Drive signal control circuit, switching power supply, and processing method

Abstract

To provide an insulation type switching power supply that can be protected.SOLUTION: A drive signal control circuit includes: an input terminal to which a drive signal for driving a gate of a switching element is input; an output terminal connected to the gate; and a switch that disconnects the input terminal and the output terminal when a voltage corresponding one-to-one to an output voltage of an isolated synchronous rectification switching power supply is equal to or less than a predetermined threshold value, and connects the input terminal and the output terminal when the voltage corresponding one to-one to the output voltage exceeds the predetermined threshold value.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a drive signal control circuit, a switching power supply, and a processing method. [Background technology]

[0002] Switching power supplies are used in a variety of fields. Patent Document 1 discloses a related technique for overvoltage protection in a non-isolated switching power supply. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-165316 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the switching power supply related to Patent Document 1, there is a demand for a technique that can protect an isolated switching power supply.

[0005] An object of each aspect of the present disclosure is to provide a drive signal control circuit, a switching power supply, and a processing method that can solve the above problems. [Means for solving the problem]

[0006] In order to achieve the above object, according to one aspect of the present disclosure, a drive signal control circuit includes an input terminal to which a drive signal for driving a gate of a switching element is input, an output terminal connected to the gate, and a switch that disconnects the input terminal from the output terminal when a voltage that corresponds one-to-one with the output voltage of an isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, and that connects the input terminal to the output terminal when the voltage that corresponds one-to-one with the output voltage exceeds the predetermined threshold.

[0007] In order to achieve the above object, according to another aspect of the present disclosure, a switching power supply includes the above drive signal control circuit, a gate drive circuit that outputs a drive signal to an input terminal of the drive signal control circuit to drive the gate of a switching element, and the switching element whose gate is connected to the output of the drive signal control circuit.

[0008] In order to achieve the above object, according to another aspect of the present disclosure, a processing method is executed by a drive signal control circuit having an input terminal to which a drive signal for driving a gate of a switching element is input and an output terminal connected to the gate, and the processing method disconnects the input terminal from the output terminal when a voltage that corresponds one-to-one to an output voltage of an isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, and connects the input terminal to the output terminal when the voltage that corresponds one-to-one to the output voltage exceeds the predetermined threshold. [Effects of the Invention]

[0009] According to each aspect of the present disclosure, it is possible to protect an isolated switching power supply. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a switching power supply to be compared. [Figure 2] FIG. 10 is a diagram showing an example of voltages at each terminal of an insulated gate driver IC included in a comparative switching power supply. [Figure 3] FIG. 1 is a diagram illustrating an example of a configuration of a switching power supply according to some embodiments of the present disclosure. [Figure 4] FIG. 2 is a diagram illustrating an example of a configuration of a gate drive signal control circuit according to some embodiments of the present disclosure. [Figure 5] FIG. 10 is a diagram illustrating an example of voltages at each terminal of an insulated gate driver IC equipped with a switching power supply according to some embodiments of the present disclosure. [Figure 6] FIG. 2 is a diagram illustrating an example of a configuration of a drive signal control circuit according to some embodiments of the present disclosure. [Figure 7] FIG. 10 is a diagram illustrating an example of a process flow of a drive signal control circuit according to some embodiments of the present disclosure. [Figure 8] FIG. 1 is a schematic block diagram illustrating the configuration of a computer according to at least one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the embodiments will be described in detail with reference to the drawings. <Embodiment> A switching power supply 1 according to an embodiment of the present disclosure will be described with reference to the drawings. The switching power supply 1 is an isolated synchronous rectification switching power supply.

[0012] (Configuration of the switching power supply to be compared) To facilitate understanding of the switching power supply 1, we will first explain a comparative switching power supply 500. Fig. 1 is a diagram showing an example of the configuration of the comparative switching power supply 500. As shown in Fig. 1, the switching power supply 500 includes a power supply circuit main body 20 and a gate drive circuit 501.

[0013] As shown in FIG. 1, the power supply circuit main body 20 includes a primary circuit 201, a secondary circuit 202, a switching power supply transformer 203, and a switching element 204.

[0014] The primary circuit 201 outputs a predetermined voltage at a predetermined timing, and also passes a current in a predetermined direction through a primary coil of the switching power supply transformer 203. The secondary circuit 202 is, for example, a load.

[0015] In the switching power supply transformer 203, a magnetic flux generated in response to a current flowing through the primary coil passes through the secondary coil, causing a current to flow through the secondary coil. As a result, a voltage corresponding to the ratio of the number of turns of the primary coil to the number of turns of the secondary coil is generated across the secondary coil. The switching element 204 is turned on or off under the control of the gate drive circuit 501, thereby rectifying the voltage generated across the secondary coil.

[0016] The gate drive circuit 501 drives the gate of the switching element 204. The gate drive circuit 501 includes a series regulator 101, an insulated gate drive IC (Integrated Circuit) 102, and a VDD voltage generation circuit 103, as shown in FIG.

[0017] Series regulator 101 generates a desired constant voltage lower than the input voltage from the input voltage, and outputs the generated constant voltage to isolated gate driver IC 102. Series regulator 101 has an IN(+) terminal, an IN(-) terminal, an OUT(+) terminal, and an OUT(-) terminal.

[0018] The isolated gate driver IC 102 generates a gate drive signal for driving the switching element 204 from the voltage generated by the series regulator 101. The isolated gate driver IC 102 outputs the generated gate drive signal to the switching element 204 when the output voltage VDD of the VDD voltage generation circuit 103 exceeds a low input voltage protection threshold (described later). The isolated gate driver IC 102 includes an IN(+) terminal, an IN(-) terminal, an OUT terminal, and a VDD terminal. The IN(+) terminal is an input terminal of the isolated gate driver IC 102. The IN(-) terminal is a reference terminal that serves as a reference potential for the isolated gate driver IC 102. The OUT terminal is an output terminal of the isolated gate driver IC 102. The VDD terminal is a terminal that serves as a low input voltage protection terminal for the isolated gate driver IC 102. The OUT terminal is a terminal that outputs a gate drive signal for driving the switching element 204. The IN(+) terminal is connected to the output terminal of the series regulator 101. The IN(-) terminal is connected to a reference terminal that serves as a reference potential for the series regulator 101. The OUT terminal is connected to the gate of the switching element 204. In the switching power supply 500, the VDD terminal is connected to an OUT terminal (described later) of the VDD voltage generation circuit 103. That is, when the voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 500 (i.e., equivalently, the output voltage from the secondary side of the switching power supply 500) is low (for example, when it is below a predetermined threshold value set for the VDD terminal (for example, a low input voltage protection threshold in FIGS. 2 and 5 described later)), the isolated gate drive IC 102 does not output a voltage from the OUT terminal and does not drive the switching element 204, even if a voltage is applied to the IN(+) and IN(-) terminals of the isolated gate drive IC 102. In addition, when the voltage VDD is high (for example, when it is equal to or higher than a predetermined threshold value set for the VDD terminal), the isolated gate drive IC 102 outputs a voltage from the OUT terminal of the isolated gate drive IC 102 to drive the switching element 204. An example of the predetermined threshold is a threshold set for voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 500, and indicates that the output voltage of the switching power supply 500 has reached a startup voltage that allows the switching power supply 500 to start up normally.

[0019] The VDD voltage generation circuit 103 (an example of a corresponding voltage generation means) generates a voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 500 (i.e., the output voltage from the secondary side of the switching power supply 500). The VDD voltage generation circuit 103 then outputs the generated voltage VDD to the VDD terminal of the insulated gate drive IC 102. The VDD voltage generation circuit 103 includes an IN1 terminal, an IN2 terminal, and an OUT terminal.

[0020] In this switching power supply 500, when the voltage VDD is less than a predetermined threshold set at the VDD terminal of the insulated gate drive IC 102, simply applying a voltage to the IN(+) and IN(-) terminals may cause the insulated gate drive IC 102 to output a voltage from the OUT terminal and drive the switching element 204 (see, for example, FIG. 2, which will be described later). The switching power supply 1 of the present disclosure, which will be described later, prevents such an operation.

[0021] Fig. 2 is a diagram showing an example of voltages at each terminal of the insulated gate driver IC 102 included in the comparative switching power supply 500. Part (a) of Fig. 2 shows the voltage change over time at the IN(+) terminal of the insulated gate driver IC 102. Part (b) of Fig. 2 shows the voltage change over time at the VDD terminal of the insulated gate driver IC 102. Part (c) of Fig. 2 shows the voltage change over time at the OUT terminal of the insulated gate driver IC 102. Part (d) of Fig. 2 shows the voltage change at the gate of the switching element 204.

[0022] 2, in the switching power supply 500, even when the voltage VDD, which has a one-to-one correspondence with the output voltage of the switching power supply 500, has not reached a predetermined threshold, the OUT terminal may output a gate drive signal for driving the switching element 204, which may result in driving the switching element 204 at an unintended timing (almost simultaneously with the output of the gate drive signal from the OUT terminal in the example shown in FIG. 2(d)). As a result, the secondary-side circuit 202 to which power is supplied from the switching power supply 500 (i.e., which serves as a load on the switching power supply 500) may malfunction or be damaged.

[0023] (Configuration of the Switching Power Supply of the Present Disclosure) A switching power supply 1 according to an embodiment of the present disclosure is a switching power supply that can prevent the switching element 204 from being driven by the gate drive signal when the voltage VDD, which corresponds one-to-one to the output voltage of the switching power supply 500, has not reached a predetermined threshold, which may occur in the switching power supply 500 or the like (i.e., the switching element 204 is driven by the gate drive signal after the voltage VDD, which corresponds one-to-one to the output voltage of the switching power supply 500, has reached a predetermined threshold).

[0024] 3 is a diagram showing an example of the configuration of a switching power supply 1 according to some embodiments of the present disclosure. As shown in FIG. 3, the switching power supply 1 includes a gate drive circuit 10 and a power supply circuit main body 20.

[0025] As shown in FIG. 3, the power supply circuit main body 20 includes a primary circuit 201, a secondary circuit 202, a switching power supply transformer 203, and a switching element 204.

[0026] The primary circuit 201 outputs a predetermined voltage at a predetermined timing, and also passes a current in a predetermined direction through a primary coil of the switching power supply transformer 203. The secondary circuit 202 is, for example, a load.

[0027] In the switching power supply transformer 203, a magnetic flux generated in response to a current flowing through the primary coil passes through the secondary coil, causing a current to flow through the secondary coil. As a result, a voltage corresponding to the ratio of the number of turns of the primary coil to the number of turns of the secondary coil is generated across the secondary coil. The switching element 204 is turned on or off under the control of the gate drive circuit 501, thereby rectifying the voltage generated across the secondary coil.

[0028] The power supply circuit main body 20 may be the same as the power supply circuit main body 20 included in the switching power supply 500.

[0029] As shown in FIG. 3, the gate drive circuit 10 includes a series regulator 101, an insulated gate drive IC 102, a VDD voltage generation circuit 103, and a gate drive signal control circuit 104.

[0030] The series regulator 101 generates a desired constant voltage lower than the input voltage from the input voltage. The series regulator 101 then outputs the generated constant voltage to the insulated gate driver IC 102. The series regulator 101 has an IN(+) terminal, an IN(-) terminal, an OUT(+) terminal, and an OUT(-) terminal. Note that the series regulator 101 may be the same as the series regulator 101 included in the switching power supply 500.

[0031] The insulated gate driver IC 102 generates a gate drive signal for driving the switching element 204 from the voltage generated by the series regulator 101. When the voltage VDD output from the VDD voltage generation circuit 103 exceeds a low input voltage protection threshold (described later), the insulated gate driver IC 102 outputs the generated gate drive signal to the switching element 204. The insulated gate driver IC 102 has an IN(+) terminal, an IN(-) terminal, an OUT terminal, and a VDD terminal. The IN(+) terminal is an input terminal of the insulated gate driver IC 102. The IN(-) terminal is a reference terminal that serves as a reference potential for the insulated gate driver IC 102. The OUT terminal is an output terminal of the insulated gate driver IC 102. The VDD terminal is a terminal that serves as low input voltage protection for the insulated gate driver IC 102. In other words, similar to the switching power supply 500 described above, when the output voltage of the switching power supply 1 (the output voltage on the secondary side of the switching power supply 1) is low (for example, when the voltage VDD, which has a one-to-one correspondence with the output voltage of the switching power supply 1, is below a predetermined threshold set in the VDD terminal), the isolated gate drive IC 102 does not output a voltage from the OUT terminal and does not drive the switching element 204, even if a voltage is applied to the IN(+) and IN(-) terminals of the isolated gate drive IC 102. Furthermore, when the output voltage of the switching power supply 1 is high (for example, when the voltage VDD is equal to or higher than a predetermined threshold set in the VDD terminal), the isolated gate drive IC 102 outputs a voltage from the OUT terminal of the isolated gate drive IC 102 to drive the switching element 204. The OUT terminal is a terminal that outputs a gate drive signal that drives the switching element 204. The IN(+) terminal is connected to the output terminal of the series regulator 101. The IN(-) terminal is connected to a reference terminal that serves as the reference potential of the series regulator 101. The OUT terminal is connected to the IN1 terminal of the gate drive signal control circuit 104. The VDD terminal is connected to the OUT terminal of the VDD voltage generation circuit 103 and the gate drive signal control circuit 104. As a result, a voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 1 is applied to the VDD terminal and the IN2 terminal of the gate drive signal control circuit 104.The insulated gate driver IC 102 may be the same as the insulated gate driver IC 102 included in the switching power supply 500.

[0032] The VDD voltage generation circuit 103 generates a voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 1 (i.e., the output voltage on the secondary side of the switching power supply 1). The VDD voltage generation circuit 103 then outputs the generated voltage VDD to the VDD terminal of the isolated gate drive IC 102 and the IN2 terminal of the gate drive signal control circuit 104. The VDD voltage generation circuit 103 includes an IN1 terminal, an IN2 terminal, and an OUT terminal. The VDD voltage generation circuit 103 may be the same as the VDD voltage generation circuit 103 included in the switching power supply 500.

[0033] The gate drive signal control circuit 104 is provided between the insulated gate drive IC 102 and the switching element 204, and between the insulated gate drive IC 102 and the VDD voltage generation circuit 103. The gate drive signal control circuit 104 has an IN1 terminal, an IN2 terminal, and an OUT terminal. As shown in FIG. 3, the IN1 terminal is connected to the OUT terminal of the insulated gate drive IC 102. The IN2 terminal is connected to the VDD terminal of the insulated gate drive IC 102 and the OUT terminal of the VDD voltage generation circuit 103. The OUT terminal is connected to the gate of the switching element 204.

[0034] 4 is a diagram illustrating an example of the configuration of a gate drive signal control circuit 104 according to some embodiments of the present disclosure. Note that Fig. 4 also illustrates a series regulator 101, an isolated gate drive IC 102, a VDD voltage generation circuit 103, a switching power supply transformer 203, and a switching element 204.

[0035] As shown in FIG. 4 , the gate drive signal control circuit 104 includes resistors 1041, 1042, 1043, and 1044 and transistors 1045 and 1046. Each of the resistors 1041, 1042, 1043, and 1044 includes a first terminal and a second terminal. Each of the transistors 1045 and 1046 includes a first terminal, a second terminal, and a third terminal. The transistor 1045 is, for example, a PNP transistor. If the transistor 1045 is a PNP transistor, the first terminal of the transistor 1045 is a base, the second terminal is a collector, and the third terminal is an emitter. The transistor 1046 is, for example, an NPN transistor. If the transistor 1046 is an NPN transistor, the first terminal of the transistor 1046 is a base, the second terminal is a collector, and the third terminal is an emitter.

[0036] 4, a first terminal of the resistor 1041 is connected to the VDD terminal of the insulated gate driver IC 102 and the OUT terminal of the VDD voltage generation circuit 103. A second terminal of the resistor 1041 is connected to the first terminal of the resistor 1042 and the first terminal of the transistor 1046. A second terminal of the resistor 1042 is connected to the ground GND.

[0037] A first terminal of the resistor 1043 is connected to a first terminal of the transistor 1045 as shown in Figure 4. A second terminal of the resistor 1043 is connected to a second terminal of the transistor 1046 as shown in Figure 4.

[0038] 4, the first terminal of the resistor 1044 is connected to the second terminal of the transistor 1045. The second terminal of the resistor 1044 is connected to the gate of the switching element 204.

[0039] 4, the third terminal of the transistor 1045 is connected to the OUT terminal of the insulated gate driver IC 102. The third terminal of the transistor 1046 is connected to the ground GND.

[0040] (Operation of the gate drive signal control circuit) Here, a description will be given of the operation of the gate drive signal control circuit 104. It is assumed here that the transistor 1045 is a PNP transistor and the transistor 1046 is an NPN transistor.

[0041] A voltage obtained by dividing the voltage VDD by the resistance value of resistor 1041 and the resistance value of resistor 1042 is applied to the base of transistor 1046. When the voltage VDD, which corresponds one-to-one to the output voltage of the switching power supply 1, is 0 volts (i.e., the ground GND potential), the base of transistor 1046 is 0 volts, and therefore no current flows to the base of transistor 1045. Therefore, transistor 1045 is in the OFF state. In other words, even if a gate drive signal is output from the OUT terminal of the insulated gate drive IC 102, the gate drive signal is not applied to the gate of the switching element 204.

[0042] When the output voltage of the switching power supply 1 rises from 0 volts, and the one-to-one corresponding voltage VDD also rises from 0 volts, and the voltage VDD becomes equal to or greater than the base-emitter voltage that turns on the transistor 1046, the transistor 1046 turns on. In this case, the transistor 1046 tries to pass current from the collector to the emitter. As a result, current flows from the base of the transistor 1045 to the resistor 1043 and from the collector of the transistor 1046 to the emitter (i.e., ground GND).

[0043] This current turns on the transistor 1045. When the transistor 1045 turns on, the gate drive signal output from the OUT terminal of the insulated gate drive IC 102 is applied to the gate of the switching element 204 via the transistor 1045 and the resistor 1044. As a result, the switching element 204 is driven by the gate drive signal.

[0044] Fig. 5 is a diagram showing an example of voltages at each terminal of the isolated gate driver IC 102 included in the switching power supply 1 according to some embodiments of the present disclosure. Part (a) of Fig. 5 shows the voltage change over time at the IN(+) terminal of the isolated gate driver IC 102. Part (b) of Fig. 5 shows the voltage change over time at the VDD terminal of the isolated gate driver IC 102. Part (c) of Fig. 5 shows the voltage change over time at the OUT terminal of the isolated gate driver IC 102. Part (d) of Fig. 5 shows the voltage change at the gate of the switching element 204.

[0045] 5, in the switching power supply 1, even if a gate drive signal for driving the switching element 204 is output from the OUT terminal of the isolated gate drive IC 102 before the voltage VDD reaches a predetermined threshold (i.e., before the output voltage of the switching power supply 1 reaches the start-up voltage, which is a voltage at which the switching power supply 1 can be started up normally), the gate drive signal does not drive the switching element 204 while the transistor 1045 is in the off state, as described above. Then, when the transistor 1045 is turned on, the gate drive signal is applied to the switching element 204.

[0046] As can be seen from the above description of operation, the timing at which transistor 1045 switches from an off state to an on state depends on the division of voltage VDD, which is determined by the resistance values ​​of resistors 1041 and 1042. In other words, the timing at which transistor 1045 switches from an off state to an on state can be set arbitrarily by adjusting the resistance values ​​of resistors 1041 and 1042. Note that resistors 1043 and 1044 are each an overcurrent protection resistor for preventing overcurrent.

[0047] By adjusting the resistance values ​​of resistors 1041 and 1042 so that the gate drive signal is applied to the gate of switching element 204 after voltage VDD exceeds the low input voltage protection threshold (i.e., a predetermined threshold), as shown in part (d) of Figure 5, it is possible to prevent switching element 204 from being driven by the gate drive signal when voltage VDD has not reached the low input voltage protection threshold (i.e., the predetermined threshold) (i.e., the switching element 204 is driven by the gate drive signal after voltage VDD has reached the predetermined threshold).

[0048] The foregoing has described the switching power supply 1 according to an embodiment of the present disclosure. In the switching power supply 1, the gate drive signal control circuit 104 (an example of a drive signal control circuit) includes an IN1 terminal (an example of an input terminal) to which a drive signal for driving the gate of the switching element 204 is input, an OUT terminal (an example of an output terminal) connected to the gate, and a transistor 1045 (an example of a switch) that disconnects the IN1 terminal and the OUT terminal when a voltage VDD that corresponds one-to-one to the output voltage of the isolated synchronous rectification switching power supply 1 is equal to or lower than a predetermined threshold, and connects the IN1 terminal and the OUT terminal when the voltage VDD exceeds the predetermined threshold.

[0049] This gate drive signal control circuit 104 (an example of a drive signal control circuit) can protect the insulated switching power supply.

[0050] 6 is a diagram illustrating an example of the configuration of a drive signal control circuit 300 according to some embodiments of the present disclosure. As shown in FIG. 6, the drive signal control circuit 300 according to the present disclosure includes an input terminal 301, an output terminal 302, and a switch 303. A drive signal for driving the gate of a switching element is input to the input terminal 301. The output terminal 302 is connected to the gate. The switch 303 disconnects the input terminal 301 from the output terminal 302 when a voltage that corresponds one-to-one to the output voltage of the isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, and connects the input terminal 301 to the output terminal 302 when the voltage that corresponds one-to-one to the output voltage of the switching power supply exceeds the predetermined threshold.

[0051] The input terminal 301 can be realized, for example, using the function of the IN1 terminal illustrated in Fig. 3 or the function of the third terminal of the transistor 1045 illustrated in Fig. 4. The output terminal 302 can be realized, for example, using the function of the OUT terminal illustrated in Fig. 3 or the function of the second terminal of the resistor 1044 illustrated in Fig. 4. The switch 303 can be realized, for example, using the function of the transistor 1045 illustrated in Fig. 4.

[0052] 7 is a diagram showing an example of a processing flow of the drive signal control circuit 300 according to some embodiments of the present disclosure. Next, the processing of the drive signal control circuit 300 according to the present disclosure will be described with reference to FIG.

[0053] A switch 303 of a drive signal control circuit 300 has an input terminal 301 to which a drive signal for driving the gate of a switching element is input, and an output terminal 302 connected to the gate. When a voltage that corresponds one-to-one with the output voltage of an isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, the switch 303 disconnects the input terminal 301 from the output terminal 302, and when the voltage that corresponds one-to-one with the output voltage exceeds the predetermined threshold (step S101).

[0054] The above has described the drive signal control circuit 300 according to the present disclosure. This drive signal control circuit 300 can protect an isolated switching power supply.

[0055] The order of the processes in the embodiments of the present disclosure may be changed as long as the processes are performed appropriately.

[0056] Although the embodiments of the present disclosure have been described, the above-mentioned switching power supply 1 and other control devices may have a computer system built therein. The above-mentioned processing steps are stored in the form of a program on a computer-readable recording medium, and the computer reads and executes this program to perform the above processing. Specific examples of computers are shown below.

[0057] 8 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. As shown in FIG. 8, the computer 5 includes a CPU (Central Processing Unit) 6, a main memory 7, a storage 8, and an interface 9.

[0058] For example, the above-described switching power supply 1 and other control devices are implemented in a computer 5. The operations of the above-described processing units are stored in the form of a program in a storage 8. A CPU 6 reads the program from the storage 8, loads it into the main memory 7, and executes the above-described processing in accordance with the program. The CPU 6 also allocates storage areas in the main memory 7 corresponding to the above-described storage units in accordance with the program.

[0059] Examples of storage 8 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 8 may be an internal medium directly connected to the bus of computer 5, or an external medium connected to computer 5 via interface 9 or a communication line. In addition, when this program is distributed to computer 5 via a communication line, computer 5 that receives the program may load the program into main memory 7 and execute the above-mentioned processing. In at least one embodiment, storage 8 is a non-transitory tangible storage medium.

[0060] The program may also implement some of the functions described above. Furthermore, the program may be a file that can implement the functions described above in combination with a program already recorded in the computer system, a so-called differential file (differential program).

[0061] Although several embodiments of the present disclosure have been described, these embodiments are merely examples and do not limit the scope of the disclosure. Various additions, omissions, substitutions, and modifications may be made to these embodiments without departing from the spirit of the disclosure.

[0062] Note that part or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0063] (Appendix 1) an input terminal to which a drive signal for driving a gate of a switching element is input; an output terminal connected to the gate; a switch that disconnects the input terminal and the output terminal when a voltage that corresponds one-to-one to an output voltage of the isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, and that connects the input terminal and the output terminal when the voltage that corresponds one-to-one to the output voltage exceeds the predetermined threshold; A drive signal control circuit is provided.

[0064] (Appendix 2) the switch is a first transistor; a second transistor that controls the on and off states of the first transistor; 2. The drive signal control circuit according to claim 1, comprising:

[0065] (Appendix 3) The second transistor is When in an on state, the first transistor is turned on, and when in an off state, the first transistor is turned off. 3. The drive signal control circuit according to claim 2.

[0066] (Appendix 4) a voltage generating means for generating either a voltage for turning on the second transistor or a voltage for turning off the second transistor from a voltage that corresponds one-to-one to the output voltage; 4. The drive signal control circuit according to claim 3, comprising:

[0067] (Appendix 5) The voltage generating means a first resistor and a second resistor; Equipped with a voltage that turns on the second transistor or a voltage that turns off the second transistor is generated by dividing a voltage that corresponds one-to-one to the output voltage by the first resistor and the second resistor; 5. The drive signal control circuit according to claim 4.

[0068] (Appendix 6) a corresponding voltage generating means for generating, from the output voltage, a voltage that corresponds one-to-one to the output voltage; 6. The drive signal control circuit according to claim 1, comprising:

[0069] (Appendix 7) A drive signal control circuit according to any one of Supplementary Note 1 to Supplementary Note 6; a gate drive circuit that outputs a drive signal to an input terminal of the drive signal control circuit to drive the gate of a switching element; the switching element, the gate of which is connected to the output of the drive signal control circuit; A switching power supply comprising:

[0070] (Appendix 8) A processing method executed by a drive signal control circuit having an input terminal to which a drive signal for driving a gate of a switching element is input, and an output terminal connected to the gate, the method comprising: When a voltage that corresponds one-to-one with the output voltage of the isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, the input terminal and the output terminal are disconnected, and when the voltage that corresponds one-to-one with the output voltage exceeds a predetermined threshold, the input terminal and the output terminal are connected. Processing method.

[0071] (Appendix 9) the switch is a first transistor; The drive signal control circuit includes: a second transistor that controls the on and off states of the first transistor; Equipped with The processing method described in Appendix 8.

[0072] (Appendix 10) The second transistor is When in an on state, the first transistor is turned on, and when in an off state, the first transistor is turned off. The processing method described in Appendix 9.

[0073] (Appendix 11) The drive signal control circuit includes: a voltage generating means for generating either a voltage for turning on the second transistor or a voltage for turning off the second transistor from a voltage that corresponds one-to-one to the output voltage; Equipped with The processing method described in Appendix 10.

[0074] (Appendix 12) The voltage generating means a first resistor and a second resistor; Equipped with a voltage that turns on the second transistor or a voltage that turns off the second transistor is generated by dividing a voltage that corresponds one-to-one to the output voltage by the first resistor and the second resistor; The processing method described in Appendix 11.

[0075] (Appendix 13) The drive signal control circuit includes: a corresponding voltage generating means for generating, from the output voltage, a voltage that corresponds one-to-one to the output voltage; Equipped with 13. The processing method according to any one of claims 8 to 12. [Explanation of symbols]

[0076] 1,500···Switching power supply 5. Computer 6, 205···CPU 7. Main memory 8. Storage 9. Interface 10, 501... Gate drive circuit 20 Power supply circuit body 101··· Series Regulator 102···Insulated Gate Driver IC 103 VDD voltage generation circuit 104 Gate drive signal control circuit 201...Primary side circuit 202...Secondary side circuit 203...Switching power supply transformer 204 Switching element 1041, 1042, 1043, 1044... Resistors 1045, 1046...Transistor

Claims

1. an input terminal to which a drive signal for driving a gate of a switching element is input; an output terminal connected to the gate; a switch that disconnects the input terminal and the output terminal when a voltage that corresponds one-to-one to an output voltage of the isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, and that connects the input terminal and the output terminal when the voltage that corresponds one-to-one to the output voltage exceeds the predetermined threshold; A drive signal control circuit is provided.

2. the switch is a first transistor; a second transistor that controls the on and off states of the first transistor; The drive signal control circuit according to claim 1 , comprising:

3. The second transistor is When in an on state, the first transistor is turned on, and when in an off state, the first transistor is turned off. The drive signal control circuit according to claim 2 .

4. a voltage generating means for generating either a voltage for turning on the second transistor or a voltage for turning off the second transistor from a voltage that corresponds one-to-one to the output voltage; The drive signal control circuit according to claim 3 , comprising:

5. The voltage generating means a first resistor and a second resistor; Equipped with a voltage that turns on the second transistor or a voltage that turns off the second transistor is generated by dividing a voltage that corresponds one-to-one to the output voltage by the first resistor and the second resistor; The drive signal control circuit according to claim 4 .

6. a corresponding voltage generating means for generating, from the output voltage, a voltage that corresponds one-to-one to the output voltage; The drive signal control circuit according to claim 1 , comprising:

7. A drive signal control circuit according to any one of claims 1 to 6; a gate drive circuit that outputs a drive signal to an input terminal of the drive signal control circuit to drive the gate of a switching element; the switching element, the gate of which is connected to the output of the drive signal control circuit; A switching power supply comprising:

8. A processing method executed by a drive signal control circuit having an input terminal to which a drive signal for driving a gate of a switching element is input, and an output terminal connected to the gate, the method comprising: When a voltage that corresponds one-to-one with an output voltage of an isolated synchronous rectification switching power supply is equal to or lower than a predetermined threshold, the input terminal and the output terminal are disconnected, and when the voltage that corresponds one-to-one with the output voltage exceeds the predetermined threshold, the input terminal and the output terminal are connected. Processing method.

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