Control circuit, power supply system, and control method

Abstract

The embodiment of the invention provides a control circuit, a power supply system and a control method.The control circuit comprises a starting circuit, the starting circuit comprises a power resistor, a first switch and a first time delay circuit, one end of the power resistor is connected with the input end of the first switch, and the input end of the first switch is used for being connected with a power supply; the other end of the power resistor is connected with the output end of the first switch; the output end of the first time delay circuit is connected with the control end of the first switch, and the input end of the first time delay circuit is connected with the output end of the first switch; the slow starting circuit comprises a second switch and a second time delay circuit, the input end of the second switch is connected with the output end of the first switch, and the output end of the second switch is used for being connected with a load; the output end of the second time-delay circuit is connected with the control end of the second switch, and the input end of the second time-delay circuit is connected with the input end of the second switch. According to the invention, the effect of effectively suppressing the transient impact current is achieved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electronic circuits, and in particular, to a control circuit, a power supply system, and a control method. Background Art

[0002] In the related art, when the power supply equipment supplies power to the equipment, there will be transient impact current, which may easily cause damage to the equipment.

[0003] It can be seen from this that the related technology has the problem of being unable to suppress transient impact current.

[0004] Currently, no effective solution has been proposed for the above-mentioned problems existing in the related technologies. Summary of the invention

[0005] The embodiments of the present invention provide a control circuit, a power supply system and a control method, so as to at least solve the problem that the transient impact current cannot be suppressed in the related art.

[0006] According to one embodiment of the present invention, a control circuit is provided, comprising: a start-up circuit, the start-up circuit comprising a power resistor, a first switch and a first delay circuit, one end of the power resistor is connected to the input end of the first switch, and the input end of the first switch is used to connect to a power supply; the other end of the power resistor is connected to the output end of the first switch; the output end of the first delay circuit is connected to the control end of the first switch, and the input end of the first delay circuit is connected to the output end of the first switch; a slow start-up circuit, the slow start-up circuit comprising a second switch and a second delay circuit, the input end of the second switch is connected to the output end of the first switch, and the output end of the second switch is used to connect to a load; the output end of the second delay circuit is connected to the control end of the second switch, and the input end of the second delay circuit is connected to the input end of the second switch; wherein, when there is a voltage at the output end of the first switch, the first delay circuit sends a first conduction signal to the first switch, and the second delay circuit sends a second conduction signal to the second switch, and the time when the first delay circuit sends the first conduction signal is earlier than the time when the second delay circuit sends the second conduction signal.

[0007] According to another embodiment of the present invention, a power supply system is provided, including: a power supply and the control circuit described in the above embodiment, the output end of the power supply is connected to the input end of the first switch, the power supply is used to output a third voltage and a fourth voltage, and the third voltage is less than the fourth voltage.

[0008] According to another embodiment of the present invention, a control method is also provided, which is applied to the power supply system in the above embodiment, including: the power supply outputs current, wherein before the first switch is turned on, the power resistor suppresses the output current; when there is a voltage at the output end of the first switch, the first delay circuit sends a first turn-on signal to the first switch to turn on the first switch and transmit the output current through the first switch; when there is a voltage at the output end of the first switch, the second delay circuit sends a second turn-on signal to the second switch to turn on the second switch and supply power to the load through the second switch; wherein the time when the first delay circuit sends the first turn-on signal is earlier than the time when the second delay circuit sends the second turn-on signal.

[0009] Through the present invention, a control circuit is provided, in which a power resistor is connected in parallel with a first switch. When power is first supplied, current flows through the output end of the first switch through the power resistor. After a first time interval, the first delay circuit sends a first conduction signal to the first switch, and the first switch is turned on, thereby avoiding current flowing through the first switch at the moment of power supply, thereby preventing the first switch from being burned out. The second delay circuit can send a second conduction signal to the second switch after a second time interval. Since the first conduction signal is sent earlier than the second conduction signal, the second delay circuit is used to ensure that the load is powered after the first switch is turned on, thereby avoiding secondary impact current and protecting the safety of the circuit. Therefore, the problem of being unable to suppress transient impact current in the related art can be solved, and the effect of effectively suppressing transient impact current can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of the control circuit structure according to an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of a specific structure of a power supply system according to an embodiment of the present invention;

[0012] Figure 3 is a schematic diagram of a specific structure of a control circuit according to an embodiment of the present invention;

[0013] Figure 4 is a schematic diagram of a specific structure of a slow start circuit according to an embodiment of the present invention;

[0014] Figure 5 is a flow chart of a control method according to an embodiment of the present invention;

[0015] Figure 6 This is a control method according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in combination with the embodiments.

[0017] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0018] In this embodiment, a control circuit is provided. Figure 1 is a schematic diagram of the control circuit structure according to an embodiment of the present invention. Figure 1 As shown, the control circuit includes:

[0019] A start-up circuit 12, the start-up circuit comprising a power resistor, a first switch and a first delay circuit, one end of the power resistor is connected to the input end of the first switch, and the input end of the first switch is used to connect to a power supply; the other end of the power resistor is connected to the output end of the first switch; the output end of the first delay circuit is connected to the control end of the first switch, and the input end of the first delay circuit is connected to the output end of the first switch;

[0020] A slow start circuit 14, the slow start circuit comprising a second switch and a second delay circuit, the input end of the second switch is connected to the output end of the first switch, and the output end of the second switch is used to connect a load; the output end of the second delay circuit is connected to the control end of the second switch, and the input end of the second delay circuit is connected to the input end of the second switch;

[0021] When there is a voltage at the output end of the first switch, the first delay circuit sends a first turn-on signal to the first switch, and the second delay circuit sends a second turn-on signal to the second switch, and the first delay circuit sends the first turn-on signal earlier than the second delay circuit sends the second turn-on signal.

[0022] In the above embodiments, the control circuit can be applied in different power supply scenarios, for example, it can be applied in high voltage power supply scenarios, low voltage power supply scenarios, wide voltage power supply scenarios, etc. When the control circuit is applied in a wide voltage power supply scenario, it can be applied in rail trains, trolleybuses, etc. The power supply equipment can be an electrical cabinet in a rail train or a trolleybus, and the load can be a camera device, such as a monitoring device, a driving recorder, etc. The electrical cabinet can provide two power supply modes, high voltage power supply and low voltage power supply, such as providing a 110V voltage and providing a 48V voltage power supply. The control circuit can be applied in a power supply system, and the power supply system can include a power supply and a control circuit. The output end of the power supply is connected to the input end of the control circuit to provide power for the control circuit. The power supply can be a power supply device such as an electrical cabinet, that is, the power supply can provide two power supply modes, high voltage power supply and low voltage power supply.

[0023] In the above embodiments, the power supply and the control circuit may also be connected through a protection circuit, such as the output end of the power supply is connected to the input end of the protection circuit, and the output end of the protection circuit is connected to the input end of the control circuit. The protection circuit may include a circuit breaker open circuit system and an input protection system. The input protection system may include a fuse, a varistor, etc. The output end of the power supply may be connected to one or more of the circuit breaker open circuit system and the input protection system. When multiple are connected, the output end of the power supply is connected to the circuit breaker open circuit system and the input protection system in sequence.

[0024] The specific structural diagram of the power supply system can be found in the attached Figure 2 ,like Figure 2 As shown, the power supply system may include a power supply system cabinet, a circuit breaker system, an input protection system, and a control circuit. Among them, the control circuit may include a slow start control system (including a slow start control system constructed by power resistors to suppress impact current and PMOS tube discrete devices), a wide input voltage power supply system (such as an isolated power supply), a +12V output slow start control system (i.e., a slow start circuit), and a DC12V output DSP (digital signal processing technology) power supply system. The +12V output slow start control system can control the DC12V output DSP power supply system to supply power to the subsequent stage after the PMOS in the slow start control system is turned on.

[0025] In the above embodiment, the specific structural diagram of the control circuit can be found in the attached Figure 3 ,like Figure 3 As shown, the start-up circuit can be a MOS tube slow start control circuit. The input end of the start-up circuit can be connected to the output end of the power supply system cabinet, for example, to the output end of the electrical cabinet, and the electrical cabinet supplies power to the load through the control circuit. Of course, the power supply system cabinet can also be connected to the control circuit through an input protection circuit.

[0026] In the above embodiment, the first switch may be a field effect transistor switch, an electromagnetic relay, etc. When the first switch is a field effect transistor switch, the first switch may be a PMOS transistor. When the first switch is a PMOS transistor, continue to refer to the attached Figure 3 , the input end of the start-up circuit can be connected to the input end of the first switch D1, and can also be connected to one end of the power resistor, and the other end of the power resistor is connected to the output end of the first switch, that is, the power resistor is connected in parallel with the first switch. The power resistor can suppress transient impact current. If the power resistor is not set, the first switch PMOS tube is directly turned on when the high voltage is input, and the voltage across Vds of the first switch PMOS tube (that is, the voltage across the drain and the source) is close to the input voltage. At this time, the voltage is very easy to exceed the SOA (Safe Operating Area curve) curve range of the PMOS tube, and the PMOS tube is burned and damaged. Therefore, a power resistor can be used in parallel with the first switch. After the power resistor is turned on, when the voltage across Vds is close to 0V, the PMOS tube is turned on to prevent burning. After only using the power resistor to suppress transient impact current, the power resistor will limit the maximum current of the load device for normal operation. When the load device is short-circuited, the input protection system fuse and the like lose their function. The load device may catch fire for a long time, causing serious losses. In addition, when the load device consumes a large amount of power, the power resistor heats up seriously and the voltage drop is large. The minimum input voltage of the power supply system cabinet is lower than the converter input voltage of the isolated power supply, so that the isolated power supply cannot start working. Therefore, a power resistor is connected in parallel with the first switch. After the power resistor suppresses the transient impact current, the first switch is turned on, and the PMOS tube is used to slowly start the control system circuit to bypass the power resistor, that is, short-circuit. When the subsequent load is short-circuited, the fuse of the input protection system blows, which can effectively protect the load equipment.

[0027] In the above embodiment, the first delay circuit may be a circuit including an RC resistor and capacitor circuit, or may be a delay circuit including a field effect transistor. When the first delay circuit is a delay circuit including a field effect transistor, the field effect transistor may be an NMOS transistor. Figure 3 , the first delay circuit may be a circuit including an NMOS tube D3 in a MOS tube slow start control circuit. The input end of the first switch may be the 3 end of the PMOS tube D1, that is, the S pole (source). The output end of the first switch may be the 4 end of the PMOS tube D1, that is, the D pole (drain). The control end of the first switch may be the 1 end of the PMOS tube D1, that is, the G pole (gate). The output end of the first delay circuit may be the 4 end of the NMOS tube D3, that is, the D pole. The input end of the first delay circuit may be the 3 end of the NMOS tube D3, that is, the S pole.

[0028] In the above embodiment, the second switch included in the slow start circuit can be a field effect transistor switch, an electromagnetic relay, etc. The second delay circuit can be a circuit including an RC (resistance and capacitance) circuit, and can also be a delay circuit including a field effect transistor. When the second switch is a field effect transistor switch, the second switch can be a PMOS transistor. When the second switch is a field effect transistor switch, the specific structural diagram of the slow start circuit can be found in the attached Figure 4 ,like Figure 4 As shown, the second switch may be a PMOS tube D2, and the second delay circuit may be a circuit including an NMOS tube D4. The input end of the second switch may be the 3 end of the PMOS tube D2, that is, the S pole, the output end of the second switch may be the 4 end of the PMOS tube D3, that is, the D pole, and the control end of the second switch may be the 1 end of the PMOS tube D2, that is, the G pole. The output end of the second delay circuit may be the 3 end of the NMOS tube D4, that is, the D pole, and the input end of the second delay circuit may be the 1 end of the NMOS tube D4, that is, the G pole.

[0029] In the above embodiment, when the voltage at the output end of the first switch is the first voltage, the first delay circuit starts delaying, and after the delay ends, the first delay circuit sends a first conduction signal to the first switch, and the first conduction signal is turned on. When the voltage at the output end of the first switch is the first voltage, the second delay circuit starts delaying, and after the delay ends, the second delay circuit sends a second conduction signal to the second switch. The first delay circuit sends the first conduction signal earlier than the second delay circuit sends the second conduction signal, so as to ensure that the first switch is turned on before power is supplied to the load to prevent current from impacting the circuit.

[0030] In the above embodiment, the first delay circuit and the second delay circuit can be delayed by a timer, and the delay time set by the timer in the first delay circuit can be set to be smaller than the delay time set by the timer in the second delay circuit. The first delay circuit and the second delay circuit can also be delayed by an RC circuit, and the resistance value of the resistor in the first delay circuit can be set to be smaller than the resistance value of the resistor in the second delay circuit, and the capacitance value in the first delay circuit can be set to be smaller than the capacitance value in the second delay circuit.

[0031] Through the present invention, a control circuit is provided, in which a power resistor is connected in parallel with a first switch. When power is first supplied, current flows through the output end of the first switch through the power resistor. After a first time interval, the first delay circuit sends a first conduction signal to the first switch, and the first switch is turned on, thereby avoiding current flowing through the first switch at the moment of power supply, thereby preventing the first switch from being burned out. The second delay circuit can send a second conduction signal to the second switch after a second time interval. Since the first conduction signal is sent earlier than the second conduction signal, the second delay circuit is used to ensure that the load is powered after the first switch is turned on, thereby avoiding secondary impact current and protecting the safety of the circuit. Therefore, the problem of being unable to suppress transient impact current in the related art can be solved, and the effect of effectively suppressing transient impact current can be achieved.

[0032] In an exemplary embodiment, the control circuit further includes an isolated power supply, wherein the isolated power supply includes an auxiliary winding; the input end of the isolated power supply is connected to the output end of the first switch, the control end of the isolated power supply is connected to the output end of the auxiliary winding, and the control end of the isolated power supply is also connected to the control end of the first delay circuit, the control end of the isolated power supply is used to obtain an electrical signal from the auxiliary winding, and send a control signal to the first delay circuit to turn on the first delay circuit, wherein the first delay circuit is used to send the first turn-on signal after being turned on; the output end of the isolated power supply is connected to the input end of the second switch; the isolated power supply is used to output a first duty cycle when the voltage received at the input end of the isolated power supply is a first voltage, so that the voltage output by the control end of the isolated power supply is a target voltage; when the voltage received at the input end of the isolated power supply is a second voltage, the isolated power supply is used to output a second duty cycle, so that the voltage output by the control end of the isolated power supply is the target voltage. In this embodiment, continue to refer to the attached Figure 3 The control circuit may further include an isolated power supply, i.e., a DC / DC isolated power supply system. The output end of the first switch may be connected to the input end of the isolated power supply, and the isolated power supply may include an auxiliary winding (not shown in the figure), which may be a transformer auxiliary winding power supply. The output end of the auxiliary winding may be connected to the control end of the isolated power supply, and the control end of the isolated power supply may also be connected to the control end of the first delay circuit, i.e., connected to the 1 end of the NMOS tube D3.

[0033] In the above embodiment, the power supply can be a wide voltage output. When the power supply outputs a high voltage, the voltage received at the input end of the isolated power supply can be a first voltage. When the power supply outputs a low voltage, the voltage received at the input end of the isolated power supply can be a second power supply. The isolated power supply can also include a power chip (not shown in the figure). When the voltage received at the input end of the isolated power supply is the first voltage, the power chip outputs a first duty cycle, and the voltage obtained by the control end of the isolated power supply from the output end of the auxiliary winding is the target voltage. When the voltage received at the input end of the isolated power supply is the second voltage, the power chip outputs a second duty cycle, and the voltage obtained by the control end of the isolated power supply from the output end of the auxiliary winding is the target voltage. Among them, the target voltage can be expressed as Vout=PWM×Vin, PWM represents the duty cycle, and Vin represents the voltage received at the input end of the isolated power supply.

[0034] In the above embodiment, the isolated power supply can send a control signal to the control end of the first delay circuit through the control end, and the first delay circuit can be turned on under the action of the control signal. After being turned on, the first delay circuit can send a first turn-on signal to the first switch to turn on the first switch. After the first switch is turned on, the power resistor is short-circuited, and the current output by the power supply can be transmitted to the next stage through the first switch. Among them, when the isolated power supply is directly connected to the first delay circuit, the control signal is the electrical signal obtained from the auxiliary winding, and the voltage of the control signal is the target voltage.

[0035] In the above embodiment, the isolated power supply can be an isolated DC / DC converter. When voltage is input to the isolated power supply, the electrolytic capacitor in the isolated power supply starts to charge. After charging is completed, a signal is sent from the control end to output a normal voltage. From the time the electrolytic capacitor is charged to the normal working output voltage of the isolated power supply, the impact current is suppressed by the power resistor. After the isolated power supply outputs the voltage normally, a control signal is sent to control the first delay circuit to turn on the first switch PMOS tube D1. After the first switch is turned on, the power resistor is short-circuited, and the current output by the power supply can be transmitted to the next stage through the first switch. Please refer to the attached Figure 4 The input end of the slow start circuit can be connected to the output end of the isolated power supply. After the first switch is turned on, the second delay circuit controls the second switch to be turned on, and the current output from the output end of the isolated power supply supplies power to the load device through the second switch PMOS tube D2.

[0036] In an exemplary embodiment, the control circuit further includes an output power supply, the input end of the output power supply is connected to the control end of the isolated power supply, and the output power supply is used to process the electrical signal received from the isolated power supply to obtain and output the control signal. Figure 3The isolated power supply can be indirectly connected to the first delay circuit through the output power supply. The output power supply can filter and rectify the electrical signal output by the isolated power supply to obtain and output the control signal.

[0037] In an exemplary embodiment, the output power supply includes: a first diode, a first capacitor, and a second capacitor; the anode of the first diode is connected to the control terminal of the isolation power supply, and the cathode of the first diode is connected to the control terminal of the first delay circuit; the first end of the first capacitor and the first end of the second capacitor are both connected to the cathode of the first diode, and the second end of the first capacitor and the second end of the second capacitor are grounded. In this embodiment, continue to refer to the attached Figure 3 The first diode may be a rectifier diode D5, the positive electrode of the rectifier diode D5 is connected to the control end of the isolated power supply, the first capacitor C1 is connected in parallel with the second capacitor C2, and the first end of the first capacitor C1 and the first end of the second capacitor C2 are both connected to the negative electrode of the rectifier diode D5. The second end of the first capacitor C1 and the second end of the second capacitor C2 are grounded. Through the rectifier diode D5 and the first capacitor C1 and the second capacitor C2, the electrical signal sent by the isolated power supply is rectified and filtered to output a stable control signal.

[0038] In the above embodiment, the output power supply may further include a ninth resistor R9. The ninth resistor R9 may be connected between the cathode of the rectifier diode and the first end of the first capacitor to play the role of a cross-line.

[0039] In the above embodiment, the isolated power supply can be an isolated DC / DC converter. When voltage is input to the isolated power supply, the electrolytic capacitor in the isolated power supply starts to charge. After charging is completed, a signal is sent from the control end to output a normal voltage. During the period from the electrolytic capacitor charging to the normal working output voltage of the isolated power supply, the impact current is suppressed by the power resistor. After the isolated power supply outputs the voltage normally, the voltage output by the output power supply is used as a control signal to control the conduction of the PMOS tube D1, and the power supply starts to supply power to the load device through the PMOS tube D1.

[0040] In the above embodiment, the auxiliary winding voltage of the isolated power supply is cleverly used to power the NMOS tube D3, without the need to increase the auxiliary power supply voltage; the GND is shared with the primary side, and no isolation chip is required, which is simple and low-cost.

[0041] In an exemplary embodiment, the first delay circuit includes: a third switch, the output end of the third switch is connected to the control end of the first switch, the input end of the third switch is connected to the output end of the first switch, and the control end of the third switch is connected to the control end of the isolated power supply; a first resistor, the first end of the first resistor is connected to the control end of the isolated power supply, and the second end of the first resistor is grounded; a third capacitor, the third capacitor is connected in parallel with the first resistor; a second resistor, the first end of the second resistor is connected to the control end of the isolated power supply, and the second end of the second resistor is connected to the first end of the first resistor. In this embodiment, continue to refer to the attached Figure 3 , the third switch can be an NMOS tube D3 included in the MOS tube slow start control circuit, the output end of the third switch, that is, the D pole of the NMOS tube D3, is connected to the G pole of the first switch PMOS tube D1, and the input end of the third switch, that is, the S pole of the NMOS tube D3, can be connected to the D pole of the first switch PMOS tube D1. The control end of the third switch, that is, the G pole of the NMOS tube D3, can be connected to the control end of the isolated power supply. When the control circuit includes an output power supply, the control end of the third switch, that is, the G pole of the NMOS tube D3, can be connected to the output end of the output power supply. When the output power supply includes a ninth resistor R9, the G pole of the NMOS tube D3 can be connected to the second end of R9. When the output power supply only includes a rectifier diode D5, a first capacitor and a second capacitor, the G pole of the NMOS tube D3 can be connected to the first end of the second capacitor.

[0042] In the above embodiment, see the attached Figure 3 The first delay circuit also includes a third capacitor C3, a first resistor R1 and a second resistor R2. The first resistor R1 is connected in parallel with the third capacitor C3. The first ends of the first resistor R1 and the third capacitor C3 are both connected to the control end of the third switch. The second ends of the first resistor R1 and the third capacitor C3 are both connected to the input end of the third switch and are grounded. Through the first resistor R1 and the third capacitor C3, the delayed sending of the first conduction signal can be achieved to achieve the purpose of delay.

[0043] In the above embodiment, see the attached Figure 3 The first end of the first resistor R1 and the first end of the third capacitor C3 can be connected to the output end of the output power supply through the second resistor R2 to play a role in protecting the circuit.

[0044] In the above embodiment, the control signal of the third switch NMOS tube D3 is powered, and the power is taken from the auxiliary winding, rectified by the first diode and filtered by the capacitor, and charged by the RC on the third switch NMOS tube D3 to turn on the third switch NMOS tube D3. Adjusting R and C can control the turn-on time of the third switch NMOS tube D3, thereby controlling the turn-on time of the first switch PMOS tube D1. It is ensured that regardless of low input voltage or high input voltage, the slow start turn-on time of the first switch PMOS tube D1 is basically the same, and there will be no large secondary transient impact current and tube burning risk. Avoid the risk of secondary transient impact current and tube burning caused by different turn-on times of PMOS due to the high and low voltage of the wide voltage input.

[0045] In the above embodiment, the startup circuit may further include a tenth resistor, and the output end of the third switch NMOS tube D3 may be connected to the control end of the first switch PMOS tube through the tenth resistor R10 to play a role in protecting the circuit.

[0046] In an exemplary embodiment, the control circuit further includes: a second diode, the cathode of the second diode is connected to the input end of the first switch, and the anode of the second diode is connected to the control end of the first switch; a third resistor, the third resistor is connected in parallel with the second diode; a fourth capacitor, the first end of the fourth capacitor is connected to the control end of the first switch; a fourth resistor, the first end of the fourth resistor is connected to the second end of the fourth capacitor, and the second end of the fourth resistor is connected to the output end of the first switch. In this embodiment, continue to refer to the attached Figure 3 , the second diode may be a voltage-stabilizing diode D6, the third resistor R3 is connected in parallel with the voltage-stabilizing diode D6, the anode of the voltage-stabilizing diode D6 is connected to the G pole of the first switch PMOS tube D1, the cathode of the voltage-stabilizing diode D6 is connected to the S pole of the input terminal of the first switch PMOS tube D1, the first end of the third resistor R3 is connected to the S pole of the input terminal of the first switch PMOS tube D1, and the second end of the third resistor R3 is connected to the G pole of the first switch PMOS tube D1. The first end of the fourth capacitor C4 may be connected to the G pole of the first switch PMOS tube D1, the second end of the fourth capacitor C4 may be connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the D pole of the output terminal of the first switch PMOS tube D1. The fourth resistor R4 and the fourth capacitor C4 may prevent the first switch from oscillating.

[0047] In the above embodiment, the voltage input into the MOS tube slow start control circuit can be an ultra-wide voltage. When a low voltage is input, the voltage can be divided by a power resistor first, and then the first switch PMOS tube D1 is turned on. When a high voltage is input, a TVS voltage regulator tube, i.e., a second diode, can be connected across the S pole and the G pole of the first switch PMOS tube D1 to clamp its VGS within the normal working range of the first switch PMOS tube D1 to prevent the VGS from being broken down under high voltage and burning the first switch PMOS tube D1. That is, the voltage regulator diode can prevent the first switch from being broken down when a high voltage is input. The third resistor can play a role in voltage division.

[0048] In an exemplary embodiment, the control circuit further includes: a suppression circuit, wherein the suppression circuit is used to suppress interference signals emitted by the isolated power supply, the first end of the suppression circuit is connected to the output end of the first switch, the second end of the suppression circuit is grounded, the third end of the suppression circuit is connected to the power ground end of the isolated power supply, and the fourth end of the suppression circuit is connected to the input end of the isolated power supply. In this embodiment, the suppression circuit can suppress interference signals emitted by the isolated power supply to achieve electromagnetic compatibility. The two inductors included in the suppression circuit are coupled inductors. The first end can be connected to the output end of the first switch, the second end is grounded, the third end is connected to the input end of the isolated power supply, and the fourth end is connected to the power ground end of the isolated power supply. Among them, the first end and the second end can be the two ends of an inductor, and the third end and the fourth end can be the two ends of another capacitor.

[0049] In an exemplary embodiment, the suppression circuit includes: a fifth capacitor, a first end of the fifth capacitor is connected to the output end of the first switch, and a second end of the fifth capacitor is grounded; a sixth capacitor, a first end of the sixth capacitor is connected to the input end of the isolated power supply, a second end of the sixth capacitor is connected to the power ground end of the isolated power supply, and the power ground end of the isolated power supply is grounded; a filter inductor, a first end of the filter inductor is connected to the first end of the fifth capacitor; a second end of the filter inductor is grounded, a third end of the filter inductor is connected to the second end of the sixth capacitor, and a fourth end of the filter inductor is connected to the input end of the isolated power supply. In this embodiment, continue to refer to the attached Figure 3The suppression circuit may include a fifth capacitor C5, a sixth capacitor C6, and a filter inductor. The filter inductor includes a first inductor and a second inductor coupled to each other, a first end of the first inductor is connected to a first end of the fifth capacitor C5, a second end of the first inductor is connected to a second end of the fifth capacitor C5, a first end of the fifth capacitor C5 is connected to an output end of the first switch, and a second end of the fifth capacitor C5 is grounded. A first end of the second inductor is connected to a first end of the sixth capacitor C6, a second end of the second inductor is connected to a second end of the sixth capacitor C6, a first end of the sixth capacitor C6 is connected to an input end of the isolated power supply, and the other end of the sixth capacitor C6 is connected to a power ground PGND end of the isolated power supply.

[0050] In an exemplary embodiment, the second delay circuit includes: a fourth switch, a first end of the fourth switch is connected to the output end of the isolated power supply, a second end of the fourth switch is grounded, and a third end of the fourth switch is connected to the control end of the second switch, for sending the second conduction signal to the control end of the second switch; a fifth resistor, a first end of the fifth resistor is connected to the first end of the fourth switch, and a second end of the fifth resistor is grounded; a seventh capacitor, the seventh capacitor is connected in parallel with the fifth resistor; a sixth resistor, a first end of the sixth resistor is connected to the output end of the isolated power supply, and a second end of the sixth resistor is connected to the first end of the fifth resistor. In this embodiment, continue to refer to the attached Figure 4 The fourth switch may be an NMOS tube D4, the first end of the fourth switch may be the 1 end of the NMOS tube D4, that is, the G pole, the second end of the fourth switch may be the 2 end of the NMOS tube D4, that is, the S pole, and the third end of the fourth switch may be the 3 end of the NMOS tube D4, that is, the D pole. The first end of the fourth switch is connected to the output end of the isolated power supply, the second end of the fourth switch is grounded, and the third end of the fourth switch is connected to the control end of the second switch, that is, the G pole of the PMOS tube D2. After the fourth switch is turned on, a second turn-on signal is sent to the G pole of the PMOS tube D2 to turn on the second switch to supply power to the load.

[0051] In the above embodiment, see the attached Figure 4 The second delay circuit also includes a seventh capacitor C7 and a fifth resistor R5. The fifth resistor R5 is connected in parallel with the seventh capacitor C7. The first ends of the fifth resistor R5 and the seventh capacitor C7 are both connected to the first end of the fourth switch. The second ends of the fifth resistor R5 and the seventh capacitor C7 are both connected to the second end of the fourth switch and are grounded. Through the fifth resistor R5 and the seventh capacitor C7, the delayed sending of the second conduction signal can be achieved to achieve the purpose of delay.

[0052] In the above embodiment, the second delay circuit may further include a sixth resistor R6, a first end of the sixth resistor R6 is connected to the output end of the isolation power supply, and a second end of the sixth resistor R6 is connected to the first end of the fifth resistor, to play a role of voltage division.

[0053] In the above embodiment, the resistance of the fifth resistor R5 is greater than that of the first resistor R1. The capacitance of the seventh capacitor C1 is greater than that of the third capacitor C3, so that the sending time of the second conduction signal is later than the sending time of the first conduction signal.

[0054] In the above embodiment, if the first switch PMOS tube D1 is not turned on, the isolated power supply directly supplies power to the load device, and the entire circuit may be in a heavy load state. At this time, a large current will flow through the power resistor, thereby forming a large voltage drop Vr. When the first switch PMOS tube D1 is turned on, Vds=Vr, Ids=Vds / Rds (on), and a high secondary impact current will also be formed. A slow start circuit is added. Before the first switch PMOS tube D1 is turned on, the second switch PMOS tube D2 is not turned on, and the load device is not powered. The entire circuit is in a light load state. At this time, the input current is almost 0, and the power resistor voltage drop Vr is about 0V. At this time, when the first switch PMOS tube D1 is turned on, Vds≈0V, and the potential at both ends is equal, and there will be no secondary impact current. By adjusting R and C, a controllable delay time can be set, so that before the first switch PMOS tube D1 is turned on, the second switch PMOS tube D2 is not turned on to work, which effectively prevents the secondary impact current.

[0055] In an exemplary embodiment, the slow start circuit further includes: an eighth capacitor, a first end of the eighth capacitor is connected to the output end of the isolated power supply, a second end of the eighth capacitor is connected to the third end of the fourth switch; and a seventh resistor, the seventh resistor is connected in parallel with the eighth capacitor. Figure 4 The slow start circuit may further include an eighth capacitor C8 and a seventh resistor R7. The eighth capacitor C8 is connected in parallel with the seventh resistor R7 to perform a start delay function.

[0056] In the above embodiment, the slow start circuit may further include an eleventh resistor R11 , and the third end of the fourth switch may be connected to the control end of the second switch through the eleventh resistor R11 .

[0057] In an exemplary embodiment, the slow start circuit further includes: an eighth resistor and a ninth capacitor; the first end of the eighth resistor is connected to the control end of the second switch, the second end of the eighth resistor is connected to the first end of the ninth capacitor, and the second end of the ninth capacitor is connected to the output end of the second switch. Figure 4 The slow start circuit may further include an eighth resistor R8 and a ninth capacitor C9. The eighth resistor R8 and the ninth capacitor C9 are connected in series and connected between the control end and the output end of the second switch to prevent the second switch from oscillating.

[0058] In the aforementioned embodiment, power is taken from the auxiliary winding of the transformer of the isolation power supply as the input of the first delay circuit, and a control signal is input to the third switch NMOS tube D3. After signal processing, perfect switching of the power resistor and the PMOS tube is achieved, transient impact current is suppressed, and tripping caused by excessive impact current when the circuit breaker is open is prevented. The auxiliary winding of the transformer is used to take power as a slow start control signal, and the first switch PMOS tube D1 is slowly opened after the isolation power supply works, ensuring that the slow start time under low voltage and high voltage is basically the same, and does not exceed the SOA curve of the MOS tube, avoiding transient impact current and the risk of burning the tube. In addition, the auxiliary winding of the transformer is used to take power as a slow start control signal, and no additional auxiliary power supply is required, the periphery is simple and the cost is low.

[0059] In the aforementioned embodiment, an output slow-start circuit is added after the isolated power supply, so that before the input first switch PMOS tube D1 is turned on, the second switch PMOS tube D2 is not turned on to work, so as to prevent the risk of forming a higher secondary impact current under heavy load conditions. When the control circuit is just powered on, the first switch PMOS tube D1 is not turned on, and the transient impact current is limited by the power resistor. When the isolated power supply starts to work, the voltage output by the auxiliary winding of the transformer is rectified and filtered, and then a fixed target voltage is output as a control signal, and the slow-start circuit is temporarily not turned on to supply power to the load. Finally, the control signal first starts to slowly turn on the first switch PMOS tube D1, and then the slow-start circuit is turned on to supply power to the load. This prevents the power supply from directly supplying power to the load device when the first switch PMOS tube D1 is not turned on, and a higher secondary impact current is formed after the first switch PMOS tube D1 is turned on under heavy load conditions.

[0060] In the aforementioned embodiment, transistors may be used for the first switch, the second switch, the third switch, and the fourth switch. Transistors are used as a slow start circuit to avoid the risk of sparking at the relay switch contacts.

[0061] The present embodiment provides a power supply system, comprising a power supply and a control circuit as in any of the above embodiments, wherein the power supply is used to output a third voltage and a fourth voltage, wherein the third voltage is less than the fourth voltage. The power supply is connected to an input end of a first switch in the control circuit to provide power to the control circuit.

[0062] In an exemplary embodiment, a protection circuit may be connected between the power supply and the input end of the first switch in the control circuit. The protection circuit may include a circuit breaker system and an input protection system. The input protection system may include a fuse and a varistor.

[0063] This embodiment also provides a control method, which is applied to the power supply system in any of the above embodiments. Figure 5 is a flow chart of a control method according to an embodiment of the present invention. Figure 5As shown, the process includes:

[0064] Step S502, the power supply outputs a current, wherein before the first switch is turned on, the power resistor suppresses the output current;

[0065] Step S504: when there is a voltage at the output end of the first switch, the first delay circuit sends a first turn-on signal to the first switch to turn on the first switch, and transmit the output current through the first switch;

[0066] Step S506: when there is a voltage at the output end of the first switch, the second delay circuit sends a second turn-on signal to the second switch to turn on the second switch, and supply power to the load through the second switch;

[0067] The first delay circuit sends the first conduction signal earlier than the second delay circuit sends the second conduction signal.

[0068] In this embodiment, the power supply starts to supply power to the control circuit. When the control circuit is just powered on, the first switch PMOS tube D1 is not turned on, and the transient impact current is limited by the power resistor. After the delay time ends, the first delay circuit sends a first conduction signal to the first switch to turn on the first switch, and the current is transmitted through the first switch in the circuit. In this process, after the delay time ends, the second delay circuit sends a second conduction signal to the second switch to turn on the second switch to supply power to the load.

[0069] In the above embodiment, when the control circuit includes an isolated power supply and an output power supply, the isolated power supply starts to work, and the voltage output by the auxiliary winding of the transformer in the isolated power supply is rectified and filtered by the output power supply to output a fixed target voltage as a control signal, and the slow start circuit does not start to supply power to the load temporarily. Finally, the control signal first starts to slowly turn on the first switch PMOS tube D1, and then the slow start circuit turns on to supply power to the load. This prevents the power supply from directly supplying power to the load device when the first switch PMOS tube D1 is not turned on, and a higher secondary impact current is formed when the first switch PMOS tube D1 is turned on in a heavy load state.

[0070] In an exemplary embodiment, sending a first turn-on signal to the first switch includes: the control end of the isolated power supply obtains an electrical signal from an auxiliary winding included in the isolated power supply; the isolated power supply sends a control signal to the first delay circuit to turn on the first delay circuit; and the first delay circuit sends the first turn-on signal to the first switch after being turned on. In this embodiment, the control end of the isolated power supply can obtain an electrical signal from the auxiliary winding of the isolated power supply, and after obtaining the electrical signal, send a control signal to the first delay circuit, the first delay circuit is turned on under the action of the control signal, and after being turned on, sends a first turn-on signal to the first switch to turn on the first switch, and supply power to the next stage through the first switch.

[0071] Figure 6 is a control method according to a specific embodiment of the present invention, such as Figure 6 As shown, the method includes:

[0072] Step S600: power on the circuit breaker.

[0073] Step S602: The power resistor suppresses the inrush current.

[0074] Step S604, determining whether the isolated power supply starts to work, if the determination result is yes, executing step S606, if the determination result is no, executing step S602.

[0075] Step S606, auxiliary winding output, secondary winding output, rectification and filtering.

[0076] Step S608 , inputting a soft start auxiliary winding control signal to turn on the input PMOS tube, namely, the first switch PMOS tube D1 .

[0077] Step S610, the output slow start turns on the output PMOS tube, that is, the second switch PMOS tube D2, and the secondary winding power supply output supplies power to the subsequent load.

[0078] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0079] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control circuit, characterized in that: include: A start-up circuit, the start-up circuit comprising a power resistor, a first switch and a first delay circuit, one end of the power resistor is connected to an input end of the first switch, and the input end of the first switch is used to connect to a power supply; the other end of the power resistor is connected to an output end of the first switch; the output end of the first delay circuit is connected to a control end of the first switch, and the input end of the first delay circuit is connected to an output end of the first switch; A slow start circuit, the slow start circuit comprising a second switch and a second delay circuit, the input end of the second switch is connected to the output end of the first switch, and the output end of the second switch is used to connect a load; the output end of the second delay circuit is connected to the control end of the second switch, and the input end of the second delay circuit is connected to the input end of the second switch; When there is a voltage at the output end of the first switch, the first delay circuit sends a first turn-on signal to the first switch, and the second delay circuit sends a second turn-on signal to the second switch, and the first delay circuit sends the first turn-on signal earlier than the second delay circuit sends the second turn-on signal.

2. The control circuit according to claim 1, characterized in that: The control circuit also includes an isolated power supply, wherein: The isolated power supply includes an auxiliary winding; The input end of the isolated power supply is connected to the output end of the first switch, the control end of the isolated power supply is connected to the output end of the auxiliary winding, and the control end of the isolated power supply is also connected to the control end of the first delay circuit. The control end of the isolated power supply is used to obtain an electrical signal from the auxiliary winding and send a control signal to the first delay circuit to turn on the first delay circuit, wherein the first delay circuit is used to send the first turn-on signal after being turned on; The output end of the isolated power supply is connected to the input end of the second switch; The isolated power supply is used to output a first duty cycle when the voltage received at the input end of the isolated power supply is a first voltage, so that the voltage output by the control end of the isolated power supply is a target voltage; and to output a second duty cycle when the voltage received at the input end of the isolated power supply is a second voltage, so that the voltage output by the control end of the isolated power supply is the target voltage.

3. The control circuit according to claim 2, characterized in that: The control circuit also includes an output power supply, the input end of the output power supply is connected to the control end of the isolated power supply, and the output power supply is used to process the electrical signal received from the isolated power supply to obtain and output the control signal.

4. The control circuit according to claim 3, characterized in that: The output power supply includes: a first diode, a first capacitor, and a second capacitor; The positive electrode of the first diode is connected to the control end of the isolation power supply, and the negative electrode of the first diode is connected to the control end of the first delay circuit; the first end of the first capacitor and the first end of the second capacitor are both connected to the negative electrode of the first diode, and the second end of the first capacitor and the second end of the second capacitor are grounded.

5. The control circuit according to claim 2, characterized in that: The first delay circuit comprises: a third switch, wherein an output end of the third switch is connected to a control end of the first switch, an input end of the third switch is connected to an output end of the first switch, and a control end of the third switch is connected to a control end of the isolated power supply; A first resistor, wherein a first end of the first resistor is connected to the control end of the isolated power supply, and a second end of the first resistor is grounded; a third capacitor, the third capacitor being connected in parallel with the first resistor; A second resistor, wherein a first end of the second resistor is connected to the control end of the isolated power supply, and a second end of the second resistor is connected to the first end of the first resistor.

6. The control circuit according to claim 1, characterized in that: The control circuit further comprises: a second diode, wherein a cathode of the second diode is connected to the input end of the first switch, and an anode of the second diode is connected to the control end of the first switch; a third resistor, the third resistor being connected in parallel with the second diode; a fourth capacitor, a first end of the fourth capacitor being connected to the control end of the first switch; a fourth resistor, wherein a first end of the fourth resistor is connected to a second end of the fourth capacitor, and a second end of the fourth resistor is connected to an output end of the first switch.

7. The control circuit according to claim 2, characterized in that: The control circuit also includes: a suppression circuit, wherein the suppression circuit is used to suppress the interference signal emitted by the isolated power supply, a first end of the suppression circuit is connected to the output end of the first switch, a second end of the suppression circuit is grounded, a third end of the suppression circuit is connected to the power ground end of the isolated power supply, and a fourth end of the suppression circuit is connected to the input end of the isolated power supply.

8. The control circuit according to claim 7, characterized in that: The suppression circuit comprises: a fifth capacitor, wherein a first end of the fifth capacitor is connected to the output end of the first switch, and a second end of the fifth capacitor is grounded; a sixth capacitor, wherein a first end of the sixth capacitor is connected to the input end of the isolated power supply, a second end of the sixth capacitor is connected to the power ground end of the isolated power supply, and the power ground end of the isolated power supply is grounded; A filter inductor, wherein the first end of the filter inductor is connected to the first end of the fifth capacitor; the second end of the filter inductor is grounded, the third end of the filter inductor is connected to the second end of the sixth capacitor, and the fourth end of the filter inductor is connected to the input end of the isolated power supply.

9. The control circuit according to claim 2, characterized in that: The second delay circuit comprises: a fourth switch, wherein a first end of the fourth switch is connected to the output end of the isolated power supply, a second end of the fourth switch is grounded, and a third end of the fourth switch is connected to the control end of the second switch, and is used to send the second conduction signal to the control end of the second switch; a fifth resistor, wherein a first end of the fifth resistor is connected to the first end of the fourth switch, and a second end of the fifth resistor is grounded; a seventh capacitor, the seventh capacitor being connected in parallel with the fifth resistor; A sixth resistor, wherein a first end of the sixth resistor is connected to the output end of the isolated power supply, and a second end of the sixth resistor is connected to the first end of the fifth resistor.

10. The control circuit according to claim 9, characterized in that: The slow start circuit also includes: an eighth capacitor, wherein a first end of the eighth capacitor is connected to the output end of the isolated power supply, and a second end of the eighth capacitor is connected to the third end of the fourth switch; A seventh resistor is connected in parallel with the eighth capacitor.

11. The control circuit according to claim 1, characterized in that: The soft start circuit further includes: an eighth resistor and a ninth capacitor; The first end of the eighth resistor is connected to the control end of the second switch, the second end of the eighth resistor is connected to the first end of the ninth capacitor, and the second end of the ninth capacitor is connected to the output end of the second switch.

12. A power supply system, characterized in that: include: A power supply and a control circuit as claimed in any one of claims 1 to 11, wherein the output end of the power supply is connected to the input end of the first switch, and the power supply is used to output a third voltage and a fourth voltage, and the third voltage is less than the fourth voltage.

13. The power supply system according to claim 12, characterized in that: The power supply system further includes a protection circuit, and the output end of the power supply is connected to the input end of the first switch through the protection circuit.

14. A control method, characterized in that: The power supply system according to any one of claims 12 to 13 comprises: The power supply outputs a current, wherein before the first switch is turned on, the power resistor suppresses the output current; When there is a voltage at the output end of the first switch, the first delay circuit sends a first turn-on signal to the first switch to turn on the first switch and transmit the output current through the first switch; When there is a voltage at the output end of the first switch, the second delay circuit sends a second turn-on signal to the second switch to turn on the second switch and supply power to the load through the second switch; The first delay circuit sends the first conduction signal earlier than the second delay circuit sends the second conduction signal.

15. The control method according to claim 14, characterized in that: Sending a first conduction signal to the first switch includes: The control end of the isolated power supply obtains an electrical signal from an auxiliary winding included in the isolated power supply; The isolated power supply sends a control signal to the first delay circuit to turn on the first delay circuit; The first delay circuit sends the first turn-on signal to the first switch after being turned on.

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