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 Art

[0002] Switching power supplies are used in various fields. Patent Document 1 discloses a technique related to overvoltage protection in a non-isolated switching power supply as a related technique.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the switching power supply related to Patent Document 1, a technique capable of protecting an isolated switching power supply is required.

[0005] Each aspect of the present disclosure aims to provide a drive signal control circuit, a switching power supply, and a processing method capable of solving the above problems.

Means for Solving the Problems

[0006] 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 and the output terminal when a voltage corresponding one-to-one to an output voltage of an isolated synchronous rectification type switching power supply is equal to or lower than a predetermined threshold, and connects the input terminal and the output terminal when the voltage corresponding one-to-one to the output voltage exceeds the predetermined threshold.

[0007] 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 for driving the gate of a switching element to an input terminal of the drive signal control circuit, and the switching element whose gate is connected to the output of the drive signal control circuit.

[0008] To achieve the above object, according to another aspect of the present disclosure, a processing method is a processing method executed by a drive signal control circuit including an input terminal to which a drive signal for driving the gate of a switching element is input and an output terminal connected to the gate. When a voltage corresponding one-to-one to the output voltage of an isolated synchronous rectification type switching power supply is below a predetermined threshold, the input terminal and the output terminal are disconnected. When the voltage corresponding one-to-one to the output voltage exceeds the predetermined threshold, the input terminal and the output terminal are connected.

Advantages of the Invention

[0009] According to each aspect of the present disclosure, an isolated switching power supply can be protected.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described in detail with reference to the drawings. <Embodiment> The 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 a switching power supply of an isolated synchronous rectification type.

[0012] (Configuration of the switching power supply for comparison) To facilitate the understanding of the switching power supply 1, first, the switching power supply 500 for comparison will be described. FIG. 1 is a diagram showing an example of the configuration of the switching power supply 500 for comparison. 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 side circuit 201, a secondary side circuit 202, a switching power supply transformer 203, and a switching element 204.

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

[0015] The switching power supply transformer 203 causes a current to flow through the secondary side coil when the magnetic flux generated according to the current flowing through the primary side coil penetrates the secondary side coil. As a result, a voltage corresponding to the ratio of the number of turns of the primary side coil to the number of turns of the secondary side coil is generated across the secondary side coil. The switching element 204 rectifies the voltage generated across both ends of the secondary coil by being turned on or off under the control of the gate drive circuit 501.

[0016] The gate drive circuit 501 drives the gate of the switching element 204. As shown in FIG. 1, the gate drive circuit 501 includes a series regulator 101, an isolated gate drive IC (Integrated Circuit) 102, and a VDD voltage generation circuit 103.

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

[0018] The isolated gate drive IC 102 generates a gate drive signal for driving the switching element 204 from the voltage generated by the series regulator 101. Then, when the voltage VDD at the output of the VDD voltage generation circuit 103 exceeds a low input voltage protection threshold value described later, the isolated gate drive IC 102 outputs the generated gate drive signal to the switching element 204. The isolated gate drive 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 drive IC 102. The IN(-) terminal is a reference terminal serving as the reference potential of the isolated gate drive IC 102. The OUT terminal is an output terminal of the isolated gate drive IC 102. The VDD terminal is a terminal that plays a role in low input voltage protection of the isolated gate drive 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 the reference terminal serving as the reference potential of 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 the OUT terminal of the VDD voltage generation circuit 103 described later. That is, when the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 500 (that is, equivalently, the output voltage of the secondary side of the switching power supply 500) is low (for example, when it is less than a predetermined threshold value set at the VDD terminal (for example, the low input voltage protection threshold value in FIGS. 2 and 5 described later)), even if a voltage is applied to the IN(+) and IN(-) terminals of the isolated gate drive IC 102, the isolated gate drive IC 102 does not output a voltage from the OUT terminal and does not drive the switching element 204. Also, when the voltage VDD is high (for example, when it is equal to or higher than a predetermined threshold value set at the VDD terminal), the isolated gate drive IC 102 outputs a voltage from the OUT terminal of the isolated gate drive IC 102 and drives the switching element 204. As an example of the predetermined threshold value, there is a threshold value set with respect to the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 500, which indicates that the output voltage of the switching power supply 500 has reached the startup voltage at which the switching power supply 500 can be normally started.

[0019] The VDD voltage generation circuit 103 (an example of corresponding voltage generation means) generates a voltage VDD that corresponds one-to-one to the output voltage of the switching power supply 500 (that is, the output voltage on the secondary side of the switching power supply 500) from the output voltage of the switching power supply 500. Then, the VDD voltage generation circuit 103 outputs the generated voltage VDD to the VDD terminal of the isolated 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 at the VDD terminal of the isolated gate drive IC 102 is less than a predetermined threshold value set at the VDD terminal of the voltage VDD isolated gate drive IC 102, a voltage is applied only to the IN(+) and IN(-) terminals, and there is a possibility that a voltage may be output from the OUT terminal to drive the switching element 204 (see, for example, FIG. 2 described later). The switching power supply 1 of the present disclosure described later prevents such an operation.

[0021] FIG. 2 is a diagram showing an example of the voltage at each terminal of the isolated gate drive IC 102 provided in the switching power supply 500 to be compared. The part (a) of FIG. 2 shows the voltage change of the IN(+) terminal of the isolated gate drive IC 102 over time. The part (b) of FIG. 2 shows the voltage change of the VDD terminal of the isolated gate drive IC 102 over time. The part (c) of FIG. 2 shows the voltage change of the OUT terminal of the isolated gate drive IC 102 over time. Note that the part (d) of FIG. 2 shows the voltage change at the gate of the switching element 204.

[0022] In the switching power supply 500, as shown in FIG. 2, although the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 500 has not reached a predetermined threshold value, a gate drive signal for driving the switching element 204 is output from the OUT terminal, and the switching element 204 may be driven at an unintended timing (in the example shown in FIG. 2(d), almost simultaneously when the gate drive signal is output from the OUT terminal). As a result, there is a possibility that the secondary circuit 202, which is supplied with power from the switching power supply 500 (i.e., becomes a load of the switching power supply 500), malfunctions or the secondary circuit 202 is damaged.

[0023] (Configuration of the switching power supply of the present disclosure) The 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 a gate drive signal when the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 500, which may occur in the switching power supply 500 or the like, has not reached a predetermined threshold value (that is, drive the switching element 204 with a gate drive signal after the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 500 has reached the predetermined threshold value).

[0024] FIG. 3 is a diagram showing an example of the configuration of the 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 side circuit 201, a secondary side circuit 202, a switching power supply transformer 203, and a switching element 204.

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

[0027] The transformer 203 for the switching power supply causes a current to flow through the secondary coil when the magnetic flux generated according to the current flowing through the primary coil penetrates 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 rectifies the voltage generated across the secondary coil by being turned on or off under the control of the gate drive circuit 501.

[0028] Note that the power supply circuit body 20 may be the same as the power supply circuit 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 isolated 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. Then, the series regulator 101 outputs the generated constant voltage to the isolated gate drive IC 102. The series regulator 101 includes 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 isolated gate drive IC 102 generates a gate drive signal for driving the switching element 204 from the voltage generated by the series regulator 101. Then, when the voltage VDD at the output of the VDD voltage generation circuit 103 exceeds a low input voltage protection threshold value described later, the isolated gate drive IC 102 outputs the generated gate drive signal to the switching element 204. The isolated gate drive 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 drive IC 102. The IN(-) terminal is a reference terminal serving as the reference potential of the isolated gate drive IC 102. The OUT terminal is an output terminal of the isolated gate drive IC 102. The VDD terminal is a terminal that plays a role in protecting the isolated gate drive IC 102 against low input voltages. That is, similar to the case of 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 corresponding one-to-one to the output voltage of the switching power supply 1 is less than a predetermined threshold value set at the VDD terminal), even if voltages are applied to the IN(+) and IN(-) terminals of the isolated gate drive IC 102, no voltage is output from the OUT terminal, and the switching element 204 is not driven. Also, when the output voltage of the switching power supply 1 is high (for example, when the voltage VDD is equal to or higher than the predetermined threshold value set at the VDD terminal), the isolated gate drive IC 102 outputs a voltage from the OUT terminal and drives the switching element 204. 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 the reference terminal serving 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 corresponding 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.Note that the isolated gate drive IC 102 may be the same as the isolated gate drive 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). Then, the VDD voltage generation circuit 103 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. Note that 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 isolated gate drive IC 102 and the switching element 204, and between the isolated gate drive IC 102 and the VDD voltage generation circuit 103. The gate drive signal control circuit 104 includes 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 isolated gate drive IC 102. The IN2 terminal is connected to the VDD terminal of the isolated 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] FIG. 4 is a diagram showing an example of the configuration of the gate drive signal control circuit 104 according to some embodiments of the present disclosure. Note that FIG. 4 also shows the series regulator 101, the isolated gate drive IC 102, the VDD voltage generation circuit 103, the switching power supply transformer 203, and the switching element 204.

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

[0036] As shown in FIG. 4, the first terminal of resistor 1041 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 second terminal of resistor 1041 is connected to the first terminal of resistor 1042 and the first terminal of transistor 1046 as shown in FIG. 4. The second terminal of resistor 1042 is connected to ground GND as shown in FIG. 4.

[0037] As shown in FIG. 4, the first terminal of resistor 1043 is connected to the first terminal of transistor 1045. The second terminal of resistor 1043 is connected to the second terminal of transistor 1046 as shown in FIG. 4.

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

[0039] As shown in FIG. 4, the third terminal of transistor 1045 is connected to the OUT terminal of the insulated gate drive IC 102. The third terminal of transistor 1046 is connected to ground GND as shown in FIG. 4.

[0040] (Operation of the Gate Drive Signal Control Circuit) Here, the operation of the gate drive signal control circuit 104 will be described. Here, it is assumed 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 the resistor 1041 and the resistance value of the resistor 1042 is applied to the base of the transistor 1046. When the voltage VDD corresponding one-to-one to the output voltage of the switching power supply 1 is 0 volts and the voltage VDD is 0 volts (i.e., the ground GND potential), since the base of the transistor 1046 is 0 volts, no current flows through the base of the transistor 1045. Therefore, the transistor 1045 is in the off state. That is, even when 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 corresponding voltage VDD rises from 0 volts and the voltage VDD becomes equal to or higher than the base-emitter voltage that turns on the transistor 1046, the transistor 1046 turns on. In this case, the transistor 1046 tries to flow a current from the collector to the emitter. As a result, a current flows from the base of the transistor 1045 through the resistor 1043 and from the collector to the emitter (i.e., the ground GND) of the transistor 1046.

[0043] Due to this current, the transistor 1045 turns on. 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 the voltage at each terminal of the isolated gate drive IC 102 included in the switching power supply 1 according to some embodiments of the present disclosure. The part (a) of FIG. 5 shows the voltage change of the IN(+) terminal of the isolated gate drive IC 102 over time. The part (b) of FIG. 5 shows the voltage change of the VDD terminal of the isolated gate drive IC 102 over time. The part (c) of FIG. 5 shows the voltage change of the OUT terminal of the isolated gate drive IC 102 over time. Note that the part (d) of FIG. 5 shows the voltage change at the gate of the switching element 204.

[0045] In the switching power supply 1, as shown in FIG. 5, even when the voltage VDD does not reach a predetermined threshold value (that is, the output voltage of the switching power supply 1 does not reach the startup voltage, which is a voltage at which the switching power supply 1 can be normally started), and a gate drive signal for driving the switching element 204 is output from the OUT terminal of the isolated gate drive IC 102, as described above, while the transistor 1045 is in the off state, the gate drive signal does not drive the switching element 204. Then, when the transistor 1045 becomes on, the gate drive signal is applied to the switching element 204.

[0046] The timing at which the transistor 1045 switches from the off state to the on state depends on the voltage division of the voltage VDD determined by the resistance value of the resistor 1041 and the resistance value of the resistor 1042, as can be understood from the above operation description. That is, by adjusting the resistance value of the resistor 1041 and the resistance value of the resistor 1042, the timing at which the transistor 1045 switches from the off state to the on state can be arbitrarily set. Each of the resistors 1043 and 1044 is an overcurrent protection resistor for preventing overcurrent.

[0047] The resistance value of resistor 1041 and the resistance value of resistor 1042 are adjusted such that, as shown in the part (d) of FIG. 5, after the voltage VDD exceeds the low input voltage protection threshold value (i.e., a predetermined threshold value), the gate drive signal is applied to the gate of the switching element 204. This prevents the switching element 204 from being driven by the gate drive signal when the voltage VDD has not reached the low input voltage protection threshold value (i.e., a predetermined threshold value) (i.e., the switching element 204 is driven by the gate drive signal after the voltage VDD reaches the predetermined threshold value).

[0048] As described above, the switching power supply 1 according to an embodiment of the present disclosure has been described. 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 the voltage VDD corresponding one-to-one to the output voltage of the isolated synchronous rectification type switching power supply 1 is equal to or lower than a predetermined threshold value, and connects the IN1 terminal and the OUT terminal when the voltage VDD exceeds the predetermined threshold value.

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

[0050] FIG. 6 is a diagram showing 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. The input terminal 301 receives a drive signal for driving the gate of a switching element. The output terminal 302 is connected to the gate. The switch 303 disconnects the input terminal 301 and the output terminal 302 when a voltage corresponding one-to-one to the output voltage of an isolated synchronous rectification type switching power supply is equal to or lower than a predetermined threshold, and connects the input terminal 301 and the output terminal 302 when the voltage corresponding one-to-one to the output voltage of the switching power supply exceeds the predetermined threshold.

[0051] The input terminal 301 can be realized by using, for example, 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 by using, for example, 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 by using, for example, the function of the transistor 1045 illustrated in FIG. 4.

[0052] FIG. 7 is a diagram showing an example of the 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. 7.

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

[0054] The driving signal control circuit 300 according to the present disclosure has been described above. By means of this driving signal control circuit 300, an isolated switching power supply can be protected.

[0055] Note that in the embodiments of the present disclosure, the order of the processes may be changed as long as appropriate processes are performed.

[0056] Although the embodiments of the present disclosure have been described, the above-described switching power supply 1 and other control devices may have a computer system inside. And the processes described above are stored in a computer-readable recording medium in the form of a program, and the above processes are performed by the computer reading and executing this program. Specific examples of the computer are shown below.

[0057] FIG. 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, each of the above-described switching power supply 1 and other control devices is implemented in the computer 5. And the operations of the above-described respective processing units are stored in the storage 8 in the form of a program. The CPU 6 reads the program from the storage 8, expands it in the main memory 7, and executes the above processes according to the program. Further, the CPU 6 secures in the main memory 7 storage areas corresponding to the above-described respective storage units according to the program.

[0059] Examples of the storage 8 include a HDD (Hard Disk Drive), an SSD (Solid State Drive), a magnetic disk, a magneto-optical disk, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), a semiconductor memory, and the like. The storage 8 may be an internal medium directly connected to the bus of the computer 5, or may be an external medium connected to the computer 5 via the interface 9 or a communication line. Further, when this program is distributed to the computer 5 via a communication line, the computer 5 that has received the distribution may expand the program in the main memory 7 and execute the above processing. In at least one embodiment, the storage 8 is a non-transitory tangible storage medium.

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

[0061] Although some embodiments of the present disclosure have been described, these embodiments are examples and do not limit the scope of the disclosure. These embodiments may be variously added, omitted, replaced, and changed without departing from the gist of the disclosure.

[0062] Note that some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto.

[0063] (Appended Claim 1) An input terminal to which a drive signal for driving the gate of the switching element is input, An output terminal connected to the gate, When the voltage corresponding one-to-one to the output voltage of the switching power supply of the isolated synchronous rectification method is below a predetermined threshold value, the input terminal and the output terminal are disconnected, and when the voltage corresponding one-to-one to the output voltage exceeds the predetermined threshold value, a switch for connecting the input terminal and the output terminal, A drive signal control circuit provided.

[0064] (Appendix 2) The switch is a first transistor, A second transistor for controlling the on state and the off state of the first transistor, The drive signal control circuit according to Appendix 1 provided with.

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

[0066] (Appendix 4) Voltage generation means for generating either the voltage for turning on the second transistor or the voltage for turning off the second transistor from the voltage corresponding one-to-one to the output voltage, The drive signal control circuit according to Appendix 3 provided with.

[0067] (Appendix 5) The voltage generation means, A first resistor and a second resistor, Provided with, By dividing the voltage corresponding one-to-one to the output voltage by the first resistor and the second resistor, the voltage for turning on the second transistor or the voltage for turning off the second transistor is generated, The drive signal control circuit according to Appendix 4.

[0068] (Appendix 6) Corresponding voltage generation means for generating a voltage corresponding one-to-one to the output voltage from the output voltage, The drive signal control circuit according to any one of Appendices 1 to 5, comprising

[0069] (Appendix 7) The drive signal control circuit according to any one of Appendices 1 to 6, and A gate drive circuit that outputs a drive signal for driving the gate of a switching element to an input terminal of the drive signal control circuit, and The switching element whose gate is connected to the output of the drive signal control circuit, and A switching power supply comprising

[0070] (Appendix 8) A processing method executed by a drive signal control circuit including an input terminal to which a drive signal for driving the gate of a switching element is input and an output terminal connected to the gate, the method comprising: When the voltage corresponding one-to-one to the output voltage of a switching power supply using an isolated synchronous rectification method is below a predetermined threshold, disconnecting the input terminal and the output terminal; and when the voltage corresponding one-to-one to the output voltage exceeds the predetermined threshold, connecting the input terminal and the output terminal. Processing method

[0071] (Appendix 9) The switch is a first transistor, and The drive signal control circuit A second transistor for controlling the on state and off state of the first transistor, and Comprising The processing method according to Appendix 8.

[0072] (Appendix 10) The second transistor Turns on the first transistor when in the on state and turns off the first transistor when in the off state. The processing method according to Appendix 9.

[0073] (Appendix 11) The drive signal control circuit Voltage generating means for generating, from a voltage corresponding one-to-one to the output voltage, either a voltage for turning on the second transistor or a voltage for turning off the second transistor comprising the processing method according to Supplementary Note 10

[0074] (Supplementary Note 12) The voltage generating means comprises a first resistor and a second resistor and generates, by voltage division of a voltage corresponding one-to-one to the output voltage by the first resistor and the second resistor, either a voltage for turning on the second transistor or a voltage for turning off the second transistor the processing method according to Supplementary Note 11

[0075] (Supplementary Note 13) The drive signal control circuit corresponding voltage generating means for generating, from the output voltage, a voltage corresponding one-to-one to the output voltage comprises the processing method according to any one of Supplementary Notes 8 to 12

Explanation of Reference Signs

[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 0>101... Series regulator 102... Isolated gate drive IC 103... VDD voltage generation circuit 104... Gate drive signal control circuit 201... Primary side circuit 202... Secondary side circuit 203... Transformer for switching power supply 204 ··· switching element 1041, 1042, 1043, 1044 ··· resistor 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 corresponding one-to-one to the output voltage of an isolated synchronous rectification type switching power supply is below 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, A drive signal control circuit comprising the same.

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

3. The second transistor, Turns on the first transistor in the on state and turns off the first transistor in the off state, The drive signal control circuit according to claim 2.

4. Voltage generation means for generating either a voltage for turning on the second transistor or a voltage for turning off the second transistor from a voltage corresponding one-to-one to the output voltage, The drive signal control circuit according to claim 3, comprising the same.

5. The voltage generation means, A first resistor and a second resistor, Comprising the same, Generates a voltage for turning on the second transistor or a voltage for turning off the second transistor by voltage division of a voltage corresponding 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. Corresponding voltage generation means for generating a voltage corresponding one-to-one to the output voltage from the output voltage, The drive signal control circuit according to claim 1, comprising the same.

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

8. A processing method executed by a drive signal control circuit comprising 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, When the voltage corresponding one-to-one to the output voltage of the switching power supply of the isolated synchronous rectification method is below a predetermined threshold, the input terminal and the output terminal are disconnected, and when the voltage corresponding one-to-one to the output voltage exceeds the predetermined threshold, the input terminal and the output terminal are connected. Processing method.

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