Protection circuit and charging equipment

Abstract

The embodiment of the utility model provides a protection circuit and a charging device, and the circuit comprises a control circuit, and the output end of the control circuit outputs a control signal under the condition that the first end of the control circuit is connected with the positive electrode of a rechargeable battery and the second end of the control circuit is connected with the negative electrode of the rechargeable battery. Under the condition that the first end of the control circuit is connected with the negative electrode of the rechargeable battery and the second end of the control circuit is connected with the positive electrode of the rechargeable battery, the control circuit is switched off; the power supply chip is used for outputting a power supply voltage under the condition that the control signal is received; and the electric energy output circuit is switched on to charge the rechargeable battery under the condition that the electric energy output circuit receives the power supply voltage, and is switched off under the condition that the electric energy output circuit does not receive the power supply voltage. According to the utility model, the problem of complex logic of a battery charging anti-backflow anti-reverse connection circuit can be solved.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and more specifically, to a protection circuit and a charging device. Background Technology

[0002] Battery charging can only begin after the positive and negative terminals are connected correctly. In related technologies, the structural foolproof design is usually used to ensure that the battery is not connected in reverse. In terms of hardware, comparators, microcontrollers or other processing chips are often used to control transistors to achieve reverse current protection and reverse connection protection functions. This has the disadvantages of complex circuit logic and high cost of processing chips.

[0003] Therefore, it can be seen that there are technical problems in the related technologies, such as the complexity of implementing the circuit logic for preventing reverse flow and reverse connection during battery charging.

[0004] The target has not yet proposed an effective solution to the aforementioned problems in the relevant technologies. Utility Model Content

[0005] This utility model provides a protection circuit and a charging device to at least solve the technical problem of complex logic in implementing battery charging anti-backflow and anti-reverse connection circuits in related technologies.

[0006] According to one embodiment of the present invention, a protection circuit is provided, comprising: a control circuit, wherein a first terminal of the control circuit is configured to be connected to one end of a rechargeable battery, and a second terminal of the control circuit is configured to be connected to the other end of the rechargeable battery; when the first terminal of the control circuit is connected to the positive terminal of the rechargeable battery and the second terminal of the control circuit is connected to the negative terminal of the rechargeable battery, the output terminal of the control circuit outputs a control signal; and when the first terminal of the control circuit is connected to the negative terminal of the rechargeable battery and the second terminal of the control circuit is connected to the positive terminal of the rechargeable battery, the control circuit is turned off; and a power chip, wherein the input terminal of the power chip is connected to the output terminal of the control circuit. The power chip is used to output a supply voltage when the control signal is received; the power output circuit has a first input terminal configured to be connected to the first output terminal of the power chip, a second input terminal configured to be connected to the second output terminal of the power chip, a first output terminal configured to be connected to one end of the rechargeable battery, and a second output terminal configured to be connected to the other end of the rechargeable battery. When the power output circuit receives the supply voltage, it is turned on to charge the rechargeable battery; when it does not receive the supply voltage, it is turned off.

[0007] In an exemplary embodiment, the control circuit includes: an optocoupler, a first terminal of which is connected to a first terminal of the control circuit, a second terminal of which is connected to a second terminal of the control circuit, a third terminal of which is connected to an output terminal of the control circuit, and a fourth terminal of which is connected to a preset power supply; wherein the third terminal of the optocoupler outputs the control signal when the voltage at the first terminal of the optocoupler is greater than the voltage at the second terminal of the optocoupler; and a first resistor, a first terminal of which is connected to the third terminal of the optocoupler, and a second terminal of which is grounded.

[0008] In one exemplary embodiment, the control circuit further includes: a second resistor, the first end of which is connected to a first end of the control circuit, and the second end of which is connected to a second end of the optocoupler; and a third resistor, the first end of which is connected to the second end of the second resistor, and the second end of which is connected to a second end of the control circuit.

[0009] In one exemplary embodiment, the control circuit further includes a first diode, the anode of which is connected to the second terminal of the third resistor, and the cathode of which is connected to the second terminal of the control circuit.

[0010] In one exemplary embodiment, the control circuit further includes: a first capacitor, a first terminal of which is connected to a second terminal of the optocoupler, and a second terminal of which is connected to a second terminal of the control circuit.

[0011] In one exemplary embodiment, the control circuit further includes: a second capacitor connected in parallel with the first resistor; and a fourth resistor, through which the third terminal of the optocoupler is connected to the output terminal of the control circuit.

[0012] In an exemplary embodiment, the power output circuit further includes: a protection chip, a first terminal of which is connected to the first input terminal, a second terminal of which is connected to the first terminal of a first control switch, a third terminal of which is connected to the first output terminal, and a fourth terminal of which is connected to the second input terminal; wherein, when the first input terminal does not receive the power supply voltage, the protection chip controls the first control switch to turn off, and when the first input terminal receives the power supply voltage, the protection chip controls the first control switch to turn on; and a first control switch, a first terminal of which is connected to the second terminal of the protection chip, a second terminal of which is connected to the first input terminal, and a third terminal of which is connected to the first output terminal; wherein, when the power chip outputs the power supply voltage, the first control switch turns on, so that the positive terminal of the rechargeable battery is connected to the first input terminal, and when the power chip does not output the power supply voltage, the first control switch turns off. A second control switch has its first end connected to the second output terminal, its second end connected to the first output terminal, and its third end connected to the first input terminal. When the first output terminal is configured to be connected to the positive terminal of the rechargeable battery and the second output terminal is configured to be connected to the negative terminal of the rechargeable battery, the second control switch is turned on; when the first output terminal is configured to be connected to the negative terminal of the rechargeable battery and the second output terminal is configured to be connected to the positive terminal of the rechargeable battery, the second control switch is turned off. A third control switch has its first end connected to the third end of the second control switch, its second end connected to the second input terminal, and its third end connected to the second output terminal. When the second control switch is turned on, the third control switch is turned on, so that the negative terminal of the rechargeable battery is connected to the second input terminal; when the second control switch is turned off, the third control switch is turned off.

[0013] In one exemplary embodiment, the power output circuit further includes: a fifth resistor, the first end of which is connected to the first output terminal, and the second end of which is connected to the second terminal of the second control switch; and a sixth resistor, the first end of which is connected to the second end of the fifth resistor, and the second end of which is connected to the second output terminal.

[0014] In one exemplary embodiment, the power output circuit further includes a second diode, the positive terminal of which is connected to the second input terminal, and the negative terminal of which is connected to the first input terminal.

[0015] In one exemplary embodiment, the power output circuit further includes a seventh resistor, the first end of which is connected to the first end of the third control switch, and the second end of which is connected to the second input terminal.

[0016] In one exemplary embodiment, the power output circuit further includes at least one of the following: a third capacitor, the first terminal of which is connected to the second terminal of the third control switch, and the second terminal of which is connected to the third terminal of the third control switch; a fourth capacitor, the first terminal of which is connected to the first output terminal, and the second terminal of which is connected to the second output terminal; and a transient voltage suppressor, the first terminal of which is connected to the first output terminal, and the second terminal of which is connected to the second output terminal.

[0017] According to one embodiment of the present invention, a charging device is provided, including a protection circuit as described in any of the above embodiments, the charging device being used to charge the rechargeable battery through the protection circuit.

[0018] The protection circuit provided by this utility model includes a control circuit, a power chip, and a power output circuit. The first terminal of the control circuit is connected to one end of the rechargeable battery, and the second terminal is connected to the other end of the rechargeable battery. When the battery is connected correctly (i.e., the first terminal of the control circuit is connected to the positive terminal of the rechargeable battery, and the second terminal of the control circuit is connected to the negative terminal of the rechargeable battery), the output terminal of the control circuit can output a control signal. When the battery is connected in reverse (i.e., the first terminal of the control circuit is connected to the negative terminal of the rechargeable battery, and the second terminal of the control circuit is connected to the positive terminal of the rechargeable battery), the control circuit can be turned off. The input terminal of the power chip is connected to the output terminal of the control circuit. Upon receiving the control signal output by the control circuit, it can output a supply voltage to the power output circuit. The first input terminal of the power output circuit is configured to be connected to the first output terminal of the power chip, and the second input terminal is configured to be connected to the second output terminal of the power chip. The first output terminal is connected to one end of the rechargeable battery, and the second output terminal is connected to the other end of the rechargeable battery. When the power output circuit receives the supply voltage from the power chip, it can conduct to charge the rechargeable battery; when it does not receive the supply voltage from the power chip, it turns off. Since the power chip can output a supply voltage through a control signal from the control circuit when the battery is connected in the correct orientation, the power output circuit can charge the rechargeable battery upon receiving the supply voltage. When the battery is connected in reverse, the power output circuit turns off, and the power output circuit that does not receive the supply voltage also turns off. This eliminates the need for excessive components for control, thus solving the problem of complex logic in battery charging reverse connection and anti-backflow circuits in related technologies, achieving a simplified effect. Attached Figure Description

[0019] Figure 1 This is a structural block diagram of the protection circuit according to an embodiment of the present utility model;

[0020] Figure 2 This is a schematic diagram of the control circuit according to an embodiment of the present utility model;

[0021] Figure 3 This is a schematic diagram of the power output circuit according to an embodiment of the present utility model. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] This embodiment provides a protection circuit. Figure 1 This is a structural block diagram of the protection circuit according to an embodiment of the present utility model, as shown below. Figure 1 As shown, the protection circuit includes:

[0025] The control circuit 102 has a first terminal configured to be connected to one end of a rechargeable battery and a second terminal configured to be connected to the other end of the rechargeable battery. When the first terminal of the control circuit is connected to the positive terminal of the rechargeable battery and the second terminal of the control circuit is connected to the negative terminal of the rechargeable battery, the output terminal of the control circuit outputs a control signal. When the first terminal of the control circuit is connected to the negative terminal of the rechargeable battery and the second terminal of the control circuit is connected to the positive terminal of the rechargeable battery, the control circuit is turned off.

[0026] The power chip 104 has its input terminal connected to the output terminal of the control circuit. The power chip is used to output a power supply voltage when it receives the control signal.

[0027] A power output circuit 106 is provided, wherein a first input terminal of the power output circuit is configured to be connected to a first output terminal of a power chip, a second input terminal of the power output circuit is configured to be connected to a second output terminal of the power chip, a first output terminal of the power output circuit is configured to be connected to one end of a rechargeable battery, and a second output terminal of the power output circuit is configured to be connected to the other end of the rechargeable battery. When the power output circuit receives the supply voltage, it is turned on to charge the rechargeable battery; when it does not receive the supply voltage, it is turned off.

[0028] In the above embodiments, the specific circuit diagram of the control circuit can be found in [reference needed]. Figure 2 , Figure 2 This is a schematic diagram of the control circuit according to an embodiment of the present utility model, such as... Figure 2 As shown, the first terminal (BAT+ terminal in the diagram) and the second terminal (BAT- terminal in the diagram) of the control circuit can be connected to the two ends of the rechargeable battery respectively. When the rechargeable battery and the control circuit are connected in the correct orientation (i.e., the BAT+ terminal of the control circuit is connected to the positive terminal of the rechargeable battery, and the BAT- terminal of the control circuit is connected to the negative terminal of the rechargeable battery), the output terminal of the control circuit can output the control signal PWR_EN; when the rechargeable battery and the control circuit are connected in the reverse orientation (i.e., the BAT+ terminal of the control circuit is connected to the negative terminal of the rechargeable battery, and the BAT- terminal of the control circuit is connected to the positive terminal of the rechargeable battery), the output terminal of the control circuit does not output a control signal, and the control circuit is turned off.

[0029] In the above embodiments, when the rechargeable battery is connected to the control circuit in the correct orientation, the control signal PWR_EN output by the control circuit can be received by the power chip. After the power chip is enabled, it can output the supply voltage PWR, which enables the power output circuit to conduct. That is, the positive terminal of the power supply is connected to the positive terminal of the rechargeable battery, the voltage levels are matched, and the rechargeable battery can be safely charged. When the battery is connected to the control circuit in the reverse orientation, the control circuit does not output the control signal PWR_EN, the power chip cannot obtain the control signal PWR_EN, and it also cannot output the supply voltage PWR, thus turning off the power output circuit. Since the power output circuit is turned off, the positive terminal of the power supply and the negative terminal of the rechargeable battery are not connected, and the power supply and the rechargeable battery are completely isolated, thus ensuring the absolute safety of the front-end power supply and the external rechargeable battery. The circuit diagram of the power output circuit can be found in the appendix. Figure 3 , Figure 3 This is a schematic diagram of the power output circuit according to an embodiment of the present utility model, such as... Figure 3 As shown, the first input terminal of the power output circuit can receive the power supply voltage PWR output by the power chip, the second input terminal is grounded, the first output terminal BAT+ can be connected to the positive terminal of the rechargeable battery, and the second output terminal BAT- can be connected to the negative terminal of the rechargeable battery.

[0030] The protection circuit provided by this utility model includes a control circuit, a power chip, and a power output circuit. The first terminal of the control circuit is connected to one end of the rechargeable battery, and the second terminal is connected to the other end of the rechargeable battery. When the battery is connected correctly (i.e., the first terminal of the control circuit is connected to the positive terminal of the rechargeable battery, and the second terminal of the control circuit is connected to the negative terminal of the rechargeable battery), the output terminal of the control circuit can output a control signal. When the battery is connected in reverse (i.e., the first terminal of the control circuit is connected to the negative terminal of the rechargeable battery, and the second terminal of the control circuit is connected to the positive terminal of the rechargeable battery), the control circuit can be turned off. The input terminal of the power chip is connected to the output terminal of the control circuit. Upon receiving the control signal output by the control circuit, it can output a supply voltage to the power output circuit. The first input terminal of the power output circuit is configured to be connected to the first output terminal of the power chip, and the second input terminal is configured to be connected to the second output terminal of the power chip. The first output terminal is connected to one end of the rechargeable battery, and the second output terminal is connected to the other end of the rechargeable battery. When the power output circuit receives the supply voltage from the power chip, it can conduct to charge the rechargeable battery; when it does not receive the supply voltage from the power chip, it turns off. Since the power chip can output a supply voltage through a control signal from the control circuit when the battery is connected in the correct orientation, the power output circuit can charge the rechargeable battery upon receiving the supply voltage. When the battery is connected in reverse, the power output circuit turns off, and the power output circuit that does not receive the supply voltage also turns off. This eliminates the need for excessive components for control, thus solving the problem of complex logic in battery charging reverse connection and anti-backflow circuits in related technologies, achieving a simplified effect.

[0031] In an exemplary embodiment, the control circuit includes: an optocoupler, a first terminal of which is connected to a first terminal of the control circuit, a second terminal of which is connected to a second terminal of the control circuit, a third terminal of which is connected to an output terminal of the control circuit, and a fourth terminal of which is connected to a preset power supply; wherein the third terminal of the optocoupler outputs the control signal when the voltage at the first terminal of the optocoupler is greater than the voltage at the second terminal of the optocoupler; and a first resistor, a first terminal of which is connected to the third terminal of the optocoupler, and a second terminal of which is grounded.

[0032] In the above embodiments, see again Figure 2The control circuit may also include an optocoupler U2 and a first resistor R8. When the power supply is positive and the optocoupler U2 is forward-biased (i.e., the voltage at the first terminal 1 of the optocoupler is greater than the voltage at the second terminal 2), the third terminal can output a control signal, which the power supply chip can obtain. Specifically, the first terminal 1 of the optocoupler power supply U2 is connected to the first terminal BAT+ of the control circuit, the second terminal 2 is connected to the second terminal BAT- of the control circuit, the third terminal 3 is connected to the output terminal of the control circuit, and the fourth terminal 4 is connected to a preset power supply, which can be 3.3V, but is not limited to this.

[0033] In the above embodiment, the first end of the first resistor R8 is connected to the third end 3 of the optocoupler, and the second end is grounded. This ensures that the resistor can maintain a suppressed low level state, i.e., a pull-down state, in the absence of a control signal. This ensures that the node will not be in a floating state and avoids uncertain levels caused by floating.

[0034] In one exemplary embodiment, the control circuit further includes: a second resistor, the first end of which is connected to a first end of the control circuit, and the second end of which is connected to a second end of the optocoupler; and a third resistor, the first end of which is connected to the second end of the second resistor, and the second end of which is connected to a second end of the control circuit.

[0035] In the above embodiments, see again Figure 2 The control circuit also includes a second resistor R5 and a third resistor R7. The first terminal of the second resistor R5 is connected to the first terminal of the control circuit, and the second terminal is connected to the second terminal 2 of the optocoupler U2. The first terminal of the third resistor R7 is connected to the second terminal of the second resistor R5, and the second terminal is connected to the second terminal BAT- of the control circuit. The second resistor R5 and the third resistor R7 are connected in series and work together to apply the power supply voltage, resulting in a lower output voltage. This prevents excessive input voltage and current from damaging the optocoupler U2.

[0036] In one exemplary embodiment, the control circuit further includes a first diode, the anode of which is connected to the second terminal of the third resistor, and the cathode of which is connected to the second terminal of the control circuit.

[0037] In the above embodiments, see again Figure 2 The control circuit also includes a first diode D6. The positive terminal of the first diode is connected to the second terminal of the third resistor R7, and the negative terminal of the first diode is connected to the second terminal BAT- of the control circuit. This ensures that the current flows from the positive terminal to the negative terminal of the first diode and does not allow reverse flow. It can provide a stable voltage protection circuit when reverse biased to prevent the voltage from exceeding the threshold and causing damage.

[0038] In one exemplary embodiment, the control circuit further includes: a first capacitor, a first terminal of which is connected to a second terminal of the optocoupler, and a second terminal of which is connected to a second terminal of the control circuit. In this embodiment, see also... Figure 2 The control circuit also includes a first capacitor C3. The first end of the first capacitor C3 is connected to the second end 2 of the optocoupler U2, and the second end is connected to the second end BAT- of the control circuit. The first capacitor C3 can help smooth voltage fluctuations on the power supply or signal line by using low-pass filtering or high-pass filtering, which can reduce noise.

[0039] In one exemplary embodiment, the control circuit further includes: a second capacitor connected in parallel with the first resistor; and a fourth resistor, through which the third terminal of the optocoupler is connected to the output terminal of the control circuit. In this embodiment, see further... Figure 2 The control circuit may also include a second capacitor C4 and a fourth resistor R6. The second capacitor C4 is connected in parallel with the first resistor R8. The second capacitor C4 can filter the voltage on the power supply or signal line. The third terminal 3 of the optocoupler U2 can be connected to the output terminal of the control circuit through the fourth resistor R6. This can limit the current of the control signal output by the optocoupler U2, preventing the output control signal from being too large and damaging the power chip.

[0040] In an exemplary embodiment, the power output circuit further includes: a protection chip, a first terminal of which is connected to the first input terminal, a second terminal of which is connected to the first terminal of a first control switch, a third terminal of which is connected to the first output terminal, and a fourth terminal of which is connected to the second input terminal; wherein, when the first input terminal does not receive the power supply voltage, the protection chip controls the first control switch to turn off, and when the first input terminal receives the power supply voltage, the protection chip controls the first control switch to turn on; and a first control switch, a first terminal of which is connected to the second terminal of the protection chip, a second terminal of which is connected to the first input terminal, and a third terminal of which is connected to the first output terminal; wherein, when the power chip outputs the power supply voltage, the first control switch turns on, so that the positive terminal of the rechargeable battery is connected to the first input terminal, and when the power chip does not output the power supply voltage, the first control switch turns off. A second control switch has its first end connected to the second output terminal, its second end connected to the first output terminal, and its third end connected to the first input terminal. When the first output terminal is configured to be connected to the positive terminal of the rechargeable battery and the second output terminal is configured to be connected to the negative terminal of the rechargeable battery, the second control switch is turned on; when the first output terminal is configured to be connected to the negative terminal of the rechargeable battery and the second output terminal is configured to be connected to the positive terminal of the rechargeable battery, the second control switch is turned off. A third control switch has its first end connected to the third end of the second control switch, its second end connected to the second input terminal, and its third end connected to the second output terminal. When the second control switch is turned on, the third control switch is turned on, so that the negative terminal of the rechargeable battery is connected to the second input terminal; when the second control switch is turned off, the third control switch is turned off.

[0041] In the above embodiments, see again Figure 3 The power output circuit also includes a protection chip U1. The first terminal of the protection chip U1 is connected to the first input terminal, the second terminal is connected to the first terminal of the first control switch, the third terminal is connected to the first output terminal, and the fourth terminal is connected to the second input terminal. The protection chip U1 can automatically activate without requiring a power supply voltage. Specifically, when the first input terminal is not outputting a power supply voltage but is connected to the rechargeable battery, the protection chip U1 can control the first control switch to turn off, preventing reverse current from the rechargeable battery. When the first input terminal is outputting a power supply voltage, the protection chip U1 can control the first control switch to turn on, thus charging the rechargeable battery.

[0042] In the above embodiments, continue to refer to Figure 3 , the power output circuit further includes a first control switch D1, a second control switch D3, and a third control switch D5. Among them, the first control switch, the second control switch, and the third control switch can be MOS (Metal Oxide Semiconductor) transistors. When the battery is connected correctly, the Vgs of the P-channel second control switch D3 is less than Vgs(th) and less than 0V, and D3 can conduct safely. When the battery is connected correctly, the optocoupler device U2 in the control circuit can be made to conduct forward, enabling the power supply chip to obtain the control signal PWR_EN. After the power supply chip is enabled, it can output the supply voltage PWR. When the power output circuit receives the supply voltage, the N-channel first control switch D1 conducts. At this time, the positive pole of the power supply is connected to the positive pole of the battery, and the levels match. The second control switch D3 can make the Vgs of the N-channel third control switch D5 greater than Vgs(th) and greater than 0V, that is, D5 conducts safely, so that the system ground can be connected to the negative pole of the rechargeable battery. When the power supply, the positive pole, and the ground of the rechargeable battery are all correctly connected, the battery can start to charge safely. When the battery is connected reversely, the Vgs of the P-channel second control switch D3 is greater than 0V and greater than Vgs(th), that is, the second control switch D3 is turned off, then the Vgs of the N-channel third control switch D5 is 0V and less than Vgs(th), that is, the third control switch D5 is turned off, so that the positive pole of the battery is not connected to the system ground, and an effective anti-backflow effect can be achieved, protecting the ground from being affected by the rechargeable battery. At the same time, in the control circuit, the optocoupler device U2 is reversely cut off, and the power supply chip cannot obtain the control signal PWR_EN, and thus cannot output the supply voltage PWR. The power supply in the power output circuit does not output, and the N-channel first control switch D1 is turned off, which can ensure that the positive pole of the power supply and the negative pole of the rechargeable battery will not be short-circuited, and can effectively prevent the positive and negative from being short-circuited and burned out. MOS transistors D1 and D5 are all turned off, and the power supply and the battery are completely isolated, so the absolute safety of the power supply and the external rechargeable battery can be ensured.

[0043] In an exemplary embodiment, the power output circuit further includes: a fifth resistor, a first end of the fifth resistor is connected to the first output end, and a second end of the fifth resistor is connected to a second end of the second control switch; a sixth resistor, a first end of the sixth resistor is connected to the second end of the fifth resistor, and a second end of the sixth resistor is connected to the second output end.

[0044] In the above embodiments, continue to refer to Figure 3The power output circuit may also include a fifth resistor R1 and a sixth resistor R3. The first end of the fifth resistor R1 is connected to the first output terminal BAT+, and the second end of the fifth resistor R1 is connected to the second terminal of the second control switch D3. The first end of the sixth resistor R3 is connected to the second end of the fifth resistor R1, and the second end of the sixth resistor R3 is connected to the second output terminal BAT-. The fifth resistor R1 and the sixth resistor R3 are connected in series, which can divide the voltage input to the rechargeable battery in the circuit, thereby protecting the opening voltage of the second control switch D3 within a safe range and preventing burnout caused by overvoltage.

[0045] In one exemplary embodiment, the power output circuit further includes a second diode, the anode of which is connected to the second input terminal, and the cathode of which is connected to the first input terminal. In this embodiment, see also... Figure 3 The power output circuit may also include a second diode D2. The second diode D2 is set to reverse connection, which can make the power signal flow only in one direction, and can effectively prevent the front power supply from being connected in reverse.

[0046] In one exemplary embodiment, the power output circuit further includes a seventh resistor, the first end of which is connected to the first end of the third control switch, and the second end of which is connected to the second input terminal.

[0047] In the above embodiments, see again Figure 3 The power output circuit may also include a seventh resistor R2. The first end of the seventh resistor R2 is connected to the first end of the third control switch D5, and the second end of the seventh resistor R2 is connected to the second input terminal. This can divide the input high voltage signal and protect the opening voltage of the third control switch D5 within a safe range to prevent overvoltage burnout when the power supply voltage or rechargeable battery voltage fluctuates.

[0048] In one exemplary embodiment, the power output circuit further includes at least one of the following: a third capacitor, the first terminal of which is connected to the second terminal of the third control switch, and the second terminal of which is connected to the third terminal of the third control switch; a fourth capacitor, the first terminal of which is connected to the first output terminal, and the second terminal of which is connected to the second output terminal; and a transient voltage suppressor, the first terminal of which is connected to the first output terminal, and the second terminal of which is connected to the second output terminal.

[0049] In the above embodiments, see again Figure 3The power output circuit may also include: a third capacitor C2, a fourth capacitor C1, and a transient voltage suppressor (D4 in the diagram). The first terminal of the third capacitor C2 is connected to the second terminal of the third control switch D5, and the second terminal of the third capacitor is connected to the third terminal of the third control switch D5. This filters out voltage peaks generated when the charging battery is connected, preventing instantaneous breakdown. The first terminal of the fourth capacitor C1 is connected to the first output terminal BAT+, and the second terminal of the fourth capacitor is connected to the second output terminal BAT-. This allows for energy storage of the power output and can also perform low-pass or high-pass filtering, which can be configured by relevant personnel according to actual conditions. The first terminal of the transient voltage suppressor D4 is connected to the first output terminal BAT+, and the second terminal of the transient voltage suppressor D4 is connected to the second output terminal BAT-. This absorbs surge power up to several kilowatts, limiting peak voltage within a safe range. When the voltage exceeds the surge threshold, it can directly divert excessive current, protecting the circuit from damage.

[0050] In the above embodiment, when the battery is correctly connected, as long as the power supply PWR does not output and MOSFET D1 is not turned on, the positive voltage at the battery terminal will not flow back and affect the circuit. When the battery is connected in reverse, MOSFET D3 is not turned on, preventing MOSFET D5 from turning on, thus preventing the positive voltage at the battery terminal from flowing back into the system ground and avoiding a short circuit to ground between the battery and the system ground. This simultaneously achieves the functions of preventing backflow and preventing reverse connection when the rechargeable battery is connected. In addition, traditional diodes generate a forward voltage drop of 0.3 to 0.7V when the power supply is forward conducting due to the physical characteristics of the diode. When charging the rechargeable battery, the charging voltage set at the power supply terminal is different from the actual charging voltage of the rechargeable battery, which will cause the rechargeable battery to not be fully charged. At the same time, the forward conduction current carrying capacity of the diode is not strong, and it can only charge the rechargeable battery with a small current, while charging with a large current will generate significant heat and large heat loss. This invention uses the on / off state of an N-channel MOSFET to prevent reverse current from flowing into the battery. The Rdson (Drain Source On Resistance) of the MOSFET is generally less than 10mR. Under the same current conditions, the voltage drop is much smaller than that of a diode, and the heat generation is also smaller. Therefore, it is more suitable for fast charging of rechargeable batteries with large currents. It has the advantages of simple circuit, low cost and small layout space.

[0051] According to one embodiment of the present invention, a charging device is provided, including a protection circuit as described in any of the above embodiments, the charging device being used to charge the rechargeable battery through the protection circuit.

[0052] In the above embodiments, the specific circuit diagram of the control circuit can be found in [reference needed]. Figure 2 , Figure 2 This is a schematic diagram of the control circuit according to an embodiment of the present utility model, such as... Figure 2 As shown, the first terminal (BAT+ terminal in the diagram) and the second terminal (BAT- terminal in the diagram) of the control circuit can be connected to the two ends of the rechargeable battery respectively. When the rechargeable battery and the control circuit are connected in the correct orientation (i.e., the BAT+ terminal of the control circuit is connected to the positive terminal of the rechargeable battery, and the BAT- terminal of the control circuit is connected to the negative terminal of the rechargeable battery), the output terminal of the control circuit can output the control signal PWR_EN; when the rechargeable battery and the control circuit are connected in the reverse orientation (i.e., the BAT+ terminal of the control circuit is connected to the negative terminal of the rechargeable battery, and the BAT- terminal of the control circuit is connected to the positive terminal of the rechargeable battery), the output terminal of the control circuit does not output a control signal, and the control circuit is turned off.

[0053] In the above embodiments, when the rechargeable battery is connected to the control circuit in the correct orientation, the control signal PWR_EN output by the control circuit can be received by the power chip. After the power chip is enabled, it can output the supply voltage PWR, which enables the power output circuit to conduct. That is, the positive terminal of the power supply is connected to the positive terminal of the rechargeable battery, the voltage levels are matched, and the rechargeable battery can be safely charged. When the battery is connected to the control circuit in the reverse orientation, the control circuit does not output a control signal, the power chip cannot obtain the control signal PWR_EN, and it also cannot output the supply voltage PWR, thus turning off the power output circuit. Because the power output circuit is turned off, the positive terminal of the power supply and the negative terminal of the rechargeable battery are not connected, and the power supply and the rechargeable battery are completely isolated, thus ensuring the absolute safety of the pre-amplifier and the external rechargeable battery. The circuit diagram of the power output circuit can be found in the attached diagram. Figure 3 , Figure 3 This is a schematic diagram of the power output circuit according to an embodiment of the present utility model, such as... Figure 3 As shown, the first input terminal of the power output circuit can receive the power supply voltage PWR output by the power chip, the second input terminal is grounded, and the first output terminal BAT+ and the second output terminal BAT- can be connected to the two ends of the rechargeable battery respectively.

[0054] In the above embodiments, see again Figure 2 The control circuit may also include an optocoupler U2 and a first resistor R8. When the power supply is positive and the optocoupler U2 is forward-biased (i.e., the voltage at the first terminal 1 of the optocoupler is greater than the voltage at the second terminal 2), the third terminal can output a control signal, which the power supply chip can obtain. Specifically, the first terminal 1 of the optocoupler power supply U2 is connected to the first terminal BAT+ of the control circuit, the second terminal 2 is connected to the second terminal BAT- of the control circuit, the third terminal 3 is connected to the output terminal of the control circuit, and the fourth terminal 4 is connected to a preset power supply, which can be 3.3V, but is not limited to this.

[0055] In the above embodiment, the first end of the first resistor R8 is connected to the third end 3 of the optocoupler, and the second end is grounded. This ensures that the resistor can maintain a suppressed low level state, i.e., a pull-down state, in the absence of a control signal. This ensures that the node will not be in a floating state and avoids uncertain levels caused by floating.

[0056] In the above embodiments, see again Figure 2 The control circuit also includes a second resistor R5 and a third resistor R7. The first terminal of the second resistor R5 is connected to the first terminal of the control circuit, and the second terminal is connected to the second terminal 2 of the optocoupler U2. The first terminal of the third resistor R7 is connected to the second terminal of the second resistor R5, and the second terminal is connected to the second terminal BAT- of the control circuit. The second resistor R5 and the third resistor R7 are connected in series and work together to apply the power supply voltage, resulting in a lower output voltage. This prevents excessive input voltage and current from damaging the optocoupler U2.

[0057] In the above embodiments, see again Figure 2 The control circuit also includes a first diode D6. The positive terminal of the first diode is connected to the second terminal of the third resistor R7, and the negative terminal of the first diode is connected to the second terminal BAT- of the control circuit. This ensures that the current flows from the positive terminal to the negative terminal of the first diode and does not allow reverse flow. It can provide a stable voltage protection circuit when reverse biased to prevent the voltage from exceeding the threshold and causing damage.

[0058] In the above embodiments, see again Figure 2 The control circuit also includes a first capacitor C3. The first end of the first capacitor C3 is connected to the second end 2 of the optocoupler U2, and the second end is connected to the second end BAT- of the control circuit. The first capacitor C3 can help smooth voltage fluctuations on the power supply or signal line by using low-pass filtering or high-pass filtering, which can reduce noise.

[0059] In the above embodiments, see again Figure 2 The control circuit may also include a second capacitor C4 and a fourth resistor R6. The second capacitor C4 is connected in parallel with the first resistor R8. The second capacitor C4 can filter the voltage on the power supply or signal line. The third terminal 3 of the optocoupler U2 can be connected to the output terminal of the control circuit through the fourth resistor R6. This can limit the current of the control signal output by the optocoupler U2, preventing the output control signal from being too large and damaging the power chip.

[0060] In the above embodiments, see again Figure 3, the power output circuit further includes a protection chip U1. The first end of the protection chip U1 is connected to the first input terminal, the second end is connected to the first end of the first control switch, the third end is connected to the first output terminal, and the fourth end is connected to the second input terminal. The protection chip U1 can be automatically started without the power supply of the supply voltage. That is, when the first input terminal does not output the supply voltage and is connected to the positive terminal of the rechargeable battery, the protection chip U1 can control the first control switch to turn off, preventing the backflow of the rechargeable battery voltage; when the first input terminal outputs the supply voltage, the protection chip U1 can control the first control switch to conduct, realizing the charging of the rechargeable battery.

[0061] In the above embodiment, continue to refer to Figure 3 , the power output circuit further includes a first control switch D1, a second control switch D3 and a third control switch D5. Among them, the first control switch, the second control switch and the third control switch can be MOS (Metal Oxide Semiconductor) transistors. When the battery is connected correctly, the Vgs of the P-channel second control switch D3 is < Vgs(th) < 0V, and D3 can conduct safely. When the battery is connected correctly, the optocoupler device U2 in the control circuit can be made to conduct forward, enabling the power supply chip to obtain the control signal PWR_EN. After the power supply chip is enabled, it can output the supply voltage PWR. When the power output circuit receives the supply voltage, the N-channel first control switch D1 conducts. At this time, the positive power supply is connected to the positive terminal of the battery, and the levels match. The second control switch D3 can control the Vgs of the N-channel third control switch D5 to be > Vgs(th) > 0V, that is, D5 conducts safely, so that the system ground can be connected to the negative terminal of the rechargeable battery. When the power supply, the positive terminal of the rechargeable battery and the ground are all correctly connected, the battery can start to charge safely. When the battery is reversely connected, the Vgs of the P-channel second control switch D3 is > 0V > Vgs(th), that is, the second control switch D3 turns off, and the Vgs of the N-channel third control switch D5 is = 0V < Vgs(th), that is, the third control switch D5 turns off, so that the positive terminal of the battery is not connected to the system ground, and an effective anti-backflow effect can be achieved, protecting the ground from being affected by the rechargeable battery. At the same time, in the control circuit, the optocoupler device U2 is reversely cut off, and the power supply chip cannot obtain the control signal PWR_EN, and thus cannot output the supply voltage PWR. The power supply in the power output circuit does not output, and the N-channel first control switch D1 turns off, which can ensure that the positive power supply and the negative terminal of the rechargeable battery will not be short-circuited, effectively preventing the positive and negative short circuit from burning out. MOS transistors D1 and D5 are all turned off, and the power supply and the battery are completely isolated, so the absolute safety of the power supply and the external rechargeable battery can be ensured.

[0062] In the above embodiment, continue to refer to Figure 3The power output circuit may also include a fifth resistor R1 and a sixth resistor R3. The first end of the fifth resistor R1 is connected to the first output terminal BAT+, and the second end of the fifth resistor R1 is connected to the second terminal of the second control switch D3. The first end of the sixth resistor R3 is connected to the second end of the fifth resistor R1, and the second end of the sixth resistor R3 is connected to the second output terminal BAT-. The fifth resistor R1 and the sixth resistor R3 are connected in series, which can divide the voltage input to the rechargeable battery in the circuit, thereby protecting the opening voltage of the second control switch D3 within a safe range and preventing burnout caused by overvoltage.

[0063] In the above embodiments, see again Figure 3 The power output circuit may also include a second diode D2. The positive terminal of the second diode is connected to the second input terminal, and the negative terminal of the second diode is connected to the first input terminal. The second diode D2 is set to reverse connection, which can make the power supply signal flow only in one direction and can effectively prevent the front-end power supply from being connected in reverse.

[0064] In the above embodiments, see again Figure 3 The power output circuit may also include a seventh resistor R2. The first end of the seventh resistor R2 is connected to the first end of the third control switch D5, and the second end of the seventh resistor R2 is connected to the second input terminal. This can divide the input high voltage signal and protect the opening voltage of the third control switch D5 within a safe range to prevent overvoltage burnout when the power supply voltage or rechargeable battery voltage fluctuates.

[0065] In the above embodiments, see again Figure 3 The power output circuit may also include: a third capacitor C2, a fourth capacitor C1, and a transient voltage suppressor (D4 in the diagram). The first terminal of the third capacitor C2 is connected to the second terminal of the third control switch D5, and the second terminal of the third capacitor is connected to the third terminal of the third control switch D5. This filters out voltage peaks generated when the charging battery is connected, preventing instantaneous breakdown. The first terminal of the fourth capacitor C1 is connected to the first output terminal BAT+, and the second terminal of the fourth capacitor is connected to the second output terminal BAT-. This allows for energy storage of the power output and can also perform low-pass or high-pass filtering, which can be configured by relevant personnel according to actual conditions. The first terminal of the transient voltage suppressor D4 is connected to the first output terminal BAT+, and the second terminal of the transient voltage suppressor D4 is connected to the second output terminal BAT-. This absorbs surge power up to several kilowatts, limiting peak voltage within a safe range. When the voltage exceeds the surge threshold, it can directly divert excessive current, protecting the circuit from damage.

[0066] In the above embodiment, when the battery is correctly connected, as long as the power supply PWR does not output and MOSFET D1 is not turned on, the positive voltage at the battery terminal will not flow back into the power supply and thus affect the circuit. When the battery is connected in reverse, MOSFET D3 is not turned on, preventing MOSFET D5 from turning on, thus preventing the positive voltage at the battery terminal from flowing back into the system ground and preventing the battery from connecting to the system ground and forming a short circuit to ground. This simultaneously achieves the functions of preventing backflow and preventing reverse connection when the rechargeable battery is connected. In addition, when a traditional diode is forward-biased, due to the physical characteristics of the diode, it will generate a forward voltage drop of 0.3 to 0.7V. When charging the rechargeable battery, the charging voltage set at the power supply terminal is different from the actual charging voltage of the rechargeable battery, which will cause the rechargeable battery to not be fully charged. At the same time, the forward current carrying capacity of the diode is not strong, and it can only charge the rechargeable battery with a small current, while charging with a large current will generate significant heat and large heat loss. This invention uses the on / off state of an N-channel MOSFET to prevent reverse current from flowing into the battery. The Rdson (Drain Source On Resistance) of the MOSFET is generally less than 10mR. Under the same current conditions, the voltage drop is much smaller than that of a diode, and the heat generation is also smaller. Therefore, it is more suitable for fast charging of rechargeable batteries with large currents. It has the advantages of simple circuit, low cost and small layout space.

[0067] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located on the same circuit board; or, the above modules are located on different circuit boards in any combination.

[0068] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A protection circuit, characterized in that, include: A control circuit, wherein a first terminal of the control circuit is configured to be connected to one end of a rechargeable battery, and a second terminal of the control circuit is configured to be connected to the other end of the rechargeable battery; when the first terminal of the control circuit is connected to the positive terminal of the rechargeable battery and the second terminal of the control circuit is connected to the negative terminal of the rechargeable battery, the output terminal of the control circuit outputs a control signal; when the first terminal of the control circuit is connected to the negative terminal of the rechargeable battery and the second terminal of the control circuit is connected to the positive terminal of the rechargeable battery, the control circuit is turned off. A power supply chip, the input terminal of which is connected to the output terminal of the control circuit, is used to output a power supply voltage when the control signal is received; A power output circuit is provided, wherein a first input terminal of the power output circuit is configured to be connected to a first output terminal of a power chip, a second input terminal of the power output circuit is configured to be connected to a second output terminal of the power chip, a first output terminal of the power output circuit is configured to be connected to one end of a rechargeable battery, and a second output terminal of the power output circuit is configured to be connected to the other end of the rechargeable battery. When the power output circuit receives the supply voltage, it is turned on to charge the rechargeable battery; when it does not receive the supply voltage, it is turned off.

2. The protection circuit according to claim 1, characterized in that, The control circuit includes: An optocoupler is provided, wherein a first terminal of the optocoupler is connected to a first terminal of the control circuit, a second terminal of the optocoupler is connected to a second terminal of the control circuit, a third terminal of the optocoupler is connected to an output terminal of the control circuit, and a fourth terminal of the optocoupler is connected to a preset power supply. When the voltage at the first terminal of the optocoupler is greater than the voltage at the second terminal of the optocoupler, the third terminal of the optocoupler outputs the control signal. The first resistor has its first end connected to the third end of the optocoupler, and its second end grounded.

3. The protection circuit according to claim 2, characterized in that, The control circuit also includes: The second resistor has its first end connected to the first end of the control circuit and its second end connected to the second end of the optocoupler. The third resistor has its first end connected to the second end of the second resistor, and its second end connected to the second end of the control circuit.

4. The protection circuit according to claim 3, characterized in that, The control circuit further includes a first diode, the positive terminal of which is connected to the second end of the third resistor, and the negative terminal of which is connected to the second end of the control circuit.

5. The protection circuit according to claim 2, characterized in that, The control circuit also includes: A first capacitor, the first end of which is connected to the second end of the optocoupler, and the second end of which is connected to the second end of the control circuit.

6. The protection circuit according to claim 2, characterized in that, The control circuit also includes: The second capacitor is connected in parallel with the first resistor; The fourth resistor connects the third terminal of the optocoupler to the output terminal of the control circuit.

7. The protection circuit according to claim 1, characterized in that, The power output circuit also includes: A protection chip, wherein a first terminal of the protection chip is connected to the first input terminal, a second terminal of the protection chip is connected to the first terminal of the first control switch, a third terminal of the protection chip is connected to the first output terminal, and a fourth terminal of the protection chip is connected to the second input terminal. When the first input terminal does not receive the power supply voltage, the protection chip controls the first control switch to turn off, and when the first input terminal receives the power supply voltage, the protection chip controls the first control switch to turn on. The first control switch has a first end connected to the second end of the protection chip, a second end connected to the first input terminal, and a third end connected to the first output terminal. When the power chip outputs the supply voltage, the first control switch is turned on so that the positive terminal of the rechargeable battery is connected to the first input terminal. When the power chip does not output the supply voltage, the first control switch is turned off. The second control switch has a first terminal connected to the second output terminal, a second terminal connected to the first output terminal, and a third terminal connected to the first input terminal. When the first output terminal is configured to be connected to the positive terminal of the rechargeable battery and the second output terminal is configured to be connected to the negative terminal of the rechargeable battery, the second control switch is turned on. When the first output terminal is configured to be connected to the negative terminal of the rechargeable battery and the second output terminal is configured to be connected to the positive terminal of the rechargeable battery, the second control switch is turned off. A third control switch is configured such that its first end is connected to the third end of the second control switch, its second end is connected to the second input terminal, and its third end is connected to the second output terminal. When the second control switch is on, the third control switch is on, thereby connecting the negative terminal of the rechargeable battery to the second input terminal. When the second control switch is off, the third control switch is off.

8. The protection circuit according to claim 7, characterized in that, The power output circuit also includes: The fifth resistor has its first end connected to the first output terminal and its second end connected to the second terminal of the second control switch. The sixth resistor has its first end connected to the second end of the fifth resistor, and its second end connected to the second output terminal.

9. The protection circuit according to claim 7, characterized in that, The power output circuit further includes a second diode, the positive terminal of which is connected to the second input terminal, and the negative terminal of which is connected to the first input terminal.

10. The protection circuit according to claim 7, characterized in that, The power output circuit further includes a seventh resistor, the first end of which is connected to the first end of the third control switch, and the second end of which is connected to the second input terminal.

11. The protection circuit according to claim 7, characterized in that, The power output circuit also includes at least one of the following: A third capacitor, wherein the first terminal of the third capacitor is connected to the second terminal of the third control switch, and the second terminal of the third capacitor is connected to the third terminal of the third control switch; A fourth capacitor, wherein the first terminal of the fourth capacitor is connected to the first output terminal, and the second terminal of the fourth capacitor is connected to the second output terminal; A transient voltage suppressor transistor, wherein the first end of the transient voltage suppressor transistor is connected to the first output terminal, and the second end of the transient voltage suppressor transistor is connected to the second output terminal.

12. A charging device, characterized in that, Includes a protection circuit as described in any one of claims 1 to 11, wherein the charging device is used to charge the rechargeable battery via the protection circuit.

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