Input under-voltage protection and auxiliary light-off circuit and power adapter
By designing input undervoltage protection and auxiliary lamp-out circuits in the power adapter, using the combination of rectifier diode and MOS tube, the heating and indicator light out problems of the power adapter during low voltage input is solved, and effective undervoltage protection and rapid lamp-out effect is achieved.
Patent Information
- Application Number
- CN202422306833.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2034-09-20
AI Technical Summary
The existing power adapters lack input undervoltage protection, which causes severe heat or damage to low voltage input, and the power indicator light is difficult to turn off quickly, which is easy to provide wrong signals.
Design an input undervoltage protection and auxiliary lamp extinguishing circuit, using rectifier diodes, voltage stabilization diodes, MOS tubes and voltage divider modules. When the mains input voltage is lower than the preset value, breaking through the voltage stabilization diodes will make the MOS tube not conduct, pulling down the voltage of the PWM control chip, stop working and turn off the indicator light.
It realizes undervoltage protection at low voltage input, prevents damage to the power supply from heating, and ensures that the indicator light goes out quickly to avoid wrong signals.
Smart Images
Figure CN223230868U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power supply, in particular to an input undervoltage protection and auxiliary light-off circuit and a power adapter. Background Art
[0002] Currently, power adapters or chargers on the market generally do not have input undervoltage protection functions or power-off quick light-off functions. Such products have certain defects. On the one hand, when the power supply is designed for 200-240VAC rated input operating conditions, if there is no input undervoltage protection function, when the power supply is applied to low voltage input scenarios (such as 120V), the power supply will overheat severely or even be damaged. On the other hand, when the power is cut off, the electrical energy stored in the electrolytic capacitor on the primary side of the transformer will continue to be transmitted to its secondary side, making it difficult for the power indicator light to be extinguished in time, which can easily cause erroneous signals.
[0003] Therefore, it is very important for those skilled in the art to design an input undervoltage protection and auxiliary light-off circuit and a power adapter. Utility Model Content
[0004] The technical problem to be solved by the embodiments of the present invention is to provide an input undervoltage protection and auxiliary light-off circuit and a power adapter to solve the problems in the prior art that the power supply is easily damaged by heat and easily provides erroneous signals.
[0005] The utility model discloses an input undervoltage protection and auxiliary light-off circuit, which is applied to a power adapter. The circuit comprises: a rectifier diode, a second voltage divider module, a voltage regulator diode, a first MOS transistor, a second MOS transistor and the first voltage divider module. The input end of the rectifier diode is connected to the mains input end of the power adapter, the output end of the rectifier diode is connected to the input end of the second voltage divider module, the output end of the second voltage divider module is connected to the negative electrode of the voltage regulator diode, the positive electrode of the voltage regulator diode is connected to the gate of the first MOS transistor, the drain of the first MOS transistor and the gate of the second MOS transistor are both connected to the output end of the first voltage divider module, the input end of the first voltage divider module is connected to the primary end of the transformer of the power adapter, the source of the first MOS transistor and the source of the second MOS transistor are both grounded, and the drain of the second MOS transistor is connected to the PWM control chip of the power adapter.
[0006] Optionally, the first voltage divider module includes a first resistor, a second resistor, and a third resistor connected in series, and the drain of the first MOS transistor and the drain of the second MOS transistor are both connected between the second resistor and the third resistor.
[0007] Optionally, the second voltage divider module includes a fourth resistor, a fifth resistor, and a sixth resistor connected in series, and the cathode of the voltage stabilizing diode is connected between the fifth resistor and the sixth resistor.
[0008] In order to solve the problems existing in the prior art, the present invention also provides a power adapter, whose solution is that it includes the input undervoltage protection and auxiliary light-off circuit as described above, and also includes a mains input end, a transformer, a PWM control chip, a charging control chip and an indicator light module. The input undervoltage protection and auxiliary light-off circuit are respectively connected to the voltage input end and the PWM control chip, the control end of the PWM control chip is connected to the primary end of the transformer, the primary end of the transformer is connected to the mains input end, the secondary end of the transformer is connected to the charging control chip, and the control end of the voltage control chip is connected to the indicator light module.
[0009] Optionally, a rectifier and filter module is further included, wherein a voltage input end of the rectifier and filter module is connected to the mains input end, and a voltage output end of the rectifier and filter module is connected to the primary end of the transformer.
[0010] Optionally, a first energy storage capacitor is provided between the rectification and filtering module and the primary end of the transformer, and an output end of the first energy storage capacitor is connected to an input end of the first voltage divider module.
[0011] Optionally, a second energy storage capacitor is further provided between the secondary end of the transformer and the charging control chip, and an output end of the second energy storage capacitor is connected to a voltage input pin of the charging control chip.
[0012] Optionally, a third MOS tube is provided between the charging control chip and the indicator light module, the gate of the third MOS tube is connected to the control end of the charging control chip, the source of the third MOS tube is grounded, and the drain of the third MOS tube is connected to the indicator light module.
[0013] Optionally, it further includes an output interface, an inductor and a step-down MOS tube, the input end of the inductor is connected to the control end of the charging control chip, the output end of the inductor is connected to the output interface, and the step-down MOS tube is connected to the inductor.
[0014] Optionally, a protection MOS tube is further included, wherein the input end of the protection MOS tube is connected to the inductor, and the output end of the protection MOS tube is connected to the output interface.
[0015] Compared with the prior art, the beneficial effects of the input undervoltage protection and auxiliary light-off circuit and the power adapter provided by the embodiments of the present invention are: by designing an input undervoltage protection and auxiliary light-off circuit, applied to the power adapter, when the voltage input at the mains input end is lower than the preset voltage, the input undervoltage protection is triggered, and the voltage input at the mains input end will enter the voltage-stabilizing diode through the rectifier diode and the second voltage divider module, and break down the voltage-stabilizing diode. Since the voltage cannot reach the turn-on condition of the first MOS tube, the first MOS tube is not turned on, so that the PWM control chip in the power adapter is pulled down by the second MOS tube, the PWM control chip stops working, and the primary-end voltage of the transformer will not be able to be transmitted to its secondary end, thereby achieving undervoltage protection and turning off the power indicator light. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:
[0017] Figure 1 This is a circuit diagram of an input undervoltage protection and auxiliary light-off circuit provided by an embodiment of the utility model;
[0018] Figure 2 The circuit of the power adapter provided by the embodiment of the utility model Figure 1 ;
[0019] Figure 3 The circuit of the power adapter provided by the embodiment of the utility model Figure 2 ;
[0020] Figure 4 The circuit of the power adapter provided by the embodiment of the utility model Figure 3 . DETAILED DESCRIPTION
[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. Now, in conjunction with the accompanying drawings, a detailed description of the preferred embodiments of the present utility model will be given.
[0022] like Figure 1 As shown, the utility model provides a specific embodiment of an input undervoltage protection and auxiliary light-off circuit.
[0023] An input undervoltage protection and auxiliary light-off circuit, used in power adapters, reference Figure 1 The input undervoltage protection and auxiliary light-off circuit includes a rectifier diode D3, a second voltage divider module 2, a voltage regulator diode ZD4, a first MOS transistor M9, a second MOS transistor M10 and a first voltage divider module 1.
[0024] Among them, reference Figure 1The input end of the rectifier diode D3 is connected to the AC input end 10 of the power adapter. The output end of the rectifier diode D3 is connected to the cathode of the voltage-stabilizing diode ZD4 through the second voltage-dividing module 2. The anode of the voltage-stabilizing diode ZD4 is connected to the gate G of the first MOS transistor M9. The drain D of the first MOS transistor M9 and the gate G of the second MOS transistor M10 are both connected to the output end of the first voltage-dividing module 1. The input end of the first voltage-dividing module 1 is connected to the primary end of the transformer 20 of the power adapter. The source S of the first MOS transistor M9 and the source S of the second MOS transistor M10 are both grounded. The drain D of the second MOS transistor M10 is connected to the PWM control chip 30 of the power adapter.
[0025] Specifically, refer to Figure 1 The input undervoltage protection and auxiliary light-off circuit is mainly used in a power adapter. The power adapter includes a mains input terminal 10, a PWM control chip 30, and a transformer 20. The mains input terminal 10 is used to input grid power. The primary end of the transformer 20 is connected to the mains input terminal 10 to obtain the voltage input by the mains input terminal 10. The transformer 20 is used to transform the voltage input by the mains input terminal 10 and output it through its secondary end to power other functional modules in the power adapter (such as the power indicator light) and external devices.
[0026] Further, refer to Figure 1 The control end of the PWM control chip 30 is connected to the primary end of the transformer 20. The PWM control chip 30 can control the on-off time of its switch tube by adjusting the duty cycle of the PWM signal, thereby controlling the changes in the current and magnetic field in the primary-end coil of the transformer 20. The transformation ratio relationship of the transformer 20 will transfer the magnetic field transformation of the primary-end coil to the secondary-end coil, thereby changing the output voltage.
[0027] Further, refer to Figure 1 The input undervoltage protection and auxiliary light-off circuit includes a rectifier diode D3, a voltage regulator diode ZD4, a first MOS transistor M9, a second MOS transistor M10, and a first voltage divider module 1; the voltage input end of the rectifier diode D3 is connected to the mains input end 10, and the voltage output end of the rectifier diode D3 is connected to the cathode of the voltage regulator diode ZD4. The rectifier diode D3 is a half-wave rectifier for rectifying the AC voltage input from the mains input end 10 into a DC voltage and outputting it to the second voltage divider module 2.
[0028] Further, refer to Figure 1Since the Zener diode ZD4 has a very stable voltage characteristic within its reverse breakdown voltage range, when the voltage exceeds its reverse breakdown voltage, the Zener diode ZD4 will be turned on, so that the voltage in the circuit is maintained at a stable level. By connecting the voltage output end of the rectifier diode D3 to the input end of the second voltage divider module 2, the cathode of the Zener diode ZD4 to the output end of the second voltage divider module 2, and the anode of the Zener diode ZD4 to the gate G of the first MOS transistor M9, when the undervoltage protection is triggered, the voltage at the mains input end 10 will be rectified by the rectifier diode D3 and output as a DC voltage, which is then output to the Zener diode ZD4 through the second voltage divider module 2, causing the Zener diode ZD4 to break down and turn on. Since this voltage does not reach the turn-on condition of the first MOS transistor M9, the first MOS transistor M9 does not turn on.
[0029] Further, refer to Figure 1 The gate G of the first MOS transistor M9 is connected to the anode of the voltage-stabilizing diode ZD4, the drain D of the first MOS transistor M9 is connected to the output end of the first voltage-dividing module 1, the source S of the first MOS transistor M9 is grounded, and a capacitor C70 is connected in parallel to the gate G of the first MOS transistor M9. When the voltage-stabilizing diode ZD4 breaks down and turns on, the voltage between the anode of the capacitor C70 and the gate G of the first MOS transistor M9 is equal to the difference between the output voltage of the rectifier diode D3 and the breakdown voltage of the voltage-stabilizing diode ZD4. This voltage difference cannot reach the turn-on voltage value of the first MOS transistor M9, and the first MOS transistor M9 does not turn on.
[0030] Further, refer to Figure 1 The gate G of the second MOS transistor M10 is connected to the voltage output end of the voltage divider module, the drain D of the second MOS transistor M10 is connected to the PWM control chip 30 of the power adapter, and the source S of the second MOS transistor M10 is grounded. When the first MOS transistor M9 is not conducting, the first voltage divider module 1 outputs a voltage to the gate G of the second MOS transistor M10, and the drain D and source S of the second MOS transistor M10 are conducting. After the second MOS transistor M10 is conducting, the PWM control chip 30 connected to the drain D of the second MOS transistor M10 will be pulled down to ground, forcing the PWM control chip 30 to stop working. The voltage at the primary end of the transformer 20 will not be able to be output to the secondary end of the transformer 20, thereby achieving input undervoltage protection.
[0031] In particular, while achieving undervoltage protection, the circuit can also promptly turn off the power indicator light to prevent the power indicator light from giving an error message. When the first MOS transistor M9 is not conducting, the voltage divider module outputs a voltage to the gate G of the second MOS transistor M10, causing the drain D and source S of the second MOS transistor M10 to conduct. After the second MOS transistor M10 is conducting, the PWM control chip 30 connected to the drain D of the second MOS transistor M10 will be pulled down to ground, forcing the PWM control chip 30 to stop working. The voltage at the primary end of the transformer 20 will not be able to be output to the secondary end of the transformer 20, so that the power indicator light, which requires power from the secondary end of the transformer 20, can no longer obtain power from the secondary end of the transformer 20, thereby achieving rapid extinguishing of the power indicator light.
[0032] Further, refer to Figure 1 The first voltage divider module 1 includes a first resistor R69, a second resistor R70, and a third resistor R71 connected in series. One end of the first resistor R69 is connected to the primary end of the transformer 20, the other end of the first resistor R69 is connected to one end of the second resistor R70, the other end of the second resistor R70 is connected to one end of the third resistor R71, and the other end of the third resistor R71 is grounded. The drain D of the second MOS transistor M10 is connected between the second resistor R70 and the third resistor R71.
[0033] Currently, power adapters or chargers on the market generally do not have input undervoltage protection functions or power-off quick light-off functions. Such products have certain defects. On the one hand, when the power supply is designed for 200-240VAC rated input working conditions, if there is no input undervoltage protection function, when the power supply is applied to low voltage input scenarios (such as 120V), the power supply will overheat severely or even be damaged. On the other hand, when the power is cut off, the electrical energy stored in the electrolytic capacitor on the primary side of the transformer will continue to be transmitted to its secondary side, making it difficult for the power indicator light to be extinguished in time, which can easily cause erroneous signals.
[0034] In this embodiment, an input undervoltage protection and auxiliary light-off circuit is designed and applied to a power adapter. When the voltage input to the mains input terminal is lower than a preset voltage, the input undervoltage protection is triggered. The voltage input to the mains input terminal will pass through the rectifier diode and the second voltage divider module into the voltage-stabilizing diode and break down the voltage-stabilizing diode. Since this voltage does not reach the turn-on condition of the first MOS tube, the first MOS tube is not turned on, so that the PWM control chip in the power adapter is pulled down by the second MOS tube, the PWM control chip stops working, and the voltage at the primary end of the transformer will not be able to be transmitted to its secondary end, thereby achieving undervoltage protection and turning off the power indicator light.
[0035] In one embodiment, reference Figure 1The input undervoltage protection and auxiliary light-off circuit also includes a second voltage divider module 2, the input end of the second voltage divider module 2 is connected to the output end of the rectifier diode D3, and the output end of the second voltage divider module 2 is connected to the cathode of the voltage regulator diode ZD4.
[0036] Specifically, refer to Figure 1 The input undervoltage protection and auxiliary light-off circuit also includes a second voltage divider module 2, which includes a fourth resistor R63, a fifth resistor R64 and a sixth resistor R65 connected in series. One end of the fourth resistor R63 is connected to the rectifier diode D3, the other end of the fourth resistor R63 is connected to one end of the fifth resistor R64, the other end of the fifth resistor R64 is connected to one end of the sixth resistor R65, and the other end of the sixth resistor R65 is grounded. The cathode of the voltage regulator diode ZD4 is connected between the fifth resistor R64 and the sixth resistor R65.
[0037] In one embodiment, reference Figure 1 The drain D of the first MOS transistor M9 and the gate G of the second MOS transistor M10 are both connected between the second resistor R70 and the third resistor R71.
[0038] like Figures 2 to 4 As shown, the utility model also provides a specific embodiment of a power adapter.
[0039] A power adapter, reference Figure 2 The power adapter includes the above-mentioned input undervoltage protection and auxiliary light-off circuit, and also includes a mains input terminal 10, a transformer 20, a PWM control chip 30, a charging control chip 40 and an indicator light module 50. The input undervoltage protection and auxiliary light-off circuit are connected to the voltage input terminal and the PWM control chip 30 respectively. The control terminal of the PWM control chip 30 is connected to the primary terminal of the transformer 20, the primary terminal of the transformer 20 is connected to the mains input terminal 10, the secondary terminal of the transformer 20 is connected to the charging control chip 40, and the control terminal of the voltage control chip is connected to the indicator light module 50.
[0040] Specifically, refer to Figure 2 The mains input terminal 10 is used to receive AC power from a power socket and to filter out noise, interference, and fluctuations in the power grid, thereby protecting the power adapter and the devices connected to the power adapter. The primary side of the transformer 20 is connected to the mains input terminal 10, and the secondary side of the transformer 20 is connected to the charging control chip 40 to convert the high-voltage AC power input from the mains input terminal 10 into the low-voltage AC power required for charging. The voltage input terminal of the PWM control chip 30 is connected to the drain D of the second MOS tube M10 in the input undervoltage protection and auxiliary light-off circuit.
[0041] Further, refer to Figure 2The indicator light module 50 is used to display the working status and power-on status of the power adapter. The control end of the indicator light module 50 is connected to the control end of the charging control chip 40 to control the switch of the indicator light through the charging control chip 40.
[0042] When the system triggers the input undervoltage protection, the voltage input to the rectifier diode D3 and after being rectified by the rectifier diode D3, the voltage input to the voltage regulator diode ZD4 through the second voltage divider module 2 will be greater than the breakdown voltage of the voltage regulator diode ZD4, causing the voltage regulator diode ZD4 to be broken down, and the first MOS tube M9 is not turned on. When the first MOS tube M9 is turned off, the voltage stored in the electrolytic capacitor on the primary side of the transformer 20 and the divided voltage of the voltage divider module are applied to the gate G of the second MOS tube M10, causing the second MOS tube M10 to be turned on. The drain D of the second MOS transistor M0 is connected to the voltage input terminal of the PWM control chip 30 in the power adapter, and the source S of the second MOS transistor M10 is grounded. When the second MOS transistor M10 is turned on, the voltage at the voltage input terminal of the PWM control chip 30 in the power adapter will be pulled to the ground, thereby stopping the PWM control chip 30 in the power adapter from working, and further preventing the energy stored in the electrolytic capacitor on the primary side of the transformer 20 from being released to its secondary side through the transformer 20. This not only cuts off the subsequent power supply, but also quickly turns off the indicator light on the secondary side of the transformer 20.
[0043] In one embodiment, reference Figure 2 The power adapter further includes a rectifier and filter module BR1 , a voltage input end of the rectifier and filter module BR1 is connected to the mains input end 10 , and a voltage output end of the rectifier and filter module BR1 is connected to the primary end of the transformer 20 .
[0044] Specifically, refer to Figure 2 The rectifier and filter module BR1 includes a full-wave rectifier bridge for rectification, which includes four diodes and is connected in a bridge configuration, which allows current to pass in two directions, so that the rectifier bridge can simultaneously utilize the positive half-cycle and negative half-cycle AC signals to improve the rectification efficiency.
[0045] In one embodiment, reference Figure 2 A first energy storage capacitor is provided between the rectifier and filter module BR1 and the primary end of the transformer 20, and the output end of the first energy storage capacitor is connected to the input end of the first voltage divider module 1; a second energy storage capacitor is also provided between the secondary end of the transformer 20 and the charging control chip 40, and the output end of the second energy storage capacitor is connected to the voltage input pin of the charging control chip 40.
[0046] Specifically, refer to Figure 2Specifically, two first energy storage capacitors can be set, namely EC1 and EC2, EC1 and EC2 are connected in parallel and arranged together at the primary end of the transformer 20, the input ends of the first energy storage capacitors EC1 and EC2 are connected to the voltage output end of the mains input end 10, and the output ends of the first energy storage capacitors EC1 and EC2 are connected to the voltage input end of the first voltage divider module 1, and specifically two second energy storage capacitors can be set, namely EC3 and EC4, EC3 and EC4 are connected in parallel, and the output ends after parallel connection are connected to the voltage input end of the charging control chip 40.
[0047] In one embodiment, reference Figure 3 The charging control chip 40 includes a voltage input pin VIN and a control pin GPIO1. The voltage input pin VIN of the charging control chip 40 serves as its voltage input end and is connected to the secondary end of the transformer 20 to obtain electrical energy. The control pin GPIO1 of the charging control chip 40 serves as its control end and is used to connect to the indicator light module 50 to control the switch of the indicator light module 50.
[0048] In one embodiment, reference Figure 3 A third MOS transistor M11 is provided between the charging control chip 40 and the indicator light module 50 . The gate G of the third MOS transistor M11 is connected to the control terminal GPIO1 of the charging control chip 40 , the source S of the third MOS transistor M11 is grounded, and the drain D of the third MOS transistor M11 is connected to the indicator light module 50 .
[0049] Specifically, refer to Figure 3 When the energy of the first energy storage capacitor on the primary side of the transformer 20 is no longer released to its secondary side through the transformer 20, the voltage input terminal VCC of the charging control chip 40 will detect that the voltage on the secondary side of the transformer 20 is lower than the voltage required for normal operation of the power adapter. The control terminal GPIO1 of the charging control chip 40 will output a low level to the third MOS transistor M11, and the third MOS transistor M11 will be turned off, and the indicator light will go out, further accelerating the light-off speed.
[0050] In one embodiment, reference Figure 4 The power adapter also includes an output interface 60, an inductor L2, and upper and lower MOS tubes M2 and M4. The input ends of the upper and lower MOS tubes M2 and M4 are connected to the control end of the charging control chip 40, and the output ends of the upper and lower MOS tubes M2 and M4 are connected to the output interface 60 to cooperate with the inductor L2 to achieve voltage reduction.
[0051] Specifically, refer to Figure 4 The voltage input terminal of the output interface 60 is connected to the voltage output terminal of the charging control chip 40 to obtain electrical energy. The protection MOS tube M3 is set between the charging control chip 40 and the input interface to perform charging and discharging protection.
[0052] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Those skilled in the art may modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.
Claims
1. An input undervoltage protection and auxiliary light-off circuit, used in a power adapter, characterized in that: include: A rectifier diode, a second voltage divider module, a voltage regulator diode, a first MOS transistor, a second MOS transistor, and the first voltage divider module, wherein the input end of the rectifier diode is connected to the mains input end of the power adapter, the output end of the rectifier diode is connected to the input end of the second voltage divider module, the output end of the second voltage divider module is connected to the cathode of the voltage regulator diode, the anode of the voltage regulator diode is connected to the gate of the first MOS transistor, the drain of the first MOS transistor and the gate of the second MOS transistor are both connected to the output end of the first voltage divider module, the input end of the first voltage divider module is connected to the primary end of the transformer of the power adapter, the source of the first MOS transistor and the source of the second MOS transistor are both grounded, and the drain of the second MOS transistor is connected to the PWM control chip of the power adapter.
2. The input undervoltage protection and auxiliary light-off circuit according to claim 1, characterized in that: The first voltage divider module includes a first resistor, a second resistor, and a third resistor connected in series. The drain of the first MOS transistor and the gate of the second MOS transistor are both connected between the second resistor and the third resistor.
3. The input undervoltage protection and auxiliary light-off circuit according to claim 1, characterized in that: The second voltage divider module includes a fourth resistor, a fifth resistor, and a sixth resistor connected in series, and the cathode of the voltage stabilizing diode is connected between the fifth resistor and the sixth resistor.
4. A power adapter, characterized in that: It includes the input undervoltage protection and auxiliary light-off circuit as described in any one of claims 1 to 3, and also includes a mains input terminal, a transformer, a PWM control chip, a charging control chip and an indicator light module, the input undervoltage protection and auxiliary light-off circuit are respectively connected to the voltage input terminal and the PWM control chip, the control terminal of the PWM control chip is connected to the primary terminal of the transformer, the primary terminal of the transformer is connected to the mains input terminal, the secondary terminal of the transformer is connected to the charging control chip, and the control terminal of the voltage control chip is connected to the indicator light module.
5. The power adapter according to claim 4, wherein: It also includes a rectifier and filter module, wherein the voltage input end of the rectifier and filter module is connected to the mains input end, and the voltage output end of the rectifier and filter module is connected to the primary end of the transformer.
6. The power adapter according to claim 5, wherein a first energy storage capacitor is provided between the rectifier and filter module and the primary end of the transformer, and an output end of the first energy storage capacitor is connected to an input end of the first voltage divider module.
7. The power adapter according to claim 5, wherein: A second energy storage capacitor is further provided between the secondary end of the transformer and the charging control chip, and an output end of the second energy storage capacitor is connected to a voltage input pin of the charging control chip.
8. The power adapter according to claim 5, wherein: A third MOS tube is provided between the charging control chip and the indicator light module, the gate of the third MOS tube is connected to the control end of the charging control chip, the source of the third MOS tube is grounded, and the drain of the third MOS tube is connected to the indicator light module.
9. The power adapter according to claim 5, wherein: It also includes an output interface, an inductor and a step-down MOS tube. The input end of the inductor is connected to the control end of the charging control chip, the output end of the inductor is connected to the output interface, and the step-down MOS tube is connected to the inductor.
10. The power adapter according to claim 9, wherein: A protection MOS tube is also included, wherein the input end of the protection MOS tube is connected to the inductor, and the output end of the protection MOS tube is connected to the output interface.