A power supply circuit

Abstract

The utility model provides a kind of power supply circuit, comprising: voltage conversion circuit, voltage maintaining circuit, voltage detection circuit, on-off control circuit and bleed circuit;By configuring voltage maintaining circuit, seamless takeover power supply when external power failure, maintain electronic equipment continuous operation to complete key data save, reach the purpose of protecting key data.Through voltage detection circuit, on-off control circuit and bleed circuit accurate control power supply circuit, solve the electronic equipment injury caused by accidental power failure, neither affect the power supply of voltage maintaining circuit, can effectively control power off when needing to close load power supply, and the excess electric quantity in circuit is rapidly released, significantly improve reliability and service life.The power supply circuit provided by the utility model has the advantages of low production cost and strong practicality.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology, specifically, to a power supply circuit. Background Technology

[0002] With the development of technology, in order to ensure that electronic devices can completely save critical data when the main power supply fails, a backup power supply is often needed to continue supplying power to the electronic devices for a certain period of time to complete the critical data saving operation. However, if the power supply circuit is not designed properly and an unexpected power outage occurs, it may cause data loss at best, and damage to the equipment or safety hazards at worst.

[0003] Chinese invention patent CN120657938A discloses a hardware-software collaborative power protection circuit for a power distribution automation terminal. The circuit includes a power input protection circuit, a voltage conversion circuit, a power failure detection circuit, a voltage maintenance protection circuit, and a clock backup battery protection circuit. The power failure detection circuit employs opto-isolation technology to monitor the power input status in real time. When a power outage or power failure is detected, a specific level signal is output to trigger a power failure event detection. At the software level, the function of the power failure detection pin is precisely defined in the device tree, configured as an interrupt trigger pin, and relevant parameters are initialized, setting the interrupt trigger condition to a level change. When the interrupt trigger condition occurs, a power failure detection event can be quickly triggered, including a delayed confirmation event and the execution event of the power failure handling function. This invention, through a hardware-software collaborative power failure detection mechanism, achieves a response to power anomalies, buying time for subsequent power failure protection operations.

[0004] However, the aforementioned invention requires hardware circuitry and corresponding software programs to manage the power protection circuit, making it unsuitable for some cost-sensitive general-purpose electronic devices. Furthermore, it does not adequately consider the impact of power disconnection, including the possibility of residual electrical energy in the circuit. If this residual energy is not promptly discharged, re-energizing the circuit may prevent it from resetting and restarting properly, leading to malfunctions. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a power supply circuit that maintains the continuous operation of electronic devices to save critical data after an abnormal power outage. This power supply circuit is characterized by its simple structure and low cost, making it suitable for various electronic devices. Through precise control of the power supply circuit, it overcomes the problem of the residual power stored inside the circuit failing to be released in time when the external power supply suddenly fails, thus preventing functional abnormalities and safety hazards to the electronic devices.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a power supply circuit, comprising: A voltage conversion circuit, whose input terminal is connected to an external input power supply, is used to receive the raw voltage output by the external input power supply and convert the raw voltage into a working voltage that is adapted to the working requirements of the load. A voltage sustaining circuit is connected in parallel with the output of the voltage conversion circuit. When the input power supply is normal, the electrical energy output by the voltage conversion circuit completes the charging and energy storage. When the external input power supply is disconnected, it automatically switches to the discharge mode to maintain the continuous power supply to the load by releasing the stored electrical energy. A voltage detection circuit, whose detection terminal is connected to the output terminal of the voltage conversion circuit, detects the voltage amplitude at the output terminal of the voltage conversion circuit in real time; when the detected voltage amplitude is higher than its preset voltage amplitude threshold, it outputs a first level signal; when the detected voltage amplitude is lower than its preset voltage amplitude threshold, it outputs a second level signal. An on / off control circuit includes a control section and a switching section; triggered by a received first level signal, the control section controls the switching section to turn on, so as to form a conduction loop from the output terminal of the voltage conversion circuit to the load; triggered by a received second level signal, the control section controls the switching section to turn off, so as to cut off the power supply loop from the output terminal of the voltage conversion circuit to the load. The discharge circuit includes a control switch and a discharge resistor; triggered by the received second level signal, the control switch is turned on, and the discharge resistor is connected to the output terminal of the voltage conversion circuit, so that the excess power in the circuit is released through the discharge resistor.

[0007] When an external power supply fails, the internal voltage conversion circuit, voltage maintenance circuit, voltage detection circuit, on / off control circuit, and discharge circuit of the power supply circuit protect the load from the impact of sudden power failure, ensuring stable load operation and guaranteeing the preservation of critical data. The voltage detection circuit collects the voltage signal from the power supply circuit in real time and detects the voltage amplitude. By comparing it with a preset voltage amplitude, it outputs a control level signal to precisely control the conduction or cutoff of the on / off control circuit and the discharge circuit, avoiding damage caused by abnormal power supply voltage and improving the reliability and safety of the load.

[0008] In a preferred embodiment, the voltage sustaining circuit includes a first supercapacitor and a second supercapacitor connected in series, and a first voltage equalizing resistor and a second voltage equalizing resistor connected in series; wherein the first voltage equalizing resistor is connected in parallel with the first supercapacitor, and the second voltage equalizing resistor is connected in parallel with the second supercapacitor.

[0009] When an external power supply fails, the voltage sustaining circuit plays a crucial role. By rapidly initiating a discharge operation, it can provide stable power support to the load for a short period, maintaining its normal operation. The capacitance value of the first and second farad capacitors, connected in series, is one of the key factors affecting the power sustaining time. The first and second voltage equalizing resistors ensure uniform voltage distribution, preventing damage or performance degradation of the first and second farad capacitors due to voltage imbalances.

[0010] In a preferred embodiment, the voltage detection circuit includes a voltage detection chip and a first current-limiting resistor; the input pin of the voltage detection chip is connected to the output terminal of the voltage conversion circuit as the detection terminal of the voltage detection circuit; the reset pin of the voltage detection chip is connected to one end of the first current-limiting resistor, and the other end of the first current-limiting resistor is connected to the on / off control circuit and the discharge circuit as the signal output terminal of the voltage detection circuit.

[0011] The voltage detection circuit can monitor the voltage status of the power supply circuit in real time and accurately. After comparing it with the preset voltage amplitude, it inputs control level signals to the on / off control circuit and the discharge circuit to precisely control the conduction or cutoff of the on / off control circuit and the discharge circuit. The magnitude of the current is limited by the first current-limiting resistor to protect the associated circuit components from damage caused by excessive current.

[0012] In a preferred embodiment, the voltage amplitude threshold is calculated as follows: U2 = U1 - (t / C) × I; Where t is the continuous power supply time required by the load when the input power is disconnected; C is the capacitance value after the first farad capacitor and the second farad capacitor are connected in series; U1 is the initial voltage value when the power is off; and I is the load current.

[0013] By calculating reasonable voltage amplitude thresholds for loads and farad capacitors of different specifications, as well as the required load power supply time when the input power supply is disconnected, the stability and reliability of the power supply circuit can be ensured.

[0014] In a preferred embodiment, the on / off control circuit includes a P-type MOSFET and an N-type MOSFET; the source of the P-type MOSFET is connected to the output terminal of the voltage conversion circuit, the drain is connected to one end of the load, the gate of the P-type MOSFET is connected to the drain of the N-type MOSFET, the gate of the N-type MOSFET is connected to the signal output terminal of the voltage detection circuit, and the source of the N-type MOSFET is grounded. The N-type MOSFET is triggered when it receives the first level signal, and after the N-type MOSFET switches the level, it drives the P-type MOSFET to turn on; the N-type MOSFET is triggered when it receives the second level signal, and after the N-type MOSFET switches the level, it drives the P-type MOSFET to turn off.

[0015] Using P-type MOSFETs as high-side switches is less expensive and does not require a charge pump, making it simple and convenient; then, using N-type MOSFETs for drive level conversion enables control of load shutdown and operation.

[0016] In a preferred embodiment, the bleeder circuit includes a PNP transistor, the emitter of which is connected to the output terminal of the voltage conversion circuit, the base of which is connected to the signal output terminal of the voltage detection circuit, and the collector of which is connected to the bleeder resistor and then grounded.

[0017] When the PNP transistor receives the second-level signal, it connects to the bleeder resistor, discharging the electrical energy in the circuit to ground. This allows for the rapid release of any remaining electrical charge stored in the circuit when the external power supply stops. This prevents the circuit from failing to reset and restart properly if the external power supply is not completely deactivated, thus avoiding malfunctions.

[0018] This invention represents a substantial improvement over existing technologies. Specifically, by configuring a voltage sustaining circuit, it seamlessly takes over power supply when the external power source fails, maintaining continuous operation of electronic devices to save critical data and thus protecting it. Through precise control of the power supply circuit via a voltage detection circuit, on / off control circuit, and discharge circuit, it solves the problem of damage to electronic devices caused by unexpected power outages. It does not affect the power supply to the voltage sustaining circuit, and effectively controls power shutdown when the load power needs to be turned off, rapidly releasing excess charge in the circuit, significantly improving reliability and lifespan. The power supply circuit provided by this invention also has the advantages of low production cost and high practicality. Attached Figure Description

[0019] Figure 1 This is a schematic block diagram of a power supply circuit provided by this utility model; Figure 2 This is a circuit diagram of a power supply circuit provided by this utility model. Detailed Implementation

[0020] The technical solution of this utility model will be further described in detail below through specific embodiments.

[0021] Example 1 like Figure 1 As shown, this utility model provides a power supply circuit, including: The voltage conversion circuit has its input terminal connected to an external input power supply. It is used to receive the original voltage VIN output by the external input power supply and convert the original voltage VIN into a working voltage VOUT that is adapted to the working requirements of the load R8. A voltage sustaining circuit is connected in parallel with the output of the voltage conversion circuit. When the input power supply is normal, the electrical energy output by the voltage conversion circuit completes the charging and energy storage. When the external input power supply is disconnected, it automatically switches to the discharge mode to maintain the continuous power supply to the load R8 by releasing the stored electrical energy. A voltage detection circuit, whose detection terminal is connected to the output terminal of the voltage conversion circuit, detects the voltage amplitude at the output terminal of the voltage conversion circuit in real time; when the detected voltage amplitude is higher than its preset voltage amplitude threshold, it outputs a first level signal; when the detected voltage amplitude is lower than its preset voltage amplitude threshold, it outputs a second level signal. The on / off control circuit includes a control section and a switching section; triggered by a received first level signal, the control section controls the switching section to conduct, so as to form a conduction loop from the output terminal of the voltage conversion circuit to the load R8; triggered by a received second level signal, the control section controls the switching section to turn off, so as to cut off the power supply loop from the output terminal of the voltage conversion circuit to the load R8. The discharge circuit includes a control switch and a discharge resistor R6; triggered by the received second level signal, the control switch is turned on, and the discharge resistor R6 is connected to the output terminal of the voltage conversion circuit, so that the excess power in the circuit is released through the discharge resistor R6.

[0022] Example 2 like Figure 2 As shown, this embodiment provides a specific implementation of a power supply circuit.

[0023] Specifically, the voltage conversion circuit can use a voltage conversion chip U1, with an input filter circuit connected in parallel to the input pins of the voltage conversion chip, and an output filter circuit connected in parallel to the output pins of the voltage conversion chip; the input filter circuit includes filter capacitors C1 and C2 connected in parallel, and the output filter circuit includes filter capacitors C3 and C4 connected in parallel.

[0024] By filtering the output through input and output filter circuits, noise such as ripple and interference in the signal is reduced, providing a more stable DC output and protecting subsequent circuits from unintentional interference.

[0025] The voltage sustaining circuit includes a first supercapacitor C5 and a second supercapacitor C6 connected in series, and a first voltage equalizing resistor R4 and a second voltage equalizing resistor R5 connected in series; wherein the first voltage equalizing resistor R4 is connected in parallel with the first supercapacitor C5, and the second voltage equalizing resistor R5 is connected in parallel with the second supercapacitor C6.

[0026] When the external input power supply is not available, the first farad capacitor C5 and the second farad capacitor C6 continue to provide power to the downstream load R8 for a certain period of time, so that it can save critical data.

[0027] The voltage detection circuit includes a voltage detection chip U2 and a first current-limiting resistor R3; the input pin of the voltage detection chip U2 is connected to the output pin of the voltage conversion circuit as the detection terminal of the voltage detection circuit; the reset pin of the voltage detection chip U2 is connected to one end of the first current-limiting resistor R3, and the other end of the first current-limiting resistor R3 is connected to the on / off control circuit and the discharge circuit as the signal output terminal of the voltage detection circuit.

[0028] The calculation expression for the voltage amplitude threshold is: U2 = U1 - (t / C) × I; Where t is the continuous power supply time required for load R8 when the input power is disconnected; C is the capacitance value after the first farad capacitor C5 and the second farad capacitor C6 are connected in series; U1 is the initial voltage value when the power is off; and I is the load R8 current.

[0029] The on / off control circuit includes a P-type MOSFET Q2 and an N-type MOSFET Q3; the source of the P-type MOSFET Q2 is connected to the output terminal of the voltage conversion circuit, the drain is connected to one end of the load, the gate of the P-type MOSFET Q2 is connected to the drain of the N-type MOSFET Q3, the gate of the N-type MOSFET Q3 is connected to the signal output terminal of the voltage detection circuit, and the source of the N-type MOSFET Q3 is grounded; When the N-type MOSFET Q3 receives the first level signal, it switches the level and drives the P-type MOSFET Q2 to turn on; when the N-type MOSFET Q3 receives the second level signal, it switches the level and drives the P-type MOSFET Q2 to turn off.

[0030] Specifically, a current-limiting resistor R9 is connected in series between the gate of the P-type MOS transistor Q2 and the drain of the N-type MOS transistor Q3. A pull-down resistor R7 and a filter capacitor C7 connected in parallel are also connected between the P-type MOS transistor Q2 and the current-limiting resistor R9. The other ends of the pull-down resistor R7 and the filter capacitor C7 are connected to the output terminal of the voltage conversion circuit. A current-limiting resistor R10 is connected in series between the gate of the N-type MOS transistor Q3 and the signal output terminal of the voltage detection circuit. A pull-down resistor R11 is connected in parallel between the N-type MOS transistor Q3 and the current-limiting resistor R10. The other end of the pull-down resistor R11 is connected to the source of the N-type MOS transistor Q3 and then grounded.

[0031] By setting components such as current-limiting resistors, pull-down resistors, and filter capacitors, damage to P-type and N-type MOSFETs caused by excessive voltage can be avoided.

[0032] Specifically, the original voltage VOUT0 is converted into the working voltage VOUT1 required by the load R8 after passing through the on / off control circuit of the two-stage MOS transistors Q2 (P-type MOS transistor Q3).

[0033] The discharge circuit includes a PNP transistor Q1, the emitter of which is connected to the output terminal of the voltage conversion circuit, the base of which is connected to the signal output terminal of the voltage detection circuit, and the collector of which is connected to the discharge resistor R6 and then grounded.

[0034] Specifically, at the connection point between the PNP transistor Q1, the current-limiting resistor R10, and the signal output terminal of the voltage detection circuit, one end of the pull-up resistor R2 is connected, and the other end of the pull-up resistor R2 is connected to the output terminal of the voltage conversion circuit.

[0035] The power supply circuit in this embodiment operates as follows: When the external power supply is normal, the input voltage VIN outputs voltage VOUT0 through the voltage conversion circuit. During the rise of VOUT0 from 0V, if VOUT0 falls below the preset threshold in the voltage detection chip U2, the chip outputs a low-level signal, turning off the N-type MOSFET Q3. The gate level of the P-type MOSFET Q2 is then pulled high, causing Q2 to turn off, resulting in no output voltage VOUT1 and the load stopping. Conversely, if the amplitude of VOUT0 exceeds the preset threshold in the voltage detection chip U2, the chip outputs a high-level signal, turning on the voltage detection chip Q3. The gate level of the P-type MOSFET Q2 is then pulled low, causing the P-type MOSFET to turn on, resulting in an output voltage VOUT1 and the load operating.

[0036] When the external power supply is suddenly disconnected, the first farad capacitor C5 and the second farad capacitor C6 continue to provide power to the downstream load for a certain period of time, facilitating the preservation of critical data. When the amplitude of voltage VOUT0 is lower than the preset threshold in voltage detection chip U2, voltage detection chip U2 outputs a low-level signal, the N-type MOSFET Q3 is turned off, and the gate level of P-type MOSFET Q2 is pulled high, causing Q2 to turn off. Voltage VOUT1 has no output, and the load stops. PNP transistor Q1 conducts after receiving the low-level signal output by voltage detection chip U2, and the remaining charge in the circuit is discharged through the bleeder resistor R6. The amplitude of voltage VOUT0 quickly drops to 0V, without affecting the next power-on of the external power supply.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A power supply circuit, characterized in that, include: A voltage conversion circuit, whose input terminal is connected to an external input power supply, is used to receive the raw voltage output by the external input power supply and convert the raw voltage into a working voltage that adapts to the working requirements of the load. A voltage sustaining circuit is connected in parallel with the output of the voltage conversion circuit. When the input power supply is normal, the electrical energy output by the voltage conversion circuit completes the charging and energy storage. When the external input power supply is disconnected, it automatically switches to the discharge mode to maintain the continuous power supply to the load by releasing the stored electrical energy. A voltage detection circuit, whose detection terminal is connected to the output terminal of the voltage conversion circuit, detects the voltage amplitude at the output terminal of the voltage conversion circuit in real time; when the detected voltage amplitude is higher than its preset voltage amplitude threshold, it outputs a first level signal; when the detected voltage amplitude is lower than its preset voltage amplitude threshold, it outputs a second level signal. On / off control circuit, including control part and switching part; Triggered by a received first-level signal, the control section controls the switch section to turn on, thereby forming a conduction loop from the output of the voltage conversion circuit to the load; Triggered by the received second level signal, the control section controls the switch section to turn off, thereby cutting off the power supply loop from the output of the voltage conversion circuit to the load; The discharge circuit includes a control switch and a discharge resistor; triggered by the received second level signal, the control switch is turned on, and the discharge resistor is connected to the output terminal of the voltage conversion circuit, so that the excess power in the circuit is released through the discharge resistor.

2. The power supply circuit according to claim 1, characterized in that: The voltage sustaining circuit includes a first supercapacitor and a second supercapacitor connected in series, and a first voltage equalizing resistor and a second voltage equalizing resistor connected in series; wherein the first voltage equalizing resistor is connected in parallel with the first supercapacitor, and the second voltage equalizing resistor is connected in parallel with the second supercapacitor.

3. The power supply circuit according to claim 2, characterized in that: The voltage detection circuit includes a voltage detection chip and a first current-limiting resistor; the input pin of the voltage detection chip is connected to the output pin of the voltage conversion circuit as the detection terminal of the voltage detection circuit; the reset pin of the voltage detection chip is connected to one end of the first current-limiting resistor, and the other end of the first current-limiting resistor is connected to the on / off control circuit and the discharge circuit as the signal output terminal of the voltage detection circuit.

4. The power supply circuit according to claim 3, characterized in that: The calculation expression for the voltage amplitude threshold is: U2 = U1 - (t / C) × I; Where t is the continuous power supply time required by the load when the input power is disconnected; C is the capacitance value after the first farad capacitor and the second farad capacitor are connected in series; U1 is the initial voltage value when the power is off; and I is the load current.

5. The power supply circuit according to claim 4, characterized in that: The on / off control circuit includes a P-type MOS transistor and an N-type MOS transistor; the source of the P-type MOS transistor is connected to the output terminal of the voltage conversion circuit, the drain is connected to one end of the load, the gate of the P-type MOS transistor is connected to the drain of the N-type MOS transistor, the gate of the N-type MOS transistor is connected to the signal output terminal of the voltage detection circuit, and the source of the N-type MOS transistor is grounded. The N-type MOSFET receives the first level signal, and after the N-type MOSFET switches the level, it drives the P-type MOSFET to turn on. The N-type MOSFET receives the second level signal, and after the N-type MOSFET switches the level, it drives the P-type MOSFET to turn off.

6. The power supply circuit according to claim 5, characterized in that: The discharge circuit includes a PNP transistor, the emitter of which is connected to the output terminal of the voltage conversion circuit, the base of which is connected to the signal output terminal of the voltage detection circuit, and the collector of which is connected to the discharge resistor and then grounded.

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