CN221042316U - Power supply function safety protection circuit and switching power supply - Google Patents
Power supply function safety protection circuit and switching power supply Download PDFInfo
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- CN221042316U CN221042316U CN202322554736.0U CN202322554736U CN221042316U CN 221042316 U CN221042316 U CN 221042316U CN 202322554736 U CN202322554736 U CN 202322554736U CN 221042316 U CN221042316 U CN 221042316U
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Abstract
The utility model discloses a power function safety protection circuit and a switching power supply, wherein the power function safety protection circuit comprises: the overvoltage detection protection circuit is used for detecting the output voltage of the power supply circuit and controlling the power supply end of the power supply chip to be grounded when the output voltage of the power supply circuit is overvoltage; the energy storage protection circuit is respectively connected with the auxiliary winding of the power supply circuit, the input end of the power supply circuit and the power supply end of the power supply chip, and is used for disconnecting the input end of the power supply circuit and the auxiliary winding from being electrically connected with the power supply chip when the power supply end of the power supply chip is grounded. The utility model can solve the problem of low power density and safety of the existing STO circuit.
Description
Technical Field
The utility model relates to the technical field of switching power supplies, in particular to a power supply function safety protection circuit and a switching power supply.
Background
For STO (Safe Torque Off), a single point fault insertion test (Fault Insertion Tsets) is required for the auxiliary power supply to prevent the power supply from a surge in output voltage due to device faults.
The topology commonly used for the auxiliary power supply is a flyback power supply, and for the flyback power supply, the most severe fault is feedback optocoupler failure, at the moment, the power supply is open-loop, the output voltage is uncontrolled, and the output voltage is abnormally risen. Therefore, it is required for the auxiliary power panel to directly cut off the power supply pin of the main control IC when an overvoltage is output. When the output voltage of the existing auxiliary power supply STO circuit is over-voltage, a voltage signal is detected through an over-voltage detection loop, and then a thyristor is conducted through optocoupler feedback, so that a power supply pin of a power supply control IC is pulled down. The total power of a power panel is tens of watts, the space occupation ratio is extremely large, and the power density of the power panel is not improved. At the same time, this approach may be re-powered after the voltage is restarted, possibly resulting in a power fryer or other safety issues.
Disclosure of utility model
The utility model mainly aims to provide a power supply function safety protection circuit, which aims to solve the problems of low power density and low safety of the existing STO circuit.
In order to achieve the above object, the present utility model provides a power function safety protection circuit, comprising:
The overvoltage detection protection circuit is used for detecting the output voltage of the power supply circuit and controlling the power supply end of the power supply chip to be grounded when the output voltage of the power supply circuit is overvoltage;
The input end of the energy storage circuit is connected with the auxiliary winding of the power supply circuit, and the energy storage circuit is used for storing electric energy output by the auxiliary winding;
the protection circuit is characterized in that one end of the protection circuit is connected with the input end of the power supply circuit and the output end of the energy storage circuit, and the other end of the protection circuit is connected with the power supply end of the power supply chip;
The energy storage circuit is also used for sending the stored electric energy to the protection circuit when the power supply end of the power supply chip is grounded, so that the protection circuit disconnects the input end of the power supply circuit and the auxiliary winding from being electrically connected with the power supply chip.
Optionally, the energy storage circuit includes an energy storage capacitor, a first end of the energy storage capacitor is connected with the protection circuit and the auxiliary winding, and a second end of the energy storage capacitor is grounded.
Optionally, the power function safety protection circuit further includes:
The input end of the first unidirectional conduction circuit is connected with the first end of the energy storage capacitor, the output end of the first unidirectional conduction circuit is respectively connected with one end of the protection circuit and the input end of the power supply circuit, and the first unidirectional conduction circuit is used for preventing electric energy at the input end of the power supply circuit from being output to the energy storage capacitor.
Optionally, the power function safety protection circuit further includes:
The input end of the second unidirectional conduction circuit is connected with the auxiliary winding of the power supply circuit, the output end of the second unidirectional conduction circuit is connected with the first end of the energy storage capacitor, and the second unidirectional conduction circuit is used for preventing electric energy of the energy storage capacitor from being output to the auxiliary winding of the power supply circuit.
Optionally, the protection circuit includes a quick-break type non-restoration fuse, a first end of the quick-break type non-restoration fuse is connected with an input end of the power supply circuit and an output end of the energy storage circuit, and a second end of the quick-break type non-restoration fuse is connected with a power supply end of the power supply chip.
Optionally, the overvoltage detection protection circuit includes:
The overvoltage detection circuit is used for detecting the output voltage of the power supply circuit and outputting an overvoltage control signal when the output voltage of the power supply circuit is overvoltage;
The controlled end of the switch circuit is connected with the output end of the overvoltage detection circuit, the first end of the switch circuit is connected with the power supply end of the power supply chip, the second end of the switch circuit is grounded, and the switch circuit is used for controlling the power supply end of the power supply chip to be grounded when receiving the overvoltage control signal.
Optionally, the overvoltage detection circuit includes a second resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third diode and an optocoupler, wherein a first end of the fourth resistor is connected with an output end of the power supply circuit, a second end of the fourth resistor is connected with a cathode of the third diode, an anode of the third diode is connected with a first end of the sixth resistor, a second end of the sixth resistor is grounded, a first end of the fifth resistor is connected with an anode of the third diode, a second end of the fifth resistor is connected with a first end of the optocoupler, a second end of the optocoupler is connected with a second end of the sixth resistor, a third end of the optocoupler is connected with a first end of the second resistor, a second end of the second resistor is connected with the energy storage protection circuit, and a fourth end of the optocoupler is connected with a controlled end of the switching circuit.
Optionally, the switch circuit includes triode and third resistance, the base of triode with overvoltage detection circuit's output is connected, the collecting electrode of triode with power supply chip's power supply end is connected, the projecting pole ground connection of triode, the first end of third resistance with the base of triode is connected, the second end of third resistance with the projecting pole of triode is connected.
The utility model also proposes a switching power supply comprising:
a power chip;
the controlled end of the power supply circuit is connected with the control end of the power supply chip; and
The power function safety protection circuit is electrically connected with the auxiliary winding of the power circuit, the input end of the power circuit and the power supply end of the power chip respectively.
Optionally, the switching power supply further includes:
And the input end of the feedback circuit is connected with the output end of the power supply circuit, the output end of the feedback circuit is connected with the power supply chip, and the feedback circuit is used for detecting the output voltage of the power supply circuit and outputting a corresponding feedback signal to the power supply chip so that the power supply chip controls the power supply circuit to work according to the feedback signal.
According to the utility model, the overvoltage detection protection circuit and the energy storage protection circuit are arranged, so that the power supply end of the power supply chip is directly disconnected from the input end of the power supply circuit and the auxiliary winding when the output overvoltage of the power supply circuit is detected, namely, the power supply end of the power supply chip is disconnected from the power supply end without providing the minimum maintenance current, and therefore, the resistor between the power supply input end and the power supply end of the power supply chip does not need to select a power resistor with smaller resistance value, thereby reducing the power consumption and the resistor volume, further reducing the integral volume of the power function safety protection circuit, and improving the space utilization rate and the power density. Meanwhile, the electric connection of the power supply end of the power supply chip is disconnected, so that the power frying machine and other safety problems caused by the fact that the power supply circuit is electrified again after being restarted are avoided.
Drawings
In order to more clearly illustrate the embodiments of the present utility model 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, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a functional block diagram of an embodiment of a power functional safety protection circuit according to the present utility model;
FIG. 2 is a schematic diagram of a circuit structure of a prior art power function safety protection circuit;
FIG. 3 is a schematic circuit diagram of an embodiment of a power functional safety protection circuit according to the present utility model;
Fig. 4 is a graph showing time-current characteristics of the fuse of the present utility model.
Reference numerals illustrate:
| Reference numerals | Name of the name | Reference numerals | Name of the name |
| 10 | Overvoltage detection protection circuit | F1 | Quick-break type non-recovery fuse |
| 20 | Energy storage circuit | R1～R6 | First to sixth resistors |
| 30 | Protection circuit | C1、C2 | First and second capacitors |
| U1 | Power supply chip | D1～D3 | First to third diodes |
| U2 | Optical coupler | Q1 | Triode transistor |
The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.
The utility model provides a power supply function safety protection circuit.
At present, as shown in fig. 2, when the output voltage is over-voltage, the existing auxiliary power STO circuit detects a voltage signal through an over-voltage detection loop, and then the thyristor Q1 is turned on through optocoupler feedback, so that the power supply pin of the power supply control IC is pulled down. The total power of a power panel is tens of watts, the space occupation ratio is extremely large, and the power density of the power panel is not improved. At the same time, this approach may be re-powered after the voltage is restarted, possibly resulting in a power fryer or other safety issues.
To solve the above-mentioned problem, referring to fig. 1 to 4, in one embodiment, the power function safety protection circuit includes:
The overvoltage detection protection circuit 10, wherein a detection end of the overvoltage detection protection circuit 10 is connected with an output end of the power supply circuit, a control end of the overvoltage detection protection circuit 10 is connected with a power supply end of the power supply chip U1, and the overvoltage detection protection circuit 10 is used for detecting the output voltage of the power supply circuit and controlling the power supply end of the power supply chip U1 to be grounded when the output voltage of the power supply circuit is overvoltage;
The input end of the energy storage circuit 20 is connected with the auxiliary winding of the power supply circuit, and the energy storage circuit 20 is used for storing electric energy output by the auxiliary winding;
A protection circuit 30, wherein one end of the protection circuit 30 is connected with the input end of the power supply circuit and the output end of the energy storage circuit 20, and the other end of the protection circuit 30 is connected with the power supply end of the power supply chip U1;
The energy storage circuit 20 is further configured to send the stored electrical energy to the protection circuit 30 when the power supply terminal of the power supply chip U1 is grounded, so that the protection circuit 30 disconnects the input terminal of the power supply circuit and the auxiliary winding from the power supply chip U1.
In this embodiment, the overvoltage detection protection circuit 10 may be composed of a voltage detection circuit and a switch circuit, the voltage detection circuit may adopt a series resistor to divide voltage or use a comparator to detect whether the output voltage of the power supply circuit is overvoltage, the switch circuit may be connected with the power supply terminal and the ground wire of the power supply chip U1, and based on the control of the voltage detection circuit, the switch circuit is turned on when the output voltage of the power supply circuit is detected to be overvoltage, so as to control the power supply terminal of the power supply chip U1 to be electrically connected with the ground.
The energy storage circuit 20 may be formed by energy storage devices such as an energy storage capacitor, and is used for storing the electric energy output by the auxiliary winding when the auxiliary winding provides a normal working power supply for the power supply chip U1, and the protection circuit 30 may be formed by protection devices such as a non-recoverable fuse or a circuit breaker. When the power supply circuit outputs normally, the power supply end of the control power supply chip U1 is electrically connected with the input end of the power supply circuit and the auxiliary winding through the energy storage circuit 20, so that the input end of the power supply circuit provides starting voltage for the power supply chip U1 or the auxiliary winding provides normal working voltage for the power supply chip U1. It will be appreciated that, as shown in fig. 2, when the overvoltage detection circuit detects that the output voltage of the power supply circuit is overvoltage, the thyristor Q1 is turned on through the optocoupler feedback, so that the power supply end of the power supply chip U1 is pulled down, and at this time, only the power supply end of the power supply chip U1 is pulled down, and the electrical connection between the power supply chip U1 and the power supply circuit is not disconnected, so that the R1 resistor power is larger, and also the power supply fryer or other safety problems may be caused when the power supply is restarted after the voltage is electrified. Therefore, in the present embodiment, when the overvoltage detection protection circuit 10 detects that the output voltage of the power supply circuit is overvoltage, and controls the power supply terminal of the power supply chip U1 to be electrically connected to ground, that is, controls one end of the protection circuit 30 to be grounded, at this time, since the other end of the protection circuit 30 is connected to the tank circuit 20, it is equivalent to the tank circuit 20 being grounded at this time, so that the tank circuit 20 starts to discharge. Because the energy storage circuit 20 generates large current during discharging, protection devices such as a non-recoverable fuse or a circuit breaker are disconnected, namely the power supply end of the power chip U1 is disconnected from the input end of the power circuit and the auxiliary winding, so that the power consumption of a resistor and the power supply explosion and other safety problems caused by the re-electrifying of the power circuit after restarting are avoided, and the overvoltage protection of the power chip U1 is realized.
According to the utility model, the overvoltage detection protection circuit 10, the energy storage circuit 20 and the protection circuit 30 are arranged, so that the power supply end of the power supply chip U1 is directly disconnected from the input end of the power supply circuit and the auxiliary winding when the output overvoltage of the power supply circuit is detected, namely, the power supply end of the power supply chip U1 is disconnected from the power supply end without providing the minimum maintenance current, and therefore, the resistor between the power supply input end and the power supply end of the power supply chip U1 does not need to select a power resistor with smaller resistance value, thereby reducing the power consumption and the resistor volume, further reducing the whole volume of the power function safety protection circuit, and improving the space utilization rate and the power density. Meanwhile, the electric connection of the power supply end of the power chip U1 is disconnected, so that the power frying machine and other safety problems caused by the fact that the power circuit is electrified again after being restarted are avoided.
Referring to fig. 1 to 4, in an embodiment, the tank circuit 20 includes a tank capacitor, a first end of the tank capacitor is connected to the protection circuit 30 and the auxiliary winding, and a second end of the tank capacitor is grounded.
Optionally, the protection circuit 30 includes a fast-breaking type non-restoration fuse, a first end of the fast-breaking type non-restoration fuse is connected to the input end of the power supply circuit and the output end of the energy storage circuit 20, and a second end of the fast-breaking type non-restoration fuse is connected to the power supply end of the power supply chip U1.
Referring to fig. 3, fig. 3 is a schematic circuit diagram of an embodiment of a power function safety protection circuit, as shown in fig. 3, the tank circuit 20 and the protection circuit 30 are composed of a tank capacitor C1 and a fast-breaking type non-recovery fuse F1, and when an auxiliary winding of the power circuit provides a normal working power for the power chip U1, the tank capacitor C1 starts to charge. When the overvoltage detection protection circuit 10 detects that the output voltage of the power supply circuit is overvoltage, and controls the power supply end of the power supply chip U1 to be electrically connected with the ground, that is, controls one end of the quick-break type non-restoration fuse F1 to be grounded, at this time, the energy storage capacitor C1 rapidly discharges through the quick-break type non-restoration fuse F1 to provide transient impact heavy current, and the quick-break type non-restoration fuse F1 is broken, so that the power supply end of the power supply chip U1 is electrically connected with the input end of the power supply circuit and the auxiliary winding, and overvoltage protection of the power supply chip U1 is realized. In addition, the capacitance and type of the energy storage capacitor C1 are selected according to the fusing current of the fast-breaking type non-restoration fuse F1. As shown in fig. 4, the breakdown current of the fuse is about 1.5A at 1ms according to the time-current characteristic of the fuse, and c=i×t/V is obtained according to the capacitances q=cv and i=q/t. In order to ensure the accurate breakdown of the fuse, the selection I is selected according to the double selection of the breakdown current of the fuse in 1ms, the voltage V is the minimum voltage of VCC in normal operation, and the minimum voltage 10V of VCC operation voltage of 2844 is generally 1ms. At this point c=200 u F was obtained. At this time, the capacitance of C1 can be selected to be 200u F.
Referring to fig. 1 to 4, in an embodiment, the power function safety protection circuit further includes:
The input end of the first unidirectional conduction circuit is connected with the first end of the energy storage capacitor, the output end of the first unidirectional conduction circuit is respectively connected with one end of the protection circuit 30 and the input end of the power supply circuit, and the first unidirectional conduction circuit is used for preventing electric energy of the input end of the power supply circuit from being output to the energy storage capacitor.
Optionally, the power function safety protection circuit further includes:
The input end of the second unidirectional conduction circuit is connected with the auxiliary winding of the power supply circuit, the output end of the second unidirectional conduction circuit is connected with the first end of the energy storage capacitor, and the second unidirectional conduction circuit is used for preventing electric energy of the energy storage capacitor from being output to the auxiliary winding of the power supply circuit.
It can be understood that the input end of the power supply circuit is electrically connected with the power supply end of the power supply chip U1 through the protection circuit 30, so as to provide the starting voltage for the power supply chip U1 during starting, and because the input end of the power supply circuit is also connected with the energy storage capacitor, when the power supply circuit provides the starting voltage for the power supply chip U1, the electric energy can be output to the energy storage capacitor first until the energy storage of the energy storage capacitor is completed, and then can be output to the power supply chip U1 to provide the starting voltage for the power supply chip U1, so that the starting time of the power supply chip U1 is long. Therefore, in this embodiment, a first unidirectional conduction circuit is further disposed between the input end of the power circuit and the energy storage capacitor, so as to prevent the electric energy of the input end of the power circuit from being output to the energy storage capacitor, thereby ensuring that the starting voltage provided by the power circuit can be directly sent to the power chip U1, so that the power chip U1 can be started normally.
Similarly, a second unidirectional conduction circuit is further arranged between the energy storage capacitor and the auxiliary winding and used for preventing electric energy at the input end of the power supply circuit and outputting the electric energy of the energy storage capacitor to the auxiliary winding, so that starting voltage provided by the power supply circuit can be directly sent to the power supply chip U1, and electric energy is prevented from flowing backwards to the auxiliary winding when the energy storage capacitor discharges, and stability and safety of the power supply function safety protection circuit are improved.
Referring to fig. 3, fig. 3 is a schematic circuit diagram of an embodiment of a power function safety protection circuit, as shown in fig. 3, a first unidirectional conduction circuit is formed by a diode D2, a second unidirectional conduction circuit is formed by a diode D1, and the diode D2 is used for preventing electric energy at an input end of the power circuit from being output to an energy storage capacitor, so as to ensure that a starting voltage provided by the power circuit can be directly sent to a power chip U1, and the power chip U1 can be started normally. The diode D1 is used for preventing the electric energy at the input end of the power supply circuit and the electric energy output auxiliary winding of the energy storage capacitor, so that the starting voltage provided by the power supply circuit can be directly sent to the power supply chip U1, and the electric energy is prevented from flowing backwards to the auxiliary winding when the energy storage capacitor discharges, and the stability and the safety of the power supply function safety protection circuit are improved.
Referring to fig. 1 to 4, in an embodiment, the overvoltage detection protection circuit 10 includes:
The overvoltage detection circuit is used for detecting the output voltage of the power supply circuit and outputting an overvoltage control signal when the output voltage of the power supply circuit is overvoltage;
The control end of the switch circuit is connected with the output end of the overvoltage detection circuit, the first end of the switch circuit is connected with the power supply end of the power supply chip U1, the second end of the switch circuit is grounded, and the switch circuit is used for controlling the power supply end of the power supply chip U1 to be grounded after receiving the overvoltage control signal.
In this embodiment, the overvoltage detection circuit may select a series resistor to divide the voltage or detect whether the output voltage of the power supply circuit is overvoltage by using the comparator, for example, one input end of the comparator may be connected to the output end of the power supply circuit, and the other input end of the comparator may be connected to the reference voltage, when the output voltage of the power supply circuit is greater than the reference voltage, that is, the output voltage of the power supply circuit is overvoltage, the comparator is enabled to output a high level or a low level to the switch circuit, so as to control the power supply terminal of the power supply chip U1 to be grounded. The switching circuit can be realized by selecting switching devices such as a triode, a MOS tube, an IGBT tube and the like, and is controlled by the overvoltage detection circuit, and is conducted when the overvoltage of the output voltage of the power supply circuit is detected, so that the power supply end of the power supply chip U1 is controlled to be electrically connected with ground.
Optionally, the overvoltage detection circuit includes a second resistor R2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third diode D3, and an optocoupler U2, where a first end of the fourth resistor R4 is connected to the output end of the power supply circuit, a second end of the fourth resistor R4 is connected to the cathode of the third diode D3, an anode of the third diode D3 is connected to the first end of the sixth resistor R6, a second end of the sixth resistor R6 is grounded, a first end of the fifth resistor R5 is connected to the anode of the third diode D3, a second end of the fifth resistor R5 is connected to the first end of the optocoupler U2, a second end of the optocoupler U2 is connected to the second end of the sixth resistor R6, a third end of the optocoupler U2 is connected to the first end of the second resistor R2, a second end of the second resistor R2 is connected to the protection circuit 30, and the fourth end of the optocoupler U2 is connected to the controlled circuit.
Optionally, the switch circuit includes triode Q1 and third resistance R3, triode Q1's base with overvoltage detection circuit's output is connected, triode Q1's collecting electrode with power chip U1's power supply end is connected, triode Q1's projecting pole ground connection, third resistance R3's first end with triode Q1's base is connected, third resistance R3's second end with triode Q1's projecting pole is connected.
Referring to fig. 3, fig. 3 is a schematic circuit diagram of an embodiment of a power function safety protection circuit, as shown in fig. 3, the overvoltage detection circuit is composed of a second resistor R2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third diode D3 and an optocoupler U2, and the switching circuit is composed of a triode Q1 and a third resistor R3. The third diode D3 is a voltage stabilizing tube or a TVS tube, etc., when the output voltage of the power supply circuit is over-voltage, the third diode D3 is turned on, so that the optocoupler U2 is turned on, and the triode Q1 is controlled to be turned on, at this moment, the power supply end VCC of the power supply chip U1 is grounded, and due to the existence of the energy storage capacitor C1, the energy storage capacitor C1 rapidly discharges through the fast-breaking type non-recovery fuse F1, provides a transient impact heavy current, breaks the fast-breaking type non-recovery fuse F1, and thereby disconnects the electrical connection between the power supply end of the power supply chip U1 and the input end and the auxiliary winding of the power supply circuit, and thus achieves overvoltage protection for the power supply chip U1. In addition, the transistor Q1 is selected by considering the transient impact current, and the transient impact current on the fuse cannot be sustained when the transistor Q1 is turned on, wherein the current on the side of the optocoupler transistor and the base current and voltage of the transistor Q1 can be adjusted by R2 and R3, and the selection should consider the turn-on speed of the transistor Q1. The voltage stabilizing tube or TVS tube D3 is selected according to the output voltage Vout of the power circuit, so that breakdown voltage of the voltage stabilizing tube or TVS tube D3 exceeds the normal overvoltage protection voltage value of the power circuit, misoperation is prevented during normal operation, D3 current is regulated jointly by R4 and R6, and side current of the photo-coupler diode is regulated by R5. In addition, the second capacitor C2 is a filter capacitor, and can filter the electric energy output by the power supply circuit and the auxiliary winding and then supply power to the power supply chip U1.
The utility model also proposes a switching power supply comprising:
A power supply chip U1;
the controlled end of the power supply circuit is connected with the control end of the power supply chip U1; and
The power function safety protection circuit is electrically connected with the auxiliary winding of the power circuit, the input end of the power circuit and the power supply end of the power chip U1 respectively. The specific structure of the power supply function safety protection circuit refers to the above embodiments, and since the switching power supply adopts all the technical solutions of all the embodiments, the switching power supply has at least all the beneficial effects brought by the technical solutions of the embodiments, and the details are not repeated here.
Optionally, the switching power supply further includes:
The input end of the feedback circuit is connected with the output end of the power supply circuit, the output end of the feedback circuit is connected with the power supply chip U1, and the feedback circuit is used for detecting the output voltage of the power supply circuit and outputting a corresponding feedback signal to the power supply chip U1 so that the power supply chip U1 controls the power supply circuit to work according to the feedback signal.
In this embodiment, the switching power supply further includes a feedback circuit, where the feedback circuit may be implemented by a voltage stabilizing circuit and an optocoupler, where the voltage stabilizing circuit is configured to convert an output voltage of the power supply circuit into a stable small voltage, and output the stable small voltage to the power supply chip U1 through optocoupler isolation, so that the power supply chip U1 can determine the output voltage of the power supply circuit through the feedback circuit, and thus can perform feedback adjustment on the power supply circuit according to the output voltage of the power supply circuit, so that the power supply circuit outputs a stable and accurate output voltage.
The foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structural changes made by the description of the present utility model and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the utility model.
Claims (10)
1. The utility model provides a power function safety protection circuit, is applied to switching power supply, switching power supply includes power supply circuit and power supply chip, power supply circuit includes auxiliary winding, its characterized in that includes:
The overvoltage detection protection circuit is used for detecting the output voltage of the power supply circuit and controlling the power supply end of the power supply chip to be grounded when the output voltage of the power supply circuit is overvoltage;
The input end of the energy storage circuit is connected with the auxiliary winding of the power supply circuit, and the energy storage circuit is used for storing electric energy output by the auxiliary winding;
the protection circuit is characterized in that one end of the protection circuit is connected with the input end of the power supply circuit and the output end of the energy storage circuit, and the other end of the protection circuit is connected with the power supply end of the power supply chip;
The energy storage circuit is also used for sending the stored electric energy to the protection circuit when the power supply end of the power supply chip is grounded, so that the protection circuit disconnects the input end of the power supply circuit and the auxiliary winding from being electrically connected with the power supply chip.
2. The power functional safety protection circuit of claim 1, wherein the tank circuit comprises a tank capacitor, a first end of the tank capacitor is connected to the protection circuit and the auxiliary winding, and a second end of the tank capacitor is grounded.
3. The power function safety protection circuit of claim 2, wherein the power function safety protection circuit further comprises:
The input end of the first unidirectional conduction circuit is connected with the first end of the energy storage capacitor, the output end of the first unidirectional conduction circuit is respectively connected with one end of the protection circuit and the input end of the power supply circuit, and the first unidirectional conduction circuit is used for preventing electric energy at the input end of the power supply circuit from being output to the energy storage capacitor.
4. The power function safety protection circuit of claim 2, wherein the power function safety protection circuit further comprises:
The input end of the second unidirectional conduction circuit is connected with the auxiliary winding of the power supply circuit, the output end of the second unidirectional conduction circuit is connected with the first end of the energy storage capacitor, and the second unidirectional conduction circuit is used for preventing electric energy of the energy storage capacitor from being output to the auxiliary winding of the power supply circuit.
5. The power function safety protection circuit of claim 1, wherein the protection circuit comprises a quick-break type non-return fuse, a first end of the quick-break type non-return fuse being connected to an input of the power circuit and an output of the tank circuit, and a second end of the quick-break type non-return fuse being connected to a power supply end of the power chip.
6. The power function safety protection circuit of claim 1, wherein the overvoltage detection protection circuit comprises:
The overvoltage detection circuit is used for detecting the output voltage of the power supply circuit and outputting an overvoltage control signal when the output voltage of the power supply circuit is overvoltage;
The controlled end of the switch circuit is connected with the output end of the overvoltage detection circuit, the first end of the switch circuit is connected with the power supply end of the power supply chip, the second end of the switch circuit is grounded, and the switch circuit is used for controlling the power supply end of the power supply chip to be grounded when receiving the overvoltage control signal.
7. The power function safety protection circuit according to claim 6, wherein the overvoltage detection circuit comprises a second resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third diode and an optocoupler, the first end of the fourth resistor is connected to the output end of the power circuit, the second end of the fourth resistor is connected to the cathode of the third diode, the anode of the third diode is connected to the first end of the sixth resistor, the second end of the sixth resistor is grounded, the first end of the fifth resistor is connected to the anode of the third diode, the second end of the fifth resistor is connected to the first end of the optocoupler, the second end of the optocoupler is connected to the second end of the sixth resistor, the third end of the optocoupler is connected to the first end of the second resistor, the second end of the second resistor is connected to the protection circuit, and the fourth end of the optocoupler is connected to the controlled end of the switching circuit.
8. The power function safety protection circuit according to claim 6, wherein the switching circuit comprises a triode and a third resistor, a base electrode of the triode is connected with an output end of the overvoltage detection circuit, a collector electrode of the triode is connected with a power supply end of the power chip, an emitter electrode of the triode is grounded, a first end of the third resistor is connected with the base electrode of the triode, and a second end of the third resistor is connected with the emitter electrode of the triode.
9. A switching power supply, comprising:
a power chip;
the controlled end of the power supply circuit is connected with the control end of the power supply chip; and
The power function safety protection circuit according to any one of claims 1 to 8, wherein the power function safety protection circuit is electrically connected to the auxiliary winding of the power circuit, the input terminal of the power circuit, and the power supply terminal of the power chip, respectively.
10. The switching power supply of claim 9 wherein said switching power supply further comprises:
And the input end of the feedback circuit is connected with the output end of the power supply circuit, the output end of the feedback circuit is connected with the power supply chip, and the feedback circuit is used for detecting the output voltage of the power supply circuit and outputting a corresponding feedback signal to the power supply chip so that the power supply chip controls the power supply circuit to work according to the feedback signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322554736.0U CN221042316U (en) | 2023-09-19 | 2023-09-19 | Power supply function safety protection circuit and switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322554736.0U CN221042316U (en) | 2023-09-19 | 2023-09-19 | Power supply function safety protection circuit and switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN221042316U true CN221042316U (en) | 2024-05-28 |
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|---|---|---|---|
| CN202322554736.0U Active CN221042316U (en) | 2023-09-19 | 2023-09-19 | Power supply function safety protection circuit and switching power supply |
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| Country | Link |
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| CN (1) | CN221042316U (en) |
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