A cigarette lighter control circuit and its energy storage power supply

Abstract

The utility model discloses an embodiment of a cigarette lighter control circuit and energy storage power supply thereof, and the circuit comprises: a current sampling module that collects the output current of the cigarette lighter and generates a current sampling signal; a feedback module that outputs a feedback control signal when the current sampling signal is greater than a preset constant current switching threshold; a control module that makes the output current constant when receiving the feedback control signal; and an overcurrent protection module that outputs an overcurrent protection signal to stop the control module from working when the voltage value of the current sampling signal is still greater than a preset overcurrent protection threshold. The utility model embodiment collects the output current of the cigarette lighter, and when the voltage value of the output current is greater than the constant current switching threshold, the feedback module works, and the cigarette lighter enters the constant current mode. After the feedback module works, the voltage value of the output current is still greater than the overcurrent protection threshold, the overcurrent protection module stops the control module from working to realize overcurrent protection, and the compatibility and safety of the cigarette lighter are improved.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a cigarette lighter control circuit and its energy storage power supply. Background Technology

[0002] With the introduction of the dual-carbon policy, energy storage power supplies have become one of the most popular new energy products today, and their functions are becoming increasingly diverse, indicating a stronger adaptability to load devices. The cigarette lighter, as an essential function of energy storage power supplies, can power load devices such as kettles, parking heaters, electric fans, and vehicle inverters. The cigarette lighter of an energy storage power supply generally uses a BUCK circuit structure, such as... Figure 1 As shown, it is generally a constant voltage source with a fixed output of 13.5Vdc, and uses sampling resistor R1 for 10A overcurrent protection.

[0003] The cigarette lighter socket of an energy storage power supply, based on current circuitry and protection strategies, is inadequate for powering the following types of load devices: For example, a 150W kettle on the market uses a pure resistance heating wire of approximately 1.19Ω. If the aforementioned cigarette lighter socket is used to power a 150W kettle, the output current will reach approximately 11.11A, triggering the circuit's overcurrent protection and preventing it from powering the kettle. Similarly, a parking heater, during startup, experiences fluctuating current with a peak current far exceeding 10A. Although its average current is below 10A, this will still trigger the circuit's overcurrent protection, preventing it from powering the parking heater.

[0004] In addition, some users find that the cigarette lighter socket of the load device and the cigarette lighter socket of the energy storage power supply do not make complete contact when using the cigarette lighter. This increases the contact resistance between the two, leading to severe overheating of the cigarette lighter socket and potentially causing the casing to melt, posing a safety hazard. In summary, the current circuitry and protection strategies of the energy storage power supply's cigarette lighter are not comprehensive enough in terms of load device compatibility, and safety cannot be guaranteed. Utility Model Content

[0005] The main technical problem solved by this utility model embodiment is to provide a cigarette lighter control circuit and its energy storage power supply, which can solve the defects of existing cigarette lighters.

[0006] In a first aspect, this utility model provides a cigarette lighter control circuit, comprising: a current sampling module, a feedback module, a control module, and an overcurrent protection module; the current sampling module is connected to the cigarette lighter, the feedback module, and the overcurrent protection module respectively, and the control module is connected to the feedback module, the overcurrent protection module, and the cigarette lighter respectively; the current sampling module is configured to collect the output current of the cigarette lighter and generate a current sampling signal based on the output current; the feedback module is configured to receive the current sampling signal and output a feedback control signal when the voltage value of the current sampling signal is greater than a preset constant current switching threshold; the control module is configured to adjust the duty cycle of the drive signal output to the cigarette lighter when it receives the feedback control signal, so that the output current is constant; the overcurrent protection module is configured to receive the current sampling signal after a preset delay, and output an overcurrent protection signal when the voltage value of the current sampling signal is still greater than the preset overcurrent protection threshold, so that the control module stops working; wherein, the constant current switching threshold is less than the overcurrent protection threshold.

[0007] Optionally, the overcurrent protection module includes a delay unit and an overcurrent protection unit. The delay unit is connected to both the current sampling module and the overcurrent protection unit, and the overcurrent protection unit is also connected to the control module. The delay unit is configured to receive the current sampling signal, delay it by the preset time, and then transmit the current sampling signal to the overcurrent protection unit. The overcurrent protection unit is configured to receive the delayed current sampling signal, and when the voltage value of the current sampling signal is greater than the overcurrent protection threshold, output the overcurrent protection signal to the control module.

[0008] Optionally, the delay unit includes a capacitor C3 and a resistor R12. The first end of the resistor R12 is connected to the first end of the capacitor C3 and the input end of the overcurrent protection unit. The second end of the resistor R12 is connected to the output end of the current sampling module. The second end of the capacitor C3 is connected to the reference ground.

[0009] Optionally, the overcurrent protection unit includes a comparator U1A, resistors R2, R6, and R8, and a transistor Q3; the first end of resistor R2 is connected to the overcurrent protection threshold, the second end of resistor R2 is connected to the inverting input of comparator U1A, the non-inverting input of comparator U1A is connected to the output of the delay unit; the output of comparator U1A is connected to the first ends of resistors R6 and R8, the ground terminal of comparator U1A is connected to reference ground, the power supply terminal of comparator U1A is connected to the power supply voltage source and the second end of resistor R8, the second end of resistor R6 is connected to the base of transistor Q3, the collector of transistor Q3 is connected to the enable terminal of the control module, and the emitter of transistor Q3 is connected to reference ground.

[0010] Optionally, the current sampling module includes an operational amplifier U2A, resistors R10, R14, R19, and R22, capacitors C4, C6, and C7; the first terminal of resistor R14 is connected to the first terminal of the sampling resistor of the cigarette lighter; the second terminal of resistor R14 is connected to the first terminal of resistor R10, the first terminal of capacitor C4, and the inverting input terminal of operational amplifier U2A; the first terminal of resistor R19 is connected to the second terminal of the sampling resistor; and the second terminal of resistor R19 is connected to the first terminal of resistor R22. The first terminal of capacitor C6 is connected to the non-inverting input terminal of operational amplifier U2A; the second terminal of resistor R22 is connected to the second terminal of capacitor C6 and a reference voltage source; the output terminal of operational amplifier U2A is connected to the second terminal of resistor R10, the second terminal of capacitor C4, the input terminal of the feedback module, and the input terminal of the overcurrent protection module; the power supply terminal of operational amplifier U2A is connected to the first terminal of capacitor C7 and a power supply voltage source; and the second terminal of capacitor C7 and the ground terminal of operational amplifier U2A are connected to reference ground.

[0011] Optionally, the current sampling module further includes a resistor R17 and a capacitor C5; the output terminal of the operational amplifier U2A is connected to the second terminal of the resistor R10, the second terminal of the capacitor C4, and the first terminal of the resistor R17; the second terminal of the resistor R17 is connected to the first terminal of the capacitor C5, the input terminal of the feedback module, and the input terminal of the overcurrent protection module; and the second terminal of the capacitor C5 is connected to reference ground.

[0012] Optionally, the feedback module includes resistors R11, R13, R15, R16, R18, R20, R21, operational amplifier U2B, and Schottky diode DS1; the first terminal of resistor R16 receives the constant current switching threshold; the second terminal of resistor R16 is connected to the first terminal of resistor R11 and the inverting input terminal of operational amplifier U2B; the first terminal of resistor R18 is connected to the output terminal of the current sampling module; and the second terminal of resistor R18 is connected to the first terminal of resistor R20 and the operational amplifier U2B. The non-inverting input terminal of the operational amplifier U2B is connected. The output terminal of the operational amplifier U2B is connected to the second terminal of the resistor R11 and the first terminal of the resistor R15. The second terminal of the resistor R20 is connected to the feedback reference voltage. The second terminal of the resistor R15 is connected to the anode of the Schottky diode DS1. The cathode of the Schottky diode DS1 is connected to the second terminal of the resistor R13, the first terminal of the resistor R21, and the feedback terminal of the control module. The first terminal of the resistor R13 is connected to the output terminal of the cigarette lighter. The second terminal of the resistor R21 is connected to the reference ground.

[0013] Optionally, the circuit further includes an over-temperature protection module, which is connected to the control module. The over-temperature protection module is configured to collect the temperature of the cigarette lighter socket and output an over-temperature protection signal when the temperature of the cigarette lighter socket exceeds a preset over-temperature protection threshold, so as to stop the control module from working.

[0014] Optionally, the over-temperature protection module includes resistors R3, R4, R5, R7, and R9, a thermistor RT1, a capacitor C2, a switching transistor Q4, and a comparator U1B; the first terminal of resistor R5 is connected to the power supply voltage source, the second terminal of resistor R5 is connected to the first terminal of resistor R9 and the first terminal of the thermistor RT1, the second terminal of resistor R9 is connected to the first terminal of capacitor C2 and the non-inverting input terminal of comparator U1B, and the second terminal of the thermistor RT1 is connected to the first terminal of capacitor C2. The second terminal of resistor 2 is connected to reference ground; the first terminal of resistor R3 is connected to the over-temperature protection threshold; the second terminal of resistor R3 is connected to the inverting input terminal of comparator U1B; the output terminal of comparator U1B is connected to the second terminal of resistor R4 and the first terminal of resistor R7; the first terminal of resistor R4 is connected to the power supply voltage source; the second terminal of resistor R7 is connected to the base of switch Q4; the collector of switch Q4 is connected to the enable terminal of the control module; and the emitter of switch Q4 is connected to reference ground.

[0015] Secondly, embodiments of the present invention provide an energy storage power supply, including: a cigarette lighter; and a cigarette lighter control circuit as described in the first aspect.

[0016] The beneficial effects of this utility model embodiment are as follows: Unlike the prior art, this utility model embodiment samples the output current of the cigarette lighter. When the voltage value of the output current is greater than the constant current switching threshold, the feedback module works and controls the cigarette lighter to enter the constant current mode through the control module. After the feedback module works, if the voltage value of the output current is still greater than the overcurrent protection threshold, the overcurrent protection module stops the control module from working, thereby realizing overcurrent protection and improving the compatibility and safety of the cigarette lighter. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a circuit diagram of a cigarette lighter provided by an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of a cigarette lighter control circuit provided by an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of an overcurrent protection module provided by an embodiment of the present invention;

[0021] Figure 4 This is a circuit diagram of a cigarette lighter control circuit provided by an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of another cigarette lighter control circuit provided by this utility model embodiment;

[0023] Figure 6 This is a circuit diagram of another cigarette lighter control circuit provided by this utility model embodiment. Detailed Implementation

[0024] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0026] Please refer to Figure 1 , Figure 1 This is a typical cigarette lighter circuit schematic in existing technology. The cigarette lighter circuit uses a BUCK step-down topology and is mainly used in energy storage power systems to power various 12V DC load devices.

[0027] like Figure 1 As shown, a traditional cigarette lighter circuit includes a control chip, a power switch Q1, a synchronous rectifier Q2, an energy storage inductor LD1, output capacitors C1 and CE1, and a sampling resistor R1. The cigarette lighter port CN1 serves as the output interface, supplying power to external load devices through the sampling resistor R1. The circuit works by controlling the on / off state of the power switch Q1, which steps down the high-voltage DC power (e.g., 24V, 36V, or 48V) from the energy storage power source to a standard 13.5V DC output, supplying power to load devices such as kettles, parking heaters, electric fans, and vehicle inverters through the cigarette lighter port CN1.

[0028] This traditional circuit uses a constant voltage source output, providing a fixed output of 13.5Vdc, and achieves 10A overcurrent protection through a sampling resistor R1. However, in practical applications, it has been found that this circuit has insufficient load adaptability. For example, for a commercially available 150W kettle, the heating wire impedance is approximately 1.19Ω. Under a constant voltage output of 13.5V, the current will reach approximately 11.11A, exceeding the 10A overcurrent protection limit, causing the protection circuit to trip and malfunction. Similarly, parking heaters experience large current fluctuations during startup, with peak currents far exceeding 10A, also triggering overcurrent protection. Furthermore, poor contact between the cigarette lighter plug and socket increases contact resistance, leading to severe overheating and posing a safety hazard.

[0029] To address the aforementioned problems, this utility model provides a cigarette lighter control circuit, the structural diagram of which is shown below. Figure 2 As shown, the cigarette lighter control circuit includes a current sampling module 100, a feedback module 200, a control module 300, and an overcurrent protection module 400.

[0030] The input terminal of the current sampling module 100 is connected to the cigarette lighter, the output terminal of the current sampling module 100 is connected to the input terminal of the feedback module 200 and the input terminal of the overcurrent protection module 400, the input terminal of the control module 300 is connected to the output terminal of the feedback module 200 and the output terminal of the overcurrent protection module 400, and the output terminal of the control module 300 is connected to the cigarette lighter.

[0031] In some embodiments of this application, the current sampling module 100 is configured to acquire the output current of the cigarette lighter and generate a current sampling signal based on the output current. The output current of the cigarette lighter refers to the current flowing through the sampling resistor of the cigarette lighter, that is, the actual current when power is supplied from the cigarette lighter to an external load device. Figure 1 Taking the cigarette lighter shown as an example, the output current is the current flowing through the sampling resistor R1. As an example and not a limitation, the current sampling module 100 acquires the output current by detecting the voltage difference across the sampling resistor, amplifies the voltage difference through an operational amplifier, and generates a smooth and stable current sampling signal after filtering.

[0032] The feedback module 200 is configured to receive a current sampling signal. When the voltage value of the current sampling signal is greater than a preset constant current switching threshold, it outputs a feedback control signal. The constant current switching threshold corresponds to a specific current value. When the output current reaches this value, the cigarette lighter needs to switch from constant voltage mode to constant current mode.

[0033] The control module 300 is configured to adjust the duty cycle of the drive signal output to the cigarette lighter when it receives a feedback control signal, so as to keep the output current of the cigarette lighter constant. The drive signal is a PWM signal output by the control module 300 to the power switching transistor. By adjusting the duty cycle, the control module 300 can change the output voltage of the cigarette lighter, thereby controlling the output current.

[0034] The overcurrent protection module 400 is configured to receive the current sampling signal after a preset delay. When the voltage value of the current sampling signal is still greater than the preset overcurrent protection threshold, it outputs an overcurrent protection signal to stop the control module 300 from operating. As an example and not a limitation, the preset delay time is implemented through an RC delay circuit to provide response time for constant current control.

[0035] It should be noted that the constant current switching threshold is less than the overcurrent protection threshold, so that when the output current of the cigarette lighter gradually increases, the control circuit first starts constant current control. After the constant current control is started, the voltage value of the current sampling signal is still greater than the preset overcurrent protection threshold before overcurrent protection is triggered.

[0036] In other embodiments of this application, such as Figure 3As shown, a detailed structural diagram of the overcurrent protection module 400 is provided. The overcurrent protection module 400 includes a delay unit 410 and an overcurrent protection unit 420, realizing a further refined design of the overcurrent protection function.

[0037] Specifically, the input terminal of the delay unit 410 is connected to the output terminal of the current sampling module 100, the output terminal of the delay unit 410 is connected to the input terminal of the overcurrent protection unit 420, and the output terminal of the overcurrent protection unit 420 is connected to the input terminal of the control module 300. The connection between the delay unit 410 and the current sampling module 100 enables it to receive current sampling signals from the current sampling module 100, and the connection between the delay unit 410 and the overcurrent protection unit 420 enables the delayed transmission of signals. The connection between the overcurrent protection unit 420 and the control module 300 enables it to send an overcurrent protection command to the control module 300 when an overcurrent condition is detected.

[0038] In this embodiment, the delay unit 410 is configured to receive a current sampling signal, delay it for a preset time, and then transmit the current sampling signal to the overcurrent protection unit 420. As an example and not a limitation, the delay unit 410 implements the delay function through an RC delay circuit, where the combination of resistors and capacitors determines the specific delay time length. When the current sampling signal arrives at the delay unit 410, the delay unit 410 does not immediately transmit the signal to the overcurrent protection unit 420, but waits until the preset time has elapsed before transmitting the current sampling signal to the overcurrent protection unit 420.

[0039] It's easy to understand that the preset delay time is set to ensure that the constant current control circuit operates before the overcurrent protection circuit. When the output current exceeds the constant current switching threshold, the feedback module activates first, causing the control module 300 to attempt to limit the output current by adjusting the duty cycle. During this period, the delay unit 410 delays the transmission of the current sampling signal, providing sufficient response time for the constant current control and preventing overcurrent protection from being triggered before the constant current control takes effect.

[0040] In this embodiment, the overcurrent protection unit 420 is configured to receive a delayed current sampling signal, and when the voltage value of the current sampling signal is greater than the overcurrent protection threshold, output an overcurrent protection signal to the control module 300. By way of example and not limitation, the overcurrent protection unit 420 compares the current sampling signal with the overcurrent protection threshold using a comparator, the overcurrent protection threshold corresponding to a preset maximum allowable current value.

[0041] Specifically, after the delay time ends, the overcurrent protection unit 420 receives the delayed current sampling signal. If the voltage value of the current sampling signal is still greater than the overcurrent protection threshold at this time, it indicates that the constant current control cannot effectively limit the current, and a constant current load or other abnormal situation may have been encountered. The overcurrent protection unit 420 immediately outputs an overcurrent protection signal, which is transmitted to the control module 300, causing the control module 300 to stop working, thereby cutting off the output of the cigarette lighter and achieving final safety protection.

[0042] In some other embodiments of this application, such as Figure 4 As shown, a detailed circuit diagram of the cigarette lighter control circuit is provided. The specific circuit configuration of each functional module is further described in detail, including the internal circuit structures of the current sampling module 100, feedback module 200, control module 300, and overcurrent protection module 400.

[0043] In some embodiments of this application, the current sampling module 100 includes an operational amplifier U2A, resistors R10, R14, R19, and R22, and capacitors C4, C6, and C7. The first terminal of resistor R14 is connected to the first terminal of the sampling resistor in the cigarette lighter, and the second terminal of resistor R14 is connected to the first terminal of resistor R10, the first terminal of capacitor C4, and the inverting input terminal of operational amplifier U2A. The sampling resistor is a current-sensing resistor connected in series in the cigarette lighter output circuit; the voltage difference across it reflects the magnitude of the output current.

[0044] Specifically, the first terminal of resistor R19 is connected to the second terminal of the sampling resistor. The second terminal of resistor R19 is connected to the first terminal of resistor R22, the first terminal of capacitor C6, and the non-inverting input terminal of operational amplifier U2A. The second terminal of resistor R22, the second terminal of capacitor C6, and the reference voltage source Vref1 are connected. Operational amplifier U2A is configured as a differential amplifier to amplify the voltage difference across the sampling resistor. The reference voltage source Vref1 provides a common-mode voltage reference for the operational amplifier.

[0045] Furthermore, the output terminal of operational amplifier U2A is connected to the second terminal of resistor R10, the second terminal of capacitor C4, the input terminal of feedback module 200, and the input terminal of overcurrent protection module 400. The power supply terminal of operational amplifier U2A is connected to the first terminal of capacitor C7 and the power supply voltage source VCC, and the second terminal of capacitor C7 and the ground terminal of operational amplifier U2A are connected to reference ground GND. Capacitor C7 provides power supply filtering for operational amplifier U2A, and resistor R10 and capacitor C4 form a negative feedback network to determine the gain of operational amplifier U2A.

[0046] Optionally, the current sampling module 100 also includes a resistor R17 and a capacitor C5. The output terminal of the operational amplifier U2A is connected to the second terminal of resistor R10, the second terminal of capacitor C4, and the first terminal of resistor R17. The second terminal of resistor R17 is connected to the first terminal of capacitor C5, the input terminal of feedback module 200, and the input terminal of overcurrent protection module 400. The second terminal of capacitor C5 is connected to reference ground. Resistor R17 and capacitor C5 form a first-order low-pass filter to filter the current sampling signal output by operational amplifier U2A, remove high-frequency noise, and output a smooth and stable current sampling signal.

[0047] In some embodiments of this application, the feedback module 200 includes resistors R11, R13, R15, R16, R18, R20, and R21, an operational amplifier U2B, and a Schottky diode DS1. The first terminal of resistor R16 receives the constant current switching threshold Vref3. The second terminal of resistor R16, the first terminal of resistor R11, and the inverting input terminal of operational amplifier U2B are connected. The constant current switching threshold Vref3 serves as a reference voltage and is input to the inverting input terminal of operational amplifier U2B through resistor R16.

[0048] Specifically, the first terminal of resistor R18 is connected to the output terminal of current sampling module 100; the second terminal of resistor R18, the first terminal of resistor R20, and the non-inverting input terminal of operational amplifier U2B are connected; the output terminal of operational amplifier U2B is connected to the second terminal of resistor R11 and the first terminal of resistor R15; and the second terminal of resistor R20 is connected to the feedback reference voltage VFB. When the current sampling signal is greater than the constant current switching threshold Vref3, operational amplifier U2B outputs a high level.

[0049] Furthermore, the second terminal of resistor R15 is connected to the anode of Schottky diode DS1, and the cathode of Schottky diode DS1 is connected to the second terminal of resistor R13, the first terminal of resistor R21, and the feedback terminal FB of control module 300. The first terminal of resistor R13 is connected to the output terminal OUT+ of the cigarette lighter, and the second terminal of resistor R21 is connected to reference ground GND. Schottky diode DS1 acts as a unidirectional conductor. When the operational amplifier U2B outputs a high level, the feedback control signal is injected into the feedback terminal FB of control module 300 through diode DS1, raising the voltage at the feedback terminal and causing control module 300 to reduce the duty cycle of the drive signal output to the cigarette lighter, thereby achieving constant current control.

[0050] In some embodiments of this application, the delay unit 410 includes a capacitor C3 and a resistor R12. The first end of resistor R12 is connected to the first end of capacitor C3 and the input terminal of overcurrent protection unit 420. The second end of resistor R12 is connected to the output terminal of current sampling module 100, and the second end of capacitor C3 is connected to reference ground. When a current sampling signal is output from current sampling module 100, capacitor C3 needs to be charged through resistor R12. The charging process generates a time delay, thus achieving the function of delaying for a preset time.

[0051] The overcurrent protection unit 420 includes a comparator U1A, resistors R2, R6, and R8, and a transistor Q3. The first terminal of resistor R2 is connected to the overcurrent protection threshold Vref2, and the second terminal of resistor R2 is connected to the inverting input of comparator U1A. The non-inverting input of comparator U1A is connected to the output of the delay unit. The overcurrent protection threshold Vref2 is input to the inverting input of comparator U1A through resistor R2 as a reference voltage, and the delayed current sampling signal is input to the non-inverting input of comparator U1A for comparison.

[0052] Furthermore, the output terminal of comparator U1A is connected to the first terminals of resistors R6 and R8. The ground terminal of comparator U1A is connected to reference ground GND. The power supply terminal of comparator U1A is connected to the power supply voltage source VCC and the second terminal of resistor R8. The second terminal of resistor R6 is connected to the base of transistor Q3. The collector of transistor Q3 is connected to the enable terminal EN of control module 300. The emitter of transistor Q3 is connected to reference ground GND. When the current sampling signal is greater than the overcurrent protection threshold, comparator U1A outputs a high level, transistor Q3 conducts, pulling the enable terminal EN of control module 300 to ground, causing control module 300 to stop working.

[0053] Unlike existing technologies, this embodiment of the invention samples the output current of the cigarette lighter. When the voltage value of the output current is greater than the constant current switching threshold, the feedback module operates and controls the cigarette lighter to enter constant current mode through the control module. After the feedback module operates, if the voltage value of the output current is still greater than the overcurrent protection threshold, the overcurrent protection module stops the control module from operating, thereby achieving overcurrent protection and improving the compatibility and safety of the cigarette lighter.

[0054] In some other embodiments of this application, another cigarette lighter control circuit is provided, the schematic diagram of which is shown below. Figure 5 As shown. The cigarette lighter control circuit is in Figure 2 Based on the cigarette lighter control circuit shown, an over-temperature protection module 500 is also included, which is connected to the control module 300.

[0055] Specifically, the output terminal of the over-temperature protection module 500 is connected to the input terminal of the control module 300. The connection between the over-temperature protection module 500 and the control module 300 enables it to send a protection command to the control module 300 when an over-temperature condition is detected, thereby realizing the temperature protection function.

[0056] The over-temperature protection module 500 is configured to collect the temperature of the cigarette lighter socket and output an over-temperature protection signal when the temperature exceeds a preset over-temperature protection threshold, causing the control module 300 to stop working. The cigarette lighter socket temperature refers to the actual temperature near the cigarette lighter socket CN1. Poor contact between the cigarette lighter head and the cigarette lighter socket or excessive load current can cause the cigarette lighter socket to overheat severely.

[0057] As an example and not a limitation, the over-temperature protection module 500 monitors the temperature change of the cigarette lighter socket in real time using a temperature sensor. The temperature sensor is installed near the cigarette lighter socket to accurately sense its temperature status. When the cigarette lighter socket temperature is normal, the over-temperature protection module 500 is in standby mode and will not interfere with the normal operation of the cigarette lighter.

[0058] In some embodiments of this application, the preset over-temperature protection threshold corresponds to a safe temperature limit. When the temperature at the cigarette lighter socket exceeds this threshold, it indicates an abnormal overheating situation. After detecting that the cigarette lighter socket temperature exceeds the over-temperature protection threshold, the over-temperature protection module 500 immediately outputs an over-temperature protection signal. This signal is transmitted to the control module 300, causing it to stop operating and thus cutting off the cigarette lighter's output, preventing safety issues such as casing melting due to overheating.

[0059] Optionally, the over-temperature protection module 500 allows the cigarette lighter control circuit to extend the overcurrent protection point from the traditional 10A to a higher current value. Due to the added cigarette lighter inlet temperature monitoring function, the cigarette lighter control circuit can disconnect the protection in time before the temperature exceeds the limit, thus allowing a larger current to pass and enhancing load adaptability. When the contact is good and the temperature is normal, the cigarette lighter can withstand a larger current; when poor contact causes overheating, the temperature protection intervenes promptly.

[0060] In some other embodiments of this application, such as Figure 6 The diagram shows a complete circuit schematic of the cigarette lighter control circuit, illustrating the circuit structure including over-temperature protection. This circuit comprises all the specific circuit components of the current sampling module 100, feedback module 200, control module 300, overcurrent protection module 400, and over-temperature protection module 500.

[0061] Specifically, the over-temperature protection module 500 includes resistors R3, R4, R5, R7, and R9, a thermistor RT1, a capacitor C2, a switching transistor Q4, and a comparator U1B. The first terminal of resistor R5 is connected to the power supply voltage source VCC. The second terminal of resistor R5 is connected to the first terminal of resistor R9 and the first terminal of the thermistor RT1. The second terminal of resistor R9 is connected to the first terminal of capacitor C2 and the non-inverting input terminal of comparator U1B. The second terminals of thermistor RT1 and capacitor C2 are connected to reference ground GND.

[0062] It should be noted that the thermistor RT1 is a negative temperature coefficient thermistor, installed near the cigarette lighter socket CN1, for real-time acquisition of the cigarette lighter socket temperature. When the cigarette lighter socket temperature rises, the resistance of the thermistor RT1 decreases. This decrease, through a voltage divider circuit composed of resistors R5 and R9, generates a corresponding temperature sampling voltage TEMP_Cig at the non-inverting input of comparator U1B. Capacitor C2 acts as a filter, reducing instantaneous fluctuations in the temperature signal.

[0063] Furthermore, the first terminal of resistor R3 is connected to the over-temperature protection threshold Vref4, the second terminal of resistor R3 is connected to the inverting input of comparator U1B, the output of comparator U1B is connected to the second terminal of resistor R4 and the first terminal of resistor R7, and the first terminal of resistor R4 is connected to the power supply voltage source VCC. The over-temperature protection threshold Vref4 is used as a reference voltage input to the inverting input of comparator U1B, and the over-temperature protection threshold Vref4 corresponds to the safe temperature limit of the cigarette lighter socket.

[0064] In some embodiments of this application, the second terminal of resistor R7 is connected to the base of switching transistor Q4, the collector of switching transistor Q4 is connected to the enable terminal EN of control module 300, and the emitter of switching transistor Q4 is connected to reference ground GND. When the temperature at the cigarette lighter socket exceeds the over-temperature protection threshold, the temperature sampling voltage TEMP_Cig is greater than the over-temperature protection threshold Vref4, comparator U1B outputs a high level, switching transistor Q4 is turned on, pulling the enable terminal EN of control module 300 to ground, causing control module 300 to stop working.

[0065] In some embodiments of this application, the circuit can also handle loads with large current fluctuations, such as parking heaters. Through the filter circuit composed of resistor R17 and capacitor C5 in the current sampling module 100, and the delay circuit in the overcurrent protection module 400, the system can smooth out current fluctuations, avoid false triggering of protection due to instantaneous current fluctuations, and ensure that devices such as parking heaters can start and work normally.

[0066] The current sampling module 100 achieves precise current detection and signal conditioning through operational amplifier U2A and a related resistor-capacitor network. The feedback module 200 achieves constant current control feedback regulation through operational amplifier U2B and Schottky diode DS1. The overcurrent protection module 400 achieves delayed overcurrent protection through the RC circuit of the delay unit and the comparator U1A of the overcurrent protection unit.

[0067] Furthermore, the over-temperature protection module 500 achieves temperature protection through temperature detection by the thermistor RT1 and threshold comparison by comparator U1B. When the cigarette lighter is working normally, each protection module is in monitoring mode; when the output current exceeds the constant current switching threshold, the feedback module 200 starts constant current control; when the output current still exceeds the overcurrent protection threshold after a delay, the overcurrent protection module 400 starts overcurrent protection; when the temperature at the cigarette lighter outlet exceeds the over-temperature protection threshold, the over-temperature protection module 500 starts over-temperature protection.

[0068] It's easy to understand that this cigarette lighter control circuit, through a multi-level protection strategy, not only solves the problem of traditional cigarette lighters being unable to power high-power loads, but also effectively prevents overheating safety hazards caused by poor contact. This allows the cigarette lighter to automatically identify load characteristics: for purely resistive loads such as kettles, it continues to supply power through constant current control; for constant current loads, it disconnects promptly through overcurrent protection; and for situations like poor contact, it disconnects promptly through overtemperature protection, ensuring safe operation.

[0069] Unlike existing technologies, this embodiment of the invention samples the output current of the cigarette lighter. When the voltage value of the output current exceeds the constant current switching threshold, the feedback module activates, and the control module controls the cigarette lighter to enter constant current mode. After the feedback module activates, if the voltage value of the output current still exceeds the overcurrent protection threshold, the overcurrent protection module stops the control module from working, thus achieving overcurrent protection. In addition, an over-temperature protection module is also provided. When the temperature at the cigarette lighter outlet exceeds a preset over-temperature protection threshold, the control module stops working, improving the compatibility and safety of the cigarette lighter and effectively avoiding potential safety hazards caused by poor contact, abnormal load, or other reasons.

[0070] In other embodiments of this application, an energy storage power source is provided, which includes a cigarette lighter and the cigarette lighter control circuit described in any of the foregoing embodiments.

[0071] Specifically, the energy storage power supply provides DC power to the cigarette lighter control circuit through its built-in battery pack. The cigarette lighter control circuit then converts the battery voltage of the energy storage power supply into 12V DC power suitable for external load devices. The cigarette lighter serves as the output interface, supplying power to load devices such as kettles, parking heaters, electric fans, and vehicle inverters through the cigarette lighter socket.

[0072] As an example, and not a limitation, the energy storage power supply uses lithium battery packs as the main energy storage unit. The output voltage of the battery packs is typically high-voltage DC such as 24V, 36V, or 48V. The cigarette lighter control circuit steps down the high-voltage DC to a standard 13.5V output and intelligently switches between constant voltage and constant current modes according to the load characteristics.

[0073] Optionally, this energy storage power supply significantly improves load adaptability and safety by integrating a cigarette lighter control circuit, enabling it to power a wider variety of load devices and meet diverse power needs in outdoor, emergency, and other scenarios, while ensuring safe and reliable operation.

[0074] It should be noted that while the preferred embodiments of this utility model are provided in the specification and accompanying drawings, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of this utility model; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this utility model specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A circuit for controlling a lighter, comprising: include: Current sampling module, feedback module, control module, and overcurrent protection module; The current sampling module is connected to the cigarette lighter, the feedback module, and the overcurrent protection module, respectively, and the control module is connected to the feedback module, the overcurrent protection module, and the cigarette lighter, respectively. The current sampling module is configured to collect the output current of the cigarette lighter and generate a current sampling signal based on the output current. The feedback module is configured to receive the current sampling signal and output a feedback control signal when the voltage value of the current sampling signal is greater than a preset constant current switching threshold. The control module is configured to adjust the duty cycle of the drive signal output to the cigarette lighter when it receives the feedback control signal, so as to keep the output current constant. The overcurrent protection module is configured to receive the current sampling signal after a preset delay. When the voltage value of the current sampling signal is still greater than the preset overcurrent protection threshold, it outputs an overcurrent protection signal to stop the control module from working. Wherein, the constant current switching threshold is less than the overcurrent protection threshold.

2. The circuit of claim 1, wherein, The overcurrent protection module includes a delay unit and an overcurrent protection unit. The delay unit is connected to the current sampling module and the overcurrent protection unit, respectively. The overcurrent protection unit is also connected to the control module. The delay unit is configured to receive the current sampling signal, delay the preset time, and then transmit the current sampling signal to the overcurrent protection unit. The overcurrent protection unit is configured to receive the delayed current sampling signal, and when the voltage value of the current sampling signal is greater than the overcurrent protection threshold, output the overcurrent protection signal to the control module.

3. The circuit of claim 2, wherein, The delay unit includes a capacitor C3 and a resistor R12. The first end of the resistor R12 is connected to the first end of the capacitor C3 and the input end of the overcurrent protection unit. The second end of the resistor R12 is connected to the output end of the current sampling module. The second end of the capacitor C3 is connected to the reference ground.

4. The circuit of claim 2, wherein, The overcurrent protection unit includes a comparator U1A, resistors R2, R6, and R8, and a transistor Q3; The first end of the resistor R2 is connected to the overcurrent protection threshold, the second end of the resistor R2 is connected to the inverting input of the comparator U1A, and the non-inverting input of the comparator U1A is connected to the output of the delay unit. The output terminal of the comparator U1A is connected to the first terminal of the resistor R6 and the first terminal of the resistor R8. The ground terminal of the comparator U1A is connected to the reference ground. The power supply terminal of the comparator U1A is connected to the power supply voltage source and the second terminal of the resistor R8. The second terminal of the resistor R6 is connected to the base of the transistor Q3. The collector of the transistor Q3 is connected to the enable terminal of the control module. The emitter of the transistor Q3 is connected to the reference ground.

5. The circuit of claim 1, wherein, The current sampling module includes an operational amplifier U2A, resistors R10, R14, R19, and R22, capacitors C4, C6, and C7. The first end of resistor R14 is connected to the first end of the sampling resistor of the cigarette lighter. The second end of resistor R14 is connected to the first end of resistor R10, the first end of capacitor C4, and the inverting input of operational amplifier U2A. The first end of resistor R19 is connected to the second end of the sampling resistor. The second end of resistor R19 is connected to the first end of resistor R22, the first end of capacitor C6, and the non-inverting input of operational amplifier U2A. The second end of resistor R22, the second end of capacitor C6, and the reference voltage source are connected. The output terminal of the operational amplifier U2A is connected to the second terminal of the resistor R10, the second terminal of the capacitor C4, the input terminal of the feedback module, and the input terminal of the overcurrent protection module. The power supply terminal of the operational amplifier U2A is connected to the first terminal of the capacitor C7 and the power supply voltage source. The second terminal of the capacitor C7 and the ground terminal of the operational amplifier U2A are connected to the reference ground.

6. The circuit of claim 5, wherein, The current sampling module also includes a resistor R17 and a capacitor C5; The output terminal of the operational amplifier U2A is connected to the second terminal of the resistor R10, the second terminal of the capacitor C4, and the first terminal of the resistor R17. The second terminal of the resistor R17 is connected to the first terminal of the capacitor C5, the input terminal of the feedback module, and the input terminal of the overcurrent protection module. The second terminal of the capacitor C5 is connected to the reference ground.

7. The circuit of claim 1, wherein, The feedback module includes resistors R11, R13, R15, R16, R18, R20, R21, operational amplifier U2B, and Schottky diode DS1; The first end of resistor R16 receives the constant current switching threshold. The second end of resistor R16 is connected to the first end of resistor R11 and the inverting input of operational amplifier U2B. The first end of resistor R18 is connected to the output of the current sampling module. The second end of resistor R18 is connected to the first end of resistor R20 and the non-inverting input of operational amplifier U2B. The output of operational amplifier U2B is connected to the second end of resistor R11 and the first end of resistor R15. The second end of resistor R20 is connected to the feedback reference voltage. The second end of resistor R15 is connected to the anode of Schottky diode DS1, the cathode of Schottky diode DS1 is connected to the second end of resistor R13, the first end of resistor R21 and the feedback terminal of the control module, the first end of resistor R13 is connected to the output terminal of the cigarette lighter, and the second end of resistor R21 is connected to reference ground.

8. The circuit according to any one of claims 1 to 7, characterized in that It also includes an over-temperature protection module, which is connected to the control module; The over-temperature protection module is configured to collect the temperature of the cigarette lighter socket and output an over-temperature protection signal when the temperature of the cigarette lighter socket exceeds a preset over-temperature protection threshold, so as to stop the control module from working.

9. The circuit of claim 8, wherein, The over-temperature protection module includes resistors R3, R4, R5, R7, and R9, a thermistor RT1, a capacitor C2, a switching transistor Q4, and a comparator U1B. The first end of resistor R5 is connected to the power supply voltage source. The second end of resistor R5 is connected to the first end of resistor R9 and the first end of the thermistor RT1. The second end of resistor R9 is connected to the first end of capacitor C2 and the non-inverting input of comparator U1B. The second end of the thermistor RT1 and the second end of capacitor C2 are connected to the reference ground. The first end of resistor R3 is connected to the over-temperature protection threshold. The second end of resistor R3 is connected to the inverting input of comparator U1B. The output of comparator U1B is connected to the second end of resistor R4 and the first end of resistor R7. The first end of resistor R4 is connected to the power supply voltage source. The second end of resistor R7 is connected to the base of switch Q4. The collector of switch Q4 is connected to the enable terminal of the control module. The emitter of switch Q4 is connected to reference ground.

10. An energy storage power supply, characterized by, include: Cigarette lighter; And the cigarette lighter control circuit as described in any one of claims 1-9.

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