A low-power heating circuit powered by a lithium battery

Abstract

This invention discloses a low-power heating circuit powered by a lithium battery, including a lithium battery protection circuit and an MCU control circuit. The lithium battery protection circuit is connected to a DC boost circuit, which is connected to an electric heating element, a DC buck circuit, and an electronic switch. The MCU control circuit controls the heating of the electric heating element and is connected to a low-voltage detection circuit for detecting whether the lithium battery is below a low-voltage set value, a level switch for setting the heating level, a temperature sensor for detecting the temperature of the electric heating element, and an LED light group for low-voltage and heating level indicator lights. The heating circuit does not require a low-power design of the MCU control circuit, simplifying the circuit structure. At the same time, the power on and off are controlled by an independent electronic switch. The electronic switch does not require MCU control circuit control and controls the DC boost circuit and DC buck circuit to work and shut down synchronously, achieving low power consumption in the standby state.

Description

[TECHNICAL FIELD]

[0001] The present application relates to a lithium battery powered low power consumption heating circuit. [BACKGROUND]

[0002] The existing heating circuit applied in the magnet heating massage and hand-held power supply products in traditional Chinese medicine physiotherapy, in standby state, MCU control circuit is in high energy consumption state, therefore, there is a problem that battery needs to be replaced or charged after standby for a long time before use again. [SUMMARY]

[0003] The present application overcomes the shortcomings of the prior art and provides a lithium battery powered low power consumption heating circuit.

[0004] To achieve the above object, the present application adopts the following technical scheme:

[0005] A lithium battery powered low power consumption heating circuit, characterized in that: comprising a lithium battery protection circuit for power-off protection when the output voltage of the lithium battery is lower than the minimum voltage setting value, and an MCU control circuit with lithium battery low voltage alarm, heating gear prompt, constant temperature heating and overvoltage and undervoltage protection functions, the lithium battery protection circuit is connected with a DC boost circuit for boosting the output voltage of the lithium battery, the DC boost circuit is connected with an electric heating sheet for heating, a DC step-down circuit for stepping down the output voltage of the DC boost circuit and supplying power to the MCU control circuit, an electronic switch for controlling the on-off of the DC boost circuit and the DC step-down circuit and being disconnected when the lithium battery protection circuit is in low voltage protection, the MCU control circuit controls the electric heating sheet to heat, and the MCU control circuit is connected with a battery low voltage detection circuit for detecting whether the lithium battery is lower than the low voltage setting value, a gear switch for setting the heating gear, a temperature sensor for detecting the temperature of the electric heating sheet, and an LED lamp group for low voltage light prompt and heating gear light prompt.

[0006] The lithium battery powered low power consumption heating circuit as described above, characterized in that: the lithium battery is connected with a charging circuit for charging the lithium battery, the charging circuit is connected with a TYPC charging interface and a charging prompt lamp.

[0007] The lithium battery powered low-power consumption heating circuit as described above, characterized in that the lithium battery protection circuit comprises a lithium battery protection chip U4, pin 1 of the lithium battery protection chip U4 is connected with pin 6 of the charge-discharge MOS tube Q2, pin 6 of the charge-discharge MOS tube Q4 and pin 6 of the charge-discharge MOS tube Q3 respectively, pin 2 of the lithium battery protection chip U4 is connected with the P- end through the resistance R8, pin 3 of the lithium battery protection chip U4 is connected with pin 4 of the charge-discharge MOS tube Q2, pin 4 of the charge-discharge MOS tube Q4 and pin 4 of the charge-discharge MOS tube Q3 respectively, pin 1 of the charge-discharge MOS tube Q2, pin 1 of the charge-discharge MOS tube Q4 and pin 1 of the charge-discharge MOS tube Q3 are connected with the negative pole GND of the lithium battery respectively, pin 3 of the charge-discharge MOS tube Q2, pin 3 of the charge-discharge MOS tube Q4 and pin 3 of the charge-discharge MOS tube Q3 are connected with the P- end respectively, pin 5 of the charge-discharge MOS tube Q2 is connected with pin 5 of the charge-discharge MOS tube Q4 and pin 5 of the charge-discharge MOS tube Q3 respectively, the lithium battery protection chip U4 is connected with one end of the resistance R7 and one end of the capacitor C21 respectively, the other end of the resistance R7 is connected with the positive pole of the lithium battery, and the other end of the capacitor C21 is connected with the negative pole GND of the lithium battery.

[0008] The lithium battery powered low-power consumption heating circuit as described above, characterized in that the MCU control circuit comprises a control chip U7, pin 1 of the control chip U7, one end of the resistance R3, one end of the resistance R15, one end of the resistance R12 and one end of the capacitor C10 are connected with the +3.3V power supply output by the DC voltage reduction circuit respectively, the other end of the capacitor C10 is connected with the P- end, the other end of the resistance R12 is connected with pin 4 of the control chip U7, the other end of the resistance R15 is connected with pin 3 of the control chip U7 and one end of the temperature sensor respectively, the other end of the temperature sensor is connected with the P- end, the other end of the resistance R3 is connected with the positive pole of the low-grade yellow lamp LED19 of the LED lamp group, the negative pole of the low-grade yellow lamp LED19 is connected with pin 4 of the control chip U7, pin 2 of the control chip U7 is connected with one end of the resistance R6 and the gate pole of the MOS tube Q5 respectively, the other end of the resistance R6 is connected with the P- end, the source pole of the MOS tube Q5 is connected with the P- end, the drain pole of the MOS tube Q5 is connected with one end of the electric heating sheet, pin 5-6 of the control chip U7 is connected with the battery low-voltage detection circuit respectively, pin 7 of the control chip U7 is connected with the positive pole of the medium-grade green lamp LED18 of the LED lamp group, the negative pole of the medium-grade green lamp LED18 is connected with the P- end through the terminal R1, pin 8 of the control chip U7 is connected with the positive pole of the high-grade red lamp LED16 of the LED lamp group, the negative pole of the high-grade red lamp LED16 is connected with the P- end through the terminal R2, pin 9 of the control chip U7 is connected with one end of the resistance R14 and the gear switch respectively, the other end of the resistance R14 is connected with the +3.3V power supply output by the DC voltage reduction circuit, and pin 10 of the control chip U7 is connected with the P- end.

[0009] The lithium battery-powered low-power heating circuit described above is characterized by: a DC boost circuit including a boost chip U3; pin 1 of the boost chip U3 is connected to pin 2 of the boost chip U3, one end of inductor L1, and the positive terminal of Zener diode D1; the negative terminal of Zener diode D1 is connected to the heating element for power supply; the other end of inductor L1, one end of capacitor C13, and the other end of capacitor C14 are connected to the positive terminal of the lithium battery; the other ends of capacitor C13 and C14 are connected to the P- terminal; pin 3 of the boost chip U3 is connected to the P- terminal through capacitor C5; pin 4 of the boost chip U3 is connected to an electronic switch; pin 5 of the boost chip U3 is connected to one end of resistor R18 and one end of resistor R19; the other end of resistor R18 is connected to the P- terminal; pin 6 of the boost chip U3 is... Do not connect one end of capacitor C8 or one end of resistor R20. Connect the other end of capacitor C8 to the P- terminal. Connect the other end of resistor R20 to the P- terminal through capacitor C7. Connect pin 7 of boost chip U3 to the P- terminal through resistor R21. Connect pin 8 of boost chip U3 to one end of resistor R17 and one end of capacitor C6. Connect the other end of capacitor C6 to the P- terminal. Connect pin 9 of boost chip U3 to the P- terminal. Connect the other ends of resistor R17, resistor R19, capacitor C2, capacitor C15, capacitor C16, and capacitor C22 to the negative terminal of diode D1. Connect the other ends of capacitor C2, capacitor C15, capacitor C16, and capacitor C22 to the P- terminal. The negative terminal of diode D1 outputs VCC 12V power.

[0010] The lithium battery-powered low-power heating circuit described above is characterized in that: the DC step-down circuit includes a step-down chip U5, pin 1 of the step-down chip U5 is connected to the VCC12V power supply output by the DC boost circuit, pin 2 of the step-down chip U5 is connected to the P- terminal, pin 3 of the step-down chip U5 is connected to an electronic switch, pin 5 of the step-down chip U5 is connected to one end of capacitor C12 and one end of capacitor C9 respectively, the other end of capacitor C12 and the other end of capacitor C9 are respectively connected to the P- terminal, and pin 5 of the step-down chip U5 outputs a +3.3V power supply.

[0011] The lithium battery-powered low-power heating circuit described above is characterized in that: the electronic switch includes a switch chip U1, pin 1 of the switch chip U1 is connected to a DC boost circuit and a DC buck circuit respectively, pin 2 of the switch chip U1 is connected to P-, pin 3 of the switch chip U1 is connected to a switch SW1, pin 5 of the switch chip U1 and capacitor C1 are connected to the positive terminal of the lithium battery respectively, and the other end of capacitor C1 is connected to the P- terminal.

[0012] The lithium battery-powered low-power heating circuit described above is characterized in that: the battery low-voltage detection circuit includes a MOSFET Q8, the source terminal of the MOSFET Q8 and one end of the resistor R23 are respectively connected to the positive terminal of the lithium battery, the gate terminal of the MOSFET Q8 is respectively connected to the other end of the resistor R23 and the MCU control circuit, the drain terminal of the MOSFET Q8 is respectively connected to the MCU control circuit and one end of the resistor R22 through the resistor R13, and the other end of the resistor R22 is connected to the P- terminal.

[0013] The lithium battery-powered low-power heating circuit described above is characterized in that: the charging circuit includes a charging chip U2, pins 1 and 3 of the charging chip U2 are respectively connected to the P- terminal, pin 2 of the charging chip U2 is connected to the P- terminal through resistor R9, pin 4 of the charging chip U2 is connected to the +5V power output from the TYPC charging interface, pin 9 of the charging chip U2 is connected to the P- terminal, pin 5 of the charging chip U2 is connected to the P- terminal through capacitor C4, pin 5 of the charging chip U2 is connected to the positive terminal of the lithium battery for charging, pin 7 of the charging chip U2 is connected to the negative terminal of the charging indicator light, the positive terminal of the charging indicator light is connected to the +5V power output from the TYPC charging interface through resistor R10, and pin 8 of the charging chip U2 is connected to the +5V power output from the TYPC charging interface.

[0014] The lithium battery-powered low-power heating circuit described above is characterized in that: the TYPC charging interface includes a charging interface USB2, and charging interface USB2 pin 1, charging interface USB2 pin 2, charging interface USB2 pin A12, and charging interface USB2 pin B12 are respectively connected to the P- terminal; charging interface USB2 pin A5 is connected to the P- terminal through resistor R24; charging interface USB2 pin B5 is connected to the P- terminal through resistor R25; charging interface USB2 pin A9 is connected to charging interface USB2 pin B9 and one end of capacitor C3; the other end of capacitor C3 is connected to the P- terminal; and charging interface USB2 pin A9 is connected to the charging circuit to output a +5V power supply.

[0015] The beneficial effects of this invention are:

[0016] The heating circuit of this invention does not require a low-power design for an MCU control circuit, simplifying the circuit structure. At the same time, it controls the power on and off through an independent electronic switch. The electronic switch does not require MCU control circuit and controls the DC boost circuit and DC buck circuit to work and shut down synchronously, achieving low power consumption in the standby state. This allows products using the heating circuit of this invention to be used immediately after a long standby period, reduces the number of charging cycles, and protects the lifespan of the lithium battery. [Image Description]

[0017] Figure 1 This is a schematic diagram of the invention;

[0018] Figure 2 This is a circuit diagram showing the connection between the lithium battery protection circuit, MCU control circuit, battery low voltage detection circuit, gear switch, temperature sensor and LED light group of the present invention.

[0019] Figure 3 This is a DC boost circuit diagram of the present invention;

[0020] Figure 4 This is a diagram of the DC step-down circuit of the present invention;

[0021] Figure 5 This is the electronic switch circuit diagram of the present invention;

[0022] Figure 6 This is a circuit diagram showing the connection of the charging circuit, TYPC charging interface, and charging indicator light of the present invention. [Detailed Implementation]

[0023] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. Furthermore, descriptions involving "preferred," "second-best," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "preferred" or "second-best" may explicitly or implicitly include at least one of those features.

[0025] like Figure 1As shown, a low-power heating circuit powered by a lithium battery includes a lithium battery protection circuit 2 that provides power-off protection when the output voltage of the lithium battery 1 is lower than a minimum voltage setting value, and an MCU control circuit 3 that provides low-voltage alarm, heating level indication, constant temperature heating, and overvoltage / undervoltage protection functions for the lithium battery 1. The lithium battery protection circuit 2 is connected to a DC boost circuit 4 for boosting the output voltage of the lithium battery 1. The DC boost circuit 4 is connected to an electric heating element 5 for heating, a DC buck circuit 6 for stepping down the output voltage of the DC boost circuit 4 and supplying power to the MCU control circuit 3, and an electronic switch 7 for controlling the power supply of the DC boost circuit 4 and the DC buck circuit 6 and for disconnecting when the lithium battery protection circuit 2 is under low-voltage. The MCU control circuit 3 controls the heating element 5 to heat, and the MCU control circuit 3 is connected to a battery low-voltage detection circuit 8 for detecting whether the lithium battery 1 is lower than the low-voltage setting value, a level switch 9 for setting the heating level, a temperature sensor 10 for detecting the temperature of the electric heating element 5, and an LED light group 11 for low-voltage indicator and heating level indicator.

[0026] In actual use, when heating is required, the trigger circuit switch 7 controls the DC boost circuit 4 and the DC buck circuit 6 to conduct. At this time, the output voltage of the lithium battery 1 is boosted by the DC boost circuit 4 and then supplies power to the electric heating element 5 and the DC buck circuit 6 respectively. The boosted voltage is then stepped down by the DC buck circuit 6 and then supplies power to the MCU control circuit 3. The MCU control circuit 3 then controls the electric heating element 5 to heat. When the heating level needs to be adjusted, the three heating levels (high, medium, and low) are set by the level switch 9. At the same time, the LED light group 11 indicates the heating level with different colored lights. After the heating level is set, the temperature sensor 10... The temperature of the electric heating element 5 is monitored in real time, and the MCU control circuit 3 controls the electric heating element 5 to achieve constant temperature heating based on the real-time temperature detection. During the heating process, the low-voltage detection circuit 8 monitors the output voltage of the lithium battery 1 in real time. When the output voltage of the lithium battery 1 is lower than the low-voltage set value of the low-voltage detection circuit 8, the MCU control circuit 3 controls the LED group 11 to flash to indicate a low-voltage alarm. When the output voltage of the lithium battery 1 is lower than the minimum voltage set value of the lithium battery protection circuit 2, the lithium battery protection circuit 2 disconnects to perform undervoltage protection. At this time, the lithium battery 1 is disconnected from the DC boost circuit and no voltage is output. This design uses a single 5000mAh lithium battery for power supply and uses Type-C charging, compatible with a 98% commercially available charger with a maximum charging current of 1A. It features overcurrent and overvoltage protection, undervoltage protection, overcurrent protection, low-voltage alarm indication, LED flashing when low voltage is detected, and the maximum output current of the protection circuit can reach 8A.

[0027] like Figure 1As shown, lithium battery 1 is connected to a charging circuit 12 for charging lithium battery 1. The charging circuit 12 is connected to a TYPC charging interface 13 and a charging indicator light 14. When the output voltage of lithium battery 1 is lower than the minimum voltage setting value set by lithium battery protection circuit 2, causing lithium battery protection circuit 2 to disconnect, lithium battery 1 needs to be charged through TYPC charging interface 13 and charging circuit 12 to activate output. During the charging process, the charging indicator light 14 illuminates and turns off when fully charged.

[0028] like Figure 2 As shown, the lithium battery protection circuit 2 includes a lithium battery protection chip U4. Pin 1 of the lithium battery protection chip U4 is connected to pins 6 of the charging / discharging MOSFETs Q2, Q4, and Q3, respectively. Pin 2 of the lithium battery protection chip U4 is connected to the P- terminal through a resistor R8. Pin 3 of the lithium battery protection chip U4 is connected to pins 4 of the charging / discharging MOSFETs Q2, Q4, and Q3, respectively. Pins 1 of the charging / discharging MOSFETs Q2 and Q4 are connected to the P- terminal. Pin 1 of discharge MOSFET Q3 is connected to the negative terminal GND of lithium battery 1. Pins 3 of charge / discharge MOSFETs Q2, Q4, and Q3 are connected to the P- terminal. Pin 5 of charge / discharge MOSFET Q2 is connected to pins 5 of charge / discharge MOSFETs Q4 and Q3. Lithium battery protection chip U4 is connected to one end of resistor R7 and one end of capacitor C21. The other end of resistor R7 is connected to the positive terminal of lithium battery 1, and the other end of capacitor C21 is connected to the negative terminal GND of lithium battery 1. The lithium battery protection chip U4 monitors the output voltage of lithium battery 1 in real time. When the output voltage of lithium battery 1 is lower than the minimum voltage setting value set by the lithium battery protection circuit 2, it controls the charging and discharging MOSFETs Q2, Q3, and Q4 to turn off, thereby realizing the lithium battery protection function. This results in no output in the main circuit between lithium battery 1 and DC boost circuit 4, requiring charging to activate the output. In this case, the minimum voltage setting value is 2.7V. When the output voltage of lithium battery 1 is lower than 2.7V, the lithium battery protection circuit 2 realizes the lithium battery protection function, and the maximum output current of the protection circuit can reach 8A.

[0029] like Figure 2As shown, the MCU control circuit 3 includes a control chip U7. Pin 1 of the control chip U7, one end of resistor R3, one end of resistor R15, one end of resistor R12, and one end of capacitor C10 are connected to the +3.3V power supply output by the DC step-down circuit 6. The other end of capacitor C10 is connected to the P- terminal. The other end of resistor R12 is connected to pin 4 of the control chip U7. The other end of resistor R15 is connected to pin 3 of the control chip U7 and one end of temperature sensor 10. The other end of temperature sensor 10 is connected to the P- terminal. The other end of resistor R3 is connected to the positive terminal of the low-power yellow LED19 of the LED group 11. The negative terminal of the low-power yellow LED19 is connected to pin 4 of the control chip U7. Pin 2 of the control chip U7 is connected to one end of resistor R6 and the gate of MOSFET Q5. The other end is connected to the P- terminal. The source terminal of MOSFET Q5 is connected to the P- terminal. The drain terminal of MOSFET Q5 is connected to one end of the electric heating element 5. Pins 5-6 of control chip U7 are connected to the low-voltage detection circuit 8 of the battery. Pin 7 of control chip U7 is connected to the positive terminal of the medium-range green light LED18 of LED group 11. The negative terminal of the medium-range green light LED18 is connected to the P- terminal through terminal R1. Pin 8 of control chip U7 is connected to the positive terminal of the high-range red light LED16 of LED group 11. The negative terminal of the high-range red light LED16 is connected to the P- terminal through terminal R2. Pin 9 of control chip U7 is connected to one end of resistor R14 and gear switch 9. The other end of resistor R14 is connected to the +3.3V power supply output by DC step-down circuit 6. Pin 10 of control chip U7 is connected to the P- terminal. When the trigger circuit switch 7 is energized for heating, the control chip U7 is powered on and operates. Based on the heating level set by the gear switch 9, it outputs a corresponding PWM signal to control the heating temperature of the electric heating element 5 via the MOSFET Q5. Simultaneously, it controls the corresponding indicator lights in the LED group 11 to illuminate. The high, medium, and low heating levels correspond to red, green, and yellow lights, respectively. In this case, the heating temperatures of each heating level are different, with the high level reaching 80 degrees Celsius.

[0030] like Figure 2As shown, the low-voltage detection circuit 8 includes a MOSFET Q8. The source terminal of MOSFET Q8 and one end of resistor R23 are connected to the positive terminal of lithium battery 1, respectively. The gate terminal of MOSFET Q8 is connected to the other end of resistor R23 and the MCU control circuit 3. The drain terminal of MOSFET Q8 is connected to the MCU control circuit 3 and one end of resistor R22 through resistor R13. The other end of resistor R22 is connected to the P- terminal. During the heating process, when the output voltage of lithium battery 1 is lower than the low-voltage set value, the low-voltage detection circuit 8 sends a low-voltage signal to the MCU control circuit 3. At this time, the control chip U7 controls the medium-range green LED18 in the LED light group 11 to flash to indicate charging. In this case, the low-voltage set value is 3.5V. When the output voltage of lithium battery 1 is detected to be lower than 3.5V, the low-voltage detection circuit 8 sends a low-voltage signal to the MCU control circuit 3.

[0031] like Figure 3 As shown, the DC boost circuit 4 includes a boost chip U3. Pin 1 of the boost chip U3 is connected to pin 2 of the boost chip U3, one end of inductor L1, and the positive terminal of Zener diode D1. The negative terminal of Zener diode D1 is connected to the heating element 5 for power supply. The other end of inductor L1, one end of capacitor C13, and the other end of capacitor C14 are connected to the positive terminal of lithium battery 1. The other ends of capacitor C13 and C14 are connected to the P- terminal. Pin 3 of the boost chip U3 is connected to the P- terminal through capacitor C5. Pin 4 of the boost chip U3 is connected to the electronic switch 7. Pin 5 of the boost chip U3 is connected to one end of resistor R18 and one end of resistor R19. The other end of resistor R18 is connected to the P- terminal. Pin 6 of the boost chip U3 is connected to one end of capacitor C8, one end of capacitor C19 ... One end of resistor R20 is connected, and the other end of capacitor C8 is connected to the P- terminal. The other end of resistor R20 is connected to the P- terminal through capacitor C7. Pin 7 of boost chip U3 is connected to the P- terminal through resistor R21. Pin 8 of boost chip U3 is connected to one end of resistor R17 and one end of capacitor C6. The other end of capacitor C6 is connected to the P- terminal. Pin 9 of boost chip U3 is connected to the P- terminal. The other ends of resistor R17, resistor R19, capacitor C2, capacitor C15, capacitor C16, and capacitor C22 are connected to the negative terminal of diode D1. The other ends of capacitor C2, capacitor C15, capacitor C16, and capacitor C22 are connected to the P- terminal. The negative terminal of diode D1 outputs VCC12V power. After the electronic switch 7 is triggered, the boost chip U3 starts working. At this time, the 4.2V voltage output by the lithium battery 1 is boosted to 12V and the current can reach 1.5A after passing through the boost chip U3 and its peripheral circuits, and then supplies power to the electric heating element 5 and the DC step-down circuit 6 respectively.

[0032] like Figure 4As shown, the DC step-down circuit 6 includes a step-down chip U5. Pin 1 of the step-down chip U5 is connected to the VCC 12V power supply output from the DC boost circuit 4. Pin 2 of the step-down chip U5 is connected to the P- terminal. Pin 3 of the step-down chip U5 is connected to the electronic switch 7. Pin 5 of the step-down chip U5 is connected to one end of capacitor C12 and one end of capacitor C9, respectively. The other ends of capacitor C12 and C9 are connected to the P- terminal, respectively. Pin 5 of the step-down chip U5 outputs a +3.3V power supply. After the electronic switch 7 is triggered, the step-down chip U5 operates and steps down the 12V voltage output from the DC boost circuit 4 to a 3.3V voltage to supply power to the MCU control circuit 3.

[0033] like Figure 5 As shown, the electronic switch 7 includes a switch chip U1. Pin 1 of switch chip U1 is connected to the DC boost circuit 4 and the DC buck circuit 6, respectively. Pin 2 of switch chip U1 is connected to P-, pin 3 of switch chip U1 is connected to switch SW1, pin 5 of switch chip U1 and capacitor C1 are connected to the positive terminal of lithium battery 1, and the other end of capacitor C1 is connected to the P- terminal. When heating is required, the electronic switch 7 is triggered to open. At this time, pin 1 of switch chip U1 simultaneously outputs a high level to the DC boost circuit 4 and the DC buck circuit 6, causing the boost chip U3 of the DC boost circuit 4 and the buck chip U5 of the DC buck circuit 6 to work. When the electronic switch 7 is triggered to close, pin 1 of switch chip U1 outputs a low level. At this time, the standby current of the entire circuit is less than 20µA, realizing low-power standby.

[0034] like Figure 6As shown, the charging circuit 12 includes a charging chip U2. Pins 1 and 3 of the charging chip U2 are connected to the P- terminal, pin 2 of the charging chip U2 is connected to the P- terminal through resistor R9, pin 4 of the charging chip U2 is connected to the +5V power output from the TYPC charging interface 13, pin 9 of the charging chip U2 is connected to the P- terminal, pin 5 of the charging chip U2 is connected to the P- terminal through capacitor C4, pin 5 of the charging chip U2 is connected to the positive terminal of the lithium battery 1 for charging, pin 7 of the charging chip U2 is connected to the negative terminal of the charging indicator light 14, the positive terminal of the charging indicator light 14 is connected to the +5V power output from the TYPC charging interface 13 through resistor R10, and pin 8 of the charging chip U2 is connected to the TYPC... The +5V power output from charging interface 13 is connected. The TYPC charging interface 13 includes a USB2 charging interface. Pins 1, 2, A12, and B12 of USB2 are connected to the P- terminal. Pin A5 and B5 are connected to the P- terminal via resistor R24 ​​and resistor R25, respectively. Pin A9 is connected to pin B9 and one end of capacitor C3, with the other end of C3 connected to the P- terminal. Pin A9 is also connected to the charging circuit 12 to output +5V power. During charging, after the USB2 charging interface of the TYPC charging interface 13 is plugged in, USB2 outputs +5V voltage to the charging chip U2, which then charges the lithium battery 1. During charging, the charging indicator light 14 illuminates and turns off when fully charged. Among them, it can be used with TYPEC charging, which is compatible with 98% of chargers on the market, and has a maximum charging current of 1A. It also has overcurrent and overvoltage protection, undervoltage protection and overcurrent protection functions.

[0035] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A low-power heating circuit powered by a lithium battery, characterized in that: The lithium battery protection circuit (2) includes a lithium battery protection chip U4, the pin 1 of the lithium battery protection chip U4 is connected with the pin 6 of the charge-discharge MOS tube Q2, the pin 6 of the charge-discharge MOS tube Q4 and the pin 6 of the charge-discharge MOS tube Q3 respectively, the pin 2 of the lithium battery protection chip U4 is connected with the P- end through the resistance R8, the pin 3 of the lithium battery protection chip U4 is connected with the pin 4 of the charge-discharge MOS tube Q2, the pin 4 of the charge-discharge MOS tube Q4 and the pin 4 of the charge-discharge MOS tube Q3 respectively, the pin 1 of the charge-discharge MOS tube Q2, the pin 1 of the charge-discharge MOS tube Q4 and the pin 1 of the charge-discharge MOS tube Q3 are connected with the negative terminal GND of the lithium battery (1) respectively, the pin 3 of the charge-discharge MOS tube Q2, the pin 3 of the charge-discharge MOS tube Q4 and the pin 3 of the charge-discharge MOS tube Q3 are connected with the P- end respectively, the pin 5 of the charge-discharge MOS tube Q2 is connected with the pin 5 of the charge-discharge MOS tube Q4 and the pin 5 of the charge-discharge MOS tube Q3 respectively, the lithium battery protection chip U4 is connected with one end of the resistance R7 and one end of the capacitor C21 respectively, the other end of the resistance R7 is connected with the positive terminal of the lithium battery (1), the other end of the capacitor C21 is connected with the negative terminal GND of the lithium battery (1). The lithium battery protection circuit (2) includes a lithium battery protection chip U4, the pin 1 of the lithium battery protection chip U4 is connected with the pin 6 of the charge-discharge MOS tube Q2, the pin 6 of the charge-discharge MOS tube Q4 and the pin 6 of the charge-discharge MOS tube Q3 respectively, the pin 2 of the lithium battery protection chip U4 is connected with the P- end through the resistance R8, the pin 3 of the lithium battery protection chip U4 is connected with the pin 4 of the charge-discharge MOS tube Q2, the pin 4 of the charge-discharge MOS tube Q4 and the pin 4 of the charge-discharge MOS tube Q3 respectively, the pin 1 of the charge-discharge MOS tube Q2, the pin 1 of the charge-discharge MOS tube Q4 and the pin 1 of the charge-discharge MOS tube Q3 are connected with the negative terminal GND of the lithium battery (1) respectively, the pin 3 of the charge-discharge MOS tube Q2, the pin 3 of the charge-discharge MOS tube Q4 and the pin 3 of the charge-discharge MOS tube Q3 are connected with the P- end respectively, the pin 5 of the charge-discharge MOS tube Q2 is connected with the pin 5 of the charge-discharge MOS tube Q4 and the pin 5 of the charge-discharge MOS tube Q3 respectively, the lithium battery protection chip U4 is connected with one end of the resistance R7 and one end of the capacitor C21 respectively, the other end of the resistance R7 is connected with the positive terminal of the lithium battery (1), the other end of the capacitor C21 is connected with the negative terminal GND of the lithium battery (1). The MCU control circuit (3) comprises a control chip U7, the pin 1 of the control chip U7, one end of the resistor R3, one end of the resistor R15, one end of the resistor R12 and one end of the capacitor C10 are connected with the +3.3V power supply output by the DC voltage reduction circuit (6) respectively, the other end of the capacitor C10 is connected with the P- terminal, the other end of the resistor R12 is connected with the pin 4 of the control chip U7, the other end of the resistor R15 is connected with the pin 3 of the control chip U7 and one end of the temperature sensor (10) respectively, the other end of the temperature sensor (10) is connected with the P- terminal, the other end of the resistor R3 is connected with the positive electrode end of the low-grade yellow lamp LED19 of the LED lamp group (11), the negative electrode end of the low-grade yellow lamp LED19 is connected with the pin 4 of the control chip U7, the pin 2 of the control chip U7 is connected with one end of the resistor R6 and the gate electrode end of the MOS tube Q5 respectively, the other end of the resistor R6 is connected with the P- terminal, the source electrode end of the MOS tube Q5 is connected with the P- terminal, one end of the electric heating sheet (5) is connected with the drain electrode end of the MOS tube Q5, the pin 5-6 of the control chip U7 is connected with the battery low-voltage detection circuit (8) respectively, the pin 7 of the control chip U7 is connected with the positive electrode end of the medium-grade green lamp LED18 of the LED lamp group (11), the negative electrode end of the medium-grade green lamp LED18 is connected with the P- terminal through the terminal R1, the pin 8 of the control chip U7 is connected with the positive electrode end of the high-grade red lamp LED16 of the LED lamp group (11), the negative electrode end of the high-grade red lamp LED16 is connected with the P- terminal through the terminal R2, the pin 9 of the control chip U7 is connected with one end of the resistor R14 and the gear switch (9) respectively, the other end of the resistor R14 is connected with the +3.3V power supply output by the DC voltage reduction circuit (6), and the pin 10 of the control chip U7 is connected with the P- terminal. The DC boost circuit (4) comprises a boost chip U3, the pin 1 of the boost chip U3 is connected with the pin 2 of the boost chip U3, one end of the inductor L1 and the positive end of the voltage stabilizing diode D1 respectively, the negative end of the voltage stabilizing diode D1 is connected with the electric heating sheet (5) for power supply, the other end of the inductor L1, one end of the capacitor C13 and the other end of the capacitor C14 are connected with the positive end of the lithium battery (1) respectively, the other end of the capacitor C13 and the other end of the capacitor C14 are connected with the P- terminal respectively, the pin 3 of the boost chip U3 is connected with the P- terminal through the capacitor C5, the pin 4 of the boost chip U3 is connected with the electronic switch (7), the pin 5 of the boost chip U3 is connected with one end of the resistor R18 and one end of the resistor R19 respectively, the other end of the resistor R18 is connected with the P- terminal, the pin 6 of the boost chip U3 is connected with one end of the capacitor C8 and one end of the resistor R20 respectively, the other end of the capacitor C8 is connected with the P- terminal, the other end of the resistor R20 is connected with the P- terminal through the capacitor C7, the pin 7 of the boost chip U3 is connected with the P- terminal through the resistor R21, the pin 8 of the boost chip U3 is connected with one end of the resistor R17 and one end of the capacitor C6 respectively, the other end of the capacitor C6 is connected with the P- terminal, the pin 9 of the boost chip U3 is connected with the P- terminal, the other end of the resistor R17, the other end of the resistor R19, one end of the capacitor C2, one end of the capacitor C15, one end of the capacitor C16 and one end of the capacitor C22 are connected with the negative end of the diode D1 respectively, the other end of the capacitor C2, the other end of the capacitor C15, the other end of the capacitor C16 and the other end of the capacitor C22 are connected with the P- terminal respectively, the negative end of the diode D1 outputs the VCC 12V power supply; The DC boost circuit (4) comprises a boost chip U3, the pin 1 of the boost chip U3 is connected with the pin 2 of the boost chip U3, one end of the inductor L1 and the positive end of the voltage stabilizing diode D1 respectively, the negative end of the voltage stabilizing diode D1 is connected with the electric heating sheet (5) for power supply, the other end of the inductor L1, one end of the capacitor C13 and the other end of the capacitor C14 are connected with the positive end of the lithium battery (1) respectively, the other end of the capacitor C13 and the other end of the capacitor C14 are connected with the P- terminal respectively, the pin 3 of the boost chip U3 is connected with the P- terminal through the capacitor C5, the pin 4 of the boost chip U3 is connected with the electronic switch (7), the pin 5 of the boost chip U5 is connected with one end of the capacitor C12 and one end of the capacitor C9 respectively, the other end of the capacitor C12 and the other end of the capacitor C9 are connected with the P- terminal respectively, the pin 5 of the boost chip U5 outputs the +3.3V power supply; The electronic switch (7) comprises a switch chip U1, the pin 1 of the switch chip U1 is connected with the DC boost circuit (4) and the DC boost circuit (6) respectively, the pin 2 of the switch chip U1 is connected with the P- terminal, the pin 3 of the switch chip U1 is connected with the switch SW1, the pin 5 of the switch chip U1 and the capacitor C1 are connected with the positive end of the lithium battery (1) respectively, the other end of the capacitor C1 is connected with the P- terminal.

2. A low power consumption heating circuit powered by a lithium battery according to claim 1, characterized in that: The lithium battery (1) is connected with the charging circuit (12) for charging the lithium battery (1), the charging circuit (12) is connected with the TYPC charging interface (13) and the charging prompt lamp (14).

3. The low power consumption heating circuit powered by a lithium battery according to claim 1, wherein: The battery low voltage detection circuit (8) comprises a MOS tube Q8, the source end of the MOS tube Q8 and one end of the resistor R23 are connected with the positive end of the lithium battery (1) respectively, the gate end of the MOS tube Q8 is connected with the other end of the resistor R23 and the MCU control circuit (3) respectively, the drain end of the MOS tube Q8 is connected with the MCU control circuit (3) and one end of the resistor R22 through the resistor R13 respectively, the other end of the resistor R22 is connected with the P- terminal.

4. The low power consumption heating circuit powered by a lithium battery according to claim 2, wherein: The charging circuit (12) includes charging chip U2, pin 1 and pin 3 of which are connected with P-terminal respectively, pin 2 of which is connected with P-terminal through resistance R9, pin 4 of which is connected with +5V power output of TYPC charging interface (13), pin 9 of which is connected with P-terminal, pin 5 of which is connected with P-terminal through capacitor C4, pin 5 of which is connected with positive pole of lithium battery (1) for charging, pin 7 of which is connected with negative pole of charging prompt lamp (14), positive pole of charging prompt lamp (14) is connected with +5V power output of TYPC charging interface (13) through resistance R10, pin 8 of which is connected with +5V power output of TYPC charging interface (13).

5. The low power consumption heating circuit powered by a lithium battery according to claim 2, wherein: The TYPC charging interface (13) includes charging interface USB2, pin 1, pin 2, pin A12 and pin B12 of which are connected with P-terminal respectively, pin A5 of which is connected with P-terminal through resistance R24, pin B5 of which is connected with P-terminal through resistance R25, pin A9 of which is connected with pin B9 of charging interface USB2 and one end of capacitor C3 respectively, the other end of capacitor C3 is connected with P-terminal, pin A9 of charging interface USB2 is connected with charging circuit (12) to output +5V power.

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