Switching power supply starting current-limiting control circuit
By designing a current-limiting control circuit for the startup of a switching power supply, timed current limiting and overcurrent detection of the switching power supply are achieved, solving the problem of the inability to provide timely current limiting protection in existing technologies and improving the intelligence and safety of control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN CHUXINZHIZHI TECHNOLOGY CO LTD
- Filing Date
- 2025-05-30
- Publication Date
- 2026-05-26
AI Technical Summary
Existing switching power supplies cannot provide timely current limiting protection during operation, resulting in low control intelligence when components experience overcurrent.
Design a switching power supply startup current limiting control circuit, including a power supply module, a startup current limiting module, a timing module, a switching power supply module, an overcurrent sampling module, and a protection module, to achieve intelligent control through timing current limiting and overcurrent detection.
It improves the control intelligence and safety of switching power supplies, ensuring timely current limiting protection under overcurrent conditions and reducing the risk of component damage.
Smart Images
Figure CN224289615U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of switching power supply technology, specifically a switching power supply startup current limiting control circuit. Background Technology
[0002] In the field of switching power supplies, in order to ensure the safe and stable operation of switching power supplies, timed current limiting protection is performed on the power input to the switching power supply when power is connected. This prevents the components of the switching power supply from overheating due to excessive input current. After the timer expires, the current limiting control stops and the original current supply is restored. However, this current limiting protection function only performs current limiting protection when power is connected. During operation, if the switching power supply components experience overcurrent, it cannot perform current limiting protection control in a timely manner. The control intelligence of the switching power supply is low, and therefore needs to be improved. Utility Model Content
[0003] This utility model provides a switching power supply startup current limiting control circuit to solve the problems mentioned in the background art.
[0004] To achieve the above objectives, this utility model provides the following technical solution:
[0005] A switching power supply startup current limiting control circuit includes: a power supply module, a startup current limiting module, a timing module, a switching power supply module, an overcurrent sampling module, and a protection module;
[0006] The power module is used to connect to DC power.
[0007] The current limiting module is activated and connected to the power module to transmit DC power and perform current limiting on the incoming DC power.
[0008] The timing module, connected to the power supply module, the startup current limiting module, and the switching power supply module, is used to set the timing time and start timing operation when receiving DC power from the startup current limiting module. After the timing ends, it controls the startup current limiting module to stop power transmission and transfer DC power to the switching power supply module.
[0009] The switching power supply module, connected to the startup current limiting module and the power supply module, is used to regulate the power of the incoming electrical energy.
[0010] The overcurrent sampling module is connected to the switching power supply module and the timing module. It is used to sample the current of the switching power supply module and detect overcurrent. When an overcurrent occurs, it outputs a first control signal, performs self-locking processing on the first control signal, and outputs a second control signal to control the timing module to stop the power transmission.
[0011] The protection module, connected to the start-up current limiting module and the overcurrent sampling module, is used to control the start-up current limiting module to stop power transmission when the first control signal and the second control signal are received simultaneously.
[0012] As a further embodiment of this utility model: the power module includes a power interface; the startup current limiting module includes a first resistor, a second resistor, a first diode, a fourth switching transistor, and a first power transistor;
[0013] Preferably, the first end of the power interface is connected to the gate of the first power transistor, one end of the second resistor, the cathode of the first diode, and the collector of the fourth switching transistor via a first resistor; the source of the first power transistor is connected to the other end of the second resistor, the anode of the first diode, the emitter of the fourth switching transistor, the second end of the power interface, and the ground terminal; and the base of the fourth switching transistor is connected to the timing module.
[0014] As a further embodiment of this utility model: the switching power supply module includes a first capacitor, a third resistor, a fourth diode, a first transformer, an output processing device, a power regulation device, and a fourth resistor;
[0015] Preferably, one end of the first capacitor is connected to the first end of the primary side of the first transformer, the first end of the power interface, and the first end of the power conditioning device, and is connected to the other end of the first capacitor and the cathode of the fourth diode through the third resistor. The anode of the fourth diode is connected to the second end of the secondary side of the first transformer and the second end of the power conditioning device. The first end and the second end of the secondary side of the first transformer are respectively connected to the first end and the second end of the output processing device. The third end of the power conditioning device is connected to the third end of the output processing device. The fourth end of the power conditioning device is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the drain of the first power transistor.
[0016] As a further embodiment of this utility model: the overcurrent sampling module includes a fifth resistor, a first reference power supply, a first comparator, a second capacitor, a sixth resistor, a third capacitor, a third diode, a first logic chip, a second diode, and a first power supply;
[0017] Preferably, the non-inverting input of the first comparator is connected to the first end of the fourth resistor through the fifth resistor, the inverting input of the first comparator is connected to the first reference power supply and one end of the third capacitor, and is connected to the other end of the third capacitor, the output terminal of the first comparator and the anode of the third diode in sequence through the sixth resistor and the second capacitor, the cathode of the third diode is connected to the cathode of the second diode and the A terminal of the first logic chip, the B terminal of the first logic chip is connected to the first power supply, and the Y terminal of the first logic chip is connected to the anode of the second diode.
[0018] As a further improvement of this utility model, the current limiting module also includes a first switching transistor, a second switching transistor, a first relay, and a first relay switch;
[0019] Preferably, the base of the first switching transistor is connected to the collector of the second switching transistor, the base of the fourth switching transistor, and the timing module; the emitter of the first switching transistor is connected to the emitter of the second switching transistor, the moving end of the first relay switch, and the second end of the power interface; the collector of the first switching transistor is connected to one end of the first relay; the other end of the first relay is connected to the first end of the power interface; and the base of the second switching transistor is connected to the Y end of the first logic chip.
[0020] As a further improvement of this utility model: the protection module includes a second logic chip and a third switching transistor;
[0021] Preferably, the A and B terminals of the second logic chip are connected to the Y terminal of the first logic chip and the output terminal of the first comparator, respectively. The Y terminal of the second logic chip is connected to the base of the third switching transistor, the emitter of the third switching transistor is grounded, and the collector of the third switching transistor is connected to the gate of the first power transistor.
[0022] As a further embodiment of this utility model: the timing module includes a fourth capacitor, a fifth diode, a seventh resistor, a first timer, and a fifth capacitor;
[0023] Preferably, the fourth and eighth terminals of the first timer are both connected to the first terminal of the power interface and connected to the cathode of the fifth diode through the fourth capacitor. The sixth and second terminals of the first timer are connected to the anode of the fifth diode and the drain of the first power transistor through the seventh resistor. The first terminal of the first timer and one terminal of the fifth capacitor are connected, the other terminal of the fifth capacitor is connected to the fifth terminal of the first timer, and the third terminal of the first timer is connected to the base of the first switching transistor.
[0024] Compared with the prior art, the beneficial effects of this utility model are as follows: The starting current limiting control circuit of this utility model can perform starting current limiting processing on the power supply module by the starting current limiting module, and transmit the processed power to the switching power supply module to control the starting operation of the switching power supply module. At the same time, the starting current limiting module starts timing, and after the timing ends, it stops the current limiting operation and supplies power to the switching power supply module normally, which then performs voltage regulation. The overcurrent sampling module detects overcurrent in the switching power supply module, and when an overcurrent occurs, it controls the starting current limiting module to re-enter the current limiting operation to reduce the operating current of the switching power supply module. If the switching power supply module is still in an overcurrent state after re-current limiting, the protection module will control the starting current limiting module to perform power-off protection, thereby improving the control intelligence and safety of the circuit. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic block diagram of a switching power supply startup current limiting control circuit provided for an example of this utility model.
[0027] Figure 2 A circuit diagram of a switching power supply start-up current limiting control circuit provided for this utility model embodiment.
[0028] Figure 3 The connection circuit diagram of the timing module provided for this utility model embodiment. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0030] In one embodiment, see Figure 1 A switching power supply startup current limiting control circuit includes: a power supply module 1, a startup current limiting module 2, a timing module 3, a switching power supply module 4, an overcurrent sampling module 5, and a protection module 6.
[0031] Specifically, power module 1 is used to connect to DC power;
[0032] Start the current limiting module 2, which is connected to the power module 1, to transmit DC power and perform current limiting transmission processing on the input DC power;
[0033] The timing module 3 is connected to the power supply module 1, the start-up current limiting module 2 and the switching power supply module 4. It is used to set the timing time and start the timing operation when receiving DC power from the start-up current limiting module 2. After the timing is completed, it controls the start-up current limiting module 2 to stop the power transmission operation and transmit DC power to the switching power supply module 4.
[0034] The switching power supply module 4 is connected to the startup current limiting module 2 and the power supply module 1, and is used to regulate the power of the incoming electrical energy.
[0035] The overcurrent sampling module 5 is connected to the switching power supply module 4 and the timing module 3. It is used to sample the current of the switching power supply module 4 and detect overcurrent. When overcurrent occurs, it outputs a first control signal, performs self-locking processing on the first control signal, and outputs a second control signal to control the timing module 3 to stop the power transmission.
[0036] The protection module 6 is connected to the start-up current limiting module 2 and the overcurrent sampling module 5. It is used to control the start-up current limiting module 2 to stop the power transmission when it receives the first control signal and the second control signal at the same time.
[0037] In a specific embodiment, the power supply module 1 can be a power circuit composed of a power interface, which can be connected to DC power; the startup current limiting module 2 can be a startup current limiting circuit composed of resistors, diodes, field-effect transistors, relays, etc., which can control the transmission of power and limit the current of the transmitted power; the timing module 3 can be a timing circuit composed of timers, capacitors, resistors, etc., which can set the timing time, start timing operation after power is received, and continuously output a high-level signal after the timing ends; the switching power supply module 4 can be a switching power supply circuit composed of power regulation device, output processing device, transformer, etc., which can perform high-frequency voltage regulation of the input power; the overcurrent sampling module 5 can be an overcurrent sampling circuit composed of resistors, comparators, logic chips, capacitors, etc., which can sample the current of the switching power supply module 4, detect overcurrent, and perform signal self-locking and output a high-level signal when overcurrent occurs; the protection module 6 can be a protection circuit composed of logic chips and transistors, which can perform logical calculations on the signal output by the overcurrent sampling module 5 and control the startup current limiting module 2 to cut off power.
[0038] In another embodiment, please refer to Figure 1 , Figure 2 and Figure 3 The power module 1 includes a power interface; the startup current limiting module 2 includes a first resistor R1, a second resistor R2, a first diode D1, a fourth switch V4, and a first power transistor Q1.
[0039] Specifically, the first end of the power interface is connected to the gate of the first power transistor Q1, one end of the second resistor R2, the cathode of the first diode D1 and the collector of the fourth switch V4 through the first resistor R1. The source of the first power transistor Q1 is connected to the other end of the second resistor R2, the anode of the first diode D1, the emitter of the fourth switch V4, the second end of the power interface and the ground. The base of the fourth switch V4 is connected to the timing module 3.
[0040] In a specific embodiment, the first power transistor Q1 can be an N-channel MOSFET; the fourth switching transistor V4 can be an NPN transistor.
[0041] Furthermore, the switching power supply module 4 includes a first capacitor C1, a third resistor R3, a fourth diode D4, a first transformer B1, an output processing device, a power regulation device, and a fourth resistor R4.
[0042] Specifically, one end of the first capacitor C1 is connected to the first end of the primary side of the first transformer B1, the first end of the power interface, and the first end of the power conditioning device, and is connected to the other end of the first capacitor C1 and the cathode of the fourth diode D4 through the third resistor R3. The anode of the fourth diode D4 is connected to the second end of the secondary side of the first transformer B1 and the second end of the power conditioning device. The first end and the second end of the secondary side of the first transformer B1 are respectively connected to the first end and the second end of the output processing device. The third end of the power conditioning device is connected to the third end of the output processing device. The fourth end of the power conditioning device is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is connected to the drain of the first power transistor Q1.
[0043] In a specific embodiment, the power regulation device can be composed of a UC3842 driver, a field-effect transistor, and a resistor, providing a PWM signal and controlling the first transformer B1 to perform high-frequency voltage regulation; the output processing device can be composed of a rectifier, a filter, and a feedback circuit composed of an optocoupler and a TL431 chip, which performs rectification, filtering, and voltage feedback sampling processing on the electrical energy.
[0044] Furthermore, the overcurrent sampling module 5 includes a fifth resistor R5, a first reference power supply VREF, a first comparator A1, a second capacitor C2, a sixth resistor R6, a third capacitor C3, a third diode D3, a first logic chip J1, a second diode D2, and a first power supply VCC1;
[0045] Specifically, the non-inverting input of the first comparator A1 is connected to the first end of the fourth resistor R4 through the fifth resistor R5. The inverting input of the first comparator A1 is connected to the first reference power supply VREF and one end of the third capacitor C3, and is connected to the other end of the third capacitor C3 through the sixth resistor R6 and the second capacitor C2, the output terminal of the first comparator A1 and the anode of the third diode D3. The cathode of the third diode D3 is connected to the cathode of the second diode D2 and the A end of the first logic chip J1. The B end of the first logic chip J1 is connected to the first power supply VCC1, and the Y end of the first logic chip J1 is connected to the anode of the second diode D2.
[0046] In a specific embodiment, the first reference power supply VREF provides an overcurrent threshold; the first comparator A1 can be an LM358 comparator; the first logic chip J1 can be an AND gate chip, which works in conjunction with the first power supply VCC1, the second diode D2 and the third diode D3 to perform self-locking.
[0047] Furthermore, the current limiting module 2 also includes a first switch V1, a second switch V2, a first relay K1, and a first relay switch K1-1;
[0048] Specifically, the base of the first switching transistor V1 is connected to the collector of the second switching transistor V2, the base of the fourth switching transistor V4, and the timing module 3; the emitter of the first switching transistor V1 is connected to the emitter of the second switching transistor V2, the moving end of the first relay switch K1-1, and the second end of the power interface; the collector of the first switching transistor V1 is connected to one end of the first relay K1; the other end of the first relay K1 is connected to the first end of the power interface; and the base of the second switching transistor V2 is connected to the Y end of the first logic chip J1.
[0049] In a specific embodiment, both the first switching transistor V1 and the second switching transistor V2 can be NPN transistors; the first relay K1 controls the closing of the first relay switch K1-1 by magnetic attraction.
[0050] Furthermore, the protection module 6 includes a second logic chip J2 and a third switch V3;
[0051] Specifically, the A and B terminals of the second logic chip J2 are connected to the Y terminal of the first logic chip J1 and the output terminal of the first comparator A1, respectively. The Y terminal of the second logic chip J2 is connected to the base of the third switch V3. The emitter of the third switch V3 is grounded, and the collector of the third switch V3 is connected to the gate of the first power transistor Q1.
[0052] In a specific embodiment, the third switch V3 can be an NPN transistor; the second logic chip J2 can be an AND gate chip.
[0053] Furthermore, the timing module 3 includes a fourth capacitor C4, a fifth diode D5, a seventh resistor R7, a first timer IC1, and a fifth capacitor C5;
[0054] Specifically, the fourth and eighth terminals of the first timer IC1 are both connected to the first terminal of the power interface and connected to the cathode of the fifth diode D5 through the fourth capacitor C4. The sixth and second terminals of the first timer IC1 are connected to the anode of the fifth diode D5 through the seventh resistor R7. The drain of the first power transistor Q1 is connected to the first terminal of the first timer IC1 and one terminal of the fifth capacitor C5. The other terminal of the fifth capacitor C5 is connected to the fifth terminal of the first timer IC1. The third terminal of the first timer IC1 is connected to the base of the first switching transistor V1.
[0055] In a specific embodiment, the first timer IC1 mentioned above can be an NE555 chip.
[0056] In this embodiment, a switching power supply startup current limiting control circuit receives DC power from the power interface. The first power transistor Q1 is triggered to conduct via the first resistor R1, the second resistor R2, and the first diode D1. The first power transistor Q1 then performs startup current limiting. A power regulation device, in conjunction with an output processing device, regulates the power output of the first transformer B1. Simultaneously, the first timer IC1, in conjunction with the fourth capacitor C4, the seventh resistor R7, the fifth capacitor C5, and the fifth diode D5, performs timing operations. After the timing expires, it continuously triggers the first switching transistor V1 to conduct, energizing the first relay K1 and controlling the first relay switch K1-1 to conduct, which in turn triggers the fourth switching transistor V4 to conduct. The first power transistor Q1 is then turned off, stopping the current limiting operation. Simultaneously, the fourth resistor R4... The power regulation device samples the current. The first comparator A1, in conjunction with the fifth resistor R5, the sixth resistor R6, the second capacitor C2, the third capacitor C3, and the first reference power supply VREF, performs overcurrent detection. When an overcurrent occurs, the first logic chip J1, in conjunction with the second diode D2, the third diode D3, and the first power supply VCC1, performs a high-level self-locking and triggers the second switch V2 to turn on. The A terminal of the second logic chip J2 becomes high, the first switch V1 turns off, and the first power transistor Q1 turns on again and performs current limiting. When the overcurrent condition persists, the first comparator A1 controls the B terminal of the second logic chip J2 to become high, the second logic chip J2 triggers the third switch V3 to turn on, triggers the first power transistor Q1 to turn off, and then stops power supply control.
[0057] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A switching power supply startup current limiting control circuit, characterized in that, The switching power supply startup current limiting control circuit includes: a power supply module, a startup current limiting module, a timing module, a switching power supply module, an overcurrent sampling module, and a protection module; The power module is used to connect to DC power. The start-up current limiting module is connected to the power supply module and is used to transmit DC power and perform current limiting transmission processing on the input DC power. The timing module is connected to the power supply module, the start-up current limiting module, and the switching power supply module. It is used to set the timing time and start timing operation when receiving DC power from the start-up current limiting module. After the timing ends, it controls the start-up current limiting module to stop power transmission and transmit DC power to the switching power supply module. The switching power supply module is connected to the start-up current limiting module and the power supply module, and is used to perform power regulation on the incoming electrical energy. The overcurrent sampling module is connected to the switching power supply module and the timing module. It is used to sample the current of the switching power supply module and detect overcurrent. When an overcurrent occurs, it outputs a first control signal, performs self-locking processing on the first control signal, and outputs a second control signal to control the timing module to stop the power transmission. The protection module is connected to the start-up current limiting module and the overcurrent sampling module, and is used to control the start-up current limiting module to stop power transmission when the first control signal and the second control signal are received simultaneously.
2. The switching power supply start-up current limiting control circuit according to claim 1, characterized in that, The power module includes a power interface; the startup current limiting module includes a first resistor, a second resistor, a first diode, a fourth switching transistor, and a first power transistor; The first end of the power interface is connected to the gate of the first power transistor, one end of the second resistor, the cathode of the first diode, and the collector of the fourth switching transistor via a first resistor. The source of the first power transistor is connected to the other end of the second resistor, the anode of the first diode, the emitter of the fourth switching transistor, the second end of the power interface, and the ground terminal. The base of the fourth switching transistor is connected to the timing module.
3. The switching power supply start-up current limiting control circuit according to claim 2, characterized in that, The switching power supply module includes a first capacitor, a third resistor, a fourth diode, a first transformer, an output processing device, a power regulation device, and a fourth resistor; One end of the first capacitor is connected to the first end of the primary side of the first transformer, the first end of the power interface, and the first end of the power conditioning device, and is connected to the other end of the first capacitor and the cathode of the fourth diode through the third resistor. The anode of the fourth diode is connected to the second end of the secondary side of the first transformer and the second end of the power conditioning device. The first end and the second end of the secondary side of the first transformer are respectively connected to the first end and the second end of the output processing device. The third end of the power conditioning device is connected to the third end of the output processing device. The fourth end of the power conditioning device is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the drain of the first power transistor.
4. The switching power supply start-up current limiting control circuit according to claim 3, characterized in that, The overcurrent sampling module includes a fifth resistor, a first reference power supply, a first comparator, a second capacitor, a sixth resistor, a third capacitor, a third diode, a first logic chip, a second diode, and a first power supply. The non-inverting input of the first comparator is connected to the first end of the fourth resistor through the fifth resistor. The inverting input of the first comparator is connected to the first reference power supply and one end of the third capacitor, and is connected to the other end of the third capacitor through the sixth resistor and the second capacitor in sequence, the output terminal of the first comparator and the anode of the third diode. The cathode of the third diode is connected to the cathode of the second diode and the A terminal of the first logic chip. The B terminal of the first logic chip is connected to the first power supply, and the Y terminal of the first logic chip is connected to the anode of the second diode.
5. The switching power supply startup current limiting control circuit according to claim 4, characterized in that, The current limiting module for startup also includes a first switching transistor, a second switching transistor, a first relay, and a first relay switch; The base of the first switching transistor is connected to the collector of the second switching transistor, the base of the fourth switching transistor, and the timing module. The emitter of the first switching transistor is connected to the emitter of the second switching transistor, the moving end of the first relay switch, and the second end of the power interface. The collector of the first switching transistor is connected to one end of the first relay. The other end of the first relay is connected to the first end of the power interface. The base of the second switching transistor is connected to the Y end of the first logic chip.
6. The switching power supply startup current limiting control circuit according to claim 5, characterized in that, The protection module includes a second logic chip and a third switching transistor; The A and B terminals of the second logic chip are respectively connected to the Y terminal of the first logic chip and the output terminal of the first comparator. The Y terminal of the second logic chip is connected to the base of the third switching transistor. The emitter of the third switching transistor is grounded, and the collector of the third switching transistor is connected to the gate of the first power transistor.
7. The switching power supply startup current limiting control circuit according to claim 6, characterized in that, The timing module includes a fourth capacitor, a fifth diode, a seventh resistor, a first timer, and a fifth capacitor; The fourth and eighth terminals of the first timer are both connected to the first terminal of the power interface and connected to the cathode of the fifth diode through the fourth capacitor. The sixth and second terminals of the first timer are connected to the anode of the fifth diode and the drain of the first power transistor through the seventh resistor. The first terminal of the first timer and one terminal of the fifth capacitor are connected. The other terminal of the fifth capacitor is connected to the fifth terminal of the first timer. The third terminal of the first timer is connected to the base of the first switching transistor.