A lithium battery charging clamping circuit and power supply

Abstract

A lithium battery charging clamping circuit comprises a voltage detection module, a switch module, a voltage stabilizing control module, a voltage boosting module and a charging voltage adjusting module; the voltage detection module is used for detecting the charging voltage of the lithium battery to generate a first voltage detection signal and generating a switch control signal according to the first voltage detection signal; the switch module is used for turning on or turning off the charging voltage of the lithium battery according to the switch control signal; the voltage boosting module is used for generating a first voltage according to the charging voltage of the lithium battery; the voltage stabilizing control module is used for detecting the charging voltage of the lithium battery to generate a second voltage detection signal and generating a pulse width modulation signal according to the second voltage detection signal; the charging voltage adjusting module is used for adjusting the charging voltage according to the pulse width modulation signal and the first voltage; the charging voltage of the lithium battery is accurately clamped, the charging of the lithium battery in a safe range can be ensured, and the adverse effects of overcharging on the lithium battery or the charging device are effectively avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium batteries, and particularly relates to a lithium battery charging clamping circuit and a power supply. BACKGROUND

[0002] At present, overcharging is prone to occur in the charging process of a lithium battery, which converts redundant electric energy into heat energy, not only causes the temperature of the lithium battery to rise and affects the service life of the lithium battery, but also can damage a charger or an electronic product without overcharge protection, and has great safety hazards. In order to avoid the overcharge of the lithium battery and affect the service life, a resistor is usually directly connected in parallel at both ends of a lithium battery equalization chip. Since the voltage of the resistor is constant, the resistor is constant, and the equalization current is also constant. However, when the charging voltage rises rapidly, the discharge current through the resistor is still small, and the equalization charging of the lithium battery cannot be realized, so that the charging voltage of the lithium battery cannot be accurately clamped.

[0003] Therefore, the lithium battery charging clamping circuit in the prior art has the problem that the lithium battery cannot be equalization charged and the charging voltage cannot be accurately clamped. SUMMARY

[0004] The application provides a lithium battery charging clamping circuit and a power supply, and aims to solve the problem that the lithium battery charging clamping circuit in the prior art cannot make the lithium battery equalization charged and cannot accurately clamp the charging voltage.

[0005] The application is implemented in the following manner. A lithium battery charging clamping circuit comprises:

[0006] a voltage detection module connected with a lithium battery, used for detecting the charging voltage of the lithium battery to generate a first voltage detection signal, and generating a switch control signal according to the first voltage detection signal;

[0007] a switch module connected with the voltage detection module and the lithium battery, used for turning on or turning off the charging voltage of the lithium battery according to the switch control signal;

[0008] a boost module connected with the switch module, used for generating a first voltage according to the charging voltage of the lithium battery;

[0009] a voltage stabilization control module connected with the lithium battery and the boost module, used for detecting the charging voltage of the lithium battery to generate a second voltage detection signal, and generating a pulse width modulation signal according to the second voltage detection signal; and

[0010] a charging voltage adjustment module connected with the voltage stabilization control module, used for adjusting the charging voltage according to the pulse width modulation signal and the first voltage.

[0011] The application further provides a power supply comprising the lithium battery charging clamping circuit.

[0012] The lithium battery charging clamping circuit comprises a voltage detection module, a switch module, a voltage boosting module, a voltage stabilizing control module and a charging voltage adjusting module. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 A module schematic diagram of the lithium battery charging clamping circuit according to an embodiment of the application is shown.

[0014] Figure 2 A circuit principle diagram of the lithium battery charging clamping circuit according to an embodiment of the application is shown. DETAILED DESCRIPTION

[0015] In order to make the objectives, technical solutions and advantages of the application clearer, the application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and not used to limit the application.

[0016] Figure 1 A module schematic diagram of the lithium battery charging clamping circuit according to an embodiment of the application is shown. For the convenience of description, only the parts related to the embodiment are shown, and the details are as follows:

[0017] REFERENCE Figure 1 The lithium battery charging clamping circuit comprises a voltage detection module 10, a switch module 20, a voltage stabilizing control module 40, a voltage boosting module 30 and a charging voltage adjusting module 50.

[0018] The voltage detection module 10 is connected with the lithium battery, and is configured to detect the charging voltage of the lithium battery to generate a first voltage detection signal, and generate a switch control signal according to the first voltage detection signal; the switch module 20 is connected with the voltage detection module 10 and the lithium battery, and is configured to turn on or turn off the charging voltage of the lithium battery according to the switch control signal; the voltage boosting module 30 is connected with the switch module 20, and is configured to generate a first voltage according to the charging voltage of the lithium battery; the voltage stabilizing control module 40 is connected with the lithium battery and the voltage boosting module 30, and is configured to detect the charging voltage of the lithium battery to generate a second voltage detection signal, and generate a pulse width modulation signal according to the second voltage detection signal; and the charging voltage adjusting module 50 is connected with the voltage stabilizing control module 40, and is configured to adjust the charging voltage according to the pulse width modulation signal and the first voltage. In a specific embodiment, the voltage detection module 10 includes a micro-power voltage detector.

[0019] In the embodiment, the voltage detection module 10 detects the charging voltage of the lithium battery to generate a first voltage detection signal, and generates a switch control signal according to the first voltage detection signal to control the switch module 20 to turn on or turn off the charging voltage of the lithium battery; the voltage boosting module 30 generates a first voltage according to the charging voltage of the lithium battery; the voltage stabilizing control module 40 detects the charging voltage of the lithium battery to generate a second voltage detection signal, and generates a pulse width modulation signal according to the second voltage detection signal; and the charging voltage adjusting module 50 adjusts the charging voltage of the lithium battery according to the pulse width modulation signal and the first voltage, so as to clamp the charging voltage of the lithium battery. The lithium battery charging clamping circuit can dynamically adjust the charging current of the lithium battery by adjusting the duty cycle of the pulse width modulation signal, so as to accurately clamp the charging voltage of the lithium battery, and can ensure that the lithium battery is charged within a safe range, and effectively avoids the adverse effects of overcharging on the lithium battery or the charging device.

[0020] In one of the embodiments, referring to Figure 2 The switch module 20 includes a first field effect transistor Q1, the control end of the first field effect transistor Q1 is the switch control end of the switch module 20, the high potential end of the first field effect transistor Q1 is the input end of the switch module 20, and the low potential end of the first field effect transistor Q1 is the output end of the switch module 20. In a specific embodiment, referring to Figure 2 The first field effect transistor Q1 includes a PMOS tube, and the gate, the drain and the source of the PMOS tube are respectively the control end, the high potential end and the low potential end of the first field effect transistor Q1. The switch module 20 of the embodiment can turn on or turn off the charging voltage of the lithium battery according to the switch control signal.

[0021] In one of the embodiments, referring to Figure 2The boost chip U1, the first inductor L1, the first diode D1, the first resistor R1, the second resistor R2 and the first capacitor C1; the working power supply end of the boost chip U1 is connected with the first end of the first inductor L1 as the input end of the boost module 30, the ground end of the boost chip U1 is grounded, the voltage output end of the boost chip U1, the second end of the first inductor L1 and the anode of the first diode D1 are connected, the voltage feedback end of the boost chip U1, the first end of the first resistor R1 and the first end of the second resistor R2 are connected, the second end of the second resistor R2 is connected to the ground, the cathode of the first diode D1 and the second end of the first resistor R1 are connected as the output end of the boost module 30. The boost module 30 of the embodiment can realize the boost of the charging voltage of the lithium battery to generate the first voltage.

[0022] In one of the embodiments, referring to Figure 2 The voltage stabilizing control module 40 includes: a voltage stabilizing control chip U2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a second capacitor C2; the first end of the fourth resistor R4 is the reference voltage input end of the voltage stabilizing control module 40, the second end of the fourth resistor R4, the first end of the fifth resistor R5 and the reference voltage input end of the voltage stabilizing control chip U2 are connected, the second end of the fifth resistor R5 is grounded, the detection voltage input end of the voltage stabilizing control chip U2 is the detection voltage input end of the voltage stabilizing control module 40, the working power supply end of the voltage stabilizing control chip U2 is the power supply end of the voltage stabilizing control module 40, the clock oscillation resistor input end of the voltage stabilizing control chip U2 is connected with the first end of the third resistor R3, the clock oscillation capacitor input end of the voltage stabilizing control chip U2 is connected with the first end of the second capacitor C2, the ground end of the voltage stabilizing control chip U2, the second end of the third resistor R3, the first end of the eighth resistor R8 and the second end of the second capacitor C2 are all connected to the ground, the first pulse width modulation signal output end of the voltage stabilizing control chip U2 is connected with the first end of the sixth resistor R6, the second pulse width modulation signal output end of the voltage stabilizing control chip U2 is connected with the first end of the seventh resistor R7, the second end of the sixth resistor R6, the second end of the seventh resistor R7 and the second end of the eighth resistor R8 are connected as the pulse width modulation signal output end of the voltage stabilizing control module 40. The voltage stabilizing control module 40 of the embodiment can generate the pulse width modulation signal of high level or the pulse width modulation signal of low level according to the charging voltage of the lithium battery, the set reference voltage and the on-off state of the switching module 20, and then control the charging voltage adjusting module 50 to turn on or turn off the charging voltage of the lithium battery to accurately clamp the charging voltage.

[0023] In one of the embodiments, referring to Figure 2The charging voltage adjustment module 50 comprises a second field effect transistor Q2, a ninth resistor R9, a first triode TV1 and a second triode TV2. The base of the first triode TV1 and the base of the second triode TV2 are connected together as the control terminal of the charging voltage adjustment module 50. The input terminal of the first triode TV1 is connected to the working power supply. The output terminal of the first triode TV1, the output terminal of the second triode TV2 and the control terminal of the second field effect transistor Q2 are connected together. The input terminal of the second triode TV2 and the low potential terminal of the second field effect transistor Q2 are connected together as the output terminal of the charging voltage adjustment module 50. The high potential terminal of the second field effect transistor Q2 is connected to the first terminal of the ninth resistor R9. The second terminal of the ninth resistor R9 is the input terminal of the charging voltage adjustment module 50. In a specific embodiment, the second field effect transistor Q2 is an NMOS transistor. The gate, the drain and the source of the NMOS transistor are respectively the control terminal, the low potential terminal and the high potential terminal of the second field effect transistor Q2. The first triode TV1 is an NPN triode. The base, the emitter and the collector of the NPN triode are respectively the control terminal, the output terminal and the input terminal of the first triode TV1. The second triode TV2 is a PNP triode. The base, the emitter and the collector of the PNP triode are respectively the control terminal, the input terminal and the output terminal of the second triode TV2. The ninth resistor R9 is a discharge resistor, which can discharge the charge stored in the equivalent capacitor of the gate of the second field effect transistor Q2, so as to prevent the second field effect transistor Q2 from being burnt out. The charging voltage adjustment module 50 of the embodiment can dynamically adjust the charging current of the lithium battery according to the pulse width modulation signal and the first voltage, so as to precisely clamp the charging voltage of the lithium battery in a closed loop.

[0024] In one of the embodiments, referring to Figure 2 The lithium battery charging clamping circuit further comprises a first filtering module 60, which is configured to perform filtering processing on the charging voltage of the lithium battery. In a specific embodiment, the first filtering module 60 comprises a tenth resistor R10 and a third capacitor C3. The first terminal of the tenth resistor R10 is connected to the input terminal of the first filtering module 60. The second terminal of the tenth resistor R10 and the second terminal of the third capacitor C3 are connected together as the output terminal of the first filtering module 60. The second terminal of the third capacitor C3 is connected to the ground. The first filtering module of the embodiment performs filtering processing on the charging voltage of the lithium battery, so as to reduce the ripple coefficient of the charging voltage and make the detection result of the charging voltage more accurate.

[0025] In one of the embodiments, referring to Figure 2The lithium battery charging clamping circuit further comprises a second filtering module 70 configured to filter the charging voltage of the lithium battery.

[0026] In addition, a power supply comprising the above battery charging clamping circuit is provided.

[0027] The working principle of the lithium battery charging clamping circuit will be described below with reference to the circuit schematic diagram shown in FIG. 1. Figure 2 The working principle of the lithium battery charging clamping circuit will be described below with reference to the circuit schematic diagram shown in FIG. 1.

[0028] During the charging process of the lithium battery, the micro-power voltage detector detects the charging voltage of the lithium battery in real time, and compares the first voltage detection signal detected by the micro-power voltage detector with the threshold voltage of the lithium battery.

[0029] When the first voltage detection signal is higher than the threshold voltage, the micro-power voltage detector outputs a low-level switching control signal, and at this time, the first field effect tube Q1 is turned on, the boost chip U1, the first inductor L1 and the first diode D1 form a boost module 30 to boost the charging voltage of the lithium battery to generate a first voltage, so as to make the voltage stabilizing control chip U2 work and detect the charging voltage of the lithium battery to generate a second voltage detection signal, and compare the second voltage detection signal with a reference voltage to output a pulse width modulation signal corresponding to the duty ratio, and the pulse width modulation signal makes the first triode TV1, the second triode TV2 and the second field effect tube Q2 turn on and off according to the duty ratio; in this way, by adjusting the duty ratio of the pulse width modulation signal output by the voltage stabilizing control chip U2, the on-off of the second field effect tube Q2 can be dynamically controlled to adjust the charging current of the lithium battery, and the charging voltage of the lithium battery can be precisely clamped.

[0030] The lithium battery charging clamping circuit has the following advantages:

[0031] (1) The charging voltage of the lithium battery is detected by the voltage detection module to generate a first voltage detection signal, and a switch control signal is generated according to the first voltage detection signal to control the switch module to turn on or turn off the charging voltage of the lithium battery, the boost module generates a first voltage according to the charging voltage of the lithium battery, at the same time, the voltage control module detects the charging voltage of the lithium battery to generate a second voltage detection signal, and a pulse width modulation signal is generated according to the second voltage detection signal, so that the charging voltage adjustment module adjusts the charging voltage of the lithium battery according to the pulse width modulation signal and the first voltage, thereby clamping the charging voltage of the lithium battery.

[0032] (2) The lithium battery charging clamping circuit can dynamically adjust the charging current of the lithium battery by adjusting the duty cycle of the pulse width modulation signal, so that the charging voltage of the lithium battery is accurately clamped, and the charging of the lithium battery in the safe range can be ensured, and the adverse effects of overcharging on the lithium battery or the charging device are effectively avoided.

[0033] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A lithium battery charge clamp circuit, characterized by, The lithium battery charging clamping circuit comprises: a voltage detection module connected with the lithium battery, configured to detect the charging voltage of the lithium battery to generate a first voltage detection signal, and generate a switch control signal according to the first voltage detection signal; a switch module connected with the voltage detection module and the lithium battery, configured to turn on or turn off the charging voltage of the lithium battery according to the switch control signal; a boost module connected with the switch module, configured to generate a first voltage according to the charging voltage of the lithium battery; when the first voltage detection signal is higher than a threshold voltage, the boost module boosts the charging voltage to generate the first voltage; a voltage stabilizing control module connected with the lithium battery and the boost module, configured to detect the charging voltage of the lithium battery to generate a second voltage detection signal, and generate a pulse width modulation signal according to the second voltage detection signal; and a charging voltage adjusting module connected with the voltage stabilizing control module, configured to adjust the charging voltage according to the pulse width modulation signal and the first voltage, the charging voltage adjusting module comprises a second field effect transistor, a ninth resistor, a first triode and a second triode; the base of the first triode and the base of the second triode are connected together as a control terminal of the charging voltage adjusting module, the input terminal of the first triode is connected to a working power supply, the output terminal of the first triode, the output terminal of the second triode and the control terminal of the second field effect transistor are connected together, the input terminal of the second triode and the low potential terminal of the second field effect transistor are connected together as an output terminal of the charging voltage adjusting module, the high potential terminal of the second field effect transistor is connected with the first terminal of the ninth resistor, the second terminal of the ninth resistor is an input terminal of the charging voltage adjusting module, and the charging voltage adjusting module dynamically adjusts the charging current of the lithium battery according to the pulse width modulation signal and the first voltage to close-loop clamp the charging voltage of the lithium battery; the lithium battery charging clamping circuit further comprises: a second filter module connected with the switch module and the boost module, configured to filter the charging voltage of the lithium battery, wherein the boost module comprises a boost chip, a first inductor, a first diode, a first resistor, a second resistor and a first capacitor; when the first voltage detection signal is higher than a threshold voltage, the boost module boosts the charging voltage to generate the first voltage; the working power supply terminal of the boost chip is connected with the first terminal of the first inductor as an input terminal of the boost module, the ground terminal of the boost chip is grounded, the voltage output terminal of the boost chip, the second terminal of the first inductor and the anode of the first diode are connected together, the voltage feedback terminal of the boost chip, the first terminal of the first resistor and the first terminal of the second resistor are connected together, the second terminal of the second resistor is connected to the ground, and the cathode of the first diode is connected with the second terminal of the first resistor as an output terminal of the boost module.

2. The lithium battery charging clamp circuit of claim 1, wherein, the lithium battery charging clamping circuit further comprises: a first filter module connected with the lithium battery and the voltage detection module, configured to filter the charging voltage of the lithium battery.

3. The lithium battery charging clamp circuit of claim 1, wherein, The switch module comprises a first field effect transistor, a control end of the first field effect transistor is a switch control end of the switch module, a high potential end of the first field effect transistor is an input end of the switch module, and a low potential end of the first field effect transistor is an output end of the switch module.

4. The lithium battery charging clamp circuit of claim 1, wherein, The voltage stabilizing control module comprises a voltage stabilizing control chip, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a second capacitor. A first end of the fourth resistor is a reference voltage input end of the voltage stabilizing control module, a second end of the fourth resistor, a first end of the fifth resistor and a reference voltage input end of the voltage stabilizing control chip are connected in common, a second end of the fifth resistor is grounded, a detection voltage input end of the voltage stabilizing control chip is a detection voltage input end of the voltage stabilizing control module, a working power supply end of the voltage stabilizing control chip is a power supply end of the voltage stabilizing control module, a clock oscillation resistor input end of the voltage stabilizing control chip is connected with a first end of the third resistor, a clock oscillation capacitor input end of the voltage stabilizing control chip is connected with a first end of the second capacitor, a ground end of the voltage stabilizing control chip, a second end of the third resistor, a first end of the eighth resistor and a second end of the second capacitor are all connected to ground, a first pulse width modulation signal output end of the voltage stabilizing control chip is connected with a first end of the sixth resistor, a second pulse width modulation signal output end of the voltage stabilizing control chip is connected with a first end of the seventh resistor, a second end of the sixth resistor, a second end of the seventh resistor and a second end of the eighth resistor are connected in common as a pulse width modulation signal output end of the voltage stabilizing control module.

5. A lithium battery charge clamp circuit as claimed in any one of claims 1 to 4, wherein, The voltage detection module comprises a micro-power-consumption voltage detector.

6. A power supply comprising the lithium battery charging clamp circuit according to any one of claims 1 to 5.

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