Switching power supply circuit and electronic equipment

Abstract

The utility model discloses a switching power supply circuit and electronic equipment. A switching power supply comprises a power supply module, a voltage transformation module, a driving switch module, a sampling module, a feedback module, a control module and a charging and discharging module. The power end of the control module is connected with the output end of the power supply module, the output end of the control module is connected with the control end of the driving switch module, the first feedback end of the control module is connected with the first end of the sampling module, and the second feedback end of the control module is connected with the second end of the feedback module; the charging and discharging module is connected with the power supply module, the power supply end of the control module and the second feedback end of the control module, the charging and discharging module discharges the power supply end of the control module when the voltage of the second feedback end of the control module is high level, and the voltage of the second feedback end of the control module is high level when the two ends of the secondary winding are short-circuited. In this way, the short-circuit protection time interval of the switching power supply can be adjusted.

Description

Technical Field

[0001] The present application relates to the field of electronic circuits, and in particular to a switching power supply circuit and an electronic device. Background Art

[0002] Switching power supply is a kind of power supply widely used in various electronic devices.

[0003] To ensure the reliability and safety of the product, there will be a short-circuit protection circuit in the switching power supply circuit. The most common method of short-circuit protection is hiccup-type overcurrent protection. When the existing technology is input in a wide voltage range, the voltage difference between the low-voltage input and the high-voltage input is large, so the short-circuit protection time is inconsistent. When the high-voltage input is used, the short-circuit protection hiccup time interval is short, resulting in a large average current in the power device during a short circuit, resulting in the risk of overheating and failure. In addition, the hiccup protection interval cannot be automatically adjusted according to the input voltage and output power, which can easily cause device damage and seriously affect the reliability of the power supply. Utility Model Content

[0004] In order to solve the above problems, the present application provides a switching power supply circuit and an electronic device, which can adjust the short-circuit protection time interval.

[0005] A technical solution adopted by the present application is: to provide a switching power supply circuit, which includes: a power supply module, the input end of the power supply module is configured to receive a first voltage signal; a transformer module, the transformer module includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module, and the non-same-name end of the secondary winding is configured to output a second voltage signal; a driving switch module, the first end of the driving switch module is connected to the non-same-name end of the primary winding; a sampling module, the first end of the sampling module is connected to the second end of the driving switch module, and the second end of the sampling module is grounded; a feedback module, the first end of the feedback module is connected to the non-same-name end of the secondary winding; a control module, The power supply end of the control module is connected to the output end of the power supply module, the output end of the control module is connected to the control end of the driving switch module, the first feedback end of the control module is connected to the first end of the sampling module, and the second feedback end of the control module is connected to the second end of the feedback module; a charge and discharge module, the charge and discharge module is connected to the power supply module, the power supply end of the control module and the second feedback end of the control module, the charge and discharge module is configured to discharge the power supply end of the control module when the voltage of the second feedback end of the control module is at a high level, the discharge time of the power supply end of the control module is positively correlated with the voltage of the first voltage signal, and the voltage of the second feedback end of the control module is at a high level when the two ends of the secondary winding are short-circuited.

[0006] In one embodiment, the power supply module includes: a first voltage dividing unit, the first end of the first voltage dividing unit is configured to receive a first voltage signal, and the voltage dividing node of the first voltage dividing unit is connected to the charging and discharging module; a first capacitor, the first end of the first capacitor is connected to the second end of the first voltage dividing unit, and the second end of the first capacitor is grounded.

[0007] In one embodiment, the charge and discharge module includes: a discharge unit, a first end of the discharge unit is connected to the power supply end of the control module, and a second end of the discharge unit is grounded; a second capacitor, a first end of the second capacitor is connected to the discharge unit, and a second end of the second capacitor is connected to a voltage dividing node of the first voltage dividing unit; a comparison unit, a first input end of the comparison unit is connected to the voltage dividing node of the first voltage dividing unit, a second input end of the comparison unit is connected to the second feedback end of the control module, and an output end of the comparison unit is connected to the second end of the second capacitor.

[0008] In one embodiment, when the voltage of the voltage dividing node of the first voltage dividing unit is greater than the voltage of the second feedback terminal of the control module, the discharge unit is disconnected, and when the voltage of the voltage dividing node of the first voltage dividing unit is less than the voltage of the second feedback terminal of the control module, the discharge unit is turned on.

[0009] In one embodiment, the charge and discharge module also includes: a second voltage dividing unit, a first end of the second voltage dividing unit is connected to the voltage dividing node of the first voltage dividing unit, a second end of the second voltage dividing unit is grounded, and the voltage dividing node of the second voltage dividing unit is connected to the second end of the second capacitor; a third voltage dividing unit, a first end of the third voltage dividing unit is connected to the voltage dividing node of the first voltage dividing unit and the power supply end of the comparison unit, a second end of the third voltage dividing unit is grounded, and the voltage dividing node of the third voltage dividing unit is connected to the first input end of the comparison unit; a fourth voltage dividing unit, a first end of the fourth voltage dividing unit is connected to the second feedback end of the control module, a second end of the fourth voltage dividing unit is grounded, and the voltage dividing node of the fourth voltage dividing unit is connected to the second input end of the comparison unit.

[0010] In one embodiment, the charge and discharge module also includes: a first resistor, a first end of the first resistor is connected to the output end of the comparison unit, and a second end of the first resistor is connected to the first input end of the comparison unit; a first diode, an anode of the first diode is connected to the voltage dividing node of the first voltage dividing unit, and a cathode of the first diode is connected to the first end of the third voltage dividing unit; a second diode, an anode of the second diode is connected to the second feedback end of the control module, and a cathode of the second diode is connected to the first end of the fourth voltage dividing unit.

[0011] In one embodiment, the charge and discharge module also includes: a third capacitor, a first end of the third capacitor is connected to the second input end of the comparison unit, and a second end of the third capacitor is grounded; a fourth capacitor, a first end of the fourth capacitor is connected to the first end of the third voltage divider unit, and a second end of the fourth capacitor is grounded; a Zener diode, an anode of the Zener diode is grounded, and a cathode of the Zener diode is connected to the first end of the third voltage divider unit.

[0012] In one embodiment, the discharge unit includes: an NPN transistor; a second resistor, a first end of the second resistor is connected to the collector of the NPN transistor, and a second end of the second resistor is connected to the power supply end of the control module; a third resistor, a first end of the third resistor is connected to the base of the NPN transistor, and a second end of the third resistor is grounded; a third diode, an anode of the third diode is connected to the emitter of the NPN transistor and the first end of the second capacitor, and a cathode of the third diode is grounded.

[0013] In one embodiment, the transformer module further includes: an auxiliary winding, wherein the same-name end of the auxiliary winding is grounded; a fourth diode, wherein the anode of the fourth diode is connected to the non-same-name end of the auxiliary winding; and a fourth resistor, wherein the first end of the fourth resistor is connected to the cathode of the fourth diode, and the second end of the fourth resistor is connected to the power supply end of the control module.

[0014] In one embodiment, the transformer module further includes: a fifth diode, an anode of the fifth diode connected to the non-same-name end of the secondary winding; a fifth capacitor, a first end of the fifth capacitor connected to the cathode of the fifth diode, and a second end of the fifth capacitor grounded.

[0015] Another technical solution adopted by the present application is to provide an electronic device, which includes the above-mentioned switching power supply circuit.

[0016] The switching power supply circuit provided by the present application includes: a power supply module, the input end of the power supply module is configured to receive a first voltage signal; a transformer module, the transformer module includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module, and the non-same-name end of the secondary winding is configured to output a second voltage signal; a driving switch module, the first end of the driving switch module is connected to the non-same-name end of the primary winding; a sampling module, the first end of the sampling module is connected to the second end of the driving switch module, and the second end of the sampling module is grounded; a feedback module, the first end of the feedback module is connected to the non-same-name end of the secondary winding; a control module, the power end of the control module is connected The output end of the power supply module and the output end of the control module are connected to the control end of the driving switch module, the first feedback end of the control module is connected to the first end of the sampling module, and the second feedback end of the control module is connected to the second end of the feedback module; a charge and discharge module, the charge and discharge module is connected to the power supply module, the power supply end of the control module and the second feedback end of the control module, the charge and discharge module is configured to discharge the power supply end of the control module when the voltage of the second feedback end of the control module is at a high level, the discharge time of the power supply end of the control module is positively correlated with the voltage of the first voltage signal, and the voltage of the second feedback end of the control module is at a high level when the two ends of the secondary winding are short-circuited.

[0017] Through the above method, when the switching power supply is short-circuited, the charging and discharging time of the power supply end of the control module can be adjusted, so that the switching power supply automatically adjusts the short-circuit protection time interval according to the actual input voltage, and can simply adjust the parameters to meet the short-circuit protection time interval under different output powers, thereby realizing the adjustment of the short-circuit protection time interval and improving the reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] in:

[0020] Figure 1 is a structural schematic diagram of a first embodiment of a switching power supply circuit provided by the present application;

[0021] Figure 2 is a structural schematic diagram of a second embodiment of a switching power supply circuit provided by the present application;

[0022] Figure 3 is a structural schematic diagram of a third embodiment of a switching power supply circuit provided by the present application;

[0023] Figure 4 is a structural schematic diagram of a fourth embodiment of a switching power supply circuit provided by the present application;

[0024] Figure 5 is a structural schematic diagram of a fifth embodiment of a switching power supply circuit provided by the present application;

[0025] Figure 6 It is a structural schematic diagram of an embodiment of an electronic device provided by the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be appreciated that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some but not all structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present application.

[0027] The terms "first", "second", etc. in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] See also Figure 1 , Figure 1 The switching power supply 100 includes a power supply module 10 , a voltage transformation module 20 , a drive switch module 30 , a sampling module 40 , a feedback module 50 , a control module 60 and a charge and discharge module 70 .

[0030] Among them, the input end of the power supply module 10 is configured to receive the first voltage signal S1; the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output the second voltage signal S2; the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding; the first end of the sampling module 40 is connected to the second end of the driving switch module 30, and the second end of the sampling module 40 is grounded; the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding; the power supply end Vcc of the control module 60 is connected to the output end of the power supply module 10, and the output end Out of the control module 60 is connected to the control end of the driving switch module 30, The first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50; the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and the charge and discharge module 70 is configured to discharge the power supply terminal Vcc of the control module 60 when the voltage of the second feedback terminal Comp of the control module 60 is at a high level, and the discharge time of the power supply terminal Vcc of the control module 60 is positively correlated with the voltage of the first voltage signal S1, and the voltage of the second feedback terminal Comp of the control module 60 is at a high level when the two ends of the secondary winding are short-circuited.

[0031] Optionally, the input end of the power supply module 10 is configured to receive the first voltage signal S1 and store the energy transmitted by the first voltage signal S1 to provide a start-up voltage for the control module 60 .

[0032] Optionally, the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output a second voltage signal S2. The primary winding stores the energy transmitted by the received first voltage signal S1, and the secondary winding provides energy to the load and provides a feedback signal to the feedback module 50.

[0033] Optionally, the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding, providing a loop for releasing energy for the primary winding and switching the switching state of the driving switch according to the high and low level driving signals received from the control module 60.

[0034] Optionally, the first end of the sampling module 40 is connected to the second end of the driving switch module 30 , and the second end of the sampling module 40 is grounded, for transmitting the sampled voltage signal to the control module 60 and providing a logic processing signal inside the control module 60 .

[0035] Optionally, the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding, and is used to transmit the feedback signal when the switching power supply circuit 100 is short-circuited to the control module 60. Specifically, when the secondary winding is short-circuited, the feedback module 50 outputs a high-level feedback signal to the second feedback end Comp, and when the secondary winding works normally, the feedback module 50 outputs a low-level feedback signal to the second feedback end Comp.

[0036] Optionally, the power supply terminal Vcc of the control module 60 is connected to the output terminal of the power supply module 10, the output terminal of the control module 60 is connected to the control terminal of the driving switch module 30, the first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50. The control module 60 is used to perform internal logic processing according to the feedback signal of the first feedback terminal Cs (that is, the sampling signal of the sampling module 40) and the feedback signal of the second feedback terminal Comp (that is, the signal generated by the feedback module 50 when detecting whether the secondary winding is short-circuited), so as to adjust the duty cycle and frequency of the driving signal output by the driving switch module 30, so as to achieve the stability of the output voltage of the switching power supply circuit 100.

[0037] Optionally, the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and is used to control the power supply terminal Vcc of the control module 60 to discharge when the switching power supply circuit 100 is short-circuited (that is, when the second feedback terminal Comp is at a high level), thereby disconnecting the output of the switching power supply circuit 100 to achieve the effect of short-circuit protection, and at the same time, adjusting the short-circuit protection time interval according to the input voltage and the output power. Specifically, the larger the voltage of the first voltage signal S1, the longer the discharge time of the power supply terminal Vcc of the control module 60.

[0038] It can be understood that, through the above method, the charging and discharging module 70 is used as the key hub of the switching power supply circuit 100. When the switching power supply circuit 100 is short-circuited, the power supply terminal Vcc of the control module 60 is discharged to achieve short-circuit protection, and the short-circuit protection time interval is automatically adjusted according to the actual input voltage. The parameters can be simply adjusted to meet the short-circuit protection time interval under different output powers, thereby improving the reliability of the circuit.

[0039] See also Figure 2 , Figure 2 The switching power supply 100 includes a power supply module 10 , a voltage transformation module 20 , a drive switch module 30 , a sampling module 40 , a feedback module 50 , a control module 60 and a charge and discharge module 70 .

[0040] Among them, the input end of the power supply module 10 is configured to receive the first voltage signal S1; the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output the second voltage signal S2; the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding; the first end of the sampling module 40 is connected to the second end of the driving switch module 30, and the second end of the sampling module 40 is grounded; the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding; the power supply end Vcc of the control module 60 is connected to the output end of the power supply module 10, and the output end Out of the control module 60 is connected to the control end of the driving switch module 30, The first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50; the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and the charge and discharge module 70 is configured to discharge the power supply terminal Vcc of the control module 60 when the voltage of the second feedback terminal Comp of the control module 60 is at a high level, and the discharge time of the power supply terminal Vcc of the control module 60 is positively correlated with the voltage of the first voltage signal S1, and the voltage of the second feedback terminal Comp of the control module 60 is at a high level when the two ends of the secondary winding are short-circuited.

[0041] Optionally, the power supply module 10 includes a first voltage dividing unit 11 and a first capacitor C1, the first end of the first voltage dividing unit 11 is configured to receive the first voltage signal S1, and the voltage dividing node of the first voltage dividing unit 11 is connected to the charging and discharging module 70; the first end of the first capacitor C1 is connected to the second end of the first voltage dividing unit 11, and the second end of the first capacitor C1 is grounded. In one embodiment, the first voltage dividing unit 11 may include a plurality of resistors connected in series, such as an eleventh resistor R11, a twelfth resistor R12, and a thirteenth resistor R13.

[0042] Optionally, the charge and discharge module 70 includes a discharge unit 71, a second capacitor C2 and a comparison unit, wherein the first end of the discharge unit 71 is connected to the power supply terminal Vcc of the control module 60, and the second end of the discharge unit 71 is grounded; the first end of the second capacitor C2 is connected to the discharge unit 71, and the second end of the second capacitor C2 is connected to the voltage dividing node of the first voltage dividing unit 11 (for example, the common end of the twelfth resistor R12 and the thirteenth resistor R13); the comparison unit includes a comparator U1, wherein the first input end of the comparator U1 is connected to the voltage dividing node of the first voltage dividing unit 11, the second input end of the comparator U1 is connected to the second feedback terminal Comp of the control module 60, and the output end of the comparator U1 is connected to the second end of the second capacitor C2.

[0043] Specifically, when the secondary output of the transformer module 20 works normally, the first voltage signal S1 charges the second capacitor C2 through the voltage dividing node of the first voltage dividing unit 11. The higher the voltage of the first voltage signal S1, the higher the voltage on the second capacitor C2. At the same time, the voltage dividing node of the first voltage dividing unit 11 also supplies power to the first input terminal of the comparator U1, and the second feedback terminal Comp supplies power to the second input terminal of the comparator U1. At this time, the voltage of the second feedback terminal Comp of the control module 60 is low level, then the voltage of the voltage dividing node of the first voltage dividing unit 11 is greater than the voltage of the second feedback terminal Comp of the control module 60, the comparator U1 is an open drain output, the voltage across the second capacitor C2 will hardly change, and the discharge unit 71 remains disconnected; when the secondary side of the transformer module 20 is short-circuited, the voltage of the second feedback terminal Comp of the control module 60 is high level, then the voltage of the voltage dividing node of the first voltage dividing unit 11 is less than the voltage of the second feedback terminal Comp of the control module 60, the comparator U1 outputs a low level, and the discharge unit 71 is turned on to discharge the power supply terminal Vcc of the control module 60.

[0044] See also Figure 3 , Figure 3 The switching power supply 100 includes a power supply module 10 , a voltage transformation module 20 , a drive switch module 30 , a sampling module 40 , a feedback module 50 , a control module 60 and a charge and discharge module 70 .

[0045] Among them, the input end of the power supply module 10 is configured to receive the first voltage signal S1; the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output the second voltage signal S2; the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding; the first end of the sampling module 40 is connected to the second end of the driving switch module 30, and the second end of the sampling module 40 is grounded; the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding; the power supply end Vcc of the control module 60 is connected to the output end of the power supply module 10, and the output end Out of the control module 60 is connected to the control end of the driving switch module 30, The first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50; the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and the charge and discharge module 70 is configured to discharge the power supply terminal Vcc of the control module 60 when the voltage of the second feedback terminal Comp of the control module 60 is at a high level, and the discharge time of the power supply terminal Vcc of the control module 60 is positively correlated with the voltage of the first voltage signal S1, and the voltage of the second feedback terminal Comp of the control module 60 is at a high level when the two ends of the secondary winding are short-circuited.

[0046] Optionally, the charge and discharge module 70 includes a discharge unit 71, a second capacitor C2 and a comparison unit, wherein the first end of the discharge unit 71 is connected to the power supply terminal Vcc of the control module 60, and the second end of the discharge unit 71 is grounded; the first end of the second capacitor C2 is connected to the discharge unit 71, and the second end of the second capacitor C2 is connected to the voltage dividing node of the first voltage dividing unit 11 (for example, the common end of the twelfth resistor R12 and the thirteenth resistor R13); the comparison unit includes a comparator U1, wherein the first input end of the comparator U1 is connected to the voltage dividing node of the first voltage dividing unit 11, the second input end of the comparator U1 is connected to the second feedback terminal Comp of the control module 60, and the output end of the comparator U1 is connected to the second end of the second capacitor C2.

[0047] Optionally, the charge and discharge module 70 also includes a second voltage dividing unit 72, a third voltage dividing unit 73 and a fourth voltage dividing unit 74, wherein the first end of the second voltage dividing unit 72 is connected to the voltage dividing node of the first voltage dividing unit 11, the second end of the second voltage dividing unit 72 is grounded, and the voltage dividing node of the second voltage dividing unit 72 is connected to the second end of the second capacitor C2; the first end of the third voltage dividing unit 73 is connected to the voltage dividing node of the first voltage dividing unit 11 and the power supply end of the comparator U1, the second end of the third voltage dividing unit 73 is grounded, and the voltage dividing node of the third voltage dividing unit 73 is connected to the first input end of the comparator U1; the first end of the fourth voltage dividing unit 74 is connected to the second feedback end Comp of the control module 60, the second end of the fourth voltage dividing unit 74 is grounded, and the voltage dividing node of the fourth voltage dividing unit 74 is connected to the second input end of the comparison unit U2.

[0048] Optionally, the charge and discharge module 70 also includes: a first resistor R1, a first diode D1 and a second diode D2, the first end of the first resistor R1 is connected to the output end of the comparator U1, and the second end of the first resistor R1 is connected to the first input end of the comparator U1; the anode of the first diode D1 is connected to the voltage dividing node of the first voltage dividing unit 11, and the cathode of the first diode D1 is connected to the first end of the third voltage dividing unit 73; the anode of the second diode D2 is connected to the second feedback end Comp of the control module 60, and the cathode of the second diode D2 is connected to the first end of the fourth voltage dividing unit 74.

[0049] Optionally, the charge and discharge module 70 also includes: a third capacitor C3, a fourth capacitor C4 and a Zener diode Z1, the first end of the third capacitor C3 is connected to the second input end of the comparator U1, and the second end of the third capacitor C3 is grounded; the first end of the fourth capacitor C4 is connected to the first end of the third voltage divider unit 73, and the second end of the fourth capacitor C4 is grounded; the anode of the Zener diode Z1 is grounded, and the cathode of the Zener diode Z1 is connected to the first end of the third voltage divider unit 73.

[0050] Specifically, when the secondary output of the transformer module 20 operates normally, the voltage of the second feedback terminal Comp of the control module 60 is at a low level, so the second input terminal of the comparator U1 is at a low level, and the first voltage signal S1 charges the second capacitor C2 through the eleventh resistor R11 and the twelfth resistor R12. At the same time, the first voltage signal S1 also charges the fourth capacitor C4 through the first diode D1 to provide a power supply voltage to the first input terminal of the comparator U1, and the power supply voltage is stabilized at a fixed value by the voltage regulator diode Z1; the voltage of the voltage regulator diode Z1 is connected to the first input terminal of the comparator U1 after being divided by the seventh resistor R7 and the eighth resistor R8, so as to set the threshold voltage of the first input terminal of the comparator U1; the voltage of the second input terminal of the comparator U1 is determined by the second feedback terminal of the control module 60. Comp provides that during normal operation, the voltage of the second feedback terminal Comp will be lower than the voltage of the first input terminal of the comparator U1 after being divided by the second diode D2, the ninth resistor R9 and the tenth resistor R10. At this time, the comparator U1 is an open-drain output, which has no effect on the voltage of the second capacitor C2. The voltage across the second capacitor C2 will hardly change, and the discharge unit 71 remains disconnected; when the secondary side of the transformer module 20 is short-circuited, the voltage of the second feedback terminal Comp of the control module 60 is a high level, which is divided by the second diode D2, the ninth resistor R9 and the tenth resistor R10, so that the voltage of the first input terminal of the comparator U1 is less than the voltage of the second input terminal, and the comparator U1 outputs a low level, and the discharge unit 71 is turned on to discharge the power supply terminal Vcc of the control module 60.

[0051] See also Figure 4 , Figure 4 The switching power supply 100 includes a power supply module 10 , a voltage transformation module 20 , a drive switch module 30 , a sampling module 40 , a feedback module 50 , a control module 60 and a charge and discharge module 70 .

[0052] Among them, the input end of the power supply module 10 is configured to receive the first voltage signal S1; the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output the second voltage signal S2; the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding; the first end of the sampling module 40 is connected to the second end of the driving switch module 30, and the second end of the sampling module 40 is grounded; the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding; the power supply end Vcc of the control module 60 is connected to the output end of the power supply module 10, and the output end Out of the control module 60 is connected to the control end of the driving switch module 30, The first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50; the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and the charge and discharge module 70 is configured to discharge the power supply terminal Vcc of the control module 60 when the voltage of the second feedback terminal Comp of the control module 60 is at a high level, and the discharge time of the power supply terminal Vcc of the control module 60 is positively correlated with the voltage of the first voltage signal S1, and the voltage of the second feedback terminal Comp of the control module 60 is at a high level when the two ends of the secondary winding are short-circuited.

[0053] Figure 4 The switching power supply circuit 100 shown in FIG. Figure 3 The main difference of the switching power supply circuit 100 shown in FIG. 1 is that the discharge unit 71 and the transformer module 20 are added. Therefore, the following mainly describes the discharge unit 71 and the transformer module 20. For other components in the switching power supply circuit 100, please refer to FIG. Figure 3 The relevant description of the embodiment shown, for example Figure 4 The charge and discharge module 70 in FIG. Figure 3 The description of the charge and discharge module 70 will not be repeated here.

[0054] Optionally, the discharge unit 71 includes: an NPN transistor Q1 、 The second resistor R2 、 The third resistor R3 and the third diode D3, the first end of the second resistor R2 is connected to the collector of the NPN transistor Q1, and the second end of the second resistor R2 is connected to the power supply terminal Vcc of the control module 60; the first end of the third resistor R3 is connected to the base of the NPN transistor Q1, and the second end of the third resistor R3 is grounded; the anode of the third diode D3 is connected to the emitter of the NPN transistor Q1 and the first end of the second capacitor C2, and the cathode of the third diode D3 is grounded.

[0055] Optionally, the transformer module 20 also includes: an auxiliary winding, a fourth diode D4 and a fourth resistor R4, the like-name end of the auxiliary winding is grounded; the anode of the fourth diode D4 is connected to the non-like-name end of the auxiliary winding; the first end of the fourth resistor R4 is connected to the cathode of the fourth diode D4, and the second end of the fourth resistor R4 is connected to the power supply terminal Vcc of the control module 60.

[0056] Optionally, the transformer module 20 further includes: a fifth diode D5 and a fifth capacitor C5, the anode of the fifth diode D5 is connected to the non-same-name end of the secondary winding; the first end of the fifth capacitor C5 is connected to the cathode of the fifth diode D5, and the second end of the fifth capacitor C5 is grounded.

[0057] Specifically, when the secondary output of the transformer module 20 works normally, the voltage of the second feedback terminal Comp of the control module 60 is at a low level, so the second input terminal of the comparator U1 is at a low level. At the same time, the voltage of the voltage dividing node of the first voltage dividing unit 11 is divided by the first diode D1, the seventh resistor R7 and the eighth resistor R8, so the voltage of the first input terminal of the comparator U1 is greater than the voltage of the second input terminal. The comparator U1 is an open-drain output, and the voltage across the second capacitor C2 hardly changes. The emitter of the NPN transistor Q1 is at a high level and is greater than the base voltage of the NPN transistor Q1, and the NPN transistor Q1 remains disconnected. When the secondary side of the transformer module 20 is short-circuited, the voltage of the second feedback terminal Comp of the control module 60 is high level, and the high level is divided by the second diode D2, the ninth resistor R9 and the tenth resistor R10, so that the voltage of the first input terminal of the comparator U1 is less than the voltage of the second input terminal, and the comparator U1 outputs a low level. Since the capacitor has the characteristic of maintaining the voltage difference, when the right side of the second capacitor C2 is pulled down to "0", the voltage on the left side of the second capacitor C2 will become lower, so that the base voltage of the NPN transistor Q1 is greater than the emitter voltage, and the NPN transistor Q1 is turned on, thereby realizing the discharge of the power supply terminal Vcc of the control module 60. When the voltage of the power supply terminal Vcc of the control module 60 is discharged to the undervoltage state, the circuit enters the protection state, the circuit has no output power, and the first voltage signal S1 charges the first capacitor C1 through the eleventh resistor R11, the twelfth resistor R12 and the thirteenth resistor R13. At this time, the power supply terminal Vcc of the control module 60 is still being discharged through the NPN transistor Q1, and the time for the first capacitor C1 to charge to the start-up voltage of the power supply terminal Vcc of the control module 60 will become longer, which means that the interval time of the protection hiccup is extended, thereby reducing the average current of the power device at the output end of the circuit, and avoiding the risk of overheating and failure of the power device; when the second capacitor C2 is completely discharged, the NPN transistor Q1 turns to the cut-off state again, the power supply terminal Vcc of the control module 60 can no longer be discharged through the NPN transistor Q1, and the first capacitor C1 is gradually charged to the start-up voltage of the power supply terminal Vcc of the control module 60, and the control module 60 works again.

[0058] See also Figure 5 , Figure 5 The switching power supply 100 includes a power supply module 10 , a voltage transformation module 20 , a drive switch module 30 , a sampling module 40 , a feedback module 50 , a control module 60 and a charge and discharge module 70 .

[0059] Among them, the input end of the power supply module 10 is configured to receive the first voltage signal S1; the transformer module 20 includes a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module 10, and the non-same-name end of the secondary winding is configured to output the second voltage signal S2; the first end of the driving switch module 30 is connected to the non-same-name end of the primary winding; the first end of the sampling module 40 is connected to the second end of the driving switch module 30, and the second end of the sampling module 40 is grounded; the first end of the feedback module 50 is connected to the non-same-name end of the secondary winding; the power supply end Vcc of the control module 60 is connected to the output end of the power supply module 10, and the output end Out of the control module 60 is connected to the control end of the driving switch module 30, The first feedback terminal Cs of the control module 60 is connected to the first terminal of the sampling module 40, and the second feedback terminal Comp of the control module 60 is connected to the second terminal of the feedback module 50; the charge and discharge module 70 is connected to the power supply module 10, the power supply terminal Vcc of the control module 60 and the second feedback terminal Comp of the control module 60, and the charge and discharge module 70 is configured to discharge the power supply terminal Vcc of the control module 60 when the voltage of the second feedback terminal Comp of the control module 60 is at a high level, and the discharge time of the power supply terminal Vcc of the control module 60 is positively correlated with the voltage of the first voltage signal S1, and the voltage of the second feedback terminal Comp of the control module 60 is at a high level when the two ends of the secondary winding are short-circuited.

[0060] Figure 5 The switching power supply circuit 100 shown in FIG. Figure 4 The main difference of the switching power supply circuit 100 shown in FIG. 1 is that the fourteenth resistor R14, the driving switch module 30, the sampling module 40 and the feedback module 50 are added. Therefore, the following mainly describes the fourteenth resistor R14, the driving switch module 30, the sampling module 40 and the feedback module 50. For other components in the switching power supply circuit 100, please refer to Figure 4 The relevant description of the embodiment shown, for example Figure 4 The charge and discharge module 70 in FIG. Figure 3 The description of the charge and discharge module 70 will not be repeated here.

[0061] Optionally, the feedback module 50 includes a feedback circuit, a first end of the feedback circuit is connected to the second feedback end Comp of the control module 60, and a second end of the feedback circuit is connected to the cathode of the fifth diode D5.

[0062] Specifically, when the second end of the feedback circuit receives a circuit short-circuit signal, the second end of the feedback circuit will transmit the processed feedback signal to the second feedback end Comp of the control module 60, and the voltage of the second feedback end Comp of the control module 60 will be pulled to a high level, and the power supply end Vcc of the control module 60 will be discharged.

[0063] Optionally, the switching power supply circuit 100 further includes a fourteenth resistor R14, a first end of the fourteenth resistor R14 is connected to the voltage dividing node of the first voltage dividing unit 11, and a second end of the fourteenth resistor R14 is connected to the anode of the first diode D1 and the second end of the fifth resistor R5.

[0064] Specifically, the fourteenth resistor R14 is mainly used to divide the voltage of the voltage dividing node of the first voltage dividing unit 11 to limit the charging voltage of the second capacitor C2 and the fourth capacitor C4.

[0065] Optionally, the driving switch module 30 includes a driving circuit and a driving switch Q2, and the sampling module 40 includes a filtering circuit and a sampling resistor Rs. A first end of the driving circuit is connected to an output end Out of the control module 60, a second end of the driving circuit is connected to a control end of the driving switch Q2, and a second end of the driving switch Q2 is connected to a first end of the sampling resistor Rs; a first end of the filtering circuit is connected to a first feedback end Cs of the control module 60, a second end of the filtering circuit is connected to a first end of the sampling resistor Rs, and a second end of the sampling resistor Rs is grounded; a first end of the feedback circuit is connected to a second feedback end Comp of the control module 60, and a second end of the feedback circuit is connected to a cathode of a fifth diode D5.

[0066] Specifically, when the drive circuit receives a high-level signal sent by the output terminal Out of the control module 60, the drive circuit controls the drive switch Q2 to be turned on. After the drive switch Q2 is turned on, the first voltage signal S1 forms a loop between the primary winding of the transformer module 20, the drive switch Q2, the sampling resistor Rs and the ground. The primary winding current of the transformer module 20 rises linearly and stores energy, and the voltage on the sampling resistor Rs also rises linearly. When the voltage on the sampling resistor Rs rises to a certain value, the voltage signal on the sampling resistor Rs is transmitted to the first feedback terminal Cs of the control module 60 through the filtering circuit. After being processed by the internal logic of the control module 60, the output terminal Out of the control module 60 outputs a low-level signal, and the drive circuit controls the drive switch Q2 to be turned off.

[0067] When the switching power supply circuit of this embodiment is applied to electronic equipment, the charging and discharging module is used as the key hub. When the switching power supply is short-circuited, the charging and discharging time of the power supply end of the control module can be adjusted through the charging and discharging module, so that the switching power supply automatically adjusts the short-circuit protection time interval according to the actual input voltage, and can simply adjust the parameters to meet the short-circuit protection time interval under different output powers, thereby realizing the adjustment of the short-circuit protection time interval and improving the safety and reliability of the circuit.

[0068] See also Figure 6 , Figure 6 1 is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. The electronic device includes a switching power supply circuit 100. The switching power supply circuit 100 is as described in the above embodiments and will not be described in detail here.

[0069] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A switching power supply circuit, characterized in that: include: A power supply module, wherein an input end of the power supply module is configured to receive a first voltage signal; A transformer module, the transformer module comprising a primary winding and a secondary winding, the same-name end of the primary winding is connected to the input end of the power supply module, and the non-same-name end of the secondary winding is configured to output a second voltage signal; A driving switch module, wherein a first end of the driving switch module is connected to a non-same-name end of the primary winding; A sampling module, wherein a first end of the sampling module is connected to a second end of the driving switch module, and a second end of the sampling module is grounded; A feedback module, wherein a first end of the feedback module is connected to a non-same-name end of the secondary winding; A control module, wherein the power supply end of the control module is connected to the output end of the power supply module, the output end of the control module is connected to the control end of the drive switch module, the first feedback end of the control module is connected to the first end of the sampling module, and the second feedback end of the control module is connected to the second end of the feedback module; A charge and discharge module, wherein the charge and discharge module is connected to the power supply module, the power supply end of the control module and the second feedback end of the control module, and the charge and discharge module is configured to discharge the power supply end of the control module when the voltage of the second feedback end of the control module is at a high level, the discharge time of the power supply end of the control module is positively correlated with the voltage of the first voltage signal, and the voltage of the second feedback end of the control module is at a high level when the two ends of the secondary winding are short-circuited.

2. The switching power supply circuit according to claim 1, characterized in that: The power supply module comprises: A first voltage dividing unit, wherein a first end of the first voltage dividing unit is configured to receive a first voltage signal, and a voltage dividing node of the first voltage dividing unit is connected to the charge and discharge module; A first capacitor, wherein a first end of the first capacitor is connected to a second end of the first voltage dividing unit, and a second end of the first capacitor is grounded.

3. The switching power supply circuit according to claim 2, characterized in that: The charging and discharging module comprises: a discharge unit, wherein a first end of the discharge unit is connected to a power supply end of the control module, and a second end of the discharge unit is grounded; a second capacitor, wherein a first end of the second capacitor is connected to the discharge unit, and a second end of the second capacitor is connected to a voltage dividing node of the first voltage dividing unit; A comparison unit, wherein a first input end of the comparison unit is connected to the voltage dividing node of the first voltage dividing unit, a second input end of the comparison unit is connected to the second feedback end of the control module, and an output end of the comparison unit is connected to the second end of the second capacitor; When the voltage of the voltage dividing node of the first voltage dividing unit is greater than the voltage of the second feedback terminal of the control module, the discharge unit is disconnected; when the voltage of the voltage dividing node of the first voltage dividing unit is less than the voltage of the second feedback terminal of the control module, the discharge unit is turned on.

4. The switching power supply circuit according to claim 3, characterized in that: The charging and discharging module also includes: a second voltage dividing unit, wherein a first end of the second voltage dividing unit is connected to a voltage dividing node of the first voltage dividing unit, a second end of the second voltage dividing unit is grounded, and a voltage dividing node of the second voltage dividing unit is connected to a second end of the second capacitor; a third voltage dividing unit, wherein a first end of the third voltage dividing unit is connected to a voltage dividing node of the first voltage dividing unit and a power supply end of the comparison unit, a second end of the third voltage dividing unit is grounded, and a voltage dividing node of the third voltage dividing unit is connected to a first input end of the comparison unit; A fourth voltage dividing unit, wherein a first end of the fourth voltage dividing unit is connected to the second feedback end of the control module, a second end of the fourth voltage dividing unit is grounded, and a voltage dividing node of the fourth voltage dividing unit is connected to the second input end of the comparison unit.

5. The switching power supply circuit according to claim 4, characterized in that: The charging and discharging module also includes: a first resistor, wherein a first end of the first resistor is connected to the output end of the comparison unit, and a second end of the first resistor is connected to the first input end of the comparison unit; a first diode, wherein an anode of the first diode is connected to the voltage dividing node of the first voltage dividing unit, and a cathode of the first diode is connected to a first end of the third voltage dividing unit; A second diode, wherein an anode of the second diode is connected to the second feedback end of the control module, and a cathode of the second diode is connected to the first end of the fourth voltage dividing unit.

6. The switching power supply circuit according to claim 4, characterized in that: The charging and discharging module also includes: a third capacitor, a first end of the third capacitor being connected to the second input end of the comparison unit, and a second end of the third capacitor being grounded; a fourth capacitor, wherein a first end of the fourth capacitor is connected to the first end of the third voltage dividing unit, and a second end of the fourth capacitor is grounded; A voltage-stabilizing diode, wherein an anode of the voltage-stabilizing diode is grounded, and a cathode of the voltage-stabilizing diode is connected to a first end of the third voltage-dividing unit.

7. The switching power supply circuit according to claim 3, characterized in that: The discharge unit comprises: NPN transistor; a second resistor, wherein a first end of the second resistor is connected to the collector of the NPN transistor, and a second end of the second resistor is connected to the power supply end of the control module; a third resistor, wherein a first end of the third resistor is connected to the base of the NPN transistor, and a second end of the third resistor is grounded; A third diode, wherein an anode of the third diode is connected to the emitter of the NPN transistor and the first end of the second capacitor, and a cathode of the third diode is grounded.

8. The switching power supply circuit according to claim 1, characterized in that: The voltage transformation module also includes: An auxiliary winding, wherein the same-name end of the auxiliary winding is grounded; a fourth diode, wherein an anode of the fourth diode is connected to a non-same-name end of the auxiliary winding; A fourth resistor, wherein a first end of the fourth resistor is connected to the cathode of the fourth diode, and a second end of the fourth resistor is connected to the power supply end of the control module.

9. The switching power supply circuit according to claim 1, characterized in that: The voltage transformation module also includes: a fifth diode, wherein an anode of the fifth diode is connected to a non-same-name end of the secondary winding; A fifth capacitor, wherein a first end of the fifth capacitor is connected to the cathode of the fifth diode, and a second end of the fifth capacitor is grounded.

10. An electronic device, characterized in that: The electronic device comprises the switching power supply circuit as claimed in any one of claims 1 to 9.

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