A circuit for reducing shutdown leakage current

Abstract

This utility model discloses a circuit for reducing power-off leakage current, connecting a charging chip and a battery. The circuit includes a switch control module and a startup module. The switch control module is connected to the startup module, the charging chip, and the battery. The startup module is connected to the battery. The startup module outputs a control signal of a corresponding level based on whether an external magnetic field triggers the circuit. The switch control module controls the battery's power supply to the charging chip based on the operating state and the control signal. In power-off mode and transport mode, the startup module outputs a low-level or 0V control signal when no external magnetic field triggers the circuit. The switch control module controls the battery to disconnect its power supply to the charging chip based on this control signal, while the battery continues to supply power to the startup module. In transport mode, only the startup module is powered, resulting in lower current consumption and saving current consumption from the charging chip, significantly reducing the overall power-off leakage current and achieving the effect of reducing power-off leakage current.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a circuit for reducing leakage current when the device is turned off. Background Technology

[0002] Currently, mobile phones generally use lithium batteries for power, which have a certain shutdown current when powered off. Mobile phones are usually transported by sea to reduce transportation costs. If the time is long (such as 1-3 months from production to delivery to the user), the battery may become too low and the phone will not turn on, requiring it to be charged before it can be sold.

[0003] Currently, the common solution used by various companies to reduce leakage current during shutdown is to put the phone into shipmode mode before it leaves the factory. For example... Figure 1 As shown, the charging chip (Charge IC) connects to the PMIC (Power Management Integrated Circuit), USB interface, and Host (the device that provides power or data); the VBUS pin receives the adapter / USB voltage. At the final testing station in production, a specific command is issued to put the phone into shipmode mode. The fourth MOSFET Q4 inside the charging chip (Charge IC) is turned off, disconnecting the VBAT pin and VSYS pin, making the VSYS voltage zero, and the PMIC chip stops working. When the user receives the phone, they can exit shipmode mode by short-pressing the power button S1 or plugging in the charger. Because the charging chip is still working in shipmode, it has a quiescent current of approximately 50uA. Since some components in other circuits are powered by VBAT and connected to the VBAT pin of the charging chip, there are also other leakage currents when the phone is powered off. Combined, this results in a shutdown leakage current, typically around 100uA, even in shipmode.

[0004] While existing solutions to reduce power-off leakage current have somewhat lowered it, the leakage current remains relatively high. If the phone has been stored for more than three months, the problem of over-discharged battery causing it to fail to power on can still occur. Furthermore, the battery continues to draw current even when the phone is off, which can lead to over-discharge over time and negatively impact battery life.

[0005] Therefore, existing technologies still need to be improved and enhanced. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a circuit that reduces power-off leakage current in order to solve the problem of large power-off leakage current in the current transportation mode.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A circuit for reducing power-off leakage current is provided, connecting a charging chip and a battery. The circuit includes a switch control module and a startup module; the switch control module is connected to the startup module, the charging chip, and the battery; the startup module is connected to the battery. The startup module outputs a control signal of a corresponding level based on whether there is an external magnetic field triggering it, and the switch control module controls the power supply state of the battery to the charging chip based on the working state and the control signal.

[0008] In the circuit for reducing leakage current during shutdown, the switch control module controls the battery to supply power to the charging chip in both the power-on and power-off states. When the device is powered off and enters transport mode, the startup module outputs a low-level or 0V control signal when no external magnetic field triggers the device. The switch control module controls the battery to disconnect the power supply to the charging chip based on this control signal, while the battery continues to supply power to the startup module. When the startup module detects an external magnetic field trigger, it outputs a high-level control signal. The switch control module then controls the battery to supply power to the charging chip based on this control signal.

[0009] In the circuit for reducing power-off leakage current, the switch control module includes a first switch transistor, a second switch transistor, and a first resistor; The drain of the first switching transistor is connected to the VBAT pin of the charging chip, the source of the first switching transistor is connected to one end of the first resistor and the positive terminal of the battery, the gate of the first switching transistor is connected to the other end of the first resistor and the drain of the second switching transistor, the source of the second switching transistor is grounded, and the gate of the second switching transistor is connected to the VSYS pin of the charging chip and the startup module.

[0010] In the circuit for reducing power-off leakage current, the first switching transistor is a PMOS transistor and the second switching transistor is an NMOS transistor.

[0011] In the circuit for reducing power-off leakage current, the switch control module further includes a diode, the positive terminal of which is connected to the VSYS pin of the charging chip, and the negative terminal of which is connected to the gate of the second switching transistor.

[0012] In the circuit for reducing shutdown leakage current, the switch control module further includes a second resistor, one end of which is connected to the gate of the second switching transistor, and the other end of which is connected to the output terminal of the startup module.

[0013] In the circuit for reducing power-off leakage current, the switch control module further includes a third resistor, which is connected between the positive terminal of the battery and the gate of the second switching transistor.

[0014] In the circuit for reducing power-off leakage current, the startup module includes a Hall sensor. The power supply pin of the Hall sensor is connected to the positive terminal of the battery, the ground pin of the Hall sensor is grounded, and the output pin of the Hall sensor is connected to the gate of the second switching transistor.

[0015] In the circuit for reducing leakage current during shutdown, the startup module includes a Hall sensor. The power supply pin of the Hall sensor is connected to the positive terminal of the battery, the ground pin of the Hall sensor is grounded, and the output pin of the Hall sensor is connected to the other end of the second resistor.

[0016] Compared to existing technologies, the circuit for reducing shutdown leakage current provided by this utility model connects a charging chip and a battery. The circuit includes a switch control module and a startup module. The switch control module connects to the startup module, the charging chip, and the battery. The startup module connects to the battery. The startup module outputs a control signal of a corresponding level based on whether an external magnetic field triggers the circuit. The switch control module controls the battery's power supply to the charging chip based on the operating state and the control signal. When the device is powered off and in transport mode, the startup module outputs a low-level or 0V control signal when no external magnetic field triggers the circuit. The switch control module controls the battery to disconnect its power supply to the charging chip based on this control signal, while the battery continues to supply power to the startup module. In transport mode, only the startup module is powered, resulting in lower current consumption and saving current consumption from the charging chip, significantly reducing the overall shutdown leakage current and achieving the effect of reducing shutdown leakage current. Attached Figure Description

[0017] Figure 1 This is an existing circuit diagram for reducing leakage current during shutdown.

[0018] Figure 2 This is a circuit diagram of the circuit for reducing power-off leakage current provided by this utility model. Detailed Implementation

[0019] This invention provides a circuit for reducing leakage current during shutdown. To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the following detailed description, with reference to the accompanying drawings and embodiments, further illustrates the invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0020] Please see Figure 2The circuit for reducing power-off leakage current provided by this utility model is integrated on the circuit board inside the mobile phone, connecting the existing charging chip U1 and battery BAT. The circuit for reducing power-off leakage current includes a switch control module 10 and a startup module 20. The switch control module 10 is connected to the startup module 20, the charging chip U1, and the battery BAT. The startup module 20 is connected to the battery BAT. The startup module 20 outputs a control signal of a corresponding level based on whether there is an external magnetic field triggering it. The switch control module 10 controls the power supply state of the battery to the charging chip based on the working state and the control signal.

[0021] In this configuration, the switch control module 10 controls the battery to supply power to the charging chip regardless of the control signal level (i.e., whether or not there is a magnetic field trigger) in both the power-on and power-off states. When the device is powered off and enters transport mode, the startup module 20 outputs a low-level or 0V control signal when there is no external magnetic field trigger. Based on this control signal, the switch control module 10 controls the battery to disconnect the power supply to the charging chip. At this time, the battery (BAT) only supplies power to the startup module 20. The power consumption of the magnetic field-triggered startup module 20 is much lower than existing solutions for reducing power-off leakage current, thereby greatly reducing power loss during power-off, preventing battery over-discharge, and extending battery life.

[0022] When the phone is powered off and in transport mode, the startup module 20 outputs a high-level control signal when triggered by an external magnetic field. The switch control module 10 controls the battery to supply power to the charging chip according to the control signal, and the phone can then be powered on and used normally.

[0023] In this embodiment, the switch control module 10 includes a first switch Q1, a second switch Q2, and a first resistor R1; the drain of the first switch Q1 is connected to the VBAT pin of the charging chip U1, the source of the first switch Q1 is connected to one end of the first resistor R1 and the positive terminal of the battery BAT, the gate of the first switch Q1 is connected to the other end of the first resistor R1 and the drain of the second switch Q2, the source of the second switch Q2 is grounded, and the gate of the second switch Q2 is connected to the VSYS pin of the charging chip U1 and the startup module 20.

[0024] In this configuration, the first switch Q1 is preferably a PMOS transistor, and the second switch Q2 is preferably an NMOS transistor. When the startup module 20 is not operating and its output is 0, the first switch Q1 is controlled by the VSYS voltage output from the VSYS pin of the charging chip U1. The VSYS voltage only becomes 0V or low level in shipmode mode; in other states, it is high level.

[0025] When VSYS voltage is high, Q1 is turned on. When Q1 is turned on, it pulls down the gate voltage (i.e., the voltage at point B) of the second switch Q2, and Q2 is turned on. The battery BAT supplies power to the charging chip U1 through Q1. When VSYS voltage is low, Q1 is turned off. At this time, the gate voltage (i.e., the voltage at point B) of the second switch Q2 is pulled up to a high level by the battery through the first resistor R1 (preferably with a resistance of 470KΩ), Q2 is turned off, and the power supply between the battery BAT and the charging chip U1 is also disconnected.

[0026] When the startup module 20 is triggered to output a high level, the gate voltage (i.e., the voltage at point A) of the first switching transistor Q2 is also high. When Q2 is turned on, Q1 is turned on, and power supply begins.

[0027] Preferably, the switch control module 10 further includes a diode D, the anode of which is connected to the VSYS pin of the charging chip U1, and the cathode of which is connected to the gate of the second switch Q2. The unidirectional conduction characteristic of the diode D prevents the high-level output from the startup module 20 from flowing back into the VSYS pin of the charging chip U1.

[0028] Preferably, the switch control module 10 further includes a second resistor R2, one end of which is connected to the gate of the second switch Q2, and the other end of which is connected to the output terminal of the start-up module 20. The resistance of R2 is preferably 47KΩ, used for current limiting to protect Q2.

[0029] Preferably, the switch control module 10 further includes a third resistor R3, which is connected between the positive terminal of the battery and the gate of the second switch Q2. The battery BAT pulls the gate voltage of Q2 high through the third resistor R3 (preferably with a resistance of 470KΩ). As long as the battery is charged, Q2 will be on, ensuring that Q1 is on by default, thus guaranteeing that power can be supplied to the charging chip U1 through Q1 when the battery is charged. The on / off state of Q2 is subsequently controlled by a control signal output from the startup module 20.

[0030] The startup module 20 includes a Hall sensor U2. The power supply pin of the Hall sensor U2 is connected to the positive terminal of the battery BAT, the ground pin of the Hall sensor U2 is grounded, and the output pin of the Hall sensor U2 (i.e. the output terminal of the startup module 20) is connected to the gate of the second switch Q2 (or the other end of the second resistor R2 if there is one).

[0031] This embodiment utilizes the Hall effect, triggered by a magnet. The Hall sensor detects the change in magnetic field generated when the magnet approaches, converting the magnetic signal into an electrical signal output. Therefore, the output of Hall sensor U2 is 0 when no magnet is nearby, and a high level is output when a magnet is nearby. When placing Hall sensor U2 on the circuit board, it should be kept away from devices that are susceptible to magnetic interference, such as antennas, speakers, earpieces, and microphones.

[0032] In practical implementation, Q1 and R2 can be removed, and the positive terminal of battery BAT can be connected to the VBAT pin of charging chip U1. Q2 can be directly connected between the negative terminal of battery BAT and ground. The switching function of the PMOS transistor on the positive terminal can be replaced by controlling the ground loop of the negative terminal of the battery. The switching method is not limited here. A capacitor for filtering can also be connected in parallel with the battery.

[0033] Please continue reading. Figure 2 The working principle of the circuit for reducing shutdown leakage current is as follows: In both the power-on and power-off states, if no magnet is near, the output of Hall sensor U2 is 0. At this time, VSYS voltage is charged, the voltage at point A is high, the second switch Q2 is turned on, and the gate voltage of the first switch Q1 (i.e., the voltage at point B) is pulled down to a low level by Q2, Q1 is turned on, and the battery BAT supplies power to the charging chip U1 through Q1. The VSYS voltage and VBAT voltage are close.

[0034] Powering off and entering shipmode: Before powering off, a command is sent to put the charging chip U1 into shipmode. In this mode, VSYS voltage is 0V or low. Since no magnet is near, the Hall sensor output is 0, the second switch Q2 is cut off, and the gate voltage of Q1 is pulled high through R1, causing Q1 to disconnect. The battery power supply to the charging chip U1 is then cut off. At this time, the leakage current in the entire system comes from the battery powering the Hall sensor U2, and the power consumption of the Hall sensor U2 is approximately 5uA.

[0035] When a magnet is brought close to Hall sensor U2, Hall sensor U2 outputs a high level, making the voltage at point A high. The second switch Q2 turns on, pulling the voltage at point B low. The first switch Q1 turns on, and battery BAT supplies power to charging chip U1 through Q1. At this time, a short press of the power button S1 will exit shipmode mode, and a long press of the power button for more than 3 seconds will turn on the device.

[0036] In both the power-on and power-off states, regardless of whether a magnet is near the Hall sensor U2, the first switch Q1 remains on, and the battery can power the entire system normally. Only after powering off and entering shipmode, and then using a magnet to approach the Hall sensor U2, will the first switch Q1 be turned on. The various states, the output of the Hall sensor U2, the corresponding gate level, and the on / off state of the first switch are shown in Table 1 below.

[0037] Table 1 In summary, the circuit for reducing power-off leakage current provided by this invention utilizes a magnet and a Hall sensor. The proximity of the magnet to the Hall sensor triggers the switching on / off of the corresponding switching transistor, thereby controlling the battery power supply path in shipmode. The control section does not rely on existing CPU control but instead uses a Hall sensor, making it more reliable and stable. This avoids situations where the CPU shuts off itself or causes uncontrollable issues due to CPU crashes. In shipmode, the Hall sensor consumes less current, resulting in a lower power-off leakage current of approximately 5uA, effectively reducing power-off leakage current.

[0038] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A circuit for reducing leakage current during shutdown, connecting a charging chip and a battery, characterized in that, The circuit for reducing power-off leakage current includes a switch control module and a startup module; the switch control module is connected to the startup module, a charging chip, and a battery; the startup module is connected to the battery. The start-up module outputs a control signal of a corresponding level based on whether there is an external magnetic field triggering it, and the switch control module controls the power supply state of the battery to the charging chip based on the working state and the control signal. When the device is powered off and enters transport mode, the startup module outputs a low-level or 0V control signal when no external magnetic field triggers the device. The switch control module controls the battery to disconnect the power supply to the charging chip based on the control signal, while the battery continues to supply power to the startup module.

2. The circuit for reducing shutdown leakage current according to claim 1, characterized in that, The switch control module controls the battery to supply power to the charging chip in the power-on and power-off states; When the startup module detects an external magnetic field trigger, it outputs a high-level control signal. The switch control module then controls the battery to supply power to the charging chip based on this control signal.

3. The circuit for reducing shutdown leakage current according to claim 2, characterized in that, The switch control module includes a first switch transistor, a second switch transistor, and a first resistor; The drain of the first switching transistor is connected to the VBAT pin of the charging chip, the source of the first switching transistor is connected to one end of the first resistor and the positive terminal of the battery, the gate of the first switching transistor is connected to the other end of the first resistor and the drain of the second switching transistor, the source of the second switching transistor is grounded, and the gate of the second switching transistor is connected to the VSYS pin of the charging chip and the startup module.

4. The circuit for reducing shutdown leakage current according to claim 3, characterized in that, The first switch is a PMOS transistor, and the second switch is an NMOS transistor.

5. The circuit for reducing shutdown leakage current according to claim 3, characterized in that, The switch control module also includes a diode, the positive terminal of which is connected to the VSYS pin of the charging chip, and the negative terminal of which is connected to the gate of the second switching transistor.

6. The circuit for reducing shutdown leakage current according to claim 3, characterized in that, The switch control module also includes a second resistor, one end of which is connected to the gate of the second switch transistor, and the other end of which is connected to the output terminal of the start-up module.

7. The circuit for reducing shutdown leakage current according to claim 3, characterized in that, The switch control module also includes a third resistor, which is connected between the positive terminal of the battery and the gate of the second switch.

8. The circuit for reducing shutdown leakage current according to claim 3, characterized in that, The startup module includes a Hall sensor, the power supply pin of which is connected to the positive terminal of the battery, the ground pin of which is grounded, and the output pin of which is connected to the gate of the second switching transistor.

9. The circuit for reducing shutdown leakage current according to claim 6, characterized in that, The startup module includes a Hall sensor, the power supply pin of which is connected to the positive terminal of the battery, the ground pin of which is grounded, and the output pin of which is connected to the other end of a second resistor.

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