Physical power-off protector for charger

Abstract

The utility model relates to the technical field of chargers, in particular to a physical power-off protector for a charger, which comprises a key switch, a voltage-stabilizing power supply module, a relay switch, a charger power supply input end, a charging circuit, a charging current detection circuit, a driving comparison module and a triode. The relay switch comprises a first normally open contact and a second normally open contact. Intelligent detection of the charging working state of the charger is achieved through the charging current detection circuit and the driving comparison module, and by detecting current signals of the charging circuit in real time, when it is detected that charging is finished, the driving comparison module immediately outputs low-level signals to control a triode to be cut off and a relay switch to be powered off and released. Therefore, the current of the power input end of the charger is cut off and the power supply is automatically and physically cut off.

Description

Technical Field

[0001] This utility model relates to the field of charger technology, specifically to a charger physical power-off protection device. Background Technology

[0002] Electronic devices such as mobile phones and tablets need to be charged with a charger after their batteries run out of power. To prevent overcharging, these devices are equipped with overcharge protection circuits that intelligently control the charging process, thereby improving charging safety and battery life. Once the device is fully charged, the overcharge protection circuit can alert the charger to switch to trickle charging mode, repeatedly replenishing the battery's power.

[0003] However, people often forget to unplug the charger from the socket or power strip after charging is complete, leaving it plugged in and energized. Although the trickle charging current of the charger is extremely small, prolonged energization will still accelerate the aging of the internal electronic components, easily leading to component failure, and prolonged standby power-on can easily cause safety accidents. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides a physical power-off protector for a charger, comprising a push-button switch AN, a regulated power supply module, a relay switch K, a charger power input terminal, a charging circuit, a charging current detection circuit, a drive comparison module, and a transistor Q1; the relay switch K includes a first normally open contact K1 and a second normally open contact K2;

[0005] The charger's power input terminal is electrically connected to the regulated power supply module and the charging circuit via a push-button switch AN. The regulated power supply module is electrically connected to the drive comparator module, the relay switch K, and the emitter of transistor Q1. The charging circuit is electrically connected to the input terminal of the charging current detection circuit, the output terminal of the charging current detection circuit is connected to the drive comparator module, the drive comparator module is electrically connected to the base of transistor Q1, and the collector of transistor Q1 is electrically connected to the relay switch K. The first normally open contact K1 is connected in parallel with the push-button switch AN, and the second normally open contact K2 is electrically connected between the charging circuit and the charger's power input terminal.

[0006] The charging current detection circuit includes a current transformer, a rectifier bridge, resistors R10-R15, capacitors C4-C6, and operational amplifier U2. The primary winding of the current transformer is connected in series with the charging circuit, and its secondary winding is electrically connected to the rectifier bridge. One end of resistor R10 is connected to the power supply electrode, and the other end of resistor R10 is connected in series with resistor R11 and grounded. One end of resistor R13 is electrically connected to the series connection node of resistors R10 and R11, and the other end of capacitor C4. The other end of resistor R13 is connected to the inverting input terminal of operational amplifier U2. One end of capacitor C5 is connected to the power supply electrode, and the other end of capacitor C5 is connected in series with resistor R12. The rectifier bridge is electrically connected to one end of resistor R14 through the series connection node of resistor R12 and capacitor C5. The other end of resistor R14 is connected to the non-inverting input terminal of operational amplifier U2. The output terminal of the operational amplifier is electrically connected to resistor R15, and capacitor C6 is connected in parallel with resistor R15.

[0007] The charging current detection circuit also includes an input protection circuit, which is electrically connected between the rectifier bridge and the resistor R14. The input protection circuit includes a resistor R2, a capacitor C1, a capacitor C2, and a Zener diode D1, which are connected in parallel in sequence.

[0008] In a specific implementation, the drive comparison module includes a voltage comparison circuit. The input terminal of the voltage comparison circuit is electrically connected to the output terminal of the charging current detection circuit, and can be compared with the output current signal of the charging current detection circuit.

[0009] The voltage comparison circuit includes resistors R3-R7, capacitor C3, and voltage comparator U1. One end of resistor R4 is connected to the power supply electrode, and the other end is connected in series with R3 and grounded. The series connection point of resistors R3 and R4 is connected to one end of capacitor C3 and one end of resistor R6, respectively. The other end of resistor R6 is connected to the inverting input terminal of voltage comparator U1, and the other end of capacitor C3 is grounded. One end of resistor R5 is connected to the output terminal of the charging current detection circuit, and the other end of resistor R5 is connected to the non-inverting input terminal of voltage comparator U1. The output terminal of the voltage comparator is connected in series with resistor R7.

[0010] In another specific embodiment, the drive comparison module includes an analog-to-digital converter and a microprocessor. The input terminal of the analog-to-digital converter is electrically connected to the charging current detection circuit, the output terminal of the analog-to-digital converter is electrically connected to the microprocessor, and the output terminal of the microprocessor is electrically connected to the transistor Q1.

[0011] The transistor Q1 is a PNP type transistor.

[0012] The charger's physical power-off protector is also equipped with a signal indicator light, which is connected in parallel with the relay switch K. The signal indicator light can display a signal based on the energization status of the relay switch K, thereby confirming the current on / off status of the charger.

[0013] Beneficial Effects: This utility model is a physical power-off protector for a charger. Through a charging current detection circuit and a drive comparison module, it achieves intelligent detection of the charger's charging status. Simultaneously, a relay switch is used to switch the charger's power on and off. By real-time detection of the charging circuit's current signal, when charging is detected to be complete, the drive comparison module outputs a low-level signal, controlling the transistor to cut off, and the relay switch to release, thereby cutting off the current to the charger's power input terminal. This achieves automatic physical power cut-off, stopping the charger from working. This not only avoids wasting electrical energy but also prevents accidents caused by component aging due to prolonged charger operation. Attached Figure Description

[0014] The advantages and features of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this invention.

[0015] In the attached diagram:

[0016] Figure 1 This is a circuit diagram of a physical power-off protection device for a charger according to the present invention;

[0017] Figure 2 This is a circuit diagram for detecting charging current. Detailed Implementation

[0018] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings.

[0019] Example

[0020] See Figure 1 This embodiment provides a physical power-off protector for a charger, including a push-button switch AN, a regulated power supply module, a relay switch K, a charger power input terminal, a charging circuit, a charging current detection circuit, a drive comparison module, and a transistor Q1; the relay switch K includes a first normally open contact K1 and a second normally open contact K2.

[0021] The charger's power input terminal is electrically connected to the regulated power supply module and the charging circuit via a push-button switch AN. The charger's power input terminal is normally connected to 220V AC mains power and is connected to the device's battery through the charging circuit for battery charging. The regulated power supply module can convert AC power into DC power supply, providing a stable voltage source for the various components inside the charger. The regulated power supply module is electrically connected to the drive comparator module and the relay switch K.

[0022] To detect the charging status of the device's battery, the charging circuit is electrically connected to the input of the charging current detection circuit, and the output of the charging current detection circuit is connected to the drive comparison module. The charging current detection circuit can detect the current signal of the charger's charging circuit and transmit the current signal to the drive comparison module for voltage comparison, thereby determining whether the charger's charging circuit is in a normal charging state or a trickle charge state. The drive comparison module can automatically perform physical power-off protection when the charger is fully charged based on the voltage comparison result.

[0023] The drive comparison module is electrically connected to the base of transistor Q1, the collector of transistor Q1 is electrically connected to relay switch K, and the emitter of transistor Q1 is grounded. Transistor Q1 is a PNP transistor. Meanwhile, the first normally open contact K1 is connected in parallel with the push button switch AN, and the second normally open contact K2 is electrically connected between the charging circuit and the power input terminal of the charger.

[0024] When using this charger, first press the button switch AN to connect the charger's power input terminal to the voltage regulator module, causing the voltage regulator module to start working. The voltage regulator module energizes the relay switch K, causing the first normally open contact K1 and the second normally open contact K2 of the relay switch K to close and connect. At this time, release the button switch AN. The voltage regulator module is still energized and working, and the charger simultaneously connects to the charging circuit to start charging. The charging current detection circuit draws power from the charging circuit, detects the current signal of the charging circuit, and transmits the current signal to the drive comparison module for comparison. The drive comparison module has a preset signal threshold. When the device battery is charging normally, the charging circuit current signal is greater than the preset signal threshold. The drive comparison module outputs a high level, the transistor Q1 is turned on, and the relay switch K remains in the energized state. The first normally open contact K1 and the second normally open contact K2 remain closed, and the charger continues to charge. When the device battery is fully charged, the current in the charging circuit decreases. The current signal detected by the charging current detection circuit is less than the preset signal threshold. The drive comparison module outputs a low level, the transistor Q1 is turned off, the relay switch K is de-energized and released, the first normally open contact K1 and the second normally open contact K2 are opened, the current at the charger voltage input terminal is cut off, and the charger stops working. Furthermore, when a short circuit fault in the charging circuit causes an abnormal increase in current, the current signal transmitted by the charging current detection circuit is greater than the protection current of the drive comparison circuit. The drive comparison circuit outputs a low-level signal to control the relay switch K to de-energize and release, and K1 and K2 are disconnected, thereby physically cutting off the power supply and preventing short circuit accidents.

[0025] See Figure 2To enable current detection in the charging circuit, the charging current detection circuit includes a current transformer, a rectifier bridge, resistors R10-R15, capacitors C4-C6, and operational amplifier U2. The primary winding of the current transformer is connected in series with the charging circuit, and its secondary winding is electrically connected to the rectifier bridge. One end of resistor R10 is connected to the power supply electrode, and the other end of resistor R10 is connected in series with resistor R11 and grounded. One end of resistor R13 is electrically connected to the series connection point of resistors R10 and R11, and the other end of capacitor C4. The other end of capacitor C3 is connected to the inverting input of operational amplifier U2; one end of capacitor C5 is connected to the power supply terminal, and the other end of capacitor C5 is connected in series with resistor R12 to form an RC circuit. The rectifier bridge is electrically connected to one end of resistor R14 through the series connection of resistor R12 and capacitor C5. The RC circuit can filter the current signal output by the rectifier bridge. The other end of resistor R14 is connected to the non-inverting input of operational amplifier U2; the output of the operational amplifier is electrically connected to resistor R15, and capacitor C6 is connected in parallel with resistor R15. The charging current detection circuit can convert AC signal into DC signal through current transformer and then process and amplify it through operational amplifier.

[0026] Meanwhile, to protect the charging current detection circuit, an input protection circuit is also included. This input protection circuit is electrically connected between the rectifier bridge and resistor R14, providing overcurrent protection to prevent excessive output current from the rectifier bridge, which could damage other components of the charging current detection circuit. The input protection circuit includes resistor R2, capacitors C1 and C2, and a Zener diode D1, which are connected in parallel.

[0027] In one embodiment, to detect and compare the electrical signal of the charging current detection circuit, the driving comparison module includes a voltage comparison circuit. The voltage comparison circuit includes resistors R3-R7, capacitor C3, and voltage comparator U1. One end of resistor R4 is connected to the power supply electrode, and the other end is connected in series with R3 and grounded. The series connection node of resistors R3 and R4 is connected to one end of capacitor C3 and one end of resistor R6, respectively. The other end of resistor R6 is connected to the inverting input terminal of voltage comparator U1, and the other end of capacitor C3 is grounded. One end of resistor R5 is connected to the output terminal of the charging current detection circuit, and the other end of resistor R5 is connected to the non-inverting input terminal of voltage comparator U1. The output terminal of the voltage comparator is connected in series with resistor R7.

[0028] In addition, to achieve the technical effect of detecting and comparing the current signal output by the charging current detection circuit, in another embodiment, the driving comparison module may further include an analog-to-digital converter (ADC) and a microprocessor. The input terminal of the ADC is electrically connected to the charging current detection circuit, and the ADC receives the current signal output by the charging current detection circuit and performs digital conversion. The output terminal of the ADC is electrically connected to the microprocessor, and the ADC transmits the converted digital signal to the microprocessor. The microprocessor is set with a signal threshold, can process and compare with the digital signal, and outputs a level signal. The output terminal of the microprocessor is electrically connected to transistor Q3, thereby realizing the switching of the charger's on / off state.

[0029] Finally, in order to clearly indicate the current on / off status of the charger, the charger is also equipped with a signal indicator light. The signal indicator light is connected in parallel with the relay switch K. When the relay switch K is energized and conducting, the signal indicator light is powered on, indicating that the charger is in the powered-on state; when the relay switch K is disengaged and released, the signal indicator light goes out, indicating that the charger is in the physically powered-off state.

Claims

1. A physical power-off protection device for a charger, characterized in that, It includes a push-button switch AN, a regulated power supply module, a relay switch K, a charger power input terminal, a charging circuit, a charging current detection circuit, a drive comparison module, and a transistor Q1; the relay switch K includes a first normally open contact K1 and a second normally open contact K2; The charger's power input terminal is electrically connected to the regulated power supply module and the charging circuit via a push-button switch AN. The regulated power supply module is electrically connected to the drive comparison module and the relay switch K. The charging circuit is electrically connected to the input terminal of the charging current detection circuit. The output terminal of the charging current detection circuit is connected to the drive comparison module. The drive comparison module is electrically connected to the base of transistor Q1. The collector of transistor Q1 is electrically connected to the relay switch K. The emitter of transistor Q1 is grounded. The first normally open contact K1 is connected in parallel with the push-button switch AN. The second normally open contact K2 is electrically connected between the charging circuit and the charger's power input terminal.

2. The charger physical power-off protector according to claim 1, characterized in that, The charging current detection circuit includes a current transformer, a rectifier bridge, resistors R10-R15, capacitors C4-C6, and operational amplifier U2. The primary winding of the current transformer is connected in series with the charging circuit, and its secondary winding is electrically connected to the rectifier bridge. One end of resistor R10 is connected to the power supply electrode, and the other end of resistor R10 is connected in series with resistor R11 and grounded. One end of resistor R13 is electrically connected to the series connection node of resistors R10 and R11, and the other end of capacitor C4. The other end of resistor R13 is connected to the inverting input terminal of operational amplifier U2. One end of capacitor C5 is connected to the power supply electrode, and the other end of capacitor C5 is connected in series with resistor R12. The rectifier bridge is electrically connected to one end of resistor R14 through the series connection node of resistor R12 and capacitor C5. The other end of resistor R14 is connected to the non-inverting input terminal of operational amplifier U2. The output terminal of the operational amplifier is electrically connected to resistor R15, and capacitor C6 is connected in parallel with resistor R15.

3. The charger physical power-off protector according to claim 2, characterized in that, The charging current detection circuit also includes an input protection circuit, which is electrically connected between the rectifier bridge and the resistor R14. The input protection circuit includes a resistor R2, a capacitor C1, a capacitor C2, and a Zener diode D1, which are connected in parallel in sequence.

4. The charger physical power-off protector according to claim 1, characterized in that, The drive comparison module includes a voltage comparison circuit.

5. The charger physical power-off protector according to claim 4, characterized in that, The voltage comparison circuit includes resistors R3-R7, capacitor C3, and voltage comparator U1. One end of resistor R4 is connected to the power supply electrode, and the other end is connected in series with R3 and grounded. The series connection point of resistors R3 and R4 is connected to one end of capacitor C3 and one end of resistor R6, respectively. The other end of resistor R6 is connected to the inverting input terminal of voltage comparator U1, and the other end of capacitor C3 is grounded. One end of resistor R5 is connected to the output terminal of the charging current detection circuit, and the other end of resistor R5 is connected to the non-inverting input terminal of voltage comparator U1. The output terminal of the voltage comparator is connected in series with resistor R7.

6. The charger physical power-off protector according to claim 1, characterized in that, The drive comparison module includes an analog-to-digital converter and a microprocessor. The input terminal of the analog-to-digital converter is electrically connected to the charging current detection circuit, and the output terminal of the analog-to-digital converter is electrically connected to the microprocessor. The output terminal of the microprocessor is electrically connected to the transistor Q1.

7. The charger physical power-off protector according to claim 1, characterized in that, The transistor Q1 is a PNP type transistor.

8. The charger physical power-off protector according to claim 1, characterized in that, It is also equipped with a signal indicator light, which is connected in parallel with the relay switch K.

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