An automatic power switch circuit and its electronic equipment

Abstract

This utility model discloses an automatic power switch circuit and its electronic device. The electronic device includes a motherboard with a main control circuit, a battery, and a power switch circuit. The power switch circuit connects the main control circuit and the battery. The power switch circuit supplies power to the main control circuit upon detecting a power connector insertion, and controls the main control circuit to perform a power-on operation when the device is off. When the battery level is below a threshold, the power switch circuit controls the main control circuit to perform a power-off operation when the device is on. This automatic power-on upon power connector insertion eliminates the need for manual operation, providing convenience for users. It also prevents battery over-discharge, protects the battery, extends its lifespan, and improves the battery life of the electronic device.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a power switch circuit and electronic device for automatic power on / off. Background Technology

[0002] With the widespread adoption of smart devices (such as low-power cameras), achieving automatic power-on and power-off while meeting low-power requirements has become a key issue. Traditional switching circuit designs typically rely on mechanical switches, requiring manual operation to power on when a charger or adapter is plugged in after the device has been turned off; automatic power-on is not possible. Furthermore, these switching circuits only automatically shut down when the battery is depleted, and excessive battery discharge reduces battery life. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model provides an automatic power switch circuit and its electronic device for power on / off, thereby solving the problems of existing switch circuits failing to automatically power on when charging while the battery is off, and the battery's lifespan being affected by over-discharge.

[0004] This utility model embodiment provides an automatic power switch circuit for power on / off, which connects a power interface, a battery, and a main control circuit. The power switch circuit includes an input module, a charging module, a power control module, a boost module, and an output module.

[0005] The input module detects the plugging / unplugging status of the power interface and outputs a corresponding level of detection voltage, which is then transmitted to the main control circuit via the output module; it also outputs the power voltage transmitted from the power interface.

[0006] The charging module converts the power supply voltage into the battery voltage to charge the battery.

[0007] The power control module turns on when it detects the power supply voltage and outputs the battery voltage as the battery input voltage; it controls the opening and closing of the internal circuit according to the received power enable signal, and stops outputting the battery input voltage when it is disconnected.

[0008] The boost module boosts the battery input voltage and outputs the battery supply voltage, which is then supplied to the main control circuit via the output module to perform the power-on operation.

[0009] The output module detects the current battery level and transmits it to the main control circuit, and outputs the power enable signal from the main control circuit to the power control module.

[0010] Optionally, in the power switch circuit of the automatic power on / off system, the input module includes a first interface, a first diode, a first capacitor, a first resistor, and a second resistor;

[0011] The power pin of the first interface is the power supply terminal, one end of the first diode, one end of the first capacitor, and one end of the first resistor; the ground pin of the first interface, the other end of the first diode, and the other end of the first capacitor are all grounded; the other end of the first resistor is connected to one end of the second resistor and the output module, and the other end of the second resistor is grounded.

[0012] Optionally, in the power switch circuit of the automatic power on / off system, the charging module includes a charging chip, a first inductor, a second capacitor, a third capacitor, a fourth capacitor, a third resistor, a fourth resistor, and a fifth resistor.

[0013] The VIN pin of the charging chip is connected to the power supply terminal and one end of the third resistor; the TS pin of the charging chip is connected to the other end of the third resistor, one end of the fourth resistor, and the output module; the other end of the fourth resistor is grounded; the PMID pin of the charging chip is grounded through the second capacitor; the PGND and GND pins of the charging chip are both grounded; the BST pin of the charging chip is connected to the SW pin of the charging chip and one end of the first inductor through the third capacitor; the CSP pin of the charging chip is connected to the other end of the first inductor and one end of the fifth resistor; the BAT pin of the charging chip is connected to the other end of the fifth resistor, one end of the fourth capacitor, and the battery; the other end of the fourth capacitor is grounded.

[0014] Optionally, in the power switch circuit for automatic power on / off, the charging module further includes an indicator light, a fifth capacitor, and a sixth resistor; the negative terminal of the indicator light is connected to the STAT pin of the charging chip, the positive terminal of the indicator light is connected to the power supply terminal through the sixth resistor, and the fifth capacitor is connected between the VIN pin of the charging chip and ground.

[0015] Optionally, in the power switch circuit of the automatic power on / off, the power control module includes a first switching transistor, a second switching transistor, a second diode, a third diode, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, and a sixth capacitor.

[0016] The source of the first switching transistor is connected to one end of the seventh resistor, one end of the sixth capacitor, the battery, and the other end of the fifth resistor; the gate of the first switching transistor is connected to the other end of the seventh resistor, the other end of the sixth capacitor, and the collector of the second switching transistor; the drain of the first switching transistor is connected to the boost module; the base of the second switching transistor is connected to one end of the eighth resistor and one end of the ninth resistor, the emitter of the second switching transistor is connected to the other end of the eighth resistor and ground, the other end of the ninth resistor is connected to the cathode of the second diode and the cathode of the third diode, the anode of the second diode is connected to the output module, the anode of the third diode is connected to one end of the tenth resistor and one end of the eleventh resistor, the other end of the tenth resistor is connected to the power supply terminal, and the other end of the eleventh resistor is grounded.

[0017] Optionally, in the power switch circuit of the automatic power on / off system, the boost module includes a boost chip, a second inductor, a fourth diode, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a seventh capacitor.

[0018] The IN pin of the boost chip is connected to one end of the second inductor, one end of the twelfth resistor, and the drain of the first switching transistor; the EN pin of the boost chip is connected to the other end of the twelfth resistor and one end of the seventh capacitor; the GND pin of the boost chip and the other end of the seventh capacitor are both grounded; the LX pin of the boost chip is connected to one end of the second inductor and the positive terminal of the fourth diode; the FB pin of the boost chip is connected to one end of the thirteenth resistor and one end of the fourteenth resistor; the other end of the thirteenth resistor is connected to the negative terminal of the fourth diode, one end of the eighth capacitor, and the output module; the other end of the fourteenth resistor and the other end of the eighth capacitor are both grounded.

[0019] Optionally, in the power switch circuit of the automatic power on / off system, the output module includes a second interface, a third interface, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor;

[0020] Pin 1 of the second interface is connected to the battery, one end of the fifteenth resistor, and the other end of the fifth resistor; pin 2 of the second interface is grounded; pin 3 of the second interface is connected to the TS pin of the charging chip; the other end of the fifteenth resistor is connected to one end of the sixteenth resistor and pin 6 of the third interface; the other end of the sixteenth resistor is grounded; the ground pin of the third interface is grounded; pin 2 of the third interface is connected to the negative terminal of the fourth diode; pin 4 of the third interface is connected to the positive terminal of the second diode; and pin 5 of the third interface is connected to the other end of the first resistor.

[0021] Optionally, in the power switch circuit for automatic power on / off, the output module further includes a fifth diode, a sixth diode, and a seventh diode; the fifth diode is connected between pin 1 of the second interface and ground, the sixth diode is connected between pin 4 of the third interface and ground, and the seventh diode is connected between pin 5 of the third interface and ground.

[0022] A second aspect of this utility model provides an electronic device with automatic power on / off, including a motherboard, on which a main control circuit and a battery are provided, wherein the motherboard is further provided with the aforementioned power switch circuit, the power switch circuit being connected to the main control circuit and the battery;

[0023] The power switch circuit detects when the power interface is inserted and supplies power to the main control circuit. In the off state, it controls the main control circuit to perform a power-on operation. When the power switch circuit detects that the current battery level is below a threshold, it controls the main control circuit to perform a power-off operation in the power-on state.

[0024] The technical solution provided in this embodiment of the utility model includes an electronic device with automatic power on / off, comprising a motherboard. The motherboard has a main control circuit, a battery, and a power switch circuit. The power switch circuit connects the main control circuit and the battery. The power switch circuit supplies power to the main control circuit upon detecting that a power interface is inserted, and controls the main control circuit to perform a power-on operation when the device is off. When the power switch circuit detects that the battery's current charge level is below a threshold, it controls the main control circuit to perform a power-off operation when the device is on. This allows for automatic power-on upon power interface insertion without manual operation, providing convenience for users. It also prevents battery over-discharge, protects the battery, extends its lifespan, and improves the battery life of the electronic device. Attached Figure Description

[0025] Figure 1 This is a structural block diagram of the electronic device that automatically turns on and off in an embodiment of this utility model.

[0026] Figure 2 This is a circuit diagram of the input module in an embodiment of this utility model.

[0027] Figure 3 This is a circuit diagram of the charging module in an embodiment of the present invention.

[0028] Figure 4 This is a circuit diagram of the power control module in an embodiment of this utility model.

[0029] Figure 5 This is a circuit diagram of the boost module in an embodiment of this utility model.

[0030] Figure 6 This is a circuit diagram of the output module in an embodiment of this utility model. Detailed Implementation

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments of the present utility model obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0032] Please see Figure 1This utility model provides an electronic device with automatic power-on / off functionality, including a motherboard. The motherboard has a main control circuit 10, a battery 20, and a power switch circuit 30. The power switch circuit 30 connects the main control circuit 10 and the battery 20. When the power interface 40 is inserted, the power switch circuit 30 supplies power to the main control circuit 10. In the off state, it controls the main control circuit 10 to perform a power-on operation. When the battery level of the battery 20 is below a threshold, the power switch circuit 30 controls the main control circuit 10 to perform a power-off operation in the on state. This eliminates the need for manual operation, automatically powering on upon power interface insertion for user convenience. It also prevents battery over-discharge, protects the battery, extends its lifespan, and improves the electronic device's battery life.

[0033] It should be understood that the main control circuit 10 and battery 20 are existing technologies. For example, the main control circuit 10 consists of an MCU and its peripheral circuits. Only the pin connections relevant to this embodiment are described here. The power switch circuit 30 is suitable for various electronic devices with battery charging functions. For example, the electronic devices may be low-power camera devices, portable terminals, wearable devices, IoT devices, etc., especially devices that need to operate for a long time and have high requirements for battery life.

[0034] The power switch circuit 30 includes an input module 31, a charging module 32, a power control module 33, a boost module 34, and an output module 35. The input module 31 is connected to an external power interface and also connects to the charging module 32, the power control module 33, and the output module 35. The charging module 32 connects to the power control module 33, the output module 35, and the battery. The power control module 33 connects to the boost module 34 and the output module 35. The output module 35 connects to the boost module 34 and is externally connected to the main control circuit 10. The input module 31 detects the plug-in / plug-out status of the power interface and outputs a corresponding detection voltage CHAR_EN, which is transmitted to the main control circuit through the output module 35. It also outputs the received power voltage +5V. The charging module 32 converts the power supply voltage +5V into the battery voltage VBAT to charge the battery 20. When the power supply voltage +5V is detected, the power control module 33 turns on and outputs the battery voltage VBAT as the battery input voltage VBAT_IN. The boost module 34 boosts the battery input voltage VBAT_IN and outputs the battery supply voltage VBAT_PW, which is then output to the main control circuit through the output module 35. The main control circuit performs a power-on operation and outputs a power enable signal POWER_EN of the corresponding level (e.g., high level), which is then output through the output module 35 to keep the power control module on. The output module 35 detects the current battery level and transmits it to the main control circuit. When the main control circuit determines that the battery level is below the threshold, it outputs a power enable signal POWER_EN of the corresponding level (e.g., low level), which is then output through the output module 35 to disconnect the power control module, stop outputting the battery input voltage VBAT_IN, stop supplying power to the main control circuit, and the main control circuit performs a power-off operation.

[0035] Please refer to the following: Figure 2 The input module 31 includes a first interface J1, a first diode D1, a first capacitor C1, a first resistor R1, and a second resistor R2. The power supply pin 2 of the first interface J1 is the power supply terminal, and is connected to one end of the first diode D1, one end of the first capacitor C1, and one end of the first resistor R1. The ground pin of the first interface J1, the other end of the first diode D1, and the other end of the first capacitor C1 are all grounded. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the output module 35, and the other end of the second resistor R2 is grounded.

[0036] The first interface J1 is connected to an external power interface 40, which provides charging voltage and can be the output interface of a charger or adapter, or a Type-C interface. After the power interface 40 is inserted into the first interface J1, the externally supplied +5V power voltage is output from the power pin of J1. This voltage is then filtered by a first diode D1 (preferably a D1006WV05C150B electrostatic diode) and further filtered by a first capacitor C1 (10uF / 25V). (In practice, C1 can be connected in parallel with another capacitor) before being output. A first resistor R1 (33KΩ) and a second resistor R2 (15KΩ) are voltage divider resistors used to detect the insertion of the power interface 40. Upon insertion, the +5V power voltage is divided, and a high-level detection voltage CHAR_EN is output to the output module 35; if no insertion occurs, the detection voltage CHAR_EN is low.

[0037] Please refer to the following: Figure 3 The charging module 32 includes a charging chip U1, a first inductor L1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The VIN pin of the charging chip U1 is connected to the power supply terminal and one end of the third resistor R3. The TS pin of the charging chip U1 is connected to the other end of the third resistor R3, one end of the fourth resistor R4, and the output module 35. The other end of the fourth resistor R4 is grounded. The PMID pin of the charging chip U1 is grounded through the second capacitor C2. The PGND and GND pins of the charging chip U1 are both grounded. The BST pin of the charging chip U1 is connected to the SW pin of the charging chip U1 and one end of the first inductor L1 through the third capacitor C3. The CSP pin of the charging chip U1 is connected to the other end of the first inductor L1 and one end of the fifth resistor R5. The BAT pin of the charging chip U1 is connected to the other end of the fifth resistor R5, one end of the fourth capacitor C4, and the battery. The other end of the fourth capacitor C4 is grounded.

[0038] The charging chip U1 is preferably a LP4030 switching charging chip. The voltage range of the VIN pin of U1 is 4.5V to 20V, corresponding to an operating temperature range of -20°C to 60°C. R3 and R4 are thermistors, which divide the input power supply voltage +5V to obtain the thermistor voltage NTC and transmit it to the TS pin of U1. They are also transmitted to the main control circuit through the output module to detect the charging temperature and issue an alarm when the temperature is too high. The power supply voltage +5V transmitted from the power supply end is converted into the battery voltage VBAT by the charging chip U1 to charge the battery 20, and is also transmitted to the power control module 33. L1, C3, C4 and R5 together perform energy storage filtering at the output of U1.

[0039] Preferably, the charging module 32 further includes an indicator light RLED, a fifth capacitor C5, and a sixth resistor R6; the negative terminal of the indicator light RLED is connected to the STAT pin of the charging chip U1, the positive terminal of the indicator light RLED is connected to the power supply terminal through the sixth resistor R6, and the fifth capacitor C5 is connected between the VIN pin of the charging chip U1 and ground.

[0040] The +5V power supply input powers the indicator light RLED. When the charging chip U1 is working, its STAT pin is pulled to ground internally, causing the indicator light RLED to light up red, indicating that it is currently charging. R6 is used for current limiting protection of the indicator light RLED, and C5 is used for filtering the input +5V power supply voltage.

[0041] Please refer to the following: Figure 4 The power control module 33 includes a first switch Q1, a second switch Q2, a second diode D2, a third diode D3, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, and a sixth capacitor C6; the source of the first switch Q1 is connected to one end of the seventh resistor R7, one end of the sixth capacitor C6, the battery, and the other end of the fifth resistor R5; the gate of the first switch Q1 is connected to the other end of the seventh resistor R7, the other end of the sixth capacitor C6, and the collector of the second switch Q2; the first switch Q... The drain of transistor 1 is connected to boost module 34; the base of the second switch Q2 is connected to one end of the eighth resistor R8 and one end of the ninth resistor R9, the emitter of the second switch Q2 is connected to the other end of the eighth resistor R8 and ground, the other end of the ninth resistor R9 is connected to the cathode of the second diode D2 and the cathode of the third diode D3, the anode of the second diode D2 is connected to output module 35, the anode of the third diode D3 is connected to one end of the tenth resistor R10 and one end of the eleventh resistor R11, the other end of the tenth resistor R10 is connected to the power supply terminal, and the other end of the eleventh resistor R11 is grounded.

[0042] In this circuit, the first switching transistor Q1 is preferably a WPM3401 PMOS transistor, and the second switching transistor Q2 is preferably an MMBT3904 NPN transistor. After the power interface 40 is inserted, the +5V power supply voltage is divided by R10 and R11, which controls the conduction of D3. The high voltage of the divided voltage turns on Q2, pulling down the gate of Q1 to a high level, thus turning on Q1. The battery voltage VBAT is output through Q1 as the battery input voltage VBAT_IN, which is then supplied to the boost module 34. After the main control circuit 10 starts working, the power enable signal POWER_EN transmitted through the output module 35 turns on the second diode D2, which also controls the conduction of Q2 and Q1 to ensure the output of the battery input voltage VBAT_IN.

[0043] Please refer to the following: Figure 5The boost module 34 includes a boost chip U2, a second inductor L2, a fourth diode D4, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a seventh capacitor C7. The IN pin of the boost chip U2 is connected to one end of the second inductor L2, one end of the twelfth resistor R12, and the drain of the first switching transistor Q1. The EN pin of the boost chip U2 is connected to the other end of the twelfth resistor R12 and one end of the seventh capacitor C7. The GND pin of the boost chip U2 and the other end of the seventh capacitor C7 are both grounded. The LX pin of the boost chip U2 is connected to one end of the second inductor L2 and the positive terminal of the fourth diode D4. The FB pin of the boost chip U2 is connected to one end of the thirteenth resistor R13 and one end of the fourteenth resistor R14. The other end of the thirteenth resistor R13 is connected to the negative terminal of the fourth diode D4, one end of the eighth capacitor C8, and the output module 35. The other ends of the fourteenth resistor R14 and the other ends of the eighth capacitor C8 are both grounded.

[0044] The preferred model of the boost chip U2 is RY3715. R12 and C7 provide power-on reset and enable functions. When the battery input voltage VBAT_IN is input, the voltage on the EN pin rises from low to high and remains high, enabling U2 to operate. It boosts the battery input voltage VBAT_IN and outputs the battery supply voltage VBAT_PW, which is then supplied to the main control circuit via output module 35. L2 and D4 are used for energy storage and single-phase conduction. R13 and R14 sample the battery supply voltage VBAT_PW and feed it back to the FB pin, causing U2 to adjust the boost voltage until it reaches the preset value. C8 filters the output battery supply voltage VBAT_PW to make it more stable.

[0045] Please refer to the following: Figure 6 The output module 35 includes a second interface J2, a third interface J3, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17. Pin 1 of the second interface J2 is connected to the battery, one end of the fifteenth resistor R15, and the other end of the fifth resistor R5. Pin 2 of the second interface J2 is grounded, pin 3 of the second interface J2 is connected to the TS pin of the charging chip U1, the other end of the fifteenth resistor R15 is connected to one end of the sixteenth resistor R16 and pin 6 of the third interface J3, the other end of the sixteenth resistor R16 is grounded, the ground pins (pin 1, pin G1, and pin G2) of the third interface J3 are grounded, pin 2 of the third interface J3 is connected to the negative terminal of the fourth diode D4, pin 4 of the third interface J3 is connected to the positive terminal of the second diode D2, and pin 5 of the third interface J3 is connected to the other end of the first resistor R1.

[0046] The second interface J2 is connected to an external battery, and the third interface J3 is connected to the MCU in the main control circuit 10. When powered by the battery, the battery voltage VBAT is input through J2, divided by resistors R15 and R16, and then output to the main control circuit 10 through J3, allowing for real-time voltage monitoring. The boosted battery supply voltage VBAT_PW is output to the main control circuit through pin 2 of J3. The detection voltage CHAR_EN, used to identify whether the power interface 40 is inserted, is output to the main control circuit through pin 5 of J3. The high-level power enable signal POWER_EN output by the main control circuit is transmitted to the power control module 33 through pin 4 of J3 to control the on / off state of Q2. When the main control circuit does not output the power enable signal POWER_EN, it is pulled down by R17 to maintain a low level.

[0047] Preferably, the output module 35 further includes a fifth diode D5, a sixth diode D6, and a seventh diode D7; the fifth diode D5 is connected between pin 1 of the second interface J2 and ground, the sixth diode D6 is connected between pin 4 of the third interface J3 and ground, and the seventh diode D7 is connected between pin 5 of the third interface J3 and ground. D5 to D7 are all electrostatic discharge (ESD) protection diodes, providing ESD protection for signals transmitted through the connected interfaces.

[0048] Please continue reading. Figures 1 to 6 Taking a power interface 40 as a Type-C interface and a main control circuit as an MCU as an example, the working principle of the electronic device is as follows:

[0049] Automatic power-on of electronic devices when powered off: When the Type-C interface is plugged in, the first interface J1 outputs an externally supplied power supply voltage of +5V. The first path of the +5V power supply voltage is divided by resistors R1 and R2 to output a high-level detection voltage CHAR_EN, which is then output to the MCU's detection pin through the third interface J3. The second path of the +5V power supply voltage is transmitted to the charging chip U1, which converts it into a battery voltage VBAT to charge battery 20. The third path of the +5V power supply voltage is divided by resistors R10 and R11 to control the conduction of diode D3. The high voltage from the divider turns on Q2, pulling down the gate of Q1 to a high level. Q1 then turns on, and the battery voltage VBAT (at this point, the converted VBAT) is output through Q1 as the battery input voltage VBAT_IN. The battery input voltage VBAT_IN is boosted by the boost chip U2 to output the battery supply voltage VBAT_PW, which is then output to the MCU's power supply pin through the third interface J3. At this time, the MCU is powered on and starts working, performing the power-on operation. It outputs a high-level power enable signal POWER_EN, which is transmitted to the positive terminal of D2 through J3. D2 is turned on, which also controls Q2 and Q1 to be turned on, ensuring the continuous output of the battery input voltage VBAT_IN.

[0050] When the Type-C interface is unplugged, although there is no +5V power supply output, Q2 will not be immediately disconnected. The battery voltage VBAT provided by the battery is output through Q2, and after being boosted, it becomes the battery power supply voltage VBAT_PW to continue to power the MCU. The MCU continues to output a high-level power enable signal POWER_EN to keep Q2 on until the battery is depleted or a shutdown operation is performed.

[0051] Power-off control: The battery voltage VBAT supplied by the battery is divided by R15 and R16 and then output to the MCU through J3. The MCU can detect the current battery level based on this voltage division. When it is determined that the battery level is lower than the preset threshold or a power-off command is received, the MCU outputs a low-level power enable signal POWER_EN. The base voltage of Q2 is reduced to a low level through R8, Q2 is turned off. The gate voltage of Q1 is increased through R7, Q1 is turned off, the battery voltage VBAT stops outputting, resulting in no battery input voltage VBAT_IN output. The boost chip U2 does not work, and there is no battery power supply voltage VBAT_PW to power the MCU, so the electronic device can automatically power off.

[0052] In summary, the automatic power switch circuit and electronic equipment provided by this utility model can automatically power on and start the electronic equipment when the power interface is plugged in while the device is off, and automatically power off when the battery level is detected to be below a threshold. This eliminates the need for manual operation of mechanical buttons, avoiding the hassle of manual operation and simplifying user experience. After charging, unplugging the power interface allows the battery to continue supplying power, maintaining operation and preventing accidental shutdowns due to external power disconnection, thus providing fault protection.

[0053] This power switch circuit employs a low-power design with a simple structure, eliminating unnecessary current conversion and amplification circuits to effectively reduce power consumption. The circuit's voltage regulation and low-battery protection ensure stable operation of the electronic device even under unstable power conditions, preventing damage caused by battery issues. Furthermore, it automatically shuts down when the battery is too low, preventing over-discharge, extending battery life, and further enhancing battery endurance.

[0054] During the operation of electronic devices, the power switch circuit can provide stable power and respond quickly to changes in battery level, preventing the device from suddenly shutting down due to low battery, thus improving stability and response speed.

[0055] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An automatic power switch circuit for switching on and off a power source, connecting a power source interface, a battery and a main control circuit, characterized in that, The power switch circuit includes an input module, a charging module, a power control module, a boost module, and an output module; The input module detects the plugging / unplugging status of the power interface and outputs a corresponding level of detection voltage, which is then transmitted to the main control circuit via the output module; it also outputs the power voltage transmitted from the power interface. The charging module converts the power supply voltage into the battery voltage to charge the battery. The power control module turns on when it detects the power supply voltage and outputs the battery voltage as the battery input voltage; it controls the opening and closing of the internal circuit according to the received power enable signal, and stops outputting the battery input voltage when it is disconnected. The boost module boosts the battery input voltage and outputs the battery supply voltage, which is then supplied to the main control circuit via the output module to perform the power-on operation. The output module detects the current battery level and transmits it to the main control circuit, and outputs the power enable signal from the main control circuit to the power control module.

2. The power switch circuit for automatic on / off operation according to claim 1, characterized in that, The input module includes a first interface, a first diode, a first capacitor, a first resistor, and a second resistor; The power pin of the first interface is the power supply terminal, one end of the first diode, one end of the first capacitor, and one end of the first resistor; the ground pin of the first interface, the other end of the first diode, and the other end of the first capacitor are all grounded; the other end of the first resistor is connected to one end of the second resistor and the output module, and the other end of the second resistor is grounded.

3. The power switch circuit for automatic on / off operation according to claim 2, characterized in that, The charging module includes a charging chip, a first inductor, a second capacitor, a third capacitor, a fourth capacitor, a third resistor, a fourth resistor, and a fifth resistor; The VIN pin of the charging chip is connected to the power supply terminal and one end of the third resistor; the TS pin of the charging chip is connected to the other end of the third resistor, one end of the fourth resistor, and the output module. The other end of the fourth resistor is grounded. The PMID pin of the charging chip is grounded through the second capacitor. The PGND and GND pins of the charging chip are both grounded. The BST pin of the charging chip is connected to the SW pin of the charging chip and one end of the first inductor through the third capacitor. The CSP pin of the charging chip is connected to the other end of the first inductor and one end of the fifth resistor. The BAT pin of the charging chip is connected to the other end of the fifth resistor, one end of the fourth capacitor, and the battery. The other end of the fourth capacitor is grounded.

4. The power switch circuit for automatic on / off operation according to claim 3, characterized in that, The charging module also includes an indicator light, a fifth capacitor, and a sixth resistor; the negative terminal of the indicator light is connected to the STAT pin of the charging chip, the positive terminal of the indicator light is connected to the power supply terminal through the sixth resistor, and the fifth capacitor is connected between the VIN pin of the charging chip and ground.

5. The power switch circuit for automatic on / off operation according to claim 3, characterized in that, The power control module includes a first switching transistor, a second switching transistor, a second diode, a third diode, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, and a sixth capacitor; The source of the first switching transistor is connected to one end of the seventh resistor, one end of the sixth capacitor, the battery, and the other end of the fifth resistor; the gate of the first switching transistor is connected to the other end of the seventh resistor, the other end of the sixth capacitor, and the collector of the second switching transistor; the drain of the first switching transistor is connected to the boost module; the base of the second switching transistor is connected to one end of the eighth resistor and one end of the ninth resistor, the emitter of the second switching transistor is connected to the other end of the eighth resistor and ground, the other end of the ninth resistor is connected to the cathode of the second diode and the cathode of the third diode, the anode of the second diode is connected to the output module, the anode of the third diode is connected to one end of the tenth resistor and one end of the eleventh resistor, the other end of the tenth resistor is connected to the power supply terminal, and the other end of the eleventh resistor is grounded.

6. The power switch circuit for automatic on / off operation according to claim 5, characterized in that, The boost module includes a boost chip, a second inductor, a fourth diode, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a seventh capacitor; The IN pin of the boost chip is connected to one end of the second inductor, one end of the twelfth resistor, and the drain of the first switching transistor; The EN pin of the boost converter chip is connected to the other end of the twelfth resistor and one end of the seventh capacitor. The GND pin of the boost converter chip and the other end of the seventh capacitor are both grounded. The LX pin of the boost converter chip is connected to one end of the second inductor and the positive terminal of the fourth diode. The FB pin of the boost converter chip is connected to one end of the thirteenth resistor and one end of the fourteenth resistor. The other end of the thirteenth resistor is connected to the negative terminal of the fourth diode, one end of the eighth capacitor, and the output module. The other end of the fourteenth resistor and the other end of the eighth capacitor are both grounded.

7. The power switch circuit for automatic on / off operation according to claim 6, characterized in that, The output module includes a second interface, a third interface, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor; Pin 1 of the second interface is connected to the battery, one end of the fifteenth resistor, and the other end of the fifth resistor; Pin 2 of the second interface is grounded, pin 3 of the second interface is connected to the TS pin of the charging chip, the other end of the fifteenth resistor is connected to one end of the sixteenth resistor and pin 6 of the third interface, the other end of the sixteenth resistor is grounded, the ground pin of the third interface is grounded, pin 2 of the third interface is connected to the negative terminal of the fourth diode, pin 4 of the third interface is connected to the positive terminal of the second diode, and pin 5 of the third interface is connected to the other end of the first resistor.

8. The power switch circuit for automatic on / off operation according to claim 7, characterized in that, The output module also includes a fifth diode, a sixth diode, and a seventh diode; the fifth diode is connected between pin 1 of the second interface and ground, the sixth diode is connected between pin 4 of the third interface and ground, and the seventh diode is connected between pin 5 of the third interface and ground.

9. An electronic device for automatic power on / off, comprising a motherboard, wherein the motherboard is provided with a main control circuit and a battery, characterized in that, The motherboard is further provided with a power switch circuit as described in any one of claims 1-8, wherein the power switch circuit is connected to the main control circuit and the battery; The power switch circuit detects when the power interface is inserted and supplies power to the main control circuit. In the off state, it controls the main control circuit to perform a power-on operation. When the power switch circuit detects that the current battery level is lower than a threshold, it controls the main control circuit to perform a power-off operation in the on state.

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