Control circuit for rapidly detecting VCC power failure and switching power supply
By combining a power supply auxiliary source, a power failure detection module, and a signal processing module, and utilizing a voltage divider circuit and an RC circuit to quickly detect VCC power failure, the problem of slow response speed and high cost in existing technologies is solved, achieving low power consumption and stable VCC power failure detection.
Patent Information
- Application Number
- CN202423098860.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2034-12-13
AI Technical Summary
Existing switching power supplies suffer from slow response speed, complex external circuitry, and high cost in VCC power failure detection.
The system employs a combination of auxiliary power supply, power failure detection module, and signal processing module. It achieves rapid detection of VCC power failure through voltage divider circuit and RC circuit, and discharges in case of abnormality using unidirectional conduction circuit. The main control chip responds quickly to the VCC power supply signal status.
It achieves fast, low-cost, and stable VCC power-down detection, simplifies the circuit structure, reduces power consumption, and reduces PCB footprint.
Smart Images
Figure CN223758163U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of switching power supply, more particularly to a kind of control circuit and switching power supply of rapid detection VCC power failure. BACKGROUND
[0002] In current switching power supply, VCC power supply occupies important role, and it supplies power to different circuits, so that each part of the circuit can work stably. In practical application process, the power supply system is prone to unpredictable power failure. In order to ensure stable operation of power supply, power failure detection control circuit is essential.
[0003] In the existing switching power supply, there are mainly two ways for VCC detection. The first way is to use MOS tube, triode, resistor, electrolytic capacitor and other components in combination, to compare and judge the voltage level of output power failure detection signal, and then control the conduction of triode or MOS tube. However, this way of detecting power failure by connecting output power failure detection signal to MCU detection IO port has high cost, and the peripheral circuit components are more, which greatly occupies the space of PCB board, resulting in the increase of the size of switching power supply. The second way is to use comparator as power failure detection circuit, and use comparator to judge voltage condition, and then output low-level alarm signal to MCU or other terminal for detection and judgment. However, this detection method not only has the problem of poor detection accuracy, but also needs peripheral conditions for use, which is difficult to realize for some circuits, and also causes high cost and large size. UTILITY MODEL CONTENTS
[0004] The utility model solves the technical problem in view of the problems existing in prior art, and provides a kind of control circuit and switching power supply of rapid detection VCC power failure.
[0005] The utility model solves the technical problem and adopts the technical scheme that a kind of control circuit of rapid detection VCC power failure is constructed, including: power supply auxiliary source, power failure detection module and signal processing module.
[0006] The detection end of the power failure detection module is connected with the power supply auxiliary source, and the output end of the power failure detection module is connected with the detection end of the signal processing module.
[0007] The power supply auxiliary source is used to generate VCC power signal.
[0008] The power failure detection module is used to detect the VCC power signal and output VCC detection signal.
[0009] The signal processing module is configured to receive the VCC detection signal and detect the state of the VCC power supply signal based on the VCC detection signal.
[0010] The power failure detection module comprises a voltage dividing circuit and an RC circuit.
[0011] The input end of the voltage dividing circuit is connected with the auxiliary power supply, the output end of the voltage dividing circuit is connected with the input end of the RC circuit, and the output end of the RC circuit is connected with the signal processing module.
[0012] The power failure detection module further comprises a unidirectional conduction circuit.
[0013] The unidirectional conduction circuit is connected with the voltage dividing circuit and is configured to perform discharging when the state of the VCC power supply signal is abnormal.
[0014] The voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor.
[0015] The first end of the first voltage dividing resistor is connected with the auxiliary power supply, the second end of the first voltage dividing resistor is connected with the first end of the second voltage dividing resistor, and the second end of the second voltage dividing resistor is connected with the input end of the RC circuit.
[0016] The first end of the first voltage dividing resistor is the input end of the voltage dividing circuit, and the second end of the second voltage dividing resistor is the output end of the voltage dividing circuit.
[0017] The RC circuit comprises a seventh capacitor and a fifth resistor.
[0018] The first end of the seventh capacitor is connected with the output end of the voltage dividing circuit, the second end of the seventh capacitor is grounded, the first end of the fifth resistor is connected with the output end of the voltage dividing circuit and connected to the detection end of the signal processing module, and the second end of the fifth resistor is grounded.
[0019] The first end of the fifth resistor is the output end of the power failure module.
[0020] The unidirectional conduction circuit comprises a twelfth diode and a tenth diode.
[0021] An anode of the tenth diode is connected with a second end of the first voltage dividing resistor and a first end of the first voltage dividing resistor, a cathode of the tenth diode is connected with an anode of the twelfth diode, and a cathode of the twelfth diode is connected with an input circuit.
[0022] The input circuit is connected with an alternating current input signal at one end and connected with the power failure detection module at the other end.
[0023] The input circuit is connected with an alternating current input signal at one end and connected with the power failure detection module at the other end.
[0024] The input circuit comprises a rectifier bridge, a first capacitor, a first inductor and a second capacitor.
[0025] An input end of the rectifier bridge is connected with the alternating current input signal, an output end of the rectifier bridge is connected with a first end of the first capacitor and a first end of the first inductor, a second end of the first capacitor is grounded, and a second end of the first inductor is connected with a first end of the second capacitor and a cathode of the twelfth diode.
[0026] The signal processing module comprises a main control chip and a peripheral power supply circuit.
[0027] A detection pin of the main control chip is connected with an output end of the power failure detection module, a power supply pin of the main control chip is connected with an output end of the peripheral power supply circuit, and an input end of the peripheral power supply circuit is connected with a chip power supply signal.
[0028] The utility model also provides a switching power supply, which comprises the control circuit for quickly detecting VCC power failure.
[0029] The control circuit for quickly detecting VCC power failure and the switching power supply have the following beneficial effects: the control circuit comprises a power supply auxiliary source, a power failure detection module and a signal processing module; a detection end of the power failure detection module is connected with the power supply auxiliary source; an output end of the power failure detection module is connected with a detection end of the signal processing module; the power supply auxiliary source is used for generating a VCC power supply signal; the power failure detection module is used for detecting the VCC power supply signal and outputting a VCC detection signal; and the signal processing module is used for receiving the VCC detection signal and detecting a state of the VCC power supply signal based on the VCC detection signal. The utility model can quickly detect the power failure of the VCC power supply signal without using a switching tube or a comparator, and has the advantages of simple circuit, low cost, low power consumption and good stability. BRIEF DESCRIPTION OF DRAWINGS
[0030] The utility model will be further described below in combination with the drawings and embodiments, wherein:
[0031] Figure 1 It is the principle block diagram of the control circuit of the utility model provides fast detection VCC power failure;
[0032] Figure 2 And Figure 3 It is the circuit diagram of the control circuit of the utility model provides fast detection VCC power failure. DETAILED DESCRIPTION
[0033] The technical solutions in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model and not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.
[0034] In view of the problems existing in the existing VCC power failure detection scheme, the utility model provides a control circuit for fast detection of VCC power failure, which can solve the problems of slow response speed, complex peripheral circuit, high cost and large PCB space occupation of the existing power failure detection circuit.
[0035] Reference Figure 1 , Figure 1 It is the principle block diagram of the control circuit of the utility model provides fast detection VCC power failure.
[0036] Specifically, as shown in Figure 1 The control circuit for fast detection of VCC power failure includes: power supply auxiliary source 20, power failure detection module 30 and signal processing module 40. Wherein, the detection end of power failure detection module 30 is connected with power supply auxiliary source 20, and the output end of power failure detection module 30 is connected with the detection end of signal processing module 40. Further, as shown in Figure 1 The control circuit for fast detection of VCC power failure further includes: input circuit 10; one end of the input circuit 10 is connected with AC input signal, and the other end of the input circuit 10 is connected with power failure detection module 30.
[0037] In the embodiments of the utility model, power supply auxiliary source 20 is used to generate VCC power supply signal. Wherein, power supply auxiliary source 20 is the auxiliary power supply network in the existing switching power supply, and its specific structure composition can refer to the existing scheme, for example, it can include fuse tube, inductor, rectifier bridge CBB, control IC transformer, electrolytic capacitor, etc. It is mainly used to provide VCC power supply signal for power supply.
[0038] The power-off detection module 30 is used for detecting the VCC power supply signal and outputting a VCC detection signal.
[0039] Optionally, the power-off detection module 30 comprises a voltage dividing circuit and an RC circuit in the embodiment of the utility model, the input end of the voltage dividing circuit is connected with the auxiliary power supply 20, the output end of the voltage dividing circuit is connected with the input end of the RC circuit, and the output end of the RC circuit is connected with the signal processing module 40.
[0040] The signal processing module 40 is used for receiving the VCC detection signal and detecting the state of the VCC power supply signal based on the VCC detection signal.
[0041] Reference Figure 2 And Figure 3 , Figure 2 The circuit diagram of a preferred embodiment of the power-off detection module 30 is shown in the figure, Figure 3 The circuit diagram of the main control chip and the peripheral power supply circuit is shown in the figure. Figure 2 The VCC in the figure is the VCC power supply signal output by the auxiliary power supply 20.
[0042] As Figure 2 And Figure 3As shown, in this embodiment, the voltage dividing circuit includes: a first voltage dividing resistor R52 and a second voltage dividing resistor R107; a first end of the first voltage dividing resistor R52 is connected to the auxiliary power supply 20, a second end of the first voltage dividing resistor R52 is connected to a first end of the second voltage dividing resistor R107, and a second end of the second voltage dividing resistor R107 is connected to an input end of the RC circuit; wherein the first end of the first voltage dividing resistor R52 is an input end of the voltage dividing circuit, and the second end of the second voltage dividing resistor R107 is an output end of the voltage dividing circuit.
[0043] The RC circuit includes: a seventh capacitor C7 and a fifth resistor R5; a first end of the seventh capacitor C7 is connected to the output end of the voltage dividing circuit (i.e. the second end of the second voltage dividing resistor R107), a second end of the seventh capacitor C7 is grounded, a first end of the fifth resistor R5 is connected to the output end of the voltage dividing circuit and connected to a detection end of the signal processing module 40 (i.e. a detection pin of the master control chip, which is the sixth pin (PA0 port) of the master control chip shown in the middle of the figure), and a second end of the fifth resistor R5 is grounded; the first end of the fifth resistor R5 is an output end of the power-off module. Figure 3
[0044] In this embodiment, the one-way conduction circuit includes: a twelfth diode D10 and a tenth diode D12; an anode of the tenth diode D12 is connected to the second end of the first voltage dividing resistor R52 and the first end of the first voltage dividing resistor R52, a cathode of the tenth diode D12 is connected to an anode of the twelfth diode D10, and a cathode of the twelfth diode D10 is connected to the input circuit 10. The input circuit 10 includes: a rectifier bridge BD1, a first capacitor CBB1, a first inductor L1, and a second capacitor CBB2; an input end of the rectifier bridge BD1 is connected to an alternating current input signal, an output end of the rectifier bridge BD1 is connected to a first end of the first capacitor CBB1 and a first end of the first inductor L1, a second end of the first capacitor CBB1 is grounded, and a second end of the first inductor L1 is connected to a first end of the second capacitor CBB2 and the cathode of the twelfth diode D10.
[0045] As shown in Figure 2 and Figure 3 , the twelfth diode D10, the tenth diode D12, the first voltage dividing resistor R52, the second voltage dividing resistor R107, the seventh capacitor C7, and the fifth resistor R5 constitute a power-off module, the twelfth diode D10 and the tenth diode D12 are used in series, Figure 3 , the VCC_VSENSE in the figure is a VCC detection signal. The MCU2 is a master control chip.
[0046] As shown in Figure 2 and Figure 3 As shown, at the power-on time, the twelfth diode D10 and the tenth diode D12 are in the reverse blocking state, the power supply auxiliary source 20 outputs the VCC power supply signal, which is transmitted to the detection pin of the main control chip through the fifth voltage dividing resistor and the second voltage dividing resistor R107, at this time, the PA0 pin can detect the stable and continuous voltage input, at this time, it is judged that the VCC is normal. When the power supply is powered off or the VCC voltage drops (that is, the VCC power supply is powered off), the voltage of the test point B drops, at this time, the detection pin of the main control chip detects the voltage fluctuation, and the main control chip can quickly process according to the fluctuation voltage VCC power supply or power supply, so as to realize the fast response. Among them, when the power supply is powered off or the VCC power supply is powered off, the twelfth diode D10 and the tenth diode D12 begin to discharge.
[0047] The utility model discloses a power-down detection module 30 is adopted to realize the detection of the voltage variation of VCC power supply signal, and then the main control chip realizes the fast response to the voltage variation of VCC according to the detection signal, reaches the purpose of fast detection VCC power-down. The detection mode is very flexible and simple. Moreover, the utility model discloses a power switch tube (such as MOS pipe, triode), comparator and the like complex circuit structure is not needed, greatly simplifies the structure of detection circuit, makes the cost of switching power supply lower, and the power consumption is lower, and the stability is also good.
[0048] The utility model also provides a switching power supply, it can include the control circuit of fast detection VCC power-down disclosed in the utility model embodiment, wherein, the switching power supply can be LED drive power supply.
[0049] The above embodiments are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable those skilled in the art to understand the content of the utility model and implement accordingly, and cannot limit the protection scope of the utility model. Any equivalent change and modification within the scope of the claims of the utility model shall belong to the scope of the claims of the utility model.
Claims
1. A control circuit for fast detection of VCC brownout, characterized in that, The application relates to a power supply auxiliary source, a power-off detection module and a signal processing module. The detection end of the power-off detection module is connected with the power supply auxiliary source, and the output end of the power-off detection module is connected with the detection end of the signal processing module. The power supply auxiliary source is used for generating a VCC power supply signal. The power-off detection module is used for detecting the VCC power supply signal and outputting a VCC detection signal. The signal processing module is used for receiving the VCC detection signal and detecting the state of the VCC power supply signal based on the VCC detection signal. The power-off detection module comprises a voltage dividing circuit and an RC circuit.
2. The control circuit for fast detection of VCC brownout according to claim 1, wherein, The input end of the voltage dividing circuit is connected with the power supply auxiliary source, the output end of the voltage dividing circuit is connected with the input end of the RC circuit, and the output end of the RC circuit is connected with the signal processing module. The power-off detection module further comprises a one-way conduction circuit.
3. The control circuit for quickly detecting VCC brownout according to claim 2, wherein, The one-way conduction circuit is connected with the voltage dividing circuit and is used for discharging when the state of the VCC power supply signal is abnormal. The voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor.
4. The control circuit for fast detection of VCC brownout according to claim 3, wherein, The first end of the first voltage dividing resistor is connected with the power supply auxiliary source, the second end of the first voltage dividing resistor is connected with the first end of the second voltage dividing resistor, and the second end of the second voltage dividing resistor is connected with the input end of the RC circuit. The first end of the first voltage dividing resistor is the input end of the voltage dividing circuit, and the second end of the second voltage dividing resistor is the output end of the voltage dividing circuit. The RC circuit comprises a seventh capacitor and a fifth resistor.
5. The control circuit for fast detection of VCC brownout according to claim 3, wherein, The first end of the seventh capacitor is connected with the output end of the voltage dividing circuit, the second end of the seventh capacitor is grounded, the first end of the fifth resistor is connected with the output end of the voltage dividing circuit and connected to the detection end of the signal processing module, and the second end of the fifth resistor is grounded. The first end of the fifth resistor is the output end of the power-off detection module. The one-way conduction circuit comprises a twelfth diode and a tenth diode.
6. The control circuit for fast detection of VCC brownout according to claim 4, wherein, The anode of the tenth diode is connected with the second end of the first voltage dividing resistor and the first end of the first voltage dividing resistor, the cathode of the tenth diode is connected with the anode of the twelfth diode, and the cathode of the twelfth diode is connected with an input circuit. Further comprising:
7. The control circuit for fast detection of VCC brownout according to claim 6, wherein, The input circuit; One end of the input circuit is connected with an alternating current input signal, and the other end of the input circuit is connected with the power-off detection module. The input circuit comprises a rectifier bridge, a first capacitor, a first inductor and a second capacitor.
8. The control circuit for fast detection of VCC brownout according to claim 7, wherein, The input end of the rectifier bridge is connected with the alternating current input signal, the output end of the rectifier bridge is connected with the first end of the first capacitor and the first end of the first inductor, the second end of the first capacitor is grounded, and the second end of the first inductor is connected with the first end of the second capacitor and the cathode of the twelfth diode. The signal processing module comprises a master control chip and a peripheral power supply circuit.
9. The control circuit for fast detection of VCC brownout according to claim 1, wherein, The detection pin of the master control chip is connected with the output end of the power-off detection module, the power supply pin of the master control chip is connected with the output end of the peripheral power supply circuit, and the input end of the peripheral power supply circuit is connected with a chip power supply signal. 10. A switching power supply, characterized by The control circuit for fast detection of VCC power-down according to any one of claims 1-9.