TW202406261A - Semiconductor protector - Google Patents

Abstract

The semiconductor protector of the invention comprises a first semiconductor, a second semiconductor, a third semiconductor, a fourth semiconductor, a first resistor, a second resistor, a third resistor, a first diode and a voltage comparator, constituting an application circuit with load overload or short circuit protection function, which avoids the damage caused by overload or short circuit at both terminals of the load.

Description

Semiconductor protector

The semiconductor protector of the present invention is in the field of electronic technology and has the function of protecting the DC power supply when overload or short circuit occurs at both ends of the load during the application of the DC circuit.

The inventor of the semiconductor protector of the present invention searched for relevant semiconductor protection devices and related electronic protector invention documents, and found no identical or similar technologies to the semiconductor protector of the present invention, especially the first semiconductor and the second semiconductor of the present invention. It has the technical means of series connection, self-protection and self-locking functions to achieve the function of protecting the DC power supply when an overload or short circuit occurs at both ends of the load during the application of the DC circuit. It is the first invention in the world; the invention has four applications An insulated gate bipolar transistor in a foot package such as TO-247-4LD is used as the fourth semiconductor. The voltage drop across the Kelvin Emitter and Power Emitter of the fourth semiconductor has The function of providing overload or short-circuit data of the fourth semiconductor collector current is a world-first invention; other circuit features are described in detail in the specification of the invention.

Purpose of the present invention:

1. The present invention uses the first semiconductor, the second semiconductor, the third semiconductor, the fourth semiconductor, the first resistor, the second resistor, the third resistor, the first diode and the voltage comparator to achieve the ability to operate in DC The DC power supply is protected when overload or short circuit occurs in the circuit power supply.

2. When the load is short-circuited, the present invention uses the first semiconductor or the fourth semiconductor to perform an open-circuit action in a very short time, achieving the function of protecting the DC power circuit and avoiding various disasters caused by the load short-circuit.

3. The first semiconductor or the fourth semiconductor of the present invention enables the load to receive power from the DC power supply when the invention is turned on, and prevents the load from receiving power from the DC power supply when the invention is turned off.

4. When the present invention is turned on, the first semiconductor or the fourth semiconductor is turned on to supply voltage from the first power supply.

5. The second semiconductor of the present invention remains in a conductive state no matter when it is turned on or off. At this time, the turning on or off action of the present invention is performed by the first semiconductor or the fourth semiconductor.

The present invention has the following characteristics:

1. The first semiconductor and the second semiconductor of the present invention have the characteristics of being connected in series, and the first semiconductor is responsible for the open circuit (Off) and conduction of the DC power supply to supply power to the load.

2. The second semiconductor of the present invention provides drain-source on-state resistance, which is generated by the drain current of the first semiconductor passing through the second semiconductor during overload or short circuit. The function of data of drain-source voltage.

3. The third semiconductor of the present invention is responsible for controlling the opening and conduction actions of the first semiconductor or the fourth semiconductor to achieve the output voltage at both ends of the load. The purpose is to protect the DC power circuit when a short circuit occurs.

4. The present invention provides a first resistor with a current limiting function to prevent the first semiconductor from being damaged due to excessive gate current.

5. The present invention provides a second resistor with the function of limiting current to prevent the second semiconductor from being damaged due to excessive gate current.

6. The present invention provides a third resistor with the function of limiting current to prevent excessive current at the positive input end of the voltage comparator from damaging the voltage comparator.

7. The present invention is provided with a first diode with the function of conducting current in one direction, so that the voltage output by the output terminal of the voltage comparator can be supplied to the positive input terminal of the voltage comparator in one direction.

8. The present invention is provided with a circuit composed of a first semiconductor, a third semiconductor and a voltage comparator, so that the first semiconductor has the function of self protection.

9. The present invention is provided with a circuit composed of a fourth semiconductor, a third semiconductor and a voltage comparator, so that the fourth semiconductor has its own protection function.

10. The present invention is provided with a voltage comparator and a first diode to achieve the self-locking (Inter Lock) function of the voltage comparator.

11. The first semiconductor of the present invention includes an N Channel Metal Oxide Semiconductor Field Effect Transistor (N Channel MOSFET) and an Insulated Gate Bipolar Transistor (IGBT). The second semiconductor is an N Channel MOSFET. Users can choose according to their needs.

12. The second semiconductor of the present invention includes an N-channel metal oxide semiconductor field effect transistor and an insulated gate bipolar transistor, both of which can be selected according to needs.

13. The third semiconductor of the present invention includes N-channel metal oxide semiconductor field effect transistor and insulated gate bipolar transistor, which can be selected according to needs.

14. The fourth semiconductor of the present invention is a four-pin packaged semiconductor, including a four-pin packaged N-channel metal oxide semiconductor field effect transistor and a four-pin packaged insulated gate bipolar transistor, which can be selected according to needs.

15. The fourth semiconductor of the present invention is a semiconductor packaged in a module, including an N-channel metal oxide semiconductor field effect transistor packaged in the module and an insulated gate bipolar transistor packaged in the module. Both can be configured according to needs. Choose by yourself.

16. The second semiconductor of the present invention can be replaced by a resistor sensor according to application requirements.

10:Load

11:First power supply

12:Second power supply

13:Third power supply

14: DC power supply

15: Positive input terminal of voltage comparator

16: Negative input terminal of voltage comparator

17: Output terminal of voltage comparator

18: First resistor

19: Second resistor

20: Voltage comparator

21:First Semiconductor

22:Second Semiconductor

23:Third Semiconductor

24:Third resistor

25:First diode

26: Resistance sensor

27:Fourth Semiconductor

Figure 1 is a first embodiment of a semiconductor protector of the present invention.

Figure 2 is a second embodiment of a semiconductor protector of the present invention.

Figure 3 is the third embodiment of the semiconductor protector of the present invention.

As shown in Figure 1, it is a first embodiment of a semiconductor protector of the present invention. As can be seen from the figure, the semiconductor protector of the present invention includes a first semiconductor 21, a second semiconductor 22, a third semiconductor 23, a first resistor 18, The second resistor 19, the third resistor 24, the first diode 25 and the voltage comparator 20. The above first semiconductor 21, the second semiconductor 22 and the third semiconductor 23 are all three-pin packaged transistors.

The drain D (Drain, D) of the first semiconductor 21 is used to provide the first terminal connection of the external load 10. The first terminal of the first resistor 18 is used to provide the connection of the external first power supply 11. The second terminal Semiconductor The source S (Source, S) of 22 is used to connect the negative terminal of the DC power supply 14. The positive terminal of the DC power supply 14 is connected to the second terminal of the load 10, in which the first semiconductor 21 and the second semiconductor 22 form a series connection. .

The gate G (Gate, G) of the first semiconductor 21 is connected to the second end of the first resistor 18 and the drain D of the third semiconductor 23 , and the source S of the third semiconductor 23 is connected to the source S of the first semiconductor 21 Connection, the gate G of the third semiconductor 23 is connected to the output terminal (Output) 17 of the voltage comparator 20, the first terminal of the first resistor 18 and the positive power terminal of the voltage comparator 20 are connected to the positive power of the first power supply 11 The terminal or the positive terminal of the second power supply 12 or another power supply are determined according to the needs and are not limited by themselves.

The positive input terminal (Non-inverting Input) 15 of the voltage comparator 20 is connected to the first terminal of the third resistor 24 and the cathode terminal (Cathode) of the first diode 25, and the anode terminal (Anode) of the first diode 25 is connected. ) is connected to the output terminal of the voltage comparator 20, the second terminal of the third resistor 24 is connected to the source S of the first semiconductor 21, the negative input terminal (Inverting Input) 16 of the voltage comparator 20 is connected to the third power supply 13, The third power supply 13 is the reference voltage (Reference Voltage) of the negative input terminal 16 of the voltage comparator 20. The negative power supply terminal of the voltage comparator 20 is connected to the source S of the second semiconductor 22 and the negative terminal of the DC power supply 14. The positive power terminal is connected to the positive terminal of the first power supply 11 or the positive terminal of the second power supply 12 .

The gate G of the second semiconductor 22 is connected to the second terminal of the second resistor 19 , and the first terminal of the second resistor 19 is connected to the positive terminal of the second power supply 12 .

As shown in Figure 1, when both ends of the load 10 are short-circuited, according to the drain-source conduction state resistance of the second semiconductor 22, when the drain current (Drain Current) of the first semiconductor 21 rises to The corresponding drain-source voltage of the body 22 reaches the positive input terminal 15 of the voltage comparator 20 through the third resistor 24, if its drain-source voltage is higher than the reference voltage of the negative input terminal 16 of the voltage comparator 20 , the output terminal 17 of the voltage comparator 20 outputs a positive voltage to supply power to the anode terminal of the first diode 25 and the gate G of the third semiconductor 23. At this time, the cathode terminal of the first diode 25 supplies power to the voltage comparator. The positive input terminal 15 of 20 keeps the output terminal 17 of the voltage comparator 20 outputting a positive voltage, so that the voltage comparator 20 has a self-locking function. At the same time, the drain D and the source S of the third semiconductor 23 are connected, and the first semiconductor The drain D and source S of 21 are open-circuited, so that the first semiconductor 21 has its own protection function. At this time, the DC power supply 14 does not supply power to the short-circuit load 10, so that the DC power supply 14 is protected; similarly, the appropriate selection of the The drain-source on-state resistance between the drain D and the source S of the two semiconductors 22 can also achieve the overload protection function in conjunction with the reference voltage of the negative input terminal 16 of the voltage comparator 20 .

When the output terminal 17 of the voltage comparator 20 outputs a positive voltage to the gate G of the third semiconductor 23, the drain D and the source S of the third semiconductor 23 are connected, and the drain D and the source of the first semiconductor 21 are connected. The pole S is open, which means that the first semiconductor 21 has its own protection function.

As shown in Figure 2, it is the second embodiment of the semiconductor protector of the present invention. As can be seen from the figure, the first semiconductor 21 and the third semiconductor 23 in Figure 1 are changed from N-channel metal oxide semiconductor field effect transistors. Insulated gate bipolar transistor, the circuit of the second semiconductor 22 is replaced by a resistance sensor 26, the first end of the resistance sensor 26 is connected to the emitter E of the first semiconductor 21, and the resistance sensor 26 The second terminal is connected to the negative power terminal of the voltage comparator 20, and other circuit structures are the same as in Figure 1 and will not be described again.

As shown in Figure 2, the collector C (Collector, C) of the first semiconductor 21 is used to provide a first terminal connection for the external load 10, and the first terminal of the first resistor 18 is used to provide a connection for the external first power supply 11. The second terminal of the resistance sensor 26 is used to connect the negative terminal of the DC power supply 14 , and the positive terminal of the DC power supply 14 is connected to the second terminal of the load 10 .

As shown in FIG. 2 , when both ends of the load 10 are short-circuited, the voltage across the resistance sensor 26 reaches the positive input terminal 15 of the voltage comparator 20 through the third resistor 24 . If its voltage is higher than the voltage comparator 20 When the reference voltage of the negative input terminal 16 is set, the output terminal 17 of the voltage comparator 20 outputs a positive voltage to supply power to the anode terminal of the first diode 25 and the gate G of the third semiconductor 23. At this time, the first diode The cathode terminal of 25 supplies power to the positive input terminal 15 of the voltage comparator 20 so that the output terminal 17 of the voltage comparator 20 maintains outputting a positive voltage. This means that the voltage comparator 20 has a self-locking function. At the same time, the third semiconductor 23 The electrode C and the emitter E are connected, and the collector C and the emitter E of the first semiconductor 21 are open-circuited, so that the first semiconductor 21 has its own protection function. At this time, the DC power supply 14 does not supply power to the short-circuit load 10, but the DC power supply 14 is protected; similarly, by appropriately selecting the resistance value of the resistance sensor 26 and matching the reference voltage value of the negative input terminal 16 of the voltage comparator 20, the overload protection function can also be achieved.

From the above, it can be seen that the function of the resistance sensor 26 is to convert the collector current of the first semiconductor 21 into a voltage as a reference data for the overload or short-circuit current of the load 10. The resistance sensor 26 can also be an equivalent resistance. A characteristic shunt or a circuit with equivalent resistance characteristics, such as a circuit with one or more resistors in series, a circuit with multiple resistors in parallel, or a circuit with multiple resistors in series and parallel, all have equivalent resistance characteristics. circuit, because of its operating principle Same, not self-limiting.

From the above, it can be seen that the shunt has the characteristics of two ends, and either end can be used as the first end or the second end of the resistance sensor 26 .

From the above, it can be seen that a circuit with equivalent resistance characteristics has the characteristics of two ends, and either end can be used as the first end or the second end of the resistance sensor 26 .

As shown in Figure 3, it is the third embodiment of the semiconductor protector of the present invention. As can be seen from the figure, the resistance sensor 26 in Figure 2 is changed into the Kelvin emitter E2 and the fourth semiconductor 27 of the four-pin package. At both ends of the power emitter E1, the Kelvin emitter E2 of the fourth semiconductor 27 is connected to the emitter E of the fourth semiconductor 27 in the four-pin package, and the Kelvin emitter E2 is connected to the emitter E of the third semiconductor 23 and the third resistor. The second terminal of 24, the power emitter E1 of the fourth semiconductor 27 is connected to the negative power terminal of the voltage comparator 20. In addition to the four-pin package, the fourth semiconductor 27 of the present invention is also available in a module package, which can be selected according to the needs. One of them, other circuit structures are the same as Figure 2 and will not be described in detail.

As shown in Figure 3, the collector C of the fourth semiconductor 27 is used to provide the first terminal connection of the external load 10, and the first terminal of the first resistor 18 is used to provide the connection of the external first power supply 11. The fourth The power emitter E1 of the semiconductor 27 is used to connect the negative terminal of the DC power supply 14 , and the positive terminal of the DC power supply 14 is connected to the second terminal of the load 10 .

As shown in Figure 3, when both ends of the load 10 are short-circuited, the voltages at both ends of the Kelvin emitter E2 and the power emitter E1 of the fourth semiconductor 27 reach the positive input terminal 15 of the voltage comparator 20 through the third resistor 24, If the voltage is higher than the reference voltage of the negative input terminal 16 of the voltage comparator 20, the output terminal 17 of the voltage comparator 20 outputs a positive voltage to supply power to the anode terminal of the first diode 25 and the third semiconductor. Gate G of body 23, at this time, the cathode terminal of the first diode 25 supplies power to the positive input terminal 15 of the voltage comparator 20, so that the output terminal 17 of the voltage comparator 20 maintains outputting a positive voltage, which means that the voltage comparator 20 has a self-locking function. At the same time, the collector C and emitter E of the third semiconductor 23 are connected, and the collector C and emitter E of the fourth semiconductor 27 are open circuit, so that the fourth semiconductor 27 has the function of self-protection. At this time, The DC power supply 14 does not supply power to the short-circuit load 10, so that the DC power supply 14 is protected; similarly, the resistance values at both ends of the Kelvin emitter E2 and the power emitter E1 of the fourth semiconductor 27 are appropriately selected and matched with the voltage comparator 20 The reference voltage value of the negative input terminal 16 can also achieve the function of overload protection.

It can be seen from the above that the first diode 25 in Figures 1, 2 and 3 has the function of conducting current in one direction. If the output terminal 17 of its voltage comparator 20 has the function of conducting current in one direction, then the first diode 25 in Figure 1, Figure 2 and Figure 3 has the function of conducting current in one direction. The pole body 25 can be omitted and directly connected to the positive input terminal 15 of the voltage comparator 20 .

It can be seen from the above that the second semiconductor 22 in Figure 1 is an N-channel metal oxide semiconductor field effect transistor and can be replaced by an insulated gate bipolar transistor. Its operating principle is the collector-emitter voltage of the insulated gate bipolar transistor. It replaces the drain-source on-state resistor of the N-channel metal oxide semiconductor field effect transistor and has the same function, which can achieve the purpose of protecting the DC power supply 14 .

As can be seen from the above, the first semiconductor 21, the second semiconductor 22 and the third semiconductor 23 in Figure 1 can be partially or completely changed from N-channel metal oxide semiconductor field effect transistors to insulated gate bipolar transistors according to their needs. Substitution, because its action principle is the same, is not self-limiting.

From the above, it can be seen that the first semiconductor 21 in FIG. 2 can be replaced by an insulated gate bipolar transistor and an N-channel metal oxide semiconductor field effect transistor according to the demand.

From the above, it can be seen that the fourth semiconductor 27 in FIG. 3 can be replaced by a four-pin packaged insulated gate bipolar transistor and a four-pin packaged N-channel metal oxide semiconductor field effect transistor according to the demand.

It can be seen from the above that when the fourth semiconductor 27 in FIG. 3 is a four-pin packaged insulated gate bipolar transistor and is changed to a four-pin packaged N-channel metal oxide semiconductor field effect transistor, the well-known N-channel metal oxide semiconductor field effect transistor is used. Take the effective transistor NTH4L080N120SC1 as an example. The drain D is used to replace the collector C, the gate G is used to replace the gate G, the Kelvin source S2 is used to replace the Kelvin emitter E2, and the power source S1 is used to replace the power emitter E1. Because of its four The operating principles of the insulated gate bipolar transistor in a four-pin package and the N-channel metal oxide semiconductor field effect transistor in a four-pin package for protecting the DC power supply 14 are the same, so they can be replaced.

It can be seen from the above that regarding the fourth semiconductor 27 in a commercially available four-pin package in Figure 3, regardless of whether it uses an insulated gate bipolar transistor or an N-channel metal oxide semiconductor field effect transistor, the electrodes with the Kelvin function have different markings. For example, S2, K or KS are used to represent electrodes with Kelvin function. It is particularly stated here that the Kelvin emitter of the present invention is represented by E2, and the power emitter is represented by E1. Here is an example of the fourth semiconductor in a commercially available four-pin package. 27 Models such as STGW75H65DFB2-4, SCT3040KR, IKY40N120CS6, C3M0120100K, NTH4L080N120SC1 and IKZ50N65EH5 are for reference.

It can be seen from the above that in Figures 2 and 3, the first power supply 11 and the third power supply 13 are connected but not the second power supply 12. For the sake of simplicity, they are marked with dots, while in Figure 1, the first power supply is connected. 11. The second power supply 12 and the third power supply 13. People with common knowledge in the industry know that power supplies have positive and negative terminals. They are not marked in the figure and are specially stated here.

From the description of the above operating principles and functional actions, it can be seen that the present invention can be implemented accordingly.

10:Load

11:First power supply

12:Second power supply

13:Third power supply

14: DC power supply

15: Positive input terminal of voltage comparator

16: Negative input terminal of voltage comparator

17: Output terminal of voltage comparator

18: First resistor

19: Second resistor

20: Voltage comparator

21:First Semiconductor

22:Second Semiconductor

23:Third Semiconductor

24:Third resistor

25:First diode

Claims (14)

A semiconductor protector including: A first semiconductor has a drain, a source and a gate. The drain of the first semiconductor has the function of providing a first terminal connection for the load. The second terminal of the load is connected to the positive terminal of the DC power supply. ; A second semiconductor has a drain, a source and a gate. The drain of the second semiconductor is connected to the source of the first semiconductor. The source of the second semiconductor has a negative terminal that provides the DC power supply. The function of connection; A third semiconductor having a drain, a source and a gate, the source of the third semiconductor is connected to the source of the first semiconductor, and the drain of the third semiconductor is connected to the gate of the first semiconductor; A first resistor has a first end and a second end. The second end of the first resistor is connected to the gate of the first semiconductor. The first end of the first resistor is provided with a first power supply. The function of connection; A second resistor has a first end and a second end. The second end of the second resistor is connected to the gate of the second semiconductor. The first end of the second resistor is provided with a second power supply. The function of connection; A third resistor has a first end and a second end, and the second end of the third resistor is connected to the source of the first semiconductor and the drain of the second semiconductor; A first diode has an anode terminal and a cathode terminal, the cathode terminal of the first diode is connected to the first terminal of the third resistor, and has the function of conducting current in one direction; and A voltage comparator has a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the voltage comparator is connected to the first terminal of the third resistor and the cathode terminal of the first diode. The output terminal of the voltage comparator is connected to the anode terminal of the first diode and the gate of the third semiconductor, and the negative input terminal of the voltage comparator is provided with a third power supply connection. function. In the semiconductor protector described in Item 1 of the patent application, the drain-source voltage of the second semiconductor has the function of providing overload or short-circuit data of the drain current of the first semiconductor. The semiconductor protector described in item 1 of the patent application, wherein the first semiconductor, the second semiconductor or the third semiconductor is an N-channel metal oxide semiconductor field effect transistor, which can be an insulated gate bipolar transistor. substitute. A semiconductor protector including: A first semiconductor has a collector, an emitter and a gate. The collector of the first semiconductor has the function of providing a first terminal connection for a load. The second terminal of the load is connected to the positive terminal of the DC power supply. ; A third semiconductor having a collector, an emitter and a gate, the emitter of the third semiconductor is connected to the emitter of the first semiconductor, and the collector of the third semiconductor is connected to the gate of the first semiconductor; A first resistor has a first end and a second end. The second end of the first resistor is connected to the gate of the first semiconductor. The first end of the first resistor is provided with a first power supply. The function of connection; a third resistor having a first end and a second end, the second end of the third resistor being connected to the emitter of the first semiconductor; a first diode having an anode terminal and a cathode terminal, and the cathode terminal of the first diode is connected to the first terminal of the third resistor; A resistance sensor has a first end and a second end. The first end of the resistance sensor is connected to the emitter of the first semiconductor and the second end of the third resistor. The resistance sensor The second terminal has the function of providing the negative terminal connection of the DC power supply; and A voltage comparator has a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the voltage comparator is connected to the first terminal of the third resistor and the cathode terminal of the first diode. voltage comparator output The output terminal is connected to the anode terminal of the first diode and the gate of the third semiconductor, and the negative input terminal of the voltage comparator has the function of providing a third power connection. For the semiconductor protector described in item 4 of the patent application, the voltage drop across the resistance sensor has the function of providing overload or short-circuit data of the collector current of the first semiconductor. For example, the semiconductor protector described in item 4 of the patent application, wherein the resistance sensor is a shunt or a circuit with equivalent resistance characteristics. For example, in the semiconductor protector described in item 4 of the patent application, the first semiconductor and the third semiconductor are insulated gate bipolar transistors, which can be replaced by N-channel metal oxide semiconductor field effect transistors. The semiconductor protector described in Item 1 or 4 of the patent application, wherein the circuit formed by the first semiconductor, the third semiconductor and the voltage comparator enables the first semiconductor to have its own protection function. A semiconductor protector including: A fourth semiconductor having a collector, a gate, a Kelvin emitter and a power emitter. The collector of the fourth semiconductor has the function of providing a first terminal connection of a load, and a second terminal connection of the load. The positive terminal of the DC power supply and the negative terminal of the DC power supply are connected to the power emitter of the fourth semiconductor; A third semiconductor having a collector, an emitter and a gate. The emitter of the third semiconductor is connected to the Kelvin emitter of the fourth semiconductor. The collector of the third semiconductor is connected to the gate of the fourth semiconductor. ; A first resistor has a first end and a second end. The second end of the first resistor is connected to the gate of the fourth semiconductor. The first end of the first resistor is provided with a first power supply. The function of connection; a third resistor having a first end and a second end, the second end of the third resistor being connected to the Kelvin emitter of the fourth semiconductor; A first diode has an anode terminal and a cathode terminal, the first and second diode The cathode end of the electrode body is connected to the first end of the third resistor; and A voltage comparator has a positive input terminal, a negative input terminal and an output terminal. The positive input terminal of the voltage comparator is connected to the first terminal of the third resistor and the cathode terminal of the first diode. The output terminal of the voltage comparator is connected to the anode terminal of the first diode and the gate of the third semiconductor, and the negative input terminal of the voltage comparator has the function of providing a third power connection. The semiconductor protector described in item 9 of the patent application, wherein the voltage drop across the Kelvin emitter and power emitter of the fourth semiconductor has the function of providing overload or short-circuit data of the collector current of the fourth semiconductor. . For example, in the semiconductor protector described in item 9 of the patent application, the fourth semiconductor is a four-pin packaged insulated gate bipolar transistor, which can be replaced by a four-pin packaged N-channel metal oxide semiconductor field effect transistor. The third semiconductor is an insulated gate bipolar transistor, which can be replaced by an N-channel metal oxide semiconductor field effect transistor. For example, in the semiconductor protector described in Item 9 of the patent application, the fourth semiconductor is a four-pin package, which can be replaced by a module package. For example, in the semiconductor protector described in Item 9 of the patent application, the circuit formed by the fourth semiconductor, the third semiconductor and the voltage comparator enables the fourth semiconductor to have its own protection function. For example, in the semiconductor protector described in Item 1, 4 or 9 of the patent application, the circuit formed by the voltage comparator and the first diode enables the voltage comparator to have a self-locking function.

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