Lithium battery charger circuit of electric lifting bed

Abstract

The utility model discloses an electric lifting bed lithium battery charger circuit, and belongs to the technical field of lithium battery charging, 1, the electric lifting bed lithium battery charger circuit comprises a voltage input end, a PWM circuit, a constant voltage and current circuit and an anti-reverse-connection protection circuit, the voltage input end is connected with the PWM circuit, the PWM circuit is connected with the constant voltage and current circuit through an optical coupler, and the anti-reverse-connection protection circuit is connected with the constant voltage and current circuit through an optical coupler; the constant voltage and current circuit is connected with the battery pack through the anti-reverse-connection protection circuit, the PWM circuit detects the voltage output by the constant voltage and current circuit and outputs a control signal for adjustment, and the anti-reverse-connection protection circuit comprises a resettable fuse; when the positive electrode and the negative electrode of the battery pack are reversely connected, the resettable fuse is disconnected to disconnect the reverse connection prevention protection circuit. The PWM circuit is adopted to control voltage output, the constant voltage and current circuit is additionally arranged to ensure stable DC voltage output, and the anti-reverse connection protection circuit is additionally arranged to protect the charger from being damaged and protect the battery pack.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery charging, and in particular to a lithium battery charger circuit for an electric lift bed. Background Art

[0002] With the application and popularization of lithium batteries, lithium batteries are widely used in people's lives due to their excellent performance. More and more products use lithium batteries, from small household kitchen appliances to large vehicles and production and processing equipment. The resulting lithium battery safety issues are also increasingly concerned and valued by lithium battery manufacturers and end users, especially the charging of lithium batteries in different environments. Because low temperature or high temperature over-specification current charging will cause changes in the chemical properties of lithium batteries, resulting in the attenuation of lithium battery life, and even leading to safety issues such as heating and short circuit. In order to solve the above problems, most lithium battery charging products are equipped with constant voltage and constant current chargers, and the charging current is a fixed normal temperature rated current.

[0003] Related prior art such as the Chinese patent "Charging Control Circuit, Power Supply Device and Electronic Equipment", application number: CN202322276872.8; discloses that the circuit includes: a voltage detection module for detecting the voltage of the battery pack and generating a voltage detection signal; a charging detection module for detecting the connection status between the charging device and the battery pack and generating a charging detection signal; a main control module for generating a switch control signal according to the voltage detection signal when the charging detection signal indicates that the charging device and the battery pack are electrically conductive; the charging control module is used to turn on or off according to the switch control signal to adjust the charging current of the battery pack. In this application, the voltage of the battery pack is detected by the voltage detection module. When it is detected that the charging device and the battery pack are electrically conductive, the main control module generates a corresponding switch control signal according to the voltage of the battery pack to control the conduction or disconnection of the charging control module, thereby adjusting the size of the charging current of the battery pack, improving the safety of charging, and ensuring the charging efficiency and charging effect.

[0004] Lithium batteries are charged at different temperatures, and their maximum charging current is different. This limitation means that if the lithium battery pack is used in a low temperature environment, the charging current will exceed the maximum charging current in a low temperature environment defined by the lithium battery manufacturer, which poses a safety hazard. Therefore, further improvements are made to the charger circuit to ensure the safety of electrical equipment. Utility Model Content

[0005] The technical problem to be solved by the present application is to provide a lithium battery charger circuit for an electric lift bed, which adopts a PWM circuit to control the output of the voltage, adds a constant voltage and current circuit to ensure the output of a stable DC voltage, and adds an anti-reverse connection protection circuit to protect the charger from damage and protect the battery pack.

[0006] The technical solution adopted in the present application is: a lithium battery charger circuit for an electric lift bed, including a voltage input terminal, a PWM circuit, a constant voltage and current circuit and an anti-reverse connection protection circuit, wherein the voltage input terminal is connected to the PWM circuit, the PWM circuit is connected to the constant voltage and current circuit through an optical coupler, the constant voltage and current circuit is connected to the battery pack through the anti-reverse connection protection circuit, the PWM circuit detects the voltage output by the constant voltage and current circuit and outputs a control signal for adjustment, and the anti-reverse connection protection circuit includes a self-resetting fuse; when the positive and negative poles of the battery pack are reversed, the self-resetting fuse is disconnected to disconnect the anti-reverse connection protection circuit.

[0007] Compared with the prior art, the advantages of the present application are that, first, a PWM circuit is added, and the PWM circuit provides a precise output overvoltage protection function. Through the detection of the PWM circuit, the output voltage is prevented from being too high and burning electrical appliances. Secondly, a constant voltage and current circuit is set, and the constant voltage and current circuit is connected to the PWM circuit through an optical coupler, and the PWM circuit is cooperated to achieve a stable output DC voltage. Thirdly, an anti-reverse connection protection circuit is added, and a resettable fuse is set in the anti-reverse connection protection circuit. If the positive and negative poles of the battery pack are reversed, the current passing through the resettable fuse becomes larger, and the resettable fuse is disconnected, thereby protecting the charger from damage and protecting the battery pack. The present application further optimizes the circuit design of the charger and improves the safety of electrical equipment.

[0008] In some embodiments of the present application, the constant voltage and current circuit is connected to a 2.5V reference voltage, and the constant voltage and current circuit includes a constant voltage circuit and a constant current circuit. In the present application, by setting a 2.5V reference voltage, the voltage is adjusted to output a stable DC voltage.

[0009] In some embodiments of the present application, the present application also includes an electromagnetic filtering circuit, a rectifier circuit and a capacitor group. The voltage input end is connected to the electromagnetic filtering circuit, the electromagnetic filtering circuit connects the rectifier circuit and the high-voltage starting circuit, the high-voltage starting circuit is connected to the PWM circuit, the PWM circuit is connected to the rectifier circuit current through the capacitor group, and the PWM circuit is connected to the VCC control circuit.

[0010] In some embodiments of the present application, the PWM circuit includes a PWM power circuit and a PWM control circuit, the PWM control circuit is connected to the constant voltage and current circuit through an optical coupler, the PWM power circuit is connected to the rectifier filter circuit through a transformer, and the rectifier filter circuit is connected to the anti-reverse connection protection circuit. In the present application, the voltage is output through the PWM power circuit and the transformer, and then a stable voltage is obtained through the rectifier filter circuit to the anti-reverse connection protection circuit.

[0011] In some embodiments of the present application, the present application further includes a battery voltage backflow prevention circuit, and the battery voltage backflow prevention circuit is connected to the positive terminal of the battery pack. By adding the battery voltage backflow prevention circuit, the safety of the present application is further ensured.

[0012] In some embodiments of the present application, the PWM circuit includes a control chip of model LD5762E, the fourth pin of the control chip is grounded, and the eighth pin of the control chip is connected to the high-voltage starting circuit.

[0013] In some embodiments of the present application, the second pin of the control chip is connected to the collector of the optocoupler through a control resistor, the emitter of the optocoupler is connected to the second pin of the control chip through a thirteenth capacitor, the anode of the optocoupler is connected to the battery voltage backflow prevention circuit, and the cathode of the optocoupler is connected to a controllable precision voltage regulator.

[0014] The present application provides a precise output overvoltage protection function, which is detected by the first pin of the control chip to prevent the output voltage from being too high and burning out electrical appliances.

[0015] In some embodiments of the present application, the third pin of the control chip is grounded after passing through the tenth capacitor, and a resistor group is connected in parallel at both ends of the tenth capacitor. Specifically, the resistor group includes a first resistor and a ninth resistor connected in series, and a second resistor is connected in parallel at both ends of the first resistor. By setting the tenth capacitor and the resistor group at the third pin of the control chip, negative pressure interference entering the control chip can be effectively filtered, thereby improving the rationality of the detection of the system of the present application. Excessive distortion of the current feedback signal and excessive output power are avoided.

[0016] In some embodiments of the present application, the constant voltage and current circuit includes a controllable precision voltage-stabilized power supply, the reference pole of the controllable precision voltage-stabilized power supply outputs a 2.5V reference voltage, the anode of the controllable precision voltage-stabilized power supply is grounded, an inductor is connected between the reference pole and the anode of the controllable precision voltage-stabilized power supply, and the cathode of the controllable precision voltage-stabilized power supply is connected to the cathode of the optical coupler. The reference 2.5V voltage output by the control chip, the optical coupler and the controllable precision voltage-stabilized power supply is adjusted to output a stable DC voltage.

[0017] In some embodiments of the present application, the rectifier filter circuit includes a protection chip of model AS358MTR, and the third pin of the protection chip is connected to the battery voltage backflow prevention circuit. In the present application, a current limiting resistor is provided, and the protection chip cooperates with the current limiting resistor to output a constant current to charge the battery pack.

[0018] The above-mentioned implementation modes can be combined arbitrarily based on the common knowledge in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present application will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be used as a limitation on the scope of the present application. In addition, unless otherwise specified, the drawings are only schematically representing the composition or structure of the described objects and may contain exaggerated displays, and the drawings are not necessarily drawn to scale.

[0020] Figure 1 This is a principle block diagram of this application;

[0021] Figure 2 Part of the circuit of this application Figure 1 ;

[0022] Figure 3 Part of the circuit of this application Figure 2 ;

[0023] Figure 4 Part of the circuit of this application Figure 3 ;

[0024] Figure 5 This is the overall circuit diagram of this application.

[0025] The specific description of the reference numerals is as follows: 1. electromagnetic filter circuit; 2. rectifier circuit; 3. PWM power circuit; 4. rectifier filter circuit; 5. battery voltage backflow prevention circuit; 6. battery pack; 7. reverse connection protection circuit; 8. constant voltage circuit; 9. constant current circuit; 10. PWM control circuit; 11. high voltage start-up circuit; 12. VCC control circuit;

[0026] C3\CL1, capacitor group; U2, optocoupler; Q6, controllable precision voltage-stabilized power supply; F2\F3, resettable fuse; C13, thirteenth capacitor; C10, tenth capacitor. DETAILED DESCRIPTION

[0027] The present application is described in detail below in conjunction with the accompanying drawings.

[0028] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] A lithium battery charger circuit for an electric lifting bed, embodiment 1 Figure 1As shown: it includes a voltage input terminal, a PWM circuit, a constant voltage and current circuit and an anti-reverse connection protection circuit 7. The voltage input terminal is connected to the PWM circuit, and a PWM circuit is added. The PWM circuit provides a precise output overvoltage protection function. Through the detection of the PWM circuit, the output voltage is prevented from being too high and burning electrical appliances. The PWM circuit is connected to the constant voltage and current circuit through an optical coupler U2. The constant voltage and current circuit is connected to the battery pack 6 through the anti-reverse connection protection circuit 7. The PWM circuit detects the voltage output by the constant voltage and current circuit and outputs a control signal for adjustment. A constant voltage and current circuit is set, and the constant voltage and current circuit is connected to the PWM circuit through the optical coupler U2, and the PWM circuit is used to output a stable DC voltage.

[0030] The anti-reverse connection protection circuit 7 includes a resettable fuse F2\F3; when the positive and negative poles of the battery pack 6 are reversed, the resettable fuse F2\F3 is disconnected to disconnect the anti-reverse connection protection circuit 7. An anti-reverse connection protection circuit 7 is added, and a resettable fuse F2\F3 is set in the anti-reverse connection protection circuit 7. If the positive and negative poles of the battery pack 6 are reversed, the current passing through the resettable fuse F2\F3 becomes larger, and the resettable fuse F2\F3 is disconnected, thereby protecting the charger from damage and protecting the battery pack 6. The present application further optimizes the circuit design of the charger and improves the safety of electrical equipment.

[0031] Embodiment 2, as Figures 1 to 5 As shown, the constant voltage and current circuit is connected to a 2.5V reference voltage, and the constant voltage and current circuit includes a constant voltage circuit 8 and a constant current circuit 9. In the present application, by setting a 2.5V reference voltage, the voltage is adjusted to output a stable DC voltage.

[0032] The present application also includes an electromagnetic filter circuit 1, a rectifier circuit 2 and a capacitor group C3\CL1. The voltage input end is connected to the electromagnetic filter circuit 1. The electromagnetic filter circuit 1 is connected to the rectifier circuit 2 and a high-voltage starting circuit 11. The high-voltage starting circuit 11 is connected to a PWM circuit. The PWM circuit is connected to the rectifier circuit 2 current through the capacitor group C3\CL1, and the PWM circuit is connected to a VCC control circuit 12.

[0033] The PWM circuit includes a PWM power circuit 3 and a PWM control circuit 10, the PWM control circuit 10 is connected to the constant voltage and current circuit through an optical coupler U2, the PWM power circuit 3 is connected to the rectifier filter circuit 4 through a transformer, and the rectifier filter circuit 4 is connected to the anti-reverse connection protection circuit 7. In the present application, the PWM power circuit 3 and the transformer output voltage are further output through the rectifier filter circuit 4 to obtain a stable voltage to the anti-reverse connection protection circuit 7.

[0034] The present application further includes a battery voltage backflow prevention circuit 5, and the battery voltage backflow prevention circuit 5 is connected to the positive terminal of the battery pack 6. By adding the battery voltage backflow prevention circuit 5, the safety of the present application is further ensured.

[0035] The PWM circuit includes a control chip of model LD5762E, the fourth pin of the control chip is grounded, and the eighth pin of the control chip is connected to the high-voltage starting circuit 11.

[0036] The second pin of the control chip is connected to the collector of the optical coupler U2 through the control resistor RJ2, the emitter of the optical coupler U2 is connected to the second pin of the control chip through the thirteenth capacitor C13, the anode of the optical coupler U2 is connected to the battery voltage backflow prevention circuit 5, and the cathode of the optical coupler U2 is connected to the controllable precision voltage source. The present application provides a function of accurately outputting overvoltage protection, which is detected through the first pin of the control chip to prevent the output voltage from being too high and burning out electrical appliances.

[0037] The third pin of the control chip is grounded after passing through the tenth capacitor C10, and the two ends of the tenth capacitor C10 are connected in parallel with a resistor group. Specifically, the resistor group includes a first resistor RS1 and a ninth resistor R9 connected in series, and a second resistor RS2 is connected in parallel at both ends of the first resistor RS1. By setting the tenth capacitor C10 and the resistor group at the third pin of the control chip, negative pressure interference entering the control chip can be effectively filtered, thereby improving the rationality of the detection of the system of the present application. Excessive distortion of the current feedback signal and excessive output power are avoided.

[0038] The constant voltage and current circuit includes a controllable precision voltage-stabilized power supply Q6, the reference pole of the controllable precision voltage-stabilized power supply Q6 outputs a 2.5V reference voltage, the anode of the controllable precision voltage-stabilized power supply Q6 is grounded, an inductor is connected between the reference pole and the anode of the controllable precision voltage-stabilized power supply Q6, and the cathode of the controllable precision voltage-stabilized power supply Q6 is connected to the cathode of the optical coupler U2. The reference 2.5V voltage output by the control chip, the optical coupler U2 and the controllable precision voltage-stabilized power supply Q6 is adjusted to output a stable DC voltage.

[0039] The rectifier filter circuit 4 includes a protection chip of model AS358MTR, and the third pin of the protection chip is connected to the battery voltage backflow prevention circuit 5. In the present application, current limiting resistors RS3 and RS4 are provided, and the protection chip cooperates with the current limiting resistors to output a constant current to charge the battery pack 6.

[0040] The rest of the content of the second embodiment is the same as that of the first embodiment.

[0041] The present application is described in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the present application and its core ideas. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A lithium battery charger circuit for an electric lifting bed, characterized in that: It includes a voltage input terminal, a PWM circuit, a constant voltage and current circuit and an anti-reverse connection protection circuit. The voltage input terminal is connected to the PWM circuit. The PWM circuit is connected to the constant voltage and current circuit through an optical coupler. The constant voltage and current circuit is connected to a battery pack through the anti-reverse connection protection circuit. The PWM circuit detects the voltage output by the constant voltage and current circuit and outputs a control signal for adjustment. The anti-reverse connection protection circuit includes a resettable fuse. When the positive and negative poles of the battery pack are reversed, the resettable fuse is disconnected to disconnect the anti-reverse connection protection circuit.

2. The lithium battery charger circuit for an electric lifting bed according to claim 1, characterized in that: The constant voltage and current circuit is connected to a 2.5V reference voltage, and the constant voltage and current circuit comprises a constant voltage circuit and a constant current circuit.

3. The lithium battery charger circuit for an electric lifting bed according to claim 1, characterized in that: It also includes an electromagnetic filtering circuit, a rectifier circuit and a capacitor group. The voltage input end is connected to the electromagnetic filtering circuit, the electromagnetic filtering circuit is connected to the rectifier circuit and the high-voltage starting circuit, the high-voltage starting circuit is connected to the PWM circuit, the PWM circuit is connected to the rectifier circuit current through the capacitor group, and the PWM circuit is connected to the VCC control circuit.

4. The lithium battery charger circuit for an electric lifting bed according to claim 1 or 3, characterized in that: The PWM circuit includes a PWM power circuit and a PWM control circuit. The PWM control circuit is connected to the constant voltage and current circuit through an optical coupler. The PWM power circuit is connected to the rectifier and filter circuit through a transformer. The rectifier and filter circuit is connected to the anti-reverse connection protection circuit.

5. The lithium battery charger circuit for an electric lifting bed according to claim 1, characterized in that: It also includes a battery voltage backflow prevention circuit, which is connected to the positive terminal of the battery pack.

6. The lithium battery charger circuit for an electric lifting bed according to claim 1, characterized in that: The PWM circuit comprises a control chip of model LD5762E, the fourth pin of the control chip is grounded, and the eighth pin of the control chip is connected to the high-voltage starting circuit.

7. The lithium battery charger circuit for an electric lifting bed according to claim 6, characterized in that: The second pin of the control chip is connected to the collector of the optocoupler through a control resistor, the emitter of the optocoupler is connected to the second pin of the control chip through a thirteenth capacitor, the anode of the optocoupler is connected to a battery voltage backflow prevention circuit, and the cathode of the optocoupler is connected to a controllable precision voltage regulator.

8. The lithium battery charger circuit for an electric lifting bed according to claim 7, characterized in that: The third pin of the control chip is grounded after passing through a tenth capacitor, and a resistor group is connected in parallel at both ends of the tenth capacitor.

9. The lithium battery charger circuit for an electric lifting bed according to claim 7, characterized in that: The constant voltage and current circuit includes a controllable precision voltage-stabilized power supply, a reference electrode of the controllable precision voltage-stabilized power supply outputs a 2.5V reference voltage, an anode of the controllable precision voltage-stabilized power supply is grounded, an inductor is connected between the reference electrode and the anode of the controllable precision voltage-stabilized power supply, and a cathode of the controllable precision voltage-stabilized power supply is connected to a cathode of an optical coupler.

10. The lithium battery charger circuit for an electric lifting bed according to claim 4, characterized in that: The rectifier and filter circuit comprises a protection chip of model AS358MTR, and the third pin of the protection chip is connected to the battery voltage backflow prevention circuit.

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