CN220105246U - Charging interface short circuit detection circuit and portable electronic equipment - Google Patents

Abstract

The utility model discloses a short circuit detection circuit of a charging interface and portable electronic equipment, which comprise a voltage sampling circuit, a controllable switch, a short circuit resistor, a detection circuit and an alarm circuit; the voltage sampling circuit is connected with a power supply pin in the charging interface and is used for sampling the voltage of a charging power supply transmitted through the power supply pin; after being connected in series with the short-circuit resistor, the controllable switch is connected between a selected functional pin in the charging interface and the system ground; the selected functional pins are default suspended functional pins or pins which do not affect the original functions of the short-circuit resistor after being connected with the short-circuit resistor; the detection circuit receives the sampling voltage output by the voltage sampling circuit, generates a switching signal according to the change of the sampling voltage, and controls the on-off of the controllable switch; the alarm circuit is used for alarming when the power supply pin is short-circuited with the selected functional pin. The utility model can realize automatic detection and alarm for the short circuit state of the charging interface, thereby playing the roles of protecting the charging interface and improving the charging safety.

Description

Charging interface short circuit detection circuit and portable electronic equipment

Technical Field

The utility model belongs to the technical field of portable electronic equipment, and particularly relates to a short circuit detection circuit designed for a charging interface on the portable electronic equipment.

Background

The portable electronic device is an electronic product which has small volume, light weight and convenient carrying. The existing portable electronic equipment is mostly provided with a rechargeable battery and a charging interface, and the rechargeable battery is used for supplying power to a system circuit in the equipment, so that the constraint of a power line can be eliminated, and the portable electronic equipment can be flexibly applied to different use places.

In the daily use process of the portable electronic equipment with the charging interface, the problem that foreign matters enter the charging interface is often encountered, particularly in summer or tropical regions, sweat of a user falls into the charging interface easily, if the sweat is not found in time, the pin in the charging interface is corroded or short-circuit fault occurs easily during charging, and then the service life and user experience of the portable electronic equipment are affected.

Disclosure of Invention

The utility model aims to provide a short circuit detection circuit of a charging interface, which aims to solve the problem that the charging interface is not easy to find when foreign matters enter, so that the use safety of the charging interface is affected.

In order to solve the technical problems, the utility model is realized by adopting the following technical scheme:

in one aspect, the utility model provides a short circuit detection circuit of a charging interface, which comprises a voltage sampling circuit, a controllable switch, a short circuit resistor, a detection circuit and an alarm circuit; the voltage sampling circuit is connected with a power supply pin in the charging interface and is used for sampling the voltage of a charging power supply transmitted through the power supply pin; the controllable switch is connected in series with the short-circuit resistor and then is connected between a selected functional pin in the charging interface and system ground; the selected functional pins are default suspended functional pins in the charging interface or pins which do not affect the original functions of the short-circuit resistor after being connected with the short-circuit resistor; the detection circuit receives the sampling voltage output by the voltage sampling circuit, generates a switching signal according to the change of the sampling voltage, and controls the on-off of the controllable switch; the alarm circuit is connected with the detection circuit and used for alarming when the power supply pin is short-circuited with the selected functional pin.

In some embodiments of the present utility model, the voltage sampling circuit may employ a resistor voltage dividing network connected between the power supply pin and system ground for dividing a charging power supply transmitted through the power supply pin to generate the sampling voltage.

In some embodiments of the present utility model, when configuring the resistance value of the shorting resistor, the following condition should be satisfied: when the short-circuit resistor is connected with the resistor voltage-dividing network in parallel, the voltage on the resistor voltage-dividing network can be obviously changed, namely, the detection circuit can accurately sense the change of the sampling voltage. The voltage change is detected by the detection circuit so as to realize automatic identification of the short circuit state of the charging interface.

In some embodiments of the present utility model, in order to achieve the purpose of enabling a voltage on the resistor divider network to change significantly when the short-circuit resistor is connected in parallel with the resistor divider network, a resistance value of a divider resistor in the resistor divider network may be configured to be above 1kΩ, and a resistance value of the short-circuit resistor may be configured to be in an ohmic level, that is, a small resistance of several ohms. Thus, when foreign matters enter the charging interface and cause the power supply pin in the charging interface to be in short circuit with the selected functional pin, the charging power supply transmitted through the power supply pin is grounded through the short circuit resistor. Because the resistance of the short-circuit resistor is far smaller than that of the voltage dividing resistor in the resistor voltage dividing network, the short-circuit resistor can be in a state similar to the short circuit to the ground on the power pin, and the voltage on the resistor voltage dividing network is lowered, so that the sampling voltage output through the resistor voltage dividing network is greatly lowered, and the sampling voltage is lower than a set threshold. The detection circuit can automatically judge whether the charging interface has short circuit fault or not by comparing the received sampling voltage with a set threshold value.

In some embodiments of the utility model, a power management chip and a processor may be configured in the detection circuit; the power management chip is used for receiving the sampling voltage output by the voltage sampling circuit, generating a fault signal and outputting the fault signal to the processor when the charging interface is connected with a charging power supply and the sampling voltage is lower than a set threshold value so as to generate a switching signal for realizing on-off control of the controllable switch.

In some embodiments of the present utility model, a buzzer and/or an indicator light may be configured in the alarm circuit, and connected to the processor; when the processor receives the fault signal sent by the power management chip, the buzzer and/or the indicator lamp can be controlled to sound and/or emit light so as to give an alarm, remind a user to pull out the charging wire in time, and avoid damage of the charging interface.

In some embodiments of the present utility model, the controllable switch may select a device such as a triode, a MOS transistor, or a thyristor that can be automatically turned on or off when receiving a switching signal.

In some embodiments of the present utility model, when the charging interface is a Type-C interface, a CC pin for detecting positive and negative insertion in the Type-C interface may be selected as the selected functional pin, and the controllable switch and the shorting resistor may be connected.

Because the Type-C interface comprises two CC pins, namely a CC1 pin and a CC2 pin, two groups of controllable switches and short-circuit resistors can be configured in order to realize an automatic detection function on the short-circuit state of the charging interface when the charging wire is inserted in the forward and reverse directions; connecting a series branch of one set of controllable switch and short-circuit resistor between the CC1 pin and system ground, and connecting a series branch of the other set of controllable switch and short-circuit resistor between the CC2 pin and system ground; the detection circuit can control the on-off of the two controllable switches according to the change of the sampling voltage output by the voltage sampling circuit, and the short circuit detection can be realized on the charging interface no matter the charging wire is inserted forward or reversely.

In another aspect, the utility model also provides a portable electronic device, which comprises a charging interface, wherein the charging interface is connected with a charging interface short circuit detection circuit; the charging interface short circuit detection circuit comprises a voltage sampling circuit, a controllable switch, a short circuit resistor, a detection circuit and an alarm circuit; the voltage sampling circuit is connected with a power supply pin in the charging interface and is used for sampling the voltage of a charging power supply transmitted through the power supply pin; the controllable switch is connected in series with the short-circuit resistor and then is connected between a selected functional pin in the charging interface and system ground; the selected functional pins are default suspended functional pins in the charging interface or pins which do not affect the original functions of the short-circuit resistor after being connected with the short-circuit resistor; the detection circuit receives the sampling voltage output by the voltage sampling circuit, generates a switching signal according to the change of the sampling voltage, and controls the on-off of the controllable switch; the alarm circuit is connected with the detection circuit and used for alarming when the power supply pin is short-circuited with the selected functional pin.

Compared with the prior art, the utility model has the advantages and positive effects that:

1. according to the utility model, the voltage sampling circuit is configured on the power supply pin of the charging interface, the short-circuit resistor is configured on the selected functional pin, when the short-circuit resistor is utilized to pull down the charging power supply on the power supply pin when foreign matters enter the charging interface to cause short circuit of the pin in the charging interface, the voltage on the voltage sampling circuit is obviously changed, and the configuration detection circuit detects the change of the sampling voltage output by the voltage sampling circuit, so that the short-circuit condition of the charging interface can be automatically identified.

2. According to the utility model, the controllable switch is configured on the selected functional pin in the charging interface, when the short circuit fault of the charging interface is detected, the path of the charging power supply for discharging electric energy to the ground through the short circuit resistor is cut off by controlling the on-off of the controllable switch, so that the charging terminal equipment and the charging interface can be protected, and the energy waste is avoided.

3. According to the utility model, by configuring the alarm circuit, when the charging interface has a short-circuit fault, a user can be timely reminded to pull out the charging wire, so that the fault is prevented from being further expanded, and the property safety of the user is ensured.

4. The short circuit detection circuit is configured in the charging interface to eliminate potential safety hazards caused by foreign matters entering the charging interface, and compared with the traditional protection mode of additionally installing the rubber plug, the utility model can improve the overall appearance attractiveness of the portable electronic equipment.

Other features and advantages of the present utility model will become apparent upon review of the detailed description of the utility model in conjunction with the drawings.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a pin layout and pin definition for a Type-C interface;

FIG. 2 is a schematic block diagram of an embodiment of a charging interface short-circuit detection circuit according to the present utility model;

fig. 3 is a schematic block diagram of another embodiment of a charging interface short circuit detection circuit according to the present utility model.

Description of the embodiments

The following description of the technical solutions according to the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by a person skilled in the art without any inventive effort, are intended to be within the scope of the present utility model based on the embodiments of the present utility model.

In the description of the present utility model, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

According to the embodiment, aiming at the characteristic that the short circuit phenomenon occurs between pins in the charging interface when foreign matters enter the charging interface, the short circuit detection circuit is designed, whether the foreign matters enter the charging interface is judged by detecting whether the short circuit occurs between a power pin in the charging interface and a selected functional pin, and an active alarm is provided to remind a user to pull down the charging wire in time so as to avoid the fault deterioration.

Existing charging interfaces often have multiple pins disposed within them, but include at least a power pin (a pin for transmitting a charging power supply), a ground pin (a pin for connecting to system ground), and a function pin (a pin for performing a certain function, such as a data pin for transmitting a signal, a status pin for detecting a plugged-in status, etc.).

In order to avoid affecting the original functions of each pin in the charging interface after the short circuit detection circuit of the embodiment is added, when the function pins of the short circuit detection circuit are selected, the function pins suspended by default in the charging interface (i.e., unused pins) or the function pins which cannot affect the original functions of the short circuit detection circuit after the short circuit detection circuit is connected should be selected as the selected function pins to participate in the design of the short circuit detection circuit of the charging interface.

Take Type-C interface as the interface that charges to describe as an example.

As shown in fig. 1, the current Type-C interface is generally configured with 24 pins, and is arranged in two rows, namely, 12 pins in each row, and the functions of the pins are as follows:

1. VBUS (power supply pin): the four charging power supplies are respectively arranged at the upper part and the lower part and used for transmitting the charging power supply;

2. GND (ground pin): the power supply pin VBUS is required to be connected with the ground pin GND at the same time for cooperation use when data communication or charging is carried out;

3. d+/D- (data communication pin pair): the method is used for high-speed data communication, and the transmission speed can reach 10Gbps;

4. CC1/CC2 (CC pins): one of the upper part and the lower part is arranged adjacent to the power supply pin VBUS and is used for detecting the forward and reverse plug state of the plug; the CC1/CC2 pin is a pin which only supports bidirectional signal transmission, wherein the CC2 pin can be named as a VCONN pin;

5. SBU1/SBU2 (auxiliary communication pin): the upper and lower parts are mainly used for operations such as audio signal transmission and video signal synchronous transmission, and are usually used when external devices such as headphones and sound boxes are connected;

6. TX/RX (data transmit/receive pin pair): it includes four pairs of Tx1+/Tx1-, tx1+/RX 1-, tx2+/Tx2-, tx2+/RX 2-, two pairs are arranged up and down for receiving and transmitting data.

In addition to the pins described above, including two suspension pins in the Type-C interface, i.e., pins that are not used, can be used to extend functionality.

Considering that the foreign matters entering the charging interface are large and small, the difference of the sizes of the foreign matters can lead to the difference of the number of pins in short circuit in the charging interface. In order to achieve the effect of accurate detection no matter the size of the foreign matters, the function pins adjacent to the power supply pins can be selected as the selected function pins, matched with the power supply pins and connected with the short circuit detection circuit so as to achieve the accurate detection of whether the foreign matters enter the charging interface.

Taking a Type-C interface as an example, CC pins CC1 and CC2 adjacent to the power supply pin VBUS may be selected as selected function pins, and connected to the short circuit detection circuit.

Specifically, as shown in fig. 2, the short-circuit detection circuit of the present embodiment includes main components such as a voltage sampling circuit, a controllable switch, a short-circuit resistor, a detection circuit, and an alarm circuit.

The voltage sampling circuit is connected to a power supply pin of the charging interface, for example, a VBUS pin of the Type-C interface, and is used for collecting the voltage of the charging power supply transmitted through the power supply pin VBUS.

In some embodiments, the voltage sampling circuit is preferably connected between a power supply pin VBUS of the charging interface and system ground by adopting a resistor voltage dividing network, so as to divide the voltage of the charging power supply transmitted through the power supply pin VBUS, thereby generating a sampling voltage, and transmitting the sampling voltage to the detection circuit to automatically identify the short-circuit state of the charging interface.

The description will be given taking, as an example, the case where two voltage dividing resistors R1, R2 are provided in a resistor voltage dividing network. After the two voltage dividing resistors R1 and R2 are connected in series, the voltage dividing resistor is connected between a power supply pin VBUS of a charging interface and system ground, the middle node of the two voltage dividing resistors R1 and R2 is connected to a detection circuit, and the divided sampling voltage is transmitted to the detection circuit. According to the actual configuration condition of the portable electronic equipment with the charging interface, the voltage threshold is reasonably set, and when the portable electronic equipment is charged, the detection circuit is used for comparing the sampling voltage with the set voltage threshold, so that whether the charging interface has a pin short circuit fault or not can be identified.

The controllable switch and the short-circuit resistor are connected to a selected functional pin in the charging interface, for example, the controllable switch SW1 and the short-circuit resistor Rd1 are connected to a CC1 pin of the Type-C interface, and a switch path of the controllable switch SW1 can be connected in series with the short-circuit resistor Rd1 and then connected between the CC1 pin and the system ground.

In this embodiment, the controllable switch SW1 may be selected from a triode, a MOS transistor, a silicon controlled rectifier, and other components that can change the on-off state thereof by using a control signal.

Taking the MOS transistor as an example, the source of the MOS transistor may be connected to the CC1 pin, the drain of the MOS transistor may be connected to the shorting resistor Rd1, and the source of the MOS transistor may be connected to the system ground through the shorting resistor Rd 1. And connecting the grid electrode of the MOS tube to the detection circuit, receiving a switching signal output by the detection circuit, and changing the on-off state of the source electrode and the drain electrode of the MOS tube under the control of the switching signal.

In order to cause obvious change of voltage on the resistor voltage-dividing network when foreign matters enter the charging interface and cause short circuit between the power supply pins of the charging interface and the selected functional pins, and meanwhile, the charging power supply transmitted through the power supply pins is not short-circuited to the ground, so that serious heat release problem occurs, the resistance values of the voltage-dividing resistors R1 and R2 in the resistor voltage-dividing network and the resistance value of the short circuit resistor Rd1 need to be reasonably configured.

In this embodiment, the resistance of the short circuit resistor Rd1 may be configured to be much smaller than the resistances of the voltage dividing resistors R1, R2. For example, the short circuit resistor Rd1 is a small resistor of ohm level, and the resistance of the voltage dividing resistors R1 and R2 is 1kΩ or more. In this way, when the power supply pins VBUS and CC1 are shorted by the foreign matter, the charging power supply is pulled down by the shorting resistor Rd1, so that the voltage across the voltage dividing resistors R1 and R2 is significantly reduced. At this time, the sampling voltage output by the intermediate node of the voltage dividing resistors R1 and R2 is reduced, and when the detection circuit detects that the sampling voltage is smaller than the set threshold, it can be considered that a foreign matter enters the Type-C interface, so that the power supply pin VBUS and the CC1 pin are shorted.

Because the Type-C interface supports forward insertion and reverse insertion, in order to realize the accurate detection function of the foreign matter entering the interface during both forward insertion and reverse insertion, the embodiment is also provided with a controllable switch SW2 and a short-circuit resistor Rd2 on the CC2 pin (or called VCONN pin) of the Type-C interface. Specifically, the switching path of the controllable switch SW2 may be connected in series with the shorting resistor Rd2, and then connected between the CC2 pin and the system ground. And the switch signals output by the detection circuit are used for controlling the on-off of the two paths of controllable switches SW1/SW2 so as to cooperate with the short circuit resistors Rd1/Rd2 to realize the detection of the pin short circuit state and the interface protection.

In some embodiments, the detection circuit may use a power management chip PMU and a processor MCU to complete the tasks of pin short circuit detection and switch on-off control in a matching manner. Specifically, a detection pin DET of the power management chip PMU may be used to connect the intermediate nodes of the voltage dividing resistors R1 and R2, receive the sampled voltage, and compare with a set threshold value to generate an effective or ineffective fault signal, and transmit the effective or ineffective fault signal to the processor MCU through the UART bus. The processor MCU generates a switch signal according to the received fault signal, and transmits the switch signal to a control end of the controllable switch SW1/SW2, such as a grid electrode of the MOS tube, through one path of GPIO port of the switch signal so as to control the controllable switch SW1/SW2 to be turned on or turned off. Meanwhile, the processor MCU can also generate a control signal according to the received fault signal and send the control signal to the alarm circuit so as to control the alarm circuit to alarm.

In this embodiment, the alarm circuit may adopt different modes such as audible alarm or luminous alarm, so as to achieve the purpose of reminding the user of timely pulling out the charging wire.

The present embodiment is described by taking an audible and visual alarm as an example. As shown in fig. 2, a buzzer and an indicator light LED may be provided in the alarm circuit, respectively connected to the processor MCU. When the processor MCU detects that the power supply pin VBUS and the CC1 pin of the Type-C interface are short-circuited, the buzzer and the indicator light LED are controlled to start to operate, and a user is reminded of timely performing fault treatment in an audible and visual alarm mode.

The working principle of the short-circuit detection circuit for charging interface of the present embodiment is described in detail below with reference to fig. 2 and 3.

Fig. 2 is a schematic diagram of the circuit connection between the host device, the Type-C charging cord, and the portable electronic device in the case of a positive plug of the Type-C charging cord.

At the host device end, the host device transmits charging power sources of +5V or +12V and the like to the power source pin VBUS of the portable electronic device through the charging line by the power source pin VBUS of the Type-C interface. Meanwhile, the host device is respectively connected to pull-up resistors Rp1 and Rp2 on the CC1 pin and the CC2 pin of the Type-C interface, and is connected to a dc power supply VCC via the pull-up resistors Rp1 and Rp 2.

In the Type-C charging line, two large-value ground resistors Ra1 and Ra2 are arranged. When the Type-C charging wire is inserted positively, a CC2 pin of a Type-C interface of the host device is connected with the system ground through a resistor Ra 1; the CC2 pin of the Type-C interface of the portable electronic equipment is connected with the system ground through a resistor Ra 2; and the CC1 pins of the Type-C interfaces of the host device and the portable electronic device are directly connected through the lead in the charging wire.

At the portable electronic device end, the controllable switches SW1, SW2 are in a default closed state.

When no foreign matters enter the Type-C interface, the power supply pin VBUS and the CC1 pin are in an isolation state. At this time, the host device and the portable electronic device can determine whether the charging wire is inserted forward or backward by detecting the level states on the CC1 pin and the CC2 pin thereof.

Under the condition that a charging wire is inserted positively, the short circuit resistor Rd1 pulls the potential of the CC1 pin low, when the host equipment detects that the potential of the CC1 pin is changed from high to low (but not zero), a charging power supply is output, and is transmitted to a power management chip PMU in the portable electronic equipment through a power pin VBUS, and under the control of the power management chip PMU, the rechargeable BATTERY BATTERY in the portable electronic equipment is charged and stored.

In this period, the voltage dividing resistors R1 and R2 divide the voltage of the charging power supply, generate a sampling voltage, and transmit the sampling voltage to the power management chip PMU to compare with a set threshold. The set threshold value is reasonably configured, so that the sampling voltage at the moment is higher than the set threshold value, the power management chip PMU outputs invalid fault signals to the processor MCU, the processor MCU keeps the default closed state of the controllable switches SW1 and SW2, and the buzzer and the indicator light LED are controlled to be in the closed state.

When foreign matters or sweat enter the Type-C interface and the power supply pin VBUS is short-circuited with the CC1 pin, the charging power supply output through the host device is pulled down by the short-circuit resistor Rd 1. At this time, the sampling voltage outputted through the voltage dividing resistors R1 and R2 is lower than the set threshold, and the power management chip PMU outputs an effective fault signal to the processor MCU. After receiving the effective fault signal, the processor MCU outputs a switching signal on the one hand, controls the controllable switches SW1 and SW2 to be disconnected, cuts off a path of the charging power supply discharging to the ground through the short circuit resistor Rd1, and protects the host equipment and the charging interface. Meanwhile, the host device detects that the potential of the CC1 pin of the host device jumps back to the high level again, and then the external output of the charging power supply is actively cut off. On the other hand, after receiving the effective fault signal, the processor MCU outputs a control signal to control the buzzer and the indicator light LEDs to be started, and the audible and visual alarm is carried out to remind a user of abnormal charging interface, and the charging wire is pulled down as soon as possible to carry out fault detection and confirmation.

When the user pulls out the charging wire, the potential of the CC1 pin of the portable electronic device becomes zero, the system recognizes that the charging wire is pulled out, the automatic control system resets, the processor MCU controls the controllable switches SW1 and SW2 to recover to the closed state, the buzzer stops sounding, and the indicator light LED stops flashing.

Fig. 3 is a schematic diagram of the circuit connection between the host device, the Type-C charging cord, and the portable electronic device in the reverse plug situation.

When the Type-C charging line is reversely inserted, a CC1 pin of a Type-C interface of the host equipment is connected with a system ground through a resistor Ra 1; the CC1 pin of the Type-C interface of the portable electronic equipment is connected with the system ground through a resistor Ra 2; and the CC2 pins of the Type-C interfaces of the host device and the portable electronic device are directly connected through the lead in the charging wire.

When no foreign matters enter the Type-C interface, the power supply pin VBUS and the CC2 pin are in an isolation state. At this time, the host device and the portable electronic device can determine whether the charging wire is inserted forward or backward by detecting the level states on the CC1 pin and the CC2 pin thereof.

Under the condition of reverse plug of a charging wire, the short circuit resistor Rd2 pulls the potential of the CC2 pin low, when the host equipment detects that the potential of the CC2 pin is changed from high to low (but not zero), a charging power supply is output, and is transmitted to a power management chip PMU in the portable electronic equipment through a power pin VBUS, and under the control of the power management chip PMU, the rechargeable BATTERY BATTERY in the portable electronic equipment is charged and stored.

In this period, the voltage dividing resistors R1 and R2 divide the voltage of the charging power supply, generate a sampling voltage, and transmit the sampling voltage to the power management chip PMU to compare with a set threshold. The set threshold value is reasonably configured, so that the sampling voltage at the moment is higher than the set threshold value, the power management chip PMU outputs invalid fault signals to the processor MCU, the processor MCU keeps the default closed state of the controllable switches SW1 and SW2, and the buzzer and the indicator light LED are controlled to be in the closed state.

When foreign matters or sweat enter the Type-C interface and the power supply pin VBUS is short-circuited with the CC2 pin, the charging power supply output through the host device is pulled down by the short-circuit resistor Rd2. At this time, the sampling voltage outputted through the voltage dividing resistors R1 and R2 is lower than the set threshold, and the power management chip PMU outputs a valid fault signal and sends the fault signal to the processor MCU. After receiving the effective fault signal, the processor MCU outputs a switching signal on the one hand, controls the controllable switches SW1 and SW2 to be disconnected, cuts off a path of the charging power supply discharging to the ground through the short circuit resistor Rd2, and protects the host equipment and the charging interface. Meanwhile, the host device detects that the potential of the CC2 pin of the host device jumps back to the high level again, and then the external output of the charging power supply is actively cut off. On the other hand, after receiving the effective fault signal, the processor MCU outputs a control signal to control the buzzer to sound, the indicator light LED flashes, the user is reminded of abnormal charging interface in an audible and visual alarm mode, and the charging wire is pulled down as soon as possible to conduct fault investigation and confirmation.

When the user pulls out the charging wire, the potential of the CC2 pin of the portable electronic device becomes zero, the system recognizes that the charging wire is pulled out, the automatic control system resets, the processor MCU controls the controllable switches SW1 and SW2 to recover to the closed state, the buzzer stops sounding, and the indicator light LED stops flashing.

Of course, the short circuit detection circuit of the embodiment can also be applied to other charging interfaces except the Type-C interface, so as to realize the abnormal detection and protection effects of the charging interface and the portable electronic device provided with the charging interface.

It should be noted that the above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting. Although the present utility model has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the techniques described in the foregoing embodiments, or equivalents may be substituted for elements thereof; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims (10)

1. A charging interface short circuit detection circuit, comprising:

the voltage sampling circuit is connected with a power supply pin in the charging interface and is used for sampling the voltage of a charging power supply transmitted through the power supply pin;

the controllable switch is connected between a selected functional pin in the charging interface and system ground after being connected with the short-circuit resistor in series; the selected functional pins are default suspended functional pins in the charging interface or pins which do not affect the original functions of the short-circuit resistor after being connected with the short-circuit resistor;

the detection circuit receives the sampling voltage output by the voltage sampling circuit, generates a switching signal according to the change of the sampling voltage and controls the on-off of the controllable switch;

and the alarm circuit is connected with the detection circuit and used for alarming when the power supply pin is short-circuited with the selected functional pin.

2. The charging interface short circuit detection circuit of claim 1, wherein the voltage sampling circuit is a resistor divider network connected between the power supply pin and system ground for dividing a charging power supply transmitted through the power supply pin to generate the sampled voltage.

3. The charge interface short-circuit detection circuit according to claim 2, wherein the resistance value of the short-circuit resistor is configured to satisfy the following condition:

when the short circuit resistor is connected with the resistor voltage dividing network in parallel, the voltage on the resistor voltage dividing network is obviously changed.

4. The charging interface short-circuit detection circuit according to claim 3, wherein the resistance of the short-circuit resistor is in an ohm level, and the resistance of the voltage dividing resistor in the resistor voltage dividing network is more than 1kΩ.

5. The charging interface short circuit detection circuit of claim 1, wherein the detection circuit comprises:

the power management chip receives the sampling voltage output by the voltage sampling circuit, and generates a fault signal when a charging power supply is connected to the charging interface and the sampling voltage is lower than a set threshold value;

and the processor is used for receiving the fault signal output by the power management chip, generating the switching signal and controlling the on-off of the controllable switch.

6. The charging interface short circuit detection circuit of claim 5, wherein the alarm circuit comprises a buzzer and/or an indicator light connected to the processor; and when the processor receives the fault signal output by the power management chip, the buzzer and/or the indicator lamp are controlled to sound and/or emit light, and an alarm is given.

7. The charging interface short circuit detection circuit of claim 1, wherein the controllable switch is a triode, a MOS transistor, or a thyristor.

8. The charging interface short circuit detection circuit of any one of claims 1 to 7, wherein the charging interface is a Type-C interface and the selected functional pin is a CC pin for detecting positive and negative insertion in the Type-C interface.

9. The charging interface short circuit detection circuit of claim 8, wherein,

the CC pins comprise two CC1 pins and CC2 pins;

the controllable switch and the short-circuit resistor comprise two groups, wherein the serial branch of one group of controllable switch and the short-circuit resistor is connected between the CC1 pin and the system ground, and the serial branch of the other group of controllable switch and the short-circuit resistor is connected between the CC2 pin and the system ground;

and the detection circuit controls the on-off of the two controllable switches according to the change of the sampling voltage output by the voltage sampling circuit.

10. A portable electronic device comprising a charging interface, wherein the charging interface is connected with a charging interface short circuit detection circuit according to any one of claims 1 to 9.