Low power start-up and shutdown circuit for a battery powered device

Abstract

The utility model discloses a low -power consumption starting circuit of cutting off electricity of battery equipment, including battery, charging circuit, battery switch circuit, MCU micro control unit and SW1 button, the input of charging circuit is connected with the output of battery electric property, the input of battery switch circuit is connected with the output of charging circuit electric property, the power input of MCU micro control unit is connected with the output of battery switch circuit electric property, the anode end of D3 diode is connected with the PD1 end of MCU micro control unit electric property, and the output of battery is connected with the cathode end of D3 diode through SW1 button electric property electric property, the anode end of D2 diode in battery switch circuit is connected with the cathode of D3 diode electric property, and the opening and break of battery switch circuit are controlled through the press of SW1 button and MCU micro control unit, realizes the starting and power off of battery equipment.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a low-power start-up and power-off circuit for a battery-equipped device. Background Technology

[0002] Existing battery-powered devices are started via mechanical switches. However, if these mechanical switches are accidentally activated, the entire battery-powered device will lose power, disrupting normal operation and reducing efficiency. Furthermore, in some devices requiring standby mode, the battery is not completely electrically disconnected from the downstream circuitry. This prolonged standby mode increases power consumption, significantly depleting battery capacity and reducing battery life. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides a low-power start-up and power-off circuit for battery-equipped devices. The battery switch circuit is controlled to turn on and off by the SW1 button and the MCU microcontroller unit, so as to achieve complete electrical disconnection between the battery and the subsequent circuit of the battery-equipped device and reduce the power consumption of the circuit.

[0004] Technical Solution: To achieve the above objectives, this utility model provides a low-power start-up and power-off circuit for a battery-powered device, comprising a battery, a charging circuit, a battery switch circuit, an MCU microcontroller unit, and an SW1 button. The output terminal of the battery is electrically connected to the input terminal of the charging circuit, the output terminal of the charging circuit is electrically connected to the input terminal of the battery switch circuit, the output terminal of the battery switch circuit is electrically connected to the power input terminal of the MCU microcontroller unit, the PD1 terminal of the MCU microcontroller unit is electrically connected to the positive terminal of diode D3, and the negative terminal of diode D3 is electrically connected to the output terminal of the battery via the SW1 button. The negative terminal of diode D3 is electrically connected to the positive terminal of diode D2 in the battery switch circuit. The opening and closing of the battery switch circuit are controlled by pressing the SW1 button and the level signal output by the MCU microcontroller unit, respectively, thereby realizing the start-up and power-off of the battery-powered device.

[0005] Furthermore, the charging circuit includes an integrated circuit U2, an inductor L1, and a diode D4. The VBAT terminal of the integrated circuit U2 is electrically connected to the output terminal of the battery, and the VBAT terminal of the integrated circuit U2 is electrically connected to one end of the inductor L1. The other end of the inductor L1 is electrically connected to the positive terminal of the diode D4, and the negative terminal of the diode D4 serves as the output terminal of the charging circuit. The LX terminal of the integrated circuit U2 is electrically connected to the other end of the inductor L1, and the OVP terminal of the integrated circuit U2 is electrically connected to the negative terminal of the diode D4. Simultaneously, the negative terminal of the diode D4 is electrically connected to the FB terminal of the integrated circuit U2 through a resistor R6, and the FB terminal of the integrated circuit U2 is grounded through a resistor R8.

[0006] Furthermore, the charging circuit also includes a resistor R5 and a diode D5; the VCC terminal of the U2 integrated circuit is electrically connected to one end of the resistor R5, and the other end of the resistor R5 serves as the charging terminal of the charging circuit; the other end of the resistor R5 is electrically connected to the positive terminal of the diode D5, and the negative terminal of the diode D5 is electrically connected to the CHRGB terminal of the U2 integrated circuit through a resistor R7.

[0007] Furthermore, the battery switching circuit includes a Q1 transistor, a Q2 transistor, and a D1 diode; the source of the Q1 transistor serves as the input terminal of the battery switching circuit and is electrically connected to the negative terminal of the D4 diode; the drain of the Q1 transistor serves as the output terminal of the battery switching circuit; and the source of the Q1 transistor is electrically connected to the gate of the Q1 transistor through a resistor R1. The collector of the Q2 transistor is electrically connected to the gate of the Q1 transistor, and the emitter of the Q2 transistor is grounded through a resistor R2. The base of the Q2 transistor is electrically connected to one end of a resistor R3, and the other end of the resistor R3 is electrically connected to the negative terminal of the D1 diode. The other end of the resistor R3 is also electrically connected to the negative terminal of the D2 diode, and the positive terminal of the D2 diode is grounded through a resistor R4.

[0008] Furthermore, when either diode D1 or diode D2 in the battery switch circuit is turned on, transistor Q1 is turned on; when both diodes D1 and D2 in the battery switch circuit are turned off, transistor Q1 is turned off.

[0009] Furthermore, the negative terminal of the D1 diode is electrically connected to the EN terminal of the U2 integrated circuit.

[0010] Furthermore, the VDD terminal of the MCU microcontroller is electrically connected to the drain of the Q1 transistor through a filter circuit, which includes capacitors C1 and C2; the VDD terminal of the MCU microcontroller is grounded through the parallel capacitors C1 and C2; and the PD4 terminal of the MCU microcontroller is electrically connected to the CHRGB terminal of the U2 integrated circuit through resistor R10.

[0011] Furthermore, the PA3 terminal of the MCU microcontroller is electrically connected to the positive terminal of the D1 diode, and outputs a POW-MCU signal to control the conduction and cutoff of the D1 diode.

[0012] Beneficial effects: This utility model provides a low-power start-up and power-off circuit for battery-powered devices. By setting the Q1 transistor in the battery switch circuit, the battery and subsequent circuits are completely electrically disconnected when the device is powered off, allowing the static current to reach the uA level and reducing the power consumption of the battery in standby or power-off states. Through the circuit connection structure of diodes D1 and D2 in the battery switch circuit, the subsequent circuits can be powered on and started by hardware without relying on the MUC microcontroller unit during initial power-on. At the same time, it can prevent the subsequent circuits from being powered off due to accidental touch of the SW1 button, avoiding sudden power outages that could affect the normal operation of the device. Attached Figure Description

[0013] Figure 1 For low-power startup and power-off circuits in battery-powered devices;

[0014] Figure 2 Circuit diagram of battery, charging circuit and battery switching circuit;

[0015] Figure 3 This is a circuit diagram of an MCU (Microcontroller Unit). Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, a low-power start-up and power-off circuit for a battery-powered device includes a battery 1, a charging circuit 2, a battery switch circuit 3, an MCU microcontroller unit 4, and an SW1 button 5. The output terminal of the battery 1 is electrically connected to the input terminal of the charging circuit 2, the output terminal of the charging circuit 2 is electrically connected to the input terminal of the battery switch circuit 3, the output terminal of the battery switch circuit 3 is electrically connected to the power input terminal of the MCU microcontroller unit 4, the PD1 terminal of the MCU microcontroller unit 4 is electrically connected to the positive terminal of a D3 diode, and the negative terminal of the D3 diode is electrically connected to the output terminal of the battery 1 via the SW1 button 5. The negative terminal of the D3 diode is electrically connected to the positive terminal of the D2 diode in the battery switch circuit 3. The opening and closing of the battery switch circuit 3 are controlled by pressing the SW1 button 5 and the level signal output by the MCU microcontroller unit 4, respectively, to realize the start-up and power-off of the battery-powered device.

[0018] like Figure 2As shown, the charging circuit 2 includes an integrated circuit U2 21, an inductor L1, and a diode D4. The VBAT terminal of the integrated circuit U2 21 is electrically connected to the output terminal of the battery 1. The VBAT terminal of the integrated circuit U2 21 is also electrically connected to one end of the inductor L1. The other end of the inductor L1 is electrically connected to the positive terminal of the diode D4, and the negative terminal of the diode D4 serves as the output terminal of the charging circuit 2. The LX terminal of the integrated circuit U2 21 is electrically connected to the other end of the inductor L1, and the OVP terminal of the integrated circuit U2 21 is electrically connected to the negative terminal of the diode D4. Simultaneously, the negative terminal of the diode D4 is electrically connected to the FB terminal of the integrated circuit U2 21 through a resistor R6, and the FB terminal of the integrated circuit U2 21 is grounded through a resistor R8. The VBAT terminal of the integrated circuit U2 21 is grounded through a capacitor C3, the negative terminal of the diode D4 is grounded through a capacitor C4, and the negative terminal of the diode D4 is grounded through a capacitor C6.

[0019] like Figure 2 As shown, the charging circuit 2 also includes a resistor R5 and a diode D5. The VCC terminal of the U2 integrated circuit 21 is electrically connected to one end of the R5 resistor, and the other end of the R5 resistor serves as the charging terminal of the charging circuit 2. The other end of the R5 resistor is electrically connected to the positive terminal of the D5 diode, and the negative terminal of the D5 diode is electrically connected to the CHRGB terminal of the U2 integrated circuit 21 through a resistor R7. The VCC terminal of the U2 integrated circuit 21 is grounded through a capacitor C5, the ground terminal of the U2 integrated circuit 21 is grounded, and the PROG terminal of the U2 integrated circuit 21 is grounded through a resistor R9. An external power source can be electrically connected through the charging terminal of the charging circuit 2, and the charging circuit 2 charges the battery 1. The D5 diode illuminates during charging.

[0020] like Figure 2 As shown, the battery switch circuit 3 includes a Q1 transistor 31, a Q2 transistor 32, and a D1 diode. The source of the Q1 transistor 31 serves as the input terminal of the battery switch circuit 3 and is electrically connected to the negative terminal of the D4 diode. The drain of the Q1 transistor 31 serves as the output terminal of the battery switch circuit 3. The source of the Q1 transistor 31 is electrically connected to the gate of the Q1 transistor 31 through a resistor R1. The collector of the Q2 transistor 32 is electrically connected to the gate of the Q1 transistor 31, and the emitter of the Q2 transistor 32 is grounded through a resistor R2. The base of the Q2 transistor 32 is electrically connected to one end of a resistor R3. The other end of the resistor R3 is electrically connected to the negative terminal of the D1 diode, and the other end of the resistor R3 is also electrically connected to the negative terminal of the D2 diode. The positive terminal of the D2 diode is grounded through a resistor R4.

[0021] When either diode D1 or diode D2 in the battery switch circuit 3 is turned on, transistor Q1 31 is turned on; when both diodes D1 and D2 in the battery switch circuit 3 are turned off, transistor Q1 31 is turned off.

[0022] like Figure 2-3 As shown, the negative terminal of diode D1 is electrically connected to the EN terminal of integrated circuit U2 21. The POW-MCU signal, input from the PA3 terminal of the MCU microcontroller unit 4 to the positive terminal of diode D1, is used as the POW-EN signal input to the EN terminal of integrated circuit U2 21. The POW-EN signal serves as an enable signal to control integrated circuit U2 21, enabling the MCU microcontroller unit 4 to control the operation of integrated circuit U2 21. For example, the MCU microcontroller unit determines the battery capacity by receiving the battery voltage signal. When the battery capacity is below a certain threshold, the MCU microcontroller unit outputs the POW-MCU signal through diode D1 as the POW-EN signal to control integrated circuit U2 21 to perform a charging operation.

[0023] like Figure 2-3 As shown, the VDD terminal of the MCU microcontroller unit 4 is electrically connected to the drain of transistor Q1 through a filter circuit, which includes capacitors C1 and C2. The VDD terminal of the MCU microcontroller unit 4 is grounded through the parallel capacitors C1 and C2. The PD4 terminal of the MCU microcontroller unit 4 is electrically connected to the CHRGB terminal of integrated circuit U2 21 through resistor R10. The VSS terminal and the EP terminal of the MCU microcontroller unit 4 are grounded.

[0024] like Figure 2-3 As shown, the PA3 terminal of the MCU microcontroller unit 4 is electrically connected to the positive terminal of diode D1, and outputs a POW-MCU signal to control the conduction and cutoff of diode D1. Diodes D1, D2, and D3 are all 1N4148WS type diodes, diode D4 is a B5819W type diode, and diode D5 is an LED diode; transistor Q2 is an MMBT5551 type transistor, and transistor Q1 is a CJ2301 type MOSFET. When button SW1 5 is pressed, button SW1 5 closes, creating a circuit at both ends; when button SW1 5 is released, button SW1 5 opens, disconnecting the circuit at both ends.

[0025] When the low-power startup power-off circuit of the battery-powered device is in its initial state, both diodes D1 and D2 are turned off; transistor Q1 is clamped to a high level by resistor R1, causing transistor Q1 to be turned off; the charging circuit cannot supply power to subsequent stages.

[0026] When the low-power startup and shutdown circuit of the battery-powered device is in the power-on startup state, press and hold button 5 on SW1. The voltage signal output by battery 1 is used as the KEY-ON signal and is input to the positive terminal of diode D2 through button 5 on SW1, causing diode D2 to conduct. The KEY-ON signal is input to the base of transistor Q2 32 through diode D2, causing transistor Q2 32 to conduct. After transistor Q2 32 conducts, the gate of transistor Q1 31 is pulled low, which in turn causes transistor Q1 31 to conduct.

[0027] When transistor Q1 31 is turned on, battery 1 can power the MCU microcontroller 4 and subsequent circuits through charging circuit 2 and battery switch circuit 3. When the MCU microcontroller receives power from the battery, the PA3 terminal of the MCU microcontroller outputs the POW-MCU signal high, causing diode D1 to conduct. The POW-MCU signal is input to the base of transistor Q2 32 through diode D2, causing transistor Q2 32 to conduct. After transistor Q2 32 conducts, the gate of transistor Q1 31 is pulled low, thus causing transistor Q1 31 to conduct. At this time, the POW-MCU signal replaces the KEY-ON signal, causing transistor Q1 31 to conduct. Even if button SW1 5 is released at this time, the circuit will still work normally and there will be no power failure.

[0028] Initially, power-on is entirely handled by hardware, including button 5 (SW1), without relying on the potentially unprepared MCU microcontroller unit 4. This ensures power-on for the MCU at the front-end hardware level. After the MCU microcontroller unit 4 completes its initial power-on, software control takes over the power supply maintenance task, setting the output POW-MCU signal to a high level. Even if button 5 (SW1) is released, diode D1 conducts, maintaining the conduction state of transistors Q2 (32) and Q1 (31), ensuring stable and reliable power supply. This combination of hardware startup and software maintenance makes the power-on / off process both reliable and flexible. During normal circuit operation, even a short press or accidental touch of button 5 (SW1) prevents power loss because diode D1 maintains the conduction state of transistors Q2 and Q1. Only button operations meeting specific conditions trigger the shutdown process, improving the device's anti-interference capabilities and user experience.

[0029] When the low-power startup power-off circuit of the battery-powered device is in a power-off state, pressing SW1 button 5 for an extended period of time, accumulating to a set time threshold, will cause the MCU microcontroller unit 4 to determine that the device is powered off. The POW-MCU signal output from the PA3 terminal of the MCU microcontroller unit will be set to a low level, causing diode D1 to turn off, which in turn causes transistor Q2 to turn off. Transistor Q1 31 will then be clamped to a high level by resistor R1, causing transistor Q1 31 to turn off and remain in the cutoff state. The battery no longer supplies power to the MCU microcontroller unit 4 and the subsequent circuits. At this time, battery 1 is in a power-off state, which is a low-power state. In the power-off state, transistor Q1 31 is completely cut off, and battery 1 is electrically disconnected from the subsequent load; the entire subsequent circuit is de-energized, and the quiescent current can reach the μA level.

[0030] The above description is merely a preferred embodiment of the present utility model. Those skilled in the art can make several modifications and optimizations based on the above disclosure without departing from the basic principles described above. These modifications and optimizations should be considered as the scope of protection of the present utility model as understood.

Claims

1. A low-power start-up and power-off circuit for a battery-powered device, characterized in that: The device includes a battery (1), a charging circuit (2), a battery switch circuit (3), an MCU microcontroller unit (4), and a SW1 button (5). The output terminal of the battery (1) is electrically connected to the input terminal of the charging circuit (2), the output terminal of the charging circuit (2) is electrically connected to the input terminal of the battery switch circuit (3), the output terminal of the battery switch circuit (3) is electrically connected to the power input terminal of the MCU microcontroller unit (4), the PD1 terminal of the MCU microcontroller unit (4) is electrically connected to the positive terminal of the D3 diode, and the negative terminal of the D3 diode is electrically connected to the output terminal of the battery (1) through the SW1 button (5). The negative terminal of the D3 diode is electrically connected to the positive terminal of the D2 diode in the battery switch circuit (3). The opening and closing of the battery switch circuit (3) are controlled by pressing the SW1 button (5) and the level signal output by the MCU microcontroller unit (4), respectively, so as to realize the start-up and power-off of the battery-powered device.

2. The low-power start-up and power-off circuit for a battery-powered device according to claim 1, characterized in that: The charging circuit (2) includes a U2 integrated circuit (21), an L1 inductor, and a D4 diode. The VBAT terminal of the U2 integrated circuit (21) is electrically connected to the output terminal of the battery (1), the VBAT terminal of the U2 integrated circuit (21) is electrically connected to one end of the L1 inductor, the other end of the L1 inductor is electrically connected to the positive terminal of the D4 diode, and the negative terminal of the D4 diode serves as the output terminal of the charging circuit (2). The LX terminal of the U2 integrated circuit (21) is electrically connected to the other end of the L1 inductor, and the OVP terminal of the U2 integrated circuit (21) is electrically connected to the negative terminal of the D4 diode. At the same time, the negative terminal of the D4 diode is electrically connected to the FB terminal of the U2 integrated circuit (21) through a resistor R6, and the FB terminal of the U2 integrated circuit (21) is grounded through a resistor R8.

3. The low-power start-up and power-off circuit for a battery-powered device according to claim 2, characterized in that: The charging circuit (2) also includes a resistor R5 and a diode D5; the VCC terminal of the U2 integrated circuit (21) is electrically connected to one end of the resistor R5, and the other end of the resistor R5 serves as the charging terminal of the charging circuit (2); the other end of the resistor R5 is electrically connected to the positive terminal of the diode D5, and the negative terminal of the diode D5 is electrically connected to the CHRGB terminal of the U2 integrated circuit (21) through the resistor R7.

4. The low-power start-up and power-off circuit for a battery-powered device according to claim 1, characterized in that: The battery switch circuit (3) includes a Q1 transistor (31), a Q2 transistor (32), and a D1 diode. The source of the Q1 transistor (31) is electrically connected to the negative terminal of the D4 diode as the input terminal of the battery switch circuit (3), and the drain of the Q1 transistor (31) is the output terminal of the battery switch circuit (3). The source of the Q1 transistor (31) is electrically connected to the gate of the Q1 transistor (31) through a resistor R1. The collector of the Q2 transistor (32) is electrically connected to the gate of the Q1 transistor (31), and the emitter of the Q2 transistor (32) is grounded through a resistor R2. The base of the Q2 transistor (32) is electrically connected to one end of a resistor R3, and the other end of the resistor R3 is electrically connected to the negative terminal of the D1 diode. The other end of the resistor R3 is also electrically connected to the negative terminal of the D2 diode, and the positive terminal of the D2 diode is grounded through a resistor R4.

5. The low-power start-up and power-off circuit for a battery-powered device according to claim 4, characterized in that: When either diode D1 or diode D2 in the battery switch circuit (3) is turned on, transistor Q1 (31) is turned on; when both diodes D1 and D2 in the battery switch circuit (3) are turned off, transistor Q1 (31) is turned off.

6. The low-power start-up and power-off circuit for a battery-powered device according to claim 4, characterized in that: The negative terminal of the D1 diode is electrically connected to the EN terminal of the U2 integrated circuit (21).

7. The low-power start-up and power-off circuit for a battery-powered device according to claim 1, characterized in that: The VDD terminal of the MCU microcontroller (4) is electrically connected to the drain of the Q1 transistor through a filter circuit, which includes capacitors C1 and C2; the VDD terminal of the MCU microcontroller (4) is grounded through capacitors C1 and C2 connected in parallel; the PD4 terminal of the MCU microcontroller (4) is electrically connected to the CHRGB terminal of the U2 integrated circuit (21) through resistor R10.

8. The low-power start-up and power-off circuit for a battery-powered device according to claim 7, characterized in that: The PA3 terminal of the MCU microcontroller unit (4) is electrically connected to the positive terminal of the D1 diode, and outputs a POW-MCU signal to control the conduction and turn-off of the D1 diode.

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