CN212811309U

CN212811309U - Automatic power-off protection circuit and charging protection data line

Info

Publication number: CN212811309U
Application number: CN202021144904.9U
Authority: CN
Inventors: 吴永来; 吴永文; 陈美如
Original assignee: Shenzhen Lianweixin Technology Co ltd
Current assignee: Shenzhen Lianweixin Technology Co ltd
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2021-03-26
Anticipated expiration: 2030-06-19

Abstract

The embodiment of the utility model discloses an automatic power-off protection circuit and charging protection data line, charging protection data line include first interface, second interface and data line body, set up a circuit board in the casing of first interface, set up automatic power-off protection circuit on the circuit board, connect through the data line body between first interface and the second interface; the automatic power-off protection circuit collects current power supply voltage and current, performs undervoltage detection, overvoltage detection, overcurrent detection and charging state detection according to the power supply voltage and the current, and performs power-off control or cycle detection according to a detection result. A charging protection function is added to the first interface, so that whether current charging is safe or full can be judged; when a problem is detected, the power supply is directly disconnected, the first interface does not have voltage and current output, the power supply at the source is directly disconnected, and charging protection can be timely and effectively carried out.

Description

Automatic power-off protection circuit and charging protection data line

Technical Field

The utility model relates to the field of electronic technology, especially, relate to an automatic power-off protection circuit and charging protection data line.

Background

At present, explosion and fire can occur in part of mobile phones in the charging process, and most of the situations are that batteries are continuously charged after the batteries are fully charged, the batteries are heated due to overcharging of the batteries, and the safety accidents of explosion and fire are easy to occur.

Although the existing mobile phone is provided with overcurrent overshoot detection protection, the existing mobile phone is usually arranged inside the mobile phone, such as a lithium battery protection board, so that charging current still flows into the mobile phone, and because current input is not disconnected at the source and the situation that overcurrent overshoot protection fails in the use process is possible, the risk of explosion still exists.

SUMMERY OF THE UTILITY MODEL

To the technical problem, the embodiment of the utility model provides an automatic power-off protection circuit and charging protection data line are provided to solve the problem that there is the explosion risk in current cell-phone charges.

The embodiment of the utility model provides an automatic power-off protection circuit, connect the data line body, wherein, the automatic power-off protection circuit sets up on the circuit board, including input module, voltage conversion module, voltage sampling module, MCU, current sampling module and output switch module; the input module is connected with the voltage conversion module, the voltage sampling module and the output switch module; the MCU is connected with the voltage conversion module, the voltage sampling module, the current sampling module and the output switch module;

the input module transmits power voltage to the voltage conversion module and the voltage sampling module, and also transmits a data signal to the data line body; the voltage conversion module converts the power voltage into a working voltage to supply power to the MCU, the voltage sampling module divides the power voltage and outputs the corresponding divided voltage to the MCU, and the current sampling module samples the output power current and outputs the corresponding current sampling voltage to the MCU;

the MCU judges whether the current state is an under-voltage state, an overvoltage state, an overcurrent state or a charging state according to the divided voltage and the current sampling voltage, and outputs a corresponding power supply control signal to the output switch module; and the output switch module controls the output state of the power supply voltage according to the power supply control signal.

Optionally, in the automatic power-off protection circuit, the input module includes a USB input port, and a VBUS pin of the USB input port inputs a power supply voltage, and is further connected to the voltage conversion module, the voltage sampling module, and the output switch module; the D-pin of the USB input port is connected with a second output bonding pad on the circuit board, the D + pin of the USB input port is connected with a third output bonding pad on the circuit board, and the GND pin of the USB input port is grounded.

Optionally, in the automatic power-off protection circuit, the voltage conversion module includes a power chip, a first capacitor, and a second capacitor;

the VIN pin of the power supply chip is connected with the VBUS pin of the USB input port and is grounded through a first capacitor; and a VOUT pin of the power supply chip is connected with the power supply end, a VDD pin of the MCU and one end of the second capacitor, and a VSS pin of the power supply chip is connected with the other end of the second capacitor and the ground.

Optionally, in the automatic power-off protection circuit, the voltage sampling module includes a first resistor and a second resistor;

one end of the first resistor is connected with a VBUS pin of the USB input port, the other end of the first resistor is connected with an ADC _ CH4 pin of the MCU and one end of the second resistor, and the other end of the second resistor is grounded.

Optionally, in the automatic power-off protection circuit, the current sampling module includes a third resistor and a fourth resistor;

one end of the third resistor is connected with one end of the fourth resistor, a fourth output bonding pad on the circuit board and an ADC _ CH7 pin of the MCU, and the other end of the third resistor is connected with the other end of the fourth resistor and the ground; the fourth output pad is a negative electrode of the USB output and is welded with a ground wire in the data wire body.

Optionally, in the automatic power-off protection circuit, the output switch module includes a first switch tube, a second switch tube, a fifth resistor, a sixth resistor, and a seventh resistor;

the base electrode of the first switch tube is connected with one end of a sixth resistor and one end of a seventh resistor, the other end of the seventh resistor is connected with a P0.6 pin of the MCU, the other end of the sixth resistor is connected with the emitting electrode of the first switch tube and the ground, the collector electrode of the first switch tube is connected with the grid electrode of the second switch tube and one end of the fifth resistor, the source electrode of the second switch tube is connected with the other end of the fifth resistor and the VBUS pin of the USB input port, and the drain electrode of the second switch tube is connected with a first output bonding pad on the circuit board; the first output pad is a positive electrode of a USB output and is welded with a power line in the data line body.

Optionally, in the automatic power-off protection circuit, the first switching tube is an NPN transistor, and the second switching tube is a PMOS tube.

Optionally, the automatic power-off protection circuit further includes an indicator light module, and the MCU outputs a corresponding light control signal according to whether the current circuit is in an under-voltage state, an over-current state, or a charging state; the indicating lamp module controls the on-off, color and state of the indicating lamp according to the lamp control signal.

Optionally, in the automatic power-off protection circuit, the indicator light module includes a first indicator light, a second indicator light, an eighth resistor, a ninth resistor, and a tenth resistor;

the positive pole of first pilot lamp connects the positive pole of second pilot lamp and the one end of eighth resistance, and the other end of eighth resistance is connected MCU's PWM0_ CH3 foot, and the negative pole of first pilot lamp passes through the P1.7 foot of ninth resistance connection MCU, and the negative pole of second pilot lamp passes through the P3.0 foot of tenth resistance connection MCU.

A second aspect of the embodiment of the present invention provides a charging protection data line, including a first interface, a second interface and a data line body, wherein a circuit board is disposed in a housing of the first interface, the circuit board is provided with the automatic power-off protection circuit, and the first interface is connected to the second interface through the data line body;

the automatic power-off protection circuit collects current power supply voltage and current, performs undervoltage detection, overvoltage detection, overcurrent detection and charging state detection according to the power supply voltage and the current, and performs power-off control or cycle detection according to a detection result.

In the technical solution provided by the embodiment of the present invention, the charging protection data line includes a first interface, a second interface and a data line body, a circuit board is arranged in the housing of the first interface, an automatic power-off protection circuit is arranged on the circuit board, and the first interface is connected with the second interface through the data line body; the automatic power-off protection circuit collects current power supply voltage and current, performs undervoltage detection, overvoltage detection, overcurrent detection and charging state detection according to the power supply voltage and the current, and performs power-off control or cycle detection according to a detection result. A charging protection function is added on the first interface, so that whether the current charging is safe (overvoltage, overcurrent or undervoltage) or whether the charging is full can be judged; when a problem is detected, the power supply is directly disconnected, the first interface does not have voltage and current output, the power supply at the source is directly disconnected, and charging protection can be timely and effectively carried out.

Drawings

Fig. 1 is a block diagram of the charging protection data line according to an embodiment of the present invention.

Fig. 2 is a block diagram of an embodiment of the present invention.

Fig. 3 is a schematic circuit diagram of the input module and the voltage conversion module according to an embodiment of the present invention.

Fig. 4 is a schematic circuit diagram of the MCU, the voltage sampling module, the current sampling module and the indicator light module in the embodiment of the present invention.

Fig. 5 is a schematic circuit diagram of an output switch module according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. The embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts, belong to the protection scope of the present invention.

Referring to fig. 1 and fig. 2, a charging protection data line according to an embodiment of the present invention includes a first interface 10, a second interface 20, and a data line body 30, wherein a circuit board is disposed in a housing of the first interface 10, and an automatic power-off protection circuit 40 is disposed on the circuit board; the first interface 10 is connected with the second interface 20 through a data line body 30, the automatic power-off protection circuit 40 collects current power voltage and current, performs undervoltage detection, overvoltage detection, overcurrent detection and charging state detection according to the power voltage and the current, and performs power-off control or cycle detection according to a detection result.

In this embodiment, the second interface 20 (smaller interface) is used for transmitting data signals (D ±) and voltages (positive OUT, negative ADC7), and is preferably USB TYPE-C male, and when the implementation is specific, the interface may further adopt Micro USB male, USB mini male, apple Lightning male, TYPE-C female, or TYPE-a male according to the requirement, where the interface TYPE is not limited, as long as data and voltage transmission can be implemented. The improvement point of this embodiment is to set an automatic power-off protection circuit 40 in the first interface 10 (larger interface) to add a charging protection function, and determine whether the current charging is safe (overvoltage, overcurrent, or undervoltage) or is fully charged by detecting the data of current and voltage output by the charging protection data line; when the safety problem occurs, the power supply at the source is directly disconnected, so that the charging protection function of the equipment (such as a mobile phone) is prevented from being invalid, and the charging dangerous condition is prevented from further deteriorating. The charging protection data line is unplugged and plugged again, then the power is automatically re-electrified and the normal power is restored, and the next use is not influenced.

The automatic power-off protection circuit 40 comprises an input module 410, a voltage conversion module 420, a voltage sampling module 430, an MCU 440, a current sampling module 450 and an output switch module 460; the input module 410 is connected with the voltage conversion module 420, the voltage sampling module 430 and the output switch module 460; the MCU 440 is connected with the voltage conversion module 420, the voltage sampling module 430, the current sampling module 450 and the output switch module 460; the input module 410 transmits the power voltage VBUS to the voltage conversion module 420 and the voltage sampling module 430, and also transmits the data signal (D +, D-) to the data line body 30; the voltage conversion module 420 converts the power voltage into a working voltage to supply power to the MCU, the voltage sampling module 430 divides the power voltage VBUS and outputs a corresponding divided voltage ADC4 to the MCU, and the current sampling module 450 samples the output power current and outputs a corresponding current sampling voltage ADC7 to the MCU; the MCU judges whether the power supply voltage is under-voltage or over-voltage according to the divided voltage ADC4, calculates the power supply current according to the current sampling voltage ADC7 and judges whether the power supply current is over-current, judges the charging state according to the divided voltage ADC4 and the current sampling voltage ADC7, and outputs a corresponding power supply control signal P06 to the output switch module 460 according to the current state; the output switch module 460 controls the output state of the power voltage according to the power control signal P06.

Referring to fig. 3 and 4, the MCU 440 is a micro control unit, preferably of a type N76E003, MS51FB9AE or STM8S003, which is not limited herein; as long as the mcu has two detection pins (e.g., ADC _ CH4 and ADC _ CH7, the numbers of these pins may vary according to the specific models, but the functions do not vary), respectively inputting the divided voltage ADC4 and the current sampling voltage ADC7, having a power pin (e.g., VCC) and a ground pin (e.g., VSS), having an IO pin (e.g., P3.0, P1.7, PWM0_ CH3) for controlling the indicator light to control the on/off state of the indicator light, and having an IO pin (e.g., P0.6) for controlling the output of the power voltage, the protection range of this embodiment can be reached; only the pins related to the present embodiment are described herein, and other pins are not described in detail.

The input module 410 includes a USB input port JP (a larger interface), for example, a Type-a male connector (or a female connector) of a USB or a Type-C male connector (or a female connector) of a USB may be adopted, and in a specific implementation, other interfaces or plugs may be adopted, and as long as the input module has a data pin (e.g., D ±), a power pin (e.g., VBUS), and a ground pin (e.g., GND), the input module is within the protection scope of the embodiment. The VBUS pin of the USB input port JP inputs power voltage and is also connected with a voltage conversion module 420, a voltage sampling module 430 and an output switch module 460; the pin D of the USB input port JP is connected to the second output pad P2 on the circuit board, the pin D + of the USB input port JP is connected to the third output pad P3 on the circuit board, and the pin GND of the USB input port JP is grounded.

The USB input port JP is an input terminal of the first interface 10, and is used for obtaining an externally input 5V-20V power supply voltage VBUS. The second output pad P2 and the third output pad P3 are used as data pins for USB output and are welded to the positive and negative data lines in the data line body 30, so that the data signals (D +, D-) can be transmitted to the data line body 30.

With reference to fig. 3, the voltage conversion module 420 includes a power chip U1, a first capacitor C1, and a second capacitor C2; the VIN pin of the power chip U1 is connected with the VBUS pin of the USB input port JP and is grounded through a first capacitor C1; the pin VOUT of the power chip U1 is connected with the power supply terminal VCC, the pin VDD of the MCU 440 and one end of the second capacitor C2, and the pin VSS of the power chip U1 is connected with the other end of the second capacitor C2 and the ground.

The power chip U1 is an ldo (low dropout regulator) power chip, and the model is preferably LR 2010B-T33. The power supply voltage VBUS is converted into 3.3V working voltage through the power supply voltage VBUS to supply power to the MCU, and the input voltage range of the MCU is 4V-24V, so that overvoltage protection can be achieved. The first capacitor C1 is used for filtering the supply voltage VBUS, and the second capacitor C2 is used for filtering the operating voltage at the supply terminal VCC. In specific implementation, the power chip U1 may also adopt the model numbers MST5333BTE, SEAWARD SE8533X2-HF, micron ME6203a33M3G, LR (langeri) LR2010B-T33, etc., and all fall within the protection range of the present embodiment as long as the input voltage can be reduced to the operating voltage (e.g., 3.3V).

With reference to fig. 4, the voltage sampling module 430 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the VBUS pin of the USB input port JP, the other end of the first resistor R1 is connected to the ADC _ CH4 pin of the MCU 440 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

The power supply voltage VBUS is divided by a first resistor R1 (the resistance value is preferably 30K Ω) and a second resistor R2 (the resistance value is preferably 10K Ω), the divided voltage ADC4 is transmitted to the MCU, and the MCU can calculate the current voltage value of the power supply voltage VBUS according to the resistance values of R1 and R2 and the divided voltage ADC4, and the current voltage value is used as a basis for determining whether the power supply voltage VBUS (i.e., the charging voltage) is under-voltage or over-voltage.

Referring to fig. 4, the current sampling module 450 includes a third resistor R3 and a fourth resistor R4, one end of the third resistor R3 is connected to one end of the fourth resistor R4, a fourth output pad P4 on the circuit board, and an ADC _ CH7 pin of the MCU 440, the other end of the third resistor R3 is connected to the other end of the fourth resistor R4 and ground, and the fourth output pad P4 is used as a negative electrode of the USB output and is soldered to a ground line in the data line 30.

The third resistor R3 (with a resistance value of preferably 0.03R Ω) and the fourth resistor R4 (with a resistance value of preferably 0.03R Ω) are disposed at the fourth output pad P4 (as a USB output cathode), the output voltage OUT output by the output switch module 460 is used as a USB output anode, the current corresponding to the current supply voltage VBUS can be sampled through R3 and R4, and the corresponding current sampling voltage ADC7 is output to the MCU as a basis for determining whether the supply current (i.e., the charging current) is overcurrent.

Referring to fig. 5, the output switch module 460 includes a first switch Q1, a second switch Q2, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7; the base electrode of the first switch tube Q1 is connected with one end of a sixth resistor R6 and one end of a seventh resistor R7, the other end of the seventh resistor R7 is connected with a P0.6 pin of the MCU, the other end of the sixth resistor R6 is connected with the emitter electrode of the first switch tube Q1 and the ground, the collector electrode of the first switch tube Q1 is connected with the gate electrode of the second switch tube Q2 and one end of the fifth resistor R5, the source electrode of the second switch tube Q2 is connected with the other end of the fifth resistor R5 and the VBUS pin of the USB input port JP, and the drain electrode of the second switch tube Q2 is connected with a first output pad P1 on the circuit board.

The first switching tube Q1 is preferably an NPN transistor, and the second switching tube Q2 is preferably a PMOS tube. The first output pad P1 is used as the positive electrode of the USB output and is soldered to the power line in the data line body. R6 and R7 are used for protecting Q1, and R5 is a pull-up resistor. When the power control signal P06 is at a high level, the first switch Q1 is turned on to pull the gate voltage of the second switch Q2 low, the second switch Q2 is turned on to output the power voltage VBUS, the power voltage VBUS is changed to the output voltage OUT through the second switch Q2 (with a voltage drop), the voltage drop of the second switch Q2 is negligible, and the output voltage OUT is actually the power voltage VBUS. When the power control signal P06 is at a low level, the first switch Q1 is turned off, the gate voltage of the second switch Q2 is pulled up to a high level by the fifth resistor R5, and the second switch Q2 turns off the output power voltage VBUS, so that the power voltage VBUS is not output through the second switch Q2 (with a voltage drop), i.e., the power supply is turned off and the charging is stopped.

In order to facilitate users to know the working state of the charging protection data line and prompt, the automatic power-off protection circuit 40 further includes an indicator lamp module 470, and the MCU 440 outputs a corresponding lamp control signal according to whether the charging protection data line is currently in an under-voltage state, an over-current state, or a charging state; the indicator light module 470 controls the on/off, color and status of the indicator light according to the light control signal (PWM03, P17, P30). A transparent window is arranged on the housing of the USB2.0TYPE-a male connector, and the indicator light module 470 is positioned below the transparent window to facilitate observing the state of the indicator light.

With continued reference to fig. 4, the indicator light module 470 includes a first indicator light LED1, a second indicator light LED2, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10; the positive pole of the first indicator light LED1 is connected with the positive pole of the second indicator light LED2 and one end of an eighth resistor R8, the other end of the eighth resistor R8 is connected with the PWM0_ CH3 pin of the MCU, the negative pole of the first indicator light LED1 is connected with the P1.7 pin of the MCU through a ninth resistor R9, and the negative pole of the second indicator light LED2 is connected with the P3.0 pin of the MCU through a tenth resistor R10.

The first indicator light LED1 emits blue light, the second indicator light LED2 emits red light, and the two lights emit light together to form purple light. The lamp control signals comprise a power supply signal PWM03, a first negative control signal P17 and a second negative control signal P30, wherein the power supply signal PWM03 is used for supplying power to the LED1 and the LED2, the indicator lamp continuously emits light when the power supply signal is high level, and the indicator lamp flickers when the power supply signal is periodic pulse signal; when the first negative control signal P17 is grounded, current flows through the positive electrode and the negative electrode of the first indicator light LED1, and the LED1 emits light; when the second negative control signal P30 is grounded, current flows through the positive and negative electrodes of the second indicator light LED2, and the LED2 emits light.

The MCU is used for grounding the first negative control signal P17 and the second negative control signal P30 and can be realized by two NPN triodes arranged in the MCU, the control end of the MCU is connected with the grid electrodes of the triodes, the source electrodes of the triodes are grounded, the drain electrodes of the triodes are respectively a first negative control signal P17 and a second negative control signal P30, and the MCU is used for controlling the conduction of the triodes, so that the first negative control signal P17 or the second negative control signal P30 can be grounded; the MCU may also directly output the first negative control signal P17 or the second negative control signal P30 with a low level to ground, which is not limited herein. In practical implementation, the power supply signal PWM03 may also be kept at a high level, and when the first negative control signal P17 is at a low level (or grounded), or periodically at a low level, the first indicator light LED1 lights or flashes; the second negative control signal P30 is similarly controlled.

Referring to fig. 1 to 5, the operation principle of the automatic power-off protection circuit is as follows:

after power-on, the MCU initializes, outputs a low-level power supply signal PWM03 to turn off both indicator lamps, and initializes each port.

The MCU carries OUT undervoltage detection, calculates the voltage value of the current power supply voltage VBUS according to the resistance values of R1 and R2 and the divided voltage ADC4, judges whether the voltage value of the power supply voltage VBUS is smaller than or equal to a preset undervoltage (such as 4V), outputs a low-level power supply control signal P06 if the voltage value of the power supply voltage VBUS is smaller than or equal to the preset undervoltage, cuts off the first switch tube Q1, cuts off the second switch tube Q2, and cuts off the output of the output voltage OUT; the MCU also outputs a periodic pulse power supply signal PWM03 and connects the second negative control signal P30 to ground (P17 is floating at this time), and the second indicator LED2 emits red light and flashes to indicate the current under-voltage condition. The MCU continues undervoltage detection after delaying the first preset time (e.g. 0.5 second), and the embodiment turns off the supply voltage VBUS at the output terminal, i.e. the output voltage OUT is 0, but the supply voltage VBUS still remains at the input terminal (i.e. the VBUS pin of the USB input port JP), so that detection can continue until the voltage is higher than the preset undervoltage, and the undervoltage detection cycle is exited.

If the voltage value of the power supply voltage VBUS is larger than the preset undervoltage, the MCU carries OUT overvoltage detection, calculates the current voltage value of the power supply voltage VBUS according to the resistance values of R1 and R2 and the divided voltage ADC4, judges whether the voltage value of the power supply voltage VBUS is larger than the preset high voltage (if the USB input port JP is a TYPE-A connector, the voltage value is set to be 12V, if the USB input port JP is a TYPE-C connector, the voltage value is set to be 20V), if yes, a low-level power supply control signal P06 is output, the first switch tube Q1 is cut off, the second switch tube Q2 is cut off, and the output of the output voltage OUT is disconnected; the MCU also outputs a periodic pulse power supply signal PWM03 and connects the second negative control signal P30 to ground to control the second indicator light LED2 to emit red light and flash to indicate that it is currently in an overvoltage state. And the MCU delays the first preset time (such as 0.5 second) to continue the overvoltage detection until the overvoltage detection is lower than the preset high voltage, and the circulation of the overvoltage detection is exited. Red light and flashing indicates possible undervoltages and possible overvoltages, both of which are voltage problems. The speed of the flicker is determined by the frequency of the power supply signal PWM 03.

If the voltage value of the power supply voltage VBUS is smaller than or equal to the preset high voltage, the MCU carries OUT overcurrent detection, calculates the current of the current power supply voltage VBUS according to the resistance values of the current sampling voltages ADC7, R3 and R4 acquired by R3 and R4, judges whether the current of the current power supply voltage VBUS is larger than the preset upper limit current (for example, 2A, the current can be correspondingly adjusted according to the type or the requirement of an interface), if so, outputs a low-level power supply control signal P06, the first switch tube Q1 is cut off, the second switch tube Q2 is cut off, and the output of the output voltage OUT is disconnected; the MCU also outputs a high power supply signal PWM03 and connects the second negative control signal P30 to ground, and controls the second indicator light LED2 to emit red light and light all the time, indicating that it is in an overcurrent state. And then entering a dead loop, namely, the working and the detection are not performed, and the charging protection data line is required to be unplugged and then inserted again, and then returning to the initialization.

If the current of the current power voltage VBUS is smaller than the preset current, the MCU carries out normal charging (the three detections are all passed before charging, so that the explosion risk can be avoided) and judges the current charging state. The MCU calculates the current of the current power supply voltage VBUS according to the collected current sampling voltage ADC7 and the resistance values of R3 and R4, judges whether the current of the current power supply voltage VBUS is smaller than a preset lower limit current (such as 50mA), and if so, indicates that the current power supply voltage VBUS is smaller and needs to return to undervoltage detection.

If the current is not less than the preset lower limit current, whether the current of the current power supply voltage VBUS is between the preset current (the current which is continuously charged after full charge) and the lower limit current is judged, if so, the full charge state is indicated, the low-level power supply control signal P06 is output to disconnect the output of the output voltage OUT, the high-level power supply signal PWM03 is also output, the first negative control signal P17 is grounded, the first indicator light LED1 is controlled to emit blue light and light all the time, the fact that the battery is full is prompted, and then the dead cycle is entered.

If the current of the current power supply voltage VBUS is larger than the preset current, whether the current power supply voltage VBUS is smaller than or equal to 5.5V or larger than 5.5V is judged.

If the current of the current power supply voltage VBUS is less than or equal to 1mA, the charging mode belongs to a 5W (power) state, and the MCU controls the first indicator lamp LED1 to emit blue light and slowly flash; if the current is larger than 1mA, the power state is 10W (power), and the MCU controls the first indicator light LED1 to emit blue light and flash. And then returns to the under-voltage detection.

If the current of the current power supply voltage VBUS is less than or equal to 1mA, the high-voltage charging state is achieved, the MCU controls the first indicator light LED1 to emit blue light and flicker, the second indicator light LED2 emits red light and flicker, and purple light and flicker can be formed; if the current is larger than 1mA, the super-fast state is achieved, the MCU controls the first indicator light LED1 to emit blue light, and the second indicator light LED2 emits red light, so that purple light can be combined and the LED is always on. And then returns to the under-voltage detection.

To sum up, the utility model provides an automatic power-off protection circuit and charge protection data line, on the basis that remains the data transmission function on general data line, increase voltage and current sample, according to the magnitude of voltage of present mains voltage VBUS and the current value that corresponds carry OUT undervoltage, excessive pressure, overcurrent detection, still carry OUT the judgement of charged state, when appearing undervoltage, excessive pressure, overcurrent or full-up automatic disconnection output voltage OUT's output, can directly disconnect the power of source when the safety problem appears, in time effectively carry OUT charge protection; different working states are distinguished through the combination of color, flashing and constant brightness of the indicating lamps, so that a user can conveniently know whether problems occur or not, and corresponding maintenance operation is carried out.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims

1. An automatic power-off protection circuit is connected with a data line body and is characterized in that the automatic power-off protection circuit is arranged on a circuit board and comprises an input module, a voltage conversion module, a voltage sampling module, an MCU (microprogrammed control unit), a current sampling module and an output switch module; the input module is connected with the voltage conversion module, the voltage sampling module and the output switch module; the MCU is connected with the voltage conversion module, the voltage sampling module, the current sampling module and the output switch module;

the MCU judges whether the current state is an under-voltage state, an overvoltage state, an overcurrent state or a charging state according to the divided voltage and the current sampling voltage, and outputs a corresponding power supply control signal to the output switch module according to the current state; and the output switch module controls the output state of the power supply voltage according to the power supply control signal.

2. The automatic power-off protection circuit of claim 1, wherein the input module comprises a USB input port, a VBUS pin of the USB input port inputs a power supply voltage, and a voltage conversion module, a voltage sampling module and an output switch module are further connected; the D-pin of the USB input port is connected with a second output bonding pad on the circuit board, the D + pin of the USB input port is connected with a third output bonding pad on the circuit board, and the GND pin of the USB input port is grounded.

3. The automatic power-off protection circuit according to claim 2, wherein the voltage conversion module comprises a power chip, a first capacitor and a second capacitor;

4. The automatic power-off protection circuit of claim 2, wherein the voltage sampling module comprises a first resistor and a second resistor;

5. The automatic power-off protection circuit of claim 1, wherein the current sampling module comprises a third resistor and a fourth resistor;

6. The automatic power-off protection circuit according to claim 2, wherein the output switch module comprises a first switch tube, a second switch tube, a fifth resistor, a sixth resistor and a seventh resistor;

7. The automatic power-off protection circuit according to claim 6, wherein the first switching tube is an NPN transistor, and the second switching tube is a PMOS tube.

8. The automatic power-off protection circuit according to claim 1, further comprising an indicator light module, wherein the MCU outputs a corresponding light control signal according to whether the current circuit is in an under-voltage state, an over-current state or a charging state; the indicating lamp module controls the on-off, color and state of the indicating lamp according to the lamp control signal.

9. The automatic power-off protection circuit of claim 8, wherein the indicator light module comprises a first indicator light, a second indicator light, an eighth resistor, a ninth resistor, and a tenth resistor;

10. A charging protection data line, comprising a first interface, a second interface and a data line body, wherein a circuit board is arranged in a shell of the first interface, the circuit board is provided with an automatic power-off protection circuit according to any one of claims 1 to 9, and the first interface is connected with the second interface through the data line body;