and electronic equipment, which can effectively prevent an electronic switch from being damaged by surge current, so that a load connected with the electronic switch safely passes through transient impact of the surge current and enters a steady-state working state.
In a first aspect, an embodiment of the present invention provides a switch protection circuit, including: the electronic switch is arranged between the power supply access end and the load access end; the surge limiting control module is configured to perform integral operation according to a target current signal flowing through the electronic switch in a first mode of the switch protection circuit to obtain an integral voltage signal, and determine whether to limit and protect the surge current according to the integral voltage signal; wherein the integrated voltage signal increases with time when the target current signal is greater than a preset reference current signal, and decreases with time when the target current signal is less than the reference current signal; the logic control module is connected with the surge limiting control module and is configured to: in the first mode, the electronic switch is controlled to be turned off in response to the surge limiting control module determining to limit protection for the surge current, or the electronic switch is controlled to be turned on in response to the surge limiting control module determining to de-limit protection for the surge current.
In one embodiment, the surge limiting control module is specifically configured to determine, in a first mode of the switch protection circuit, limiting protection for the surge current according to a comparison result of the integrated voltage signal and a first voltage threshold, or determining, in a second mode of the switch protection circuit, releasing limiting protection for the surge current according to a comparison result of the integrated voltage signal and a second voltage threshold, wherein the first voltage threshold is greater than the second voltage threshold.
In one embodiment, the switch protection circuit further comprises: the current sampling module is connected in series between the power supply access end and the electronic switch or between the electronic switch and the load access end; the current sampling module is also connected with the surge limiting control module and is configured to sample the target current signal to obtain a sampling signal, and the sampling signal is input into the surge limiting control module; the surge limiting control module is configured to perform integral operation according to the sampling signal output by the current sampling module in the first mode to obtain an integral voltage signal, and determine whether to limit and protect the surge current according to the integral voltage signal.
In one embodiment, the surge limit control module includes: an integrated reference signal providing sub-module configured to provide an integrated reference signal based on the reference current signal; the integration operation submodule is respectively connected with the current sampling module and the reference signal providing submodule and is configured to perform integration operation on time according to the difference between the sampling signal and the integration reference signal to obtain the integration voltage signal; and the control submodule is connected with the integral operation submodule and is configured to determine to limit and protect the surge current according to the comparison result of the integral voltage signal and a first voltage threshold value or determine to release the limit and protect the surge current according to the comparison result of the integral voltage signal and a second voltage threshold value in a first mode of the switch protection circuit, wherein the first voltage threshold value is larger than the second voltage threshold value.
In one embodiment, the control submodule includes: the input end of the first comparison unit is connected with the integration operation submodule and is configured to compare the integrated voltage signal with the first voltage threshold value and output a first comparison result; the input end of the second comparison unit is connected with the integration operation submodule and is configured to compare the integrated voltage signal with the second voltage threshold value and output a second comparison result; the first input end of the control unit is connected with the output end of the first comparison unit, and the second input end of the control unit is connected with the output end of the second comparison unit; the control unit is configured to: outputting a first level signal in response to the first comparison result being that the integrated voltage signal is greater than the first voltage threshold; or outputting a second level signal in response to the second comparison result being that the integrated voltage signal is less than the second voltage threshold; wherein the first level signal is different from the second level signal; the logic control module is configured to turn off the electronic switch according to a first level signal output by the control unit or turn on the electronic switch according to a second level signal output by the control unit.
In one embodiment, the control unit includes a circuit module with a set input and a reset input.
In one embodiment, the control submodule includes a hysteresis comparator; the input end of the hysteresis comparator is connected with the integration operation submodule, and the hysteresis comparator is configured to: outputting a first level signal in response to the integrated voltage signal increasing with time and the integrated voltage signal being greater than the first voltage threshold; or outputting a second level signal in response to the integrated voltage signal decreasing with time and the integrated voltage signal being less than the second voltage threshold; wherein the first level signal is different from the second level signal; the logic control module is configured to turn off the electronic switch according to a first level signal output by the hysteresis comparator or turn on the electronic switch according to a second level signal output by the hysteresis comparator.
In one embodiment, the switch protection circuit further comprises: and the first mode detection module is connected with the surge limiting control module and is configured to determine whether the switch protection circuit enters the first mode according to a first input signal.
In one embodiment, the switch protection circuit is configured to operate in a second mode by default, and the logic control module is further configured to control the electronic switch to be turned on or off in accordance with a second input signal in the second mode, wherein the second input signal is different from the first input signal.
In one embodiment, the protection circuit further includes: the first input end of the driving module is connected with the logic control module and is configured to drive the electronic switch to be turned off or on according to a control signal output by the logic control module; the second input end of the driving module is connected with the first mode detection module, and the driving module is further configured to adjust the starting voltage output to the electronic switch so that the switching rate of the electronic switch in the first mode is smaller than the switching rate in the second mode in response to the first mode detection module determining that the switch protection circuit enters the first mode, wherein the starting voltage is a level signal for controlling the electronic switch to be turned on.
In one embodiment, the switch protection circuit further comprises an overcurrent protection module, and the overcurrent protection module is connected with the logic control module; the first mode detection module is also connected with the logic control module; the logic control module is further configured to: in response to the first mode detection module determining that the switch protection circuit enters the first mode, prohibiting the overcurrent protection module from performing overcurrent protection on the electronic switch; and in response to the first mode detection module determining that the switch protection circuit does not enter the first mode, allowing the overcurrent protection module to carry out overcurrent protection on the electronic switch.
In one embodiment, the reference current signal is greater than or equal to a steady state current signal, wherein the steady state current signal is a current signal flowing through the electronic switch when the load is operating in steady state.
In a second aspect, an embodiment of the present invention further includes an electronic device, where the electronic device includes any of the switch protection circuits provided by the embodiments of the present invention.
According to the switch protection circuit and the electronic device provided by the embodiment of the invention, as the integration operation is performed based on the target current signal, the accumulation effect of the target current signal in time can be reflected, and the surge current has a large peak value and acts fast, but the current thermal effect which damages the electronic switch generally needs to be accumulated for a certain time, therefore, the switch protection circuit provided by the embodiment of the invention can simulate the thermal effect caused by the target current signal by utilizing the integration operation of the surge limit control module: in the case that the target current signal is greater than a preset reference current signal, the integral voltage signal increases with time, which means that the thermal effect of the target current signal is accumulating, and in the case that the target current signal is less than the reference current signal, the integral voltage signal decreases with time, which means that the thermal effect of the target current signal is dissipating, so that the accumulating degree or dissipating degree of the current thermal effect can be evaluated according to the integral voltage signal, thereby determining whether the electronic switch needs to be turned off to make the target current signal 0 to suspend the accumulating of the current thermal effect, or whether the electronic switch needs to be turned on to restore the target current signal. With the recovery of the target current signal, the integral voltage signal of the surge limiting control module generates a new round of change, and the electronic switch is controlled to be turned off or on accordingly, so that the surge current can be effectively limited, the electronic switch is prevented from being damaged by the surge current, and a load connected with the electronic switch safely passes through the transient impact of the surge current and enters a steady-state working state.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a switch protection circuit according to an embodiment of the present invention;
FIG. 2 is a graph showing the change of the target current signal and the integrated voltage signal with time according to an embodiment of the present invention;
Fig. 3 is a schematic diagram of another structure of a switch protection circuit according to an embodiment of the present invention;
fig. 4 is a schematic diagram of still another structure of a switch protection circuit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of an integration operation sub-module in a switch protection circuit according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a control sub-module in a switch protection circuit according to an embodiment of the present invention;
fig. 7 is a schematic diagram of another configuration of a control submodule in the switch protection circuit according to an embodiment of the present invention;
fig. 8 is a schematic diagram of still another structure of a switch protection circuit according to an embodiment of the present invention;
Fig. 9 is a schematic diagram of still another structure of a switch protection circuit according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In a first aspect, an embodiment of the present invention provides a switch protection circuit, which can effectively avoid damage of an electronic switch by a surge current, so that a load connected to the electronic switch safely passes through transient impact of the surge current and enters a steady state working state.
As shown in fig. 1, an embodiment of the present invention provides a switch protection circuit, including:
an electronic switch 10, the electronic switch 10 being disposed between the power supply access terminal Vdd and the load access terminal VL;
A surge limit control module 11 configured to perform an integration operation according to a target current signal Io flowing through the electronic switch 10 in a first mode of the switch protection circuit, to obtain an integrated voltage signal, and to determine whether to limit and protect a surge current according to the integrated voltage signal; wherein the integrated voltage signal increases with time when the target current signal Io is greater than the preset reference current signal Iref, and decreases with time when the target current signal Io is less than the reference current signal Iref;
A logic control module 12, connected to the surge limit control module 11, configured to: in the first mode, the electronic switch 10 is controlled to be turned off in response to the surge limiting control module 11 determining to limit protection for the surge current, or the electronic switch 10 is controlled to be turned on in response to the surge limiting control module 11 determining to de-limit protection for the surge current.
In the first mode of the switch protection circuit, the surge limit control module 11 is configured to perform an integral operation according to a target current signal flowing through the electronic switch 10 to obtain an integral voltage signal, determine whether to limit and protect a surge current according to the integral voltage signal, and the logic control module 12 is electrically connected with the surge limit control module 11 and is configured to: in the first mode, the electronic switch 10 is controlled to be turned off in response to the surge limiting control module 11 determining to limit protection for the surge current, or the electronic switch 10 is controlled to be turned on in response to the surge limiting control module 11 determining to de-limit protection for the surge current. Because the integration operation based on the target current signal can reflect the accumulation effect of the target current signal in time, and the surge current has a large peak value and fast action, but the current thermal effect which damages the electronic switch generally needs to be accumulated for a certain time, the switch protection circuit provided by the embodiment of the invention can simulate the thermal effect caused by the target current signal by utilizing the integration operation of the surge limit control module 11: in the case where the target current signal is greater than the preset reference current signal, the integrated voltage signal increases with time, indicating that the thermal effect of the target current signal is accumulating, and in the case where the target current signal is less than the reference current signal, the integrated voltage signal decreases with time, indicating that the thermal effect of the target current signal is dissipating, so that the degree of accumulation or dissipation of the thermal effect of the current can be evaluated from the integrated voltage signal, thereby determining whether the electronic switch 10 needs to be turned off to make the target current signal 0 to suspend the accumulation of the thermal effect of the current, or whether the electronic switch needs to be turned on to restore the target current signal. Along with the recovery of the target current signal, the integrated voltage signal of the surge limiting control module 11 generates a new round of change, and accordingly, the electronic switch 10 is controlled to be turned off or on, so that the surge current can be effectively limited, the electronic switch is prevented from being damaged by the surge current, and a load connected with the electronic switch safely passes through the transient impact of the surge current and enters a steady-state working state.
In an embodiment of the present invention, the switch protection circuit includes a power supply access terminal Vdd and a load access terminal VL, where the power supply access terminal Vdd is used for accessing a power supply, and the load access terminal VL is used for accessing a load. In one example, the load may be a capacitive load with a large capacitance that tends to cause a large inrush current at the moment of power-on.
The electronic switch 10 may be connected between a load and a power source for controlling whether the load is connected to the power source. The current signal flowing through the electronic switch is the target current signal. The surge limit control module may obtain the target current signal Io flowing through the electronic switch 10 in a variety of ways (e.g., coupled, sampled, etc.). Alternatively, in an embodiment of the present invention, the electronic switch may include various semiconductor switches, such as a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, a Metal-Oxide-semiconductor field-effect transistor) (see Ts in fig. 3), a bipolar transistor, an IGBT (Insulated Gate Bipolar Transistor ), and the like.
In one embodiment of the invention, the first mode is an operation mode of the switch protection circuit, and in other embodiments of the invention, the switch protection circuit may also include other operation modes. The working modes of the switch protection circuit can be switched according to the requirement. The embodiments of the present invention are not limited in this regard.
Specifically, in one embodiment of the present invention, the surge limiting control module 11 may be specifically configured to determine to limit the surge current according to a comparison result of the integrated voltage signal and a first voltage threshold value, or determine to release the limit protection of the surge current according to a comparison result of the integrated voltage signal and a second voltage threshold value, in the first mode of the switch protection circuit, wherein the first voltage threshold value is greater than the second voltage threshold value. In this embodiment, since the surge current can reach a very high peak value in a very short time, this results in that the integrated voltage signal rises at a relatively high speed, and when the integrated voltage signal is greater than the first voltage threshold, the surge limiting control module 11 can determine that the thermal effect of the current has reached a relatively high level, so as to determine that the surge current needs to be limited and protected, based on this, the logic control module 12 can turn off the electronic switch so that the target current signal is 0, the thermal effect of the current is suspended, and meanwhile, since the target current signal is 0, which is smaller than the reference current signal, the integrated voltage signal starts to drop. With the integrated voltage signal falling, when the integrated voltage signal is smaller than the second voltage threshold, the surge limit control module 11 may determine that the thermal effect of the current has reached a lower level, so as to turn on the electronic switch again, and restore the target current signal, and at this time, if the surge current is still larger (for example, greater than the reference current signal), then a new round of integration operation and switch control will be triggered again. Therefore, the surge current can be simply, conveniently and effectively limited and protected, and the electronic switch is prevented from being damaged by the surge current, so that a load connected with the electronic switch stably passes through the transient impact process of the surge current, and the electronic switch smoothly enters a steady-state working state. For example, the target current signal and the integrated voltage signal may vary over time as shown in fig. 2.
Alternatively, the values of the first voltage threshold, the second voltage threshold and the reference current signal may be set and modified as desired. In particular, the first voltage threshold is related to the opening of the electronic switch. The greater the target current signal, the greater its thermal effect and, under equivalent conditions, the faster it is necessary to turn off the electronic switch 10. Similarly, the greater the target current signal, the faster the integrated voltage signal obtained by the surge limit control module 11 reaches the first voltage threshold, thereby opening the electronic switch 10. The second voltage threshold is related to the re-turn-on of the electronic switch 10. The difference between the first voltage threshold and the second voltage threshold may affect the time interval from off to on again of electronic switch 10. During this time interval, the target current signal is 0, no new heat is generated, and the electronic switch 10 can efficiently dissipate heat in preparation for the next turn-on. In one example, where it is desired that the surge limit control module 11 may open the controlled switch if the integrated voltage signal is near 0, the second voltage threshold may be set to a value slightly greater than 0, such as 0 to 0.1 volts.
In the integration operation process, the reference current signal is a demarcation point that the integrated voltage signal increases or decreases with time, and in an embodiment of the present invention, the reference current signal may be greater than or equal to a steady-state current signal, where the steady-state current signal is a current signal flowing through the electronic switch 10 when the load is in steady-state operation.
In an embodiment of the present invention, the surge limiting control module 11 may perform an integration operation according to a target current signal flowing through the electronic switch in the first mode of the switch protection circuit. In order to introduce the target current signal into the integration operation, in one embodiment of the present invention, the switch protection circuit may further include: the current sampling module 13, the current sampling module 13 may be connected in series between the power supply access terminal Vdd and the electronic switch 10, or between the electronic switch 10 and the load access terminal VL; the current sampling module 13 may also be connected to the surge limiting control module 11, and the current sampling module 13 may be configured to sample the target current signal to obtain a sampling signal Vsmp, and input the sampling signal Vsmp to the surge limiting control module 11; based on this, the surge limit control module 11 may be configured to perform an integration operation according to the sampling signal output from the current sampling module 13 to obtain an integrated voltage signal, and determine whether to limit the surge current according to the integrated voltage signal in the first mode. As shown in fig. 3, in one example, the current sampling module 13 may include a sampling resistor Rs and an operational amplifier connected in parallel across the sampling resistor. The sampling resistor Rs may be connected in series with the electronic switch so that the current flowing through the sampling resistor Rs is equal to the target current signal flowing through the electronic switch. The target current signal may generate a voltage drop on the sampling resistor Rs, and the operational amplifier may amplify the voltage drop by a suitable factor (the amplification factor may be greater than 1 or less than or equal to 1) and output the amplified voltage drop to the surge limiting control module 11. Since the resistance of the sampling resistor Rs is known, the voltage drop of the target current signal across the sampling resistor Rs can also be measured, and thus the target current signal can be represented by the voltage drop and the ratio of the sampling resistor Rs.
In one embodiment of the present invention, as shown in fig. 4, the surge limiting control module 11 may specifically include:
an integrated reference signal providing sub-module 111 configured to provide an integrated reference signal Vref according to the reference current signal Iref;
An integration operation sub-module 112, respectively connected to the current sampling module 13 and the reference signal providing sub-module 111, configured to perform an integration operation on time according to a difference between the sampling signal Vsmp and the integration reference signal Vref, to obtain an integrated voltage signal Vint;
a control submodule 113, connected to the integration operator submodule 112, is configured to determine, in a first mode of the switch protection circuit, to limit protection for the inrush current according to a comparison result of the integration voltage signal and a first voltage threshold, or to determine to release limit protection for the inrush current according to a comparison result of the integration voltage signal and a second voltage threshold, wherein the first voltage threshold is greater than the second voltage threshold.
In this embodiment, the integrated reference signal providing sub-module 111 may provide an integrated reference signal according to the reference current signal, wherein the type and the magnitude of the integrated reference signal may be set or adjusted according to the integration operation requirement of the integration operation sub-module 112. For example, in one example, the integration operation sub-module 112 needs to perform an integration operation on the voltage signal, and then the integration reference signal may be of a voltage signal type, and the integration reference signal providing sub-module 111 may convert the reference current signal into a corresponding reference voltage signal through a resistive element, for example.
In one example, the integration operator module 112 may include various circuits capable of performing integration operations, such as an integrator composed of an operational amplifier, a capacitor, a resistor, and the like. By way of example, a schematic diagram of the integration operator module 112 may be as shown in FIG. 5. The positive input end of the operational amplifier may be used to connect to the current sampling module 13, the negative input end may be used to connect to the integral reference signal providing sub-module 111, the integral operation sub-module 112 may be used to perform integral operation on the difference between the sampling signal provided by the current sampling module 13 and the integral reference signal provided by the integral operation sub-module 112, and an integral voltage signal is obtained at the output end of the operational amplifier. As known from the principle of an integrating circuit, the integrated voltage signal Vint satisfies the following formula:
Vint= （1）
Specifically, as can be seen from fig. 2 and 5, the electronic switch 10 is in the on state at the period t0 to t2, vint is equal to (Vsmp-Vref) integrated between t0 to t2, i.e. the algebraic sum of the areas of R1 and R2, and the electronic switch 10 is in the off state at the period t2 to t3, vint is equal to (Vsmp-Vref) integrated between t2 to t3, i.e. the area indicated by R3. It should be noted that, in the integration operation, the reference current signal Iref is used as a reference, so that in the whole integration period from t0 to t4, the areas of R1 and R3 are located below the reference current signal Iref, and thus are negative values, the area of R2 is above the reference current signal Iref, and thus are positive values, and the algebraic sum of R1, R2, and R3 is 0.
Alternatively, the control submodule 113 may be implemented in a number of ways. Specifically, as shown in fig. 6, in one embodiment of the present invention, the control sub-module 113 may include: a first comparing unit 1131, an input terminal of which is connected to the integration operator module 112, configured to compare the integrated voltage signal Vint with a first voltage threshold V1 and output a first comparison result; a second comparing unit 1132, an input terminal of which is connected to the integration operator module 112, configured to compare the integrated voltage signal Vint with a second voltage threshold V2, and output a second comparison result; the first input end of the control unit 1133 is connected with the output end of the first comparison unit 1131, and the second input end of the control unit 1133 is connected with the output end of the second comparison unit 1132; a control unit 1133 configured to: outputting a first level signal lev1 in response to the first comparison result being that the integrated voltage signal Vint is greater than a first voltage threshold V1; or outputting a second level signal lev2 in response to the second comparison result being that the integrated voltage signal Vint is smaller than a second voltage threshold V2; the first level signal may be different from the second level signal, for example, the first level signal may be a high level, the second level signal may be a low level, or the first level signal may be a low level signal, and the second level signal may be a high level signal. Based on this, the logic control module 12 may be configured to turn off the electronic switch 10 according to the first level signal lev1 output from the control unit 1133, or to turn on the electronic switch 10 according to the second level signal lev2 output from the control unit 1133.
Optionally, each of the first comparing unit 1131 and the second comparing unit 1132 may include a voltage comparator, where a comparison object of the integrated voltage signal is a first voltage threshold, and a comparison object of the integrated voltage signal is a second voltage threshold, where the voltage comparator corresponding to the second comparing unit 1132. The first voltage threshold is higher than the second voltage threshold, for example in one example, the first voltage threshold is 1.2 volts and the second voltage threshold is 0.1 volts.
The control unit 1133 may output different level signals lev according to the first comparison result of the first comparison unit 1131 and the second comparison result of the second comparison unit 1132. Specifically, the control unit 1133 may output a first level signal if the first comparison result is that the integrated voltage signal is greater than the first voltage threshold, and the control unit 1133 may output a second level signal if the second comparison result is that the integrated voltage signal is less than the second voltage threshold. In an embodiment of the present invention, the control unit 1133 may include various circuits capable of achieving the above objects, for example, the control unit 1133 may include a circuit module with a set input and a reset input, such as a counter with a set input and a reset input, and the like. The effective signal input by the set input end can make the output end of the circuit module be in high level, and the effective signal input by the reset input end can make the output end of the circuit module be in low level. Alternatively, in one example, the set input of the control unit 1133 may be connected to the output of the first comparing unit 1131, the reset input of the control unit 1133 may be connected to the output of the second comparing unit 1132, or vice versa, the set input of the control unit 1133 may be connected to the output of the second comparing unit 1132, and the reset input of the control unit 1133 may be connected to the output of the first comparing unit 1131.
In the above embodiment, the control submodule 113 may be implemented by the first comparing unit 1131, the second comparing unit 1132 and the control unit 1133, but the embodiment of the present invention is not limited thereto, and in other embodiments of the present invention, the control submodule 113 may be implemented in other manners.
For example, as shown in fig. 7, in another embodiment of the present invention, the control sub-module 113 may include a hysteresis comparator; wherein an input of the hysteresis comparator may be connected to the integration operator module 112, the hysteresis comparator may be configured to: outputting a first level signal lev1 in response to the integrated voltage signal increasing with time and the integrated voltage signal being greater than the first voltage threshold; or in response to an increase in the integrated voltage signal over time decreasing and the integrated voltage signal being less than the second voltage threshold, outputting a second level signal lev2; the first level signal may be different from the second level signal, for example, the first level signal may be a high level, the second level signal may be a low level, or the first level signal may be a low level signal, and the second level signal may be a high level signal. Here, the first voltage threshold and the second voltage threshold may be two threshold voltages of the hysteresis comparator, respectively. Based on this, the logic control module 12 may specifically be configured to turn off the electronic switch according to the first level signal output by the hysteresis comparator, or turn on the electronic switch according to the second level signal output by the hysteresis comparator.
In the foregoing embodiment, the embodiment of the present invention provides the switch protection circuit mainly operating in the first mode, but the embodiment of the present invention is not limited thereto, and in other embodiments of the present invention, the switch protection circuit may further include other operating modes, and in order to make the switch protection circuit enter the first mode, as shown in fig. 8, in one embodiment of the present invention, the switch protection circuit may further include: the first mode detection module 14, the first mode detection module 14 may be connected to the surge limit control module 11, for example may be connected to the enable terminal EN of the integration operator module 112 in the surge limit control module 11, and configured to determine whether the switch protection circuit enters the first mode according to the first input signal. For example, the first mode detection module 14 may detect an input signal, and when detecting that the input signal is the first input signal, may cause the integration operation submodule 112 to enter an enabled state, and trigger the switch protection circuit to enter the first mode; when it is detected that the input signal is not the first input signal, the switch protection circuit may put the integration operation submodule 112 in a disabled state and not enter the first mode. The first input signal may be a signal input from a designated signal input terminal, or the first input signal may be a signal having a designated signal characteristic, for example, a signal having a preset frequency, or the like.
The operation mode of the switch protection circuit provided by the embodiment of the invention can further comprise a second mode opposite to the first mode. For example, in one embodiment of the present invention, the switch protection circuit is configured to operate in a second mode by default, based on which the logic control module 12 is further configured to control the electronic switch 10 to be turned on or off according to a second input signal, wherein the second input signal is different from the first input signal. That is, in the second mode, the electronic switch 10 may be turned on or off directly according to the second input signal (for example, the electronic switch is turned on when the second input signal is high and the electronic switch is turned off when the second input signal is low), without performing an integration operation according to the target current signal flowing through the electronic switch.
IN one embodiment, the second input signal and the first input signal may be different from each other, or the second input signal and the first input signal may be from the same input terminal (for example, as shown IN fig. 3, the first input signal and the second input signal may each be input through the input terminal IN), but the signal characteristics, for example, the signal frequencies, may be different, or the input terminal and the signal characteristics may be different, which is not limited by the embodiment of the present invention.
Further, in one embodiment of the present invention, the switch protection circuit may be switched between the first mode and the second mode by control of the first input signal and the second input signal. Specifically, in one embodiment, the second input signal may be input to the switch protection circuit by default, and then the switch protection circuit operates in the second mode, and the logic control module 12 may control the electronic switch 10 to be turned on or off according to the second input signal. For example, when the second input signal is at a high level, the logic control module 12 turns on the electronic switch 10, and when the second input signal is at a low level, the logic control module 12 turns off the electronic switch 10. When the first mode detection module 14 detects that the first input signal is input into the switch protection circuit, the first mode detection module 14 may trigger the switch protection circuit to enter the first mode, and accordingly, the logic control module 12 may control the electronic switch 10 to be turned on or turned off according to the output of the surge limiting control module 11, so as to limit and protect the surge current. Since the duration of the inrush current is generally short, when the inrush current becomes a steady state current, the input of the first input signal can be stopped, and the switch protection circuit ends the first mode and reenters the second mode.
In an embodiment of the present invention, the timing of providing the first input signal to the switch protection circuit may be determined as needed. For example, in one example, a first input signal may be provided to the switch protection circuit for a brief period of time (e.g., 0.5 seconds or 1 second) during which the load is just powered on or off, to limit the inrush current, and a second input signal may be provided to the switch protection circuit for a subsequent period of time to allow the load to enter steady state operation.
In some embodiments of the present invention, as shown in fig. 1 and 3, the switch protection circuit further includes a driving module 15, where a first input terminal of the driving module 15 may be connected to the logic control module 12, and is configured to drive the electronic switch 10 to be turned off or on according to a control signal output by the logic control module 12. For example, the driving module 15 may output a high level or a low level to control the electronic switch 10 to be turned on or off.
Further, in one example, the second input terminal of the driving module 15 may be further connected to the first mode detection module 14, and the driving module 15 may be further configured to adjust the turn-on voltage (see V G in fig. 3) output to the electronic switch 10 in response to the first mode detection module 14 determining that the switch protection circuit 10 enters the first mode, so that the switching rate of the electronic switch 10 in the first mode is smaller than the switching rate in the second mode, where the turn-on voltage is a level signal for controlling the electronic switch 10 to be turned on. For example, in one example, the turn-on voltage of the driving module 15 output to the electronic switch 10 is 1.2 volts in the second mode, so that the electronic switch 10 is turned on at a faster rate, and the turn-on voltage of the driving module 15 output to the electronic switch 10 is 0.9 volts in the first mode, so that the electronic switch 10 is turned on at a slower rate. Thus, since the electronic switch 10 is turned on slowly in the first mode, the surge current can be suppressed to some extent.
It has been mentioned above that the switch protection circuit provided by the embodiments of the present invention may operate in the first mode or the second mode, however, the limit protection against the surge current mainly operates in the first mode. In order to protect the circuit in the second mode, in one embodiment of the present invention, as shown in fig. 9, the switch protection circuit provided in the embodiment of the present invention may further include an overcurrent protection module 16, where the overcurrent protection module 16 may be connected to the logic control module 12; the first mode detection module 14 may also be coupled to the logic control module 12; the logic control module 12 is further configured to: in response to the first mode detection module 14 determining that the switch protection circuit enters the first mode, disabling the over-current protection module 16 from over-current protecting the electronic switch 10; in response to the first mode detection module 14 determining that the switch protection circuit does not enter the first mode, the overcurrent protection module 16 is permitted to overcurrent protect the electronic switch 10. Wherein the over-current protection module 16 may be configured to, in the second mode, open the electronic switch 10 and maintain the open state of the electronic switch 10 until the over-current protection module 16 is reset in response to the target current signal being greater than a preset over-current protection threshold.
Accordingly, in a second aspect, an embodiment of the present invention further provides an electronic device, where the electronic device may include any of the switch protection circuits provided in the embodiments of the present invention, so that corresponding technical effects can also be achieved, and the foregoing details are not described herein.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments.
In particular, for the device embodiments, since they are substantially similar to the method embodiments, the description is relatively simple, and reference is made to the description of the method embodiments in part.
For convenience of description, the above apparatus is described as being functionally divided into various units/modules, respectively. Of course, the functions of the various elements/modules may be implemented in the same piece or pieces of software and/or hardware when implementing the present invention.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (10)
1. A switch protection circuit, comprising:
the electronic switch is arranged between the power supply access end and the load access end;
The surge limiting control module is configured to perform integral operation according to a target current signal flowing through the electronic switch in a first mode of the switch protection circuit to obtain an integral voltage signal, and determine whether to limit and protect the surge current according to the integral voltage signal; wherein the integrated voltage signal increases with time when the target current signal is greater than a preset reference current signal, and decreases with time when the target current signal is less than the reference current signal;
The logic control module is connected with the surge limiting control module and is configured to: in the first mode, the electronic switch is controlled to be turned off in response to the surge limiting control module determining to limit protection for the surge current, or the electronic switch is controlled to be turned on in response to the surge limiting control module determining to de-limit protection for the surge current.
2. The protection circuit according to claim 1, wherein the surge limiting control module is specifically configured to determine, in a first mode of the switching protection circuit, limiting protection of the surge current based on a comparison of the integrated voltage signal and a first voltage threshold, or determining de-limiting protection of the surge current based on a comparison of the integrated voltage signal and a second voltage threshold, wherein the first voltage threshold is greater than the second voltage threshold.
3. The protection circuit of claim 1, further comprising:
The current sampling module is connected in series between the power supply access end and the electronic switch or between the electronic switch and the load access end; the current sampling module is also connected with the surge limiting control module and is configured to sample the target current signal to obtain a sampling signal, and the sampling signal is input into the surge limiting control module;
The surge limiting control module is configured to perform integral operation according to the sampling signal output by the current sampling module in the first mode to obtain an integral voltage signal, and determine whether to limit and protect the surge current according to the integral voltage signal.
4. A protection circuit according to claim 3, wherein the surge limit control module comprises:
an integrated reference signal providing sub-module configured to provide an integrated reference signal based on the reference current signal;
the integration operation submodule is respectively connected with the current sampling module and the reference signal providing submodule and is configured to perform integration operation on time according to the difference between the sampling signal and the integration reference signal to obtain the integration voltage signal;
And the control submodule is connected with the integral operation submodule and is configured to determine to limit and protect the surge current according to the comparison result of the integral voltage signal and a first voltage threshold value or determine to release the limit and protect the surge current according to the comparison result of the integral voltage signal and a second voltage threshold value in a first mode of the switch protection circuit, wherein the first voltage threshold value is larger than the second voltage threshold value.
5. The protection circuit of claim 4, wherein the control submodule includes:
The input end of the first comparison unit is connected with the integration operation submodule and is configured to compare the integrated voltage signal with the first voltage threshold value and output a first comparison result;
the input end of the second comparison unit is connected with the integration operation submodule and is configured to compare the integrated voltage signal with the second voltage threshold value and output a second comparison result;
the first input end of the control unit is connected with the output end of the first comparison unit, and the second input end of the control unit is connected with the output end of the second comparison unit;
The control unit is configured to: outputting a first level signal in response to the first comparison result being that the integrated voltage signal is greater than the first voltage threshold; or outputting a second level signal in response to the second comparison result being that the integrated voltage signal is less than the second voltage threshold; wherein the first level signal is different from the second level signal;
The logic control module is configured to turn off the electronic switch according to a first level signal output by the control unit or turn on the electronic switch according to a second level signal output by the control unit.
6. The protection circuit of claim 5, wherein the control unit includes a circuit module having a set input and a reset input.
7. The protection circuit of claim 5, wherein the control submodule includes a hysteresis comparator; the input end of the hysteresis comparator is connected with the integration operation submodule, and the hysteresis comparator is configured to: outputting a first level signal in response to the integrated voltage signal increasing with time and the integrated voltage signal being greater than the first voltage threshold; or outputting a second level signal in response to the integrated voltage signal decreasing with time and the integrated voltage signal being less than the second voltage threshold; wherein the first level signal is different from the second level signal;
The logic control module is configured to turn off the electronic switch according to a first level signal output by the hysteresis comparator or turn on the electronic switch according to a second level signal output by the hysteresis comparator.
8. The protection circuit of claim 1, further comprising:
And the first mode detection module is connected with the surge limiting control module and is configured to determine whether the switch protection circuit enters the first mode according to a first input signal.
9. The protection circuit of claim 8, wherein the switch protection circuit is configured to operate in a second mode by default, the logic control module further configured to control the electronic switch to be turned on or off in accordance with a second input signal in the second mode, wherein the second input signal is different from the first input signal.
10. The protection circuit of claim 9, further comprising: the first input end of the driving module is connected with the logic control module and is configured to drive the electronic switch to be turned off or on according to a control signal output by the logic control module;
The second input end of the driving module is connected with the first mode detection module, and the driving module is further configured to adjust the starting voltage output to the electronic switch so that the switching rate of the electronic switch in the first mode is smaller than the switching rate in the second mode in response to the first mode detection module determining that the switch protection circuit enters the first mode, wherein the starting voltage is a level signal for controlling the electronic switch to be turned on.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410478180.8A CN118199584A (en) | 2024-04-19 | 2024-04-19 | Switch protection circuit and electronic equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202410478180.8A CN118199584A (en) | 2024-04-19 | 2024-04-19 | Switch protection circuit and electronic equipment |
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| CN118199584A true CN118199584A (en) | 2024-06-14 |
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| CN202410478180.8A Pending CN118199584A (en) | 2024-04-19 | 2024-04-19 | Switch protection circuit and electronic equipment |
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| CN116805871A (en) * | 2022-03-24 | 2023-09-26 | 英飞凌科技股份有限公司 | Intelligent semiconductor switch |
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