A low-power power supply start-stop circuit

Abstract

The present invention relates to a power start-stop circuit with low power consumption, which includes a start-up module, a drive module, a power wake-up module, a power supply module, and an MCU module. The first input terminal of the start-up module is connected to the VCC terminal, the second input terminal is connected to the output terminals of the power wake-up module and the drive module, the output terminal is connected to the input terminal of the power supply module, and the output terminal of the power supply module is connected to the MCU module; the MCU module is also connected to the input terminal of the drive module; and the input terminal of the power wake-up module is connected to the VCC terminal. The start-up circuit of the present invention is valid for one rising edge. After the power supply outputs normally, the start-up circuit will no longer consume power, improving the working efficiency of the power supply.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly relates to a low-power power supply start-stop circuit. Background Art

[0002] In electronic circuits, a power supply start-stop circuit is usually applied to control the on-off of the power supply. However, the current power supply start-stop circuits all have the following problems:

[0003] (1) Some power supply circuits use the hysteresis of the power supply chip itself to control the start and stop of the power supply (usually controlling the EN pin). When the input voltage is higher than the rated value V2, the power supply is turned on. When the power supply is lower than the rated value V1, the power supply is turned off. When the input is connected to a photovoltaic panel and the light is very weak, the input voltage is unstable, and the power supply is prone to frequent hiccups.

[0004] (2) After some power supply circuits are started, there is still relatively large power consumption on the start-stop circuit, which is not applicable in occasions where low power consumption is required.

[0005] (3) Some power supply circuits control the on-off of the power supply through hard switches such as buttons, but do not have the function of software control.

[0006] (4) Some power supplies can implement the function of hardware start and software shutdown. However, when the MCU module crashes, the state of the IO port cannot be estimated, and the power supply cannot be turned off normally. Abnormal conditions such as overcurrent and short circuit are likely to occur in the main circuit, and even serious consequences such as fire may occur.

[0007] In view of this, the designer of the present invention deeply considered the problems existing in the existing power supply start-stop circuit, and thus this case was generated. Summary of the Invention

[0008] The purpose of the present invention is to provide a low-power power supply start-stop circuit to improve the working efficiency of the power supply.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is:

[0010] A low-power power supply start-stop circuit includes a start module, a drive module, a power supply wake-up module, a power supply module, and an MCU module. The first input terminal of the start module is connected to the VCC terminal, the second input terminal is connected to the output terminals of the power supply wake-up module and the drive module, the output terminal is connected to the input terminal of the power supply module, and the output terminal of the power supply module is connected to the MCU module; the MCU module is also connected to the input terminal of the drive module; and the input terminal of the power supply wake-up module is connected to the VCC terminal;

[0011] The startup module includes optocoupler IC1, resistor R1, resistor R2, resistor R4, electrolytic capacitor C2, and triode Q1. The anode of optocoupler IC1 is connected to the VCC terminal via resistor R4, and the cathode is grounded via electrolytic capacitor C2. The collector of optocoupler IC1 is connected to the base of triode Q1 via resistor R2. At the same time, the collector of optocoupler IC1 is also connected to the power wake-up module, and the emitter of optocoupler IC1 is grounded. The emitter of triode Q1 is connected to the VCC terminal, and the collector of triode Q1 is connected to the power supply module. One end of resistor R1 is connected to the VCC terminal, and the other end is connected to the base of triode Q1.

[0012] The drive module includes capacitor C3, capacitor C4, diode D1, diode D2, resistor R6, resistor R7, resistor R10, and triode Q2. One end of capacitor C3 is connected to the TPM2_CH1 pin of the MCU module, and the other end is connected to the anode of diode D2. The cathode of diode D2 is connected to the anode terminal of diode D1. One end of the parallel combination of capacitor C4 and resistor R10 is connected to the cathode of diode D2, and the other end is grounded. The cathode of diode D1 is connected to the base of triode Q2 via resistor R6. The collector of triode Q2 is connected to the collector of optocoupler IC1 of the startup module, and the emitter of triode Q2 is grounded. One end of resistor R7 is connected to the base of triode Q2, and the other end is grounded.

[0013] The power wake-up module includes button SW1, resistor R5, resistor R6, resistor R7, capacitor C1, diode D1, and triode Q2. The input terminal of button SW1 is connected to the VCC terminal, and the output terminal is connected to the first anode terminal of diode D1. The cathode of diode D1 is connected to the base of triode Q2 via resistor R6. The collector of triode Q2 is connected to the collector of optocoupler IC1 of the startup module, and the emitter of triode Q2 is grounded. One end of resistor R7 is connected to the base of triode Q2, and the other end is grounded. One end of the parallel combination of resistor R5 and capacitor C1 is connected to the output terminal of button SW1, and the other end is grounded.

[0014] The power module includes capacitor C5, capacitor C6, capacitor C10, capacitor C7, capacitor C8, capacitor C9, capacitor C11, resistor R11, resistor R12, resistor R13, power chip IC2, and inductor L1; one end of capacitor C6 is connected to the collector of transistor Q1 in the startup module, and the other end is grounded; one end of resistor R11 is connected to the collector of transistor Q1 in the startup module, and the other end is connected to the EN pin of chip IC2; the VIN pin of chip IC2 is connected to the collector of transistor Q1 in the startup module, and the pd pin and GND pin of chip IC2 are directly grounded , the ss pin and VREG5 pin of chip IC2 are grounded via capacitor C10 and capacitor C11 respectively; the VBST pin of chip IC2 is connected to the SW pin of chip IC2 via capacitor C5, and the SW pin is connected to the VDD pin of the MCU module through inductor L1; capacitor C7 and capacitor C8 are connected in parallel, one end of which is connected to the VDD pin of the MCU module, and the other end is grounded; resistor R12 and capacitor C9 are connected in parallel, one end of which is connected to the VDD pin of the MCU module, and the other end is grounded via resistor R13 on one hand, and connected to the VFB pin of chip IC2 on the other hand.

[0015] The power start-stop circuit also includes a fast discharge module connected to the start module.

[0016] The fast discharge module includes a transistor Q3, a resistor R3, a resistor R8, and a resistor R9. The base of the transistor Q3 is connected to the VCC terminal via the resistor R3 on one hand, and is grounded via the resistor R8 on the other hand; the emitter of the transistor Q3 is connected to the cathode of the optocoupler IC1 of the start-up module; and the collector of the transistor Q3 is grounded via the resistor R9.

[0017] After adopting the above scheme, the present invention has the following beneficial effects:

[0018] (1) The startup circuit of the present invention is effective for a single rise delay. When the power supply is output normally, the startup circuit will no longer consume power, thereby improving the working efficiency of the power supply.

[0019] (2) The present invention has the functions of hardware start, software shutdown, hardware wake-up, etc., and the control of the power supply circuit is more perfect.

[0020] (3) When the power is turned on, the MCU module blocks the driver to ensure the normal output of the power supply. When the power is turned off, the MCU module turns off the driver, which makes the control logic simpler and less prone to hiccups.

[0021] (4) The present invention adds a watchdog circuit to prevent the MCU module from freezing or failing and causing its input and output states to be out of control, which may lead to serious consequences. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1It is the principle block diagram of the present invention;

[0023] Figure 2 It is the circuit diagram of the start-up module, drive module and power supply wake-up module;

[0024] Figure 3 It is the circuit diagram of the power supply module;

[0025] Figure 4 It is the schematic diagram of the connection terminal CN1;

[0026] Figure 5 It is the schematic diagram of the MCU module.

[0027] Label description:

[0028] Start-up module 10; drive module 20; power supply wake-up module 30; power supply module 40; fast discharge module 50; MCU module 60. Specific implementation manner

[0029] As Figure 1 shown, the present invention discloses a low-power power supply start-stop circuit, which includes a start-up module 10, a drive module 20, a power supply wake-up module 30, and a power supply module 40. The first input end of the start-up module 10 is connected to the VCC end, the second input end is connected to the output ends of the power supply wake-up module 30 and the drive module 20, the output end is connected to the input end of the power supply module 40, and the output end of the power supply module 40 is connected to the MCU module 60; the MCU module 60 is also connected to the input end of the drive module 20; and the input end of the power supply wake-up module 30 is connected to the VCC end.

[0030] Among them, as Figure 2 shown, the start-up module 10 includes an optocoupler IC1, a resistor R1, a resistor R2, a resistor R4, an electrolytic capacitor C2, and a triode Q1. The anode of the optocoupler IC1 is connected to the VCC end via the resistor R4 (the end where the resistor R4 is connected to the VCC end is the first input end of the start-up module 10), and the cathode is grounded via the electrolytic capacitor C2; the collector of the optocoupler IC1 is connected to the base of the triode Q1 via the resistor R2, and at the same time, the collector of the optocoupler IC1 is also connected to the power supply wake-up module 30 (the collector of the optocoupler IC1 is the second input end of the start-up module 10), and the emitter of the optocoupler IC1 is grounded. The emitter of the triode Q1 is connected to the VCC end, and the collector of the triode Q1 is connected to the power supply module 40 (the collector of the triode Q1 is the output end of the start-up module 10). One end of the resistor R1 is connected to the VCC end, and the other end is connected to the base of the triode Q1.

[0031] As Figure 3As shown in the figure, the power module 40 can adopt a BUCK power module, a Boost power module or a buck-boost power module. In this embodiment, the BUCK power module is taken as an example for illustration, and the applications of other power modules are the same. Specifically, the power module 40 of this embodiment includes a capacitor C5, a capacitor C6, a capacitor C10, a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C11, a resistor R11, a resistor R12, a resistor R13, a power chip IC2, and an inductor L1. One end of the capacitor C6 is connected to the startup module 10 (i.e., the collector of the triode Q1), and the other end is grounded; one end of the resistor R11 is connected to the startup module 10, and the other end is connected to the EN pin of the chip IC2; the VIN pin of the chip IC2 is connected to the collector of the triode Q1 in the startup module 10 (one end of the capacitor C6, the resistor R11 and the chip IC2 connected to the startup module 10 is the input end of the power module 40), the pd pin and the GND pin of the chip IC2 are directly grounded, and the ss pin and the VREG5 pin of the chip IC2 are grounded via the capacitor C10 and the capacitor C11 respectively; the VBST pin of the chip IC2 is connected to the SW pin of the chip IC2 via the capacitor C5, and the SW pin is connected to the VDD pin of the MCU module 60 through the inductor L1. The capacitors C7 and C8 are connected in parallel, one end is connected to the VDD pin of the MCU module 60, and the other end is grounded. The resistor R12 and the capacitor C9 are connected in parallel, one end is connected to the VDD pin of the MCU module 60, and the other end is grounded via the resistor R13 on the one hand and connected to the VFB pin of the chip IC2 on the other hand. As Figure 2 shown, the +3.3V_D end point of the power module 40 is the output end of the power module 40, and the components in the power module 40 are all connected to the MCU module 60 through this end point. In this embodiment, the model of the chip IC2 is TPS54227, which has the advantages of high efficiency, wide input range, adjustable output range, and small output ripple (Vout-pp = 20mv).

[0032] Continue to refer to Figure 2 shown, the power wake-up module 30 includes a button SW1, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a diode D1, and a triode Q2. The input end of the button SW1 (also the input end of the power wake-up module 30) is connected to the VCC end, the output end is connected to the first anode end of the diode D1, the cathode of the diode D1 is connected to the base of the triode Q2 via the resistor R6, the collector of the triode Q2 is connected to the collector of the optocoupler IC1 in the startup module 10, and the emitter of the triode Q2 is grounded; one end of the resistor R7 is connected to the base of the triode Q2 (the collector of the triode Q2 is the output end of the drive circuit), and the other end is grounded; the resistor R5 and the capacitor C1 are connected in parallel, one end is connected to the output end of the button SW1, and the other end is grounded.

[0033] Combined with Figure 4 and Figure 5As shown in the figure, the driving module 20 includes a capacitor C3, a capacitor C4, a diode D1, a diode D2, a resistor R6, a resistor R7, a resistor R10, and a triode Q2. One end of the capacitor C3 (this end is the input end of the driving module 20) is connected to the TPM2_CH1 pin of the MCU module 60, and the other end is connected to the anode of the diode D2. The cathode of the diode D2 is connected to the second anode of the diode D1. One end of the capacitor C4 and the resistor R10 in parallel is connected to the cathode of the diode D2, and the other end is grounded. The driving module 20 shares the resistor R6, the resistor R7, the resistor R10, and the triode Q2 with the power wake-up module 30. Therefore, the connection relationship is not described herein again. The collector of the triode Q2 is also the output end of the driving module 20.

[0034] Continue to refer to Figure 2 and in combination with Figure 4 As shown in the figure, in this embodiment, in order to ensure that the startup circuit can always work normally when the power supply at the VCC terminal is repeatedly turned on and off. The startup module 10 is also connected with a fast discharge module 50, which includes a triode Q3, a resistor R3, a resistor R8, and a resistor R9. The base of the triode Q3 is connected to the VCC terminal via the resistor R3 on the one hand and grounded via the resistor R8 on the other hand; the emitter of the triode Q3 is connected to the cathode of the optocoupler IC1 of the startup module 10; the collector of the triode Q3 is grounded via the resistor R9. In addition, in this embodiment, the power supply at the VCC terminal is provided by the connection terminal CN1, and the model of the connection terminal CN1 is RJ45.

[0035] When power is first applied, the triode Q1 in the startup module 10 conducts, the power supply module 40 starts, and provides a 3.3V power supply for the MCU module 60. After a period of time, the startup circuit is turned off. Before the startup circuit is turned off, the MCU module 60 outputs a driving signal to the driving module 20 to keep the triode Q1 continuously conducting and continue to supply power to the BUCK circuit to achieve power self-locking. When the power needs to be turned off, the MCU module 60 turns off the drive, the triode Q1 disconnects, the power supply module 40 stops working, and the MCU module 60 stops running. Therefore, the MCU module 60 can control the turning on and off of the power supply module 40. After the power is turned off, press the button SW1, the triode Q1 conducts, and then the MCU module 60 controls the drive circuit to achieve power self-locking, the BUCK circuit works continuously, and the power wake-up circuit successfully turns on the power. When the power supply VCC at the connection terminal CN1 is disconnected, the fast discharge module 50 quickly discharges the charge on the capacitor C2 to prepare for the next power startup. Due to the fast discharge speed, even if the power supply VCC is immediately reconnected, the power supply module 40 can work immediately. Therefore, even if the connection terminal CN1 is repeatedly and quickly hot-plugged, the power supply can still work normally.

[0036] The working principle of the present invention is as follows:

[0037] Connect the DC power supply VCC to the connection terminal CN1. VCC charges the capacitor C2 through R4 and the internal diode of the optocoupler IC1. After the diode on the primary side of the optocoupler IC1 conducts, the loop composed of the triode Q1, the resistor R1, the resistor R2, and the triode on the secondary side of the optocoupler conducts, and the triode Q1 conducts. Then, the power supply module 40 with the chip IC2 as the core works normally and provides 3.3V power for the MCU module 60. As the charge accumulates on the capacitor C2, the charging speed decreases, and the conduction current of the triode Q1 becomes smaller, completing the soft-start process. As the current flowing through the internal diode of the optocoupler IC1 becomes smaller and smaller, when the current is small enough that the triode on the secondary side of the optocoupler IC1 cannot conduct, the triode Q1 disconnects at the same time. At this point, the mission of the startup module 10 is completed.

[0038] If you want the triode Q1 to be continuously turned on, before the triode on the secondary side of the optocoupler IC1 disconnects, the MCU module 60 needs to output a PWM wave (Debug dog) to control the drive module 20 to make the triode Q2 continuously conduct, and then the triode Q1 can continuously conduct. As long as the drive of the MCU module 60 is not turned off, the triode Q1 will not turn off, and the power supply module 40 can continuously work and, in turn, provide 3.3V power for the MCU module 60 to achieve power self-locking. Sometimes, for power consumption, it is necessary to turn off the power supply module 40. As long as the MCU module 60 detects the voltage of the input power supply in real time, when the input power supply reaches the low-voltage shutdown threshold, the MCU module 60 actively turns off the drive, and then the power supply module 40 shuts down. Of course, it is also possible to send a power-off command to the MCU module 60 from the upper computer through RS485 communication, and then the MCU module 60 turns off the drive, and the power supply shuts down to achieve low power consumption.

[0039] The power wake-up module 30 can restart the power supply. Press the button SW1, and Key up outputs a high level to drive the triode Q2 to conduct, and then the triode Q1 conducts, and the power supply module 40 restarts to output 3.3V. When the power supply VCC is disconnected, the charge on the capacitor C2 is quickly discharged through the fast-discharge circuit composed of the triode Q3, the resistor R8, and the resistor R9, and the voltage on the capacitor C2 quickly drops below 1V. Without this fast-discharge circuit, the charge on the electrolytic capacitor is slowly discharged, and it may take dozens of seconds for the voltage on the capacitor C2 to drop from 12V to below 1V. Moreover, because there is still a lot of charge stored in the capacitor C2, the current flowing through the internal diode of the optocoupler is very small, which is not enough to make the triode on the secondary side of the optocoupler conduct or fully conduct, so the triode Q1 is not fully conducted, and the power supply module 40 cannot work normally. Therefore, adding a fast-discharge circuit enables the function of repeated hot-plugging and power-on / off of the connection terminal CN1 to be realized.

[0040] When the MCU module 60 freezes or fails, the IO port may output a high level or a low level. However, since the capacitor C3 in the drive module 20 blocks direct current and passes alternating current, Dog_HD can only be at a low level. Therefore, the drive module 20 is turned off, the triode Q1 cannot conduct, the BUCK circuit is turned off after losing the input power supply, and the MCU module 60 powered by 3.3V stops operating. Therefore, the drive circuit composed of the capacitor C3, the diode D2, the capacitor C4, and the resistor R10 acts as a "watchdog" to prevent serious consequences caused by the freeze of the MCU module 60.

[0041] In summary, the present invention has the following beneficial effects:

[0042] (1) The startup circuit of the present invention is effective with a single rising edge. After the power supply outputs normally, the startup circuit will no longer consume power, improving the working efficiency of the power supply.

[0043] (2) The present invention simultaneously has functions such as hardware startup, software shutdown, and hardware wake-up, making the control of the power supply circuit more perfect.

[0044] (3) After the power supply is turned on, the MCU module 60 blocks the drive to ensure the normal output of the power supply. When the power supply needs to be turned off, the MCU module 60 turns off the drive, and the control logic is simpler, and it is not easy to have the hiccup phenomenon.

[0045] (4) The present invention adds a watchdog circuit to prevent serious consequences that may occur when the input and output states of the MCU module 60 cannot be controlled after it freezes or fails.

[0046] The above is only an example of the present invention, and it does not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A low-power power-on and power-off circuit, characterized in that: It includes a start-up module, a drive module, a power wake-up module, a power supply module, and an MCU module. The first input terminal of the start-up module is connected to the VCC terminal, the second input terminal is connected to the output terminals of the power wake-up module and the drive module, the output terminal is connected to the input terminal of the power supply module, and the output terminal of the power supply module is connected to the MCU module; the MCU module is also connected to the input terminal of the drive module; the input terminal of the power wake-up module is connected to the VCC terminal; The start-up module includes an optocoupler IC1, a resistor R1, a resistor R2, a resistor R4, an electrolytic capacitor C2, and a triode Q1; the anode of the optocoupler IC1 is connected to the VCC terminal via the resistor R4, and the cathode is grounded via the electrolytic capacitor C2; the collector of the optocoupler IC1 is connected to the base of the triode Q1 via the resistor R2. At the same time, the collector of the optocoupler IC1 is also connected to the power wake-up module, and the emitter of the optocoupler IC1 is grounded; the emitter of the triode Q1 is connected to the VCC terminal, and the collector of the triode Q1 is connected to the power supply module; one end of the resistor R1 is connected to the VCC terminal, and the other end is connected to the base of the triode Q1; The drive module includes a capacitor C3, a capacitor C4, a diode D1, a diode D2, a resistor R6, a resistor R7, a resistor R10, and a triode Q2. One end of the capacitor C3 is connected to the TPM2_CH1 pin of the MCU module, and the other end is connected to the anode of the diode D2. The cathode of the diode D2 is connected to the anode of the diode D1; after the capacitor C4 and the resistor R10 are connected in parallel, one end is connected to the cathode of the diode D2, and the other end is grounded; the cathode of the diode D1 is connected to the base of the triode Q2 via the resistor R6. The collector of the triode Q2 is connected to the collector of the optocoupler IC1 of the start-up module, and the emitter of the triode Q2 is grounded; one end of the resistor R7 is connected to the base of the triode Q2, and the other end is grounded; The power supply start-stop circuit further includes a fast discharge module connected to the start-up module.

2. The power-on and power-off circuit with low power consumption according to claim 1, wherein: The power wake-up module includes a button SW1, a resistor R5, a resistor R6, a resistor R7, a capacitor C1, a diode D1, and a triode Q2; the input terminal of the button SW1 is connected to the VCC terminal, the output terminal is connected to the first anode of the diode D1, and the cathode of the diode D1 is connected to the base of the triode Q2 via the resistor R6. The collector of the triode Q2 is connected to the collector of the optocoupler IC1 of the start-up module, and the emitter of the triode Q2 is grounded; one end of the resistor R7 is connected to the base of the triode Q2, and the other end is grounded; after the resistor R5 and the capacitor C1 are connected in parallel, one end is connected to the output terminal of the button SW1, and the other end is grounded.

3. The power-on and power-off circuit with low power consumption according to claim 1, wherein: The power supply module includes capacitor C5, capacitor C6, capacitor C10, capacitor C7, capacitor C8, capacitor C9, capacitor C11, resistor R11, resistor R12, resistor R13, power supply chip IC2, and inductor L1; one end of capacitor C6 is connected to the collector of transistor Q1 in the startup module, and the other end is grounded; one end of resistor R11 is connected to the collector of transistor Q1 in the startup module, and the other end is connected to the EN pin of chip IC2; the VIN pin of chip IC2 is connected to the collector of transistor Q1 in the startup module, the pd pin and GND pin of chip IC2 are directly grounded, and the ss pin and VREG5 pin of chip IC2 are grounded via capacitor C10 and capacitor C11 respectively; the VBST pin of chip IC2 is connected to the SW pin of chip IC2 via capacitor C5, and the SW pin is connected to the VDD pin of the MCU module through inductor L1; capacitor C7 and capacitor C8 are connected in parallel, one end is connected to the VDD pin of the MCU module, and the other end is grounded; resistor R12 and capacitor C9 are connected in parallel, one end is connected to the VDD pin of the MCU module, and the other end is grounded via resistor R13 on one hand and connected to the VFB pin of chip IC2 on the other hand.

4. The power-on and power-off circuit with low power consumption according to claim 1, characterized in that: The fast discharge module includes transistor Q3, resistor R3, resistor R8, and resistor R9. One end of the base of transistor Q3 is connected to the VCC terminal via resistor R3, and the other end is grounded via resistor R8; the emitter of transistor Q3 is connected to the cathode of optocoupler IC1 in the startup module; the collector of transistor Q3 is grounded via resistor R9.

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