CN220711108U - Protection circuit for preventing connector from corrosion and short circuit and portable electronic equipment - Google Patents

Abstract

The utility model discloses a protection circuit for preventing connector corrosion and short circuit and portable electronic equipment, comprising a controllable switch, a temperature sensing element, a differential resistor, a differential operational amplifier and a detection circuit; the controllable switch is connected in a circuit for transmitting power or signals through a selected function pin of the connector; the differential resistor is connected between adjacent selected function pins in a bridging way; the non-inverting input end and the inverting input end of the differential operational amplifier are connected across the two ends of the differential resistor and are used for amplifying the differential pressure of the two ends of the differential resistor; when the temperature of the connector is sensed to be increased to exceed a safety threshold value through the temperature sensing element or the variation amplitude of the differential operational amplifier output signal exceeds a set threshold value, the detection circuit generates a switch signal to control the controllable switch to cut off a circuit for transmitting power or signals through the pins with the selected functions. The protection circuit can solve the problems of short circuit, micro short circuit or corrosion of the interface pins possibly caused by the foreign matters or liquid entering into the connector interface.

Description

Protection circuit for preventing connector from corrosion and short circuit and portable electronic equipment

Technical Field

The utility model belongs to the technical field of portable electronic equipment, and particularly relates to an anti-corrosion and short-circuit-proof protection circuit designed for a connector on the portable electronic equipment.

Background

The portable electronic device is a small-sized, lightweight, portable electronic product, such as VR product, etc. At present, most portable electronic devices are equipped with a rechargeable battery and a connector for both charging and data communication, such as a Type-C connector and a USB connector. The rechargeable battery is used for supplying power to a system circuit in the portable electronic 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.

As the connector that the interface used charges, often meet in daily use have foreign matter, sweat or other liquid get into the interface that charges, cause to appear short circuit, little short circuit or by circumstances such as liquid corrosion in the interface that charges between certain pin, then influence portable electronic equipment's life, reduce user's satisfaction to the product.

Disclosure of Invention

The utility model aims to provide a protection circuit for preventing corrosion and short circuit of a connector, which solves the problem that the use safety of the connector is affected because a connector interface is not easy to find when foreign matters or liquid enter.

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 protection circuit for preventing corrosion and short circuit of a connector, which is connected with at least two selected function pins in the connector and comprises a controllable switch, a temperature sensing element, a differential resistor, a differential operational amplifier and a detection circuit; wherein the controllable switch is connected in a circuit for transmitting power or signals to the selected functional pin; the temperature sensing element is used for sensing the temperature change of the connector; the differential resistor is connected between adjacent selected function pins in a bridging way; the non-inverting input end and the inverting input end of the differential operational amplifier are connected with the two ends of the differential resistor in a crossing way and are used for amplifying the differential pressure at the two ends of the differential resistor; the detection circuit is connected with the temperature sensing element and the output end of the differential operational amplifier, and generates a switching signal when the temperature sensing element senses that the temperature of the connector rises to exceed a safety threshold or the variation amplitude of the differential operational amplifier output signal exceeds a set threshold, and controls the controllable switch to cut off a circuit for transmitting power or signals through the selected functional pins.

In some embodiments of the present application, the temperature sensing element may be a thermistor, connected to the selected functional pin, and disposed in a position adjacent to the selected functional pin, so as to improve the sensitivity of connector temperature variation sensing; the detection circuit can convert the temperature change of the connector into the temperature change of the connector according to the resistance change of the thermistor, and then the on-off control of the controllable switch is completed.

In some embodiments of the present application, to reduce system power consumption, the detection circuit may select a low power microprocessor, including an analog-to-digital conversion pin; the analog-digital conversion pin is configured to be connected with a pull-up circuit, and the pull-up circuit can be externally connected or internally arranged; and one end of the thermistor is grounded, and the other end of the thermistor is respectively connected with the selected function pin and the analog-to-digital conversion pin of the low-power consumption microprocessor. Thus, when the resistance of the thermistor changes along with the temperature change of the connector, the voltage applied to the analog-to-digital conversion pin of the low-power-consumption microprocessor changes. The low-power consumption microprocessor can convert the resistance change of the thermistor according to the voltage change on the analog-to-digital conversion pin of the low-power consumption microprocessor, so that the real-time temperature of the connector is identified.

In some embodiments of the present application, the controllable switch may be a transistor, a MOS transistor, or a thyristor, so as to reduce the volume of the protection circuit, and facilitate the layout in the portable electronic device.

In some embodiments of the present application, the differential resistance may be configured as a kilo-ohm-scale resistance to increase the sensitivity to whether there is any fluid drip in the connector.

In some embodiments of the present application, for the case that the connector is a Type-C interface, the selected function pin may select a power pin VBUS, a positive and negative plug detection pin CC, a differential data communication pin pair d+, D-and an auxiliary communication pin SBU in the Type-C interface; the differential resistors are respectively connected between the power supply pin VBUS and the positive and negative plug detection pin CC, between the positive and negative plug detection pin CC and the differential data communication pin D+, between the differential data communication pin pair D+ and D-, and between the differential data communication pin D-and the auxiliary communication pin SBU in a bridging mode, and the differential operational amplifier is respectively connected at two ends of each differential resistor in a bridging mode, so that the protection effect on key pins in a Type-C interface can be achieved.

In some embodiments of the present application, for the case that the Type-C interface has two rows of upper and lower interfaces with the same function pins defined, two groups of protection circuits may be configured and connected to the two rows of upper and lower function pins in the Type-C interface in a one-to-one correspondence manner. Therefore, whether the plug inserted into the Type-C interface is in the forward plug or the reverse plug, the protection function of preventing the key pins in the Type-C interface from being corroded or shorted can be achieved.

In another aspect, the utility model also proposes a portable electronic device comprising a housing on which a connector for charging or data communication is provided; a protection circuit is packaged in the shell, and the protection circuit is connected with at least two selected function pins in the connector and comprises a controllable switch, a temperature sensing element, a differential resistor, a differential operational amplifier and a detection circuit; wherein the controllable switch is connected in a circuit for transmitting power or signals to the selected functional pin; the temperature sensing element is used for sensing the temperature change of the connector; the differential resistor is connected between adjacent selected function pins in a bridging way; the non-inverting input end and the inverting input end of the differential operational amplifier are connected with the two ends of the differential resistor in a crossing way and are used for amplifying the differential pressure at the two ends of the differential resistor; the detection circuit is connected with the temperature sensing element and the output end of the differential operational amplifier, and generates a switching signal when the temperature sensing element senses that the temperature of the connector rises to exceed a safety threshold or the variation amplitude of the differential operational amplifier output signal exceeds a set threshold, and controls the controllable switch to cut off a circuit for transmitting power or signals through the selected functional pins.

In some embodiments of the present application, for a portable electronic device having a battery and a charging chip in the housing that controls the charging and discharging of the battery, selected functional pins in the connector may be configured to connect to the charging chip through the controllable switch. Therefore, when foreign matters or liquid enter the connector interface, the charging process can be finished in time, and further expansion of fault influence is avoided.

In some embodiments of the present application, to achieve the connector protection function during shutdown of the portable electronic device, the detection circuit and the differential op-amp receiving electronic device may be configured to be battery powered such that the protection circuit remains operational during shutdown of the portable electronic device.

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

1. the utility model uses some key pins in the connector as selected function pins, and configures the temperature sensing element for the key pins. When foreign matters enter the connector interface and cause short circuit or micro short circuit faults between adjacent pins, the short circuit or micro short circuit position can continuously generate heat, and the temperature rise of the connector is abnormal. When the temperature of the connector exceeds a safety threshold, a power supply or a signal transmission line connected with the short-circuit pin is cut off in time, so that the temperature rising process can be ended, the connector or a shell around the connector is prevented from being burnt, and then the short-circuit/micro-short-circuit protection function is achieved.

2. According to the utility model, the differential resistor and the differential operational amplifier are arranged between the adjacent selected functional pins in the connector, when liquid falls between the adjacent two selected functional pins, the differential resistor is short-circuited, so that the differential pressure difference at two ends of the differential resistor is obviously changed, the change can be accurately monitored by the detection circuit after the differential operational amplifier is amplified, and the power supply or the signal transmission line connected with the pins is cut off, so that the phenomenon that electric charge and liquid exist simultaneously can be broken, and the problem that the electric charge and the liquid exist on the pins of the connector for a long time to cause corrosion and loss of functions of the pins is solved.

3. The utility model designs the anti-corrosion and micro-short circuit prevention protection circuit aiming at the connector arranged on the portable electronic equipment shell, greatly improves the safety and reliability of the portable electronic equipment on the premise of increasing smaller cost, is beneficial to prolonging the service life of the electronic equipment and improves the use experience of users.

4. The protection circuit is configured in the portable electronic equipment to eliminate potential safety hazards caused by foreign matters or liquid entering the connector interface, and compared with the traditional protection mode of additionally installing the rubber plug, the protection circuit can improve the overall appearance aesthetic degree of the portable electronic equipment and improve the overall quality 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 circuit diagram of one embodiment of a protection circuit for preventing corrosion and shorting of a connector in accordance with the present utility model;

FIG. 3 is a schematic diagram of an equivalent circuit between a differential operational amplifier and a differential resistor when no liquid is present in the connector interface;

fig. 4 is a schematic diagram of an equivalent circuit between the differential op-amp and the differential resistor when there is a liquid drop in the connector interface.

Detailed Description

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, unless otherwise indicated, the meaning of "a plurality" is two or more.

Aiming at the phenomenon that when foreign matters, sweat or other liquid enter the interface, certain functional pins in the interface of the connector can be short-circuited, micro-short-circuited or corroded, a protection circuit is designed, and whether the foreign matters enter the interface is identified by detecting the temperature rise condition of the connector; and judging whether liquid drops on the pins or not by detecting the change condition of differential impedance between adjacent pins in the interface. When the detection result indicates that foreign matters or liquid fall into the connector interface, the electric charge on the problem pin is eliminated by cutting off the power transmission line or the signal transmission line connected with the problem pin, so that the purpose of protecting the connector pin and avoiding damage to the connector or electronic equipment where the connector is positioned is achieved.

Existing connectors often have multiple pins disposed within them, including but not limited to a power pin (a pin for transmitting power), a ground pin (a pin for connecting to system ground), a function-specific pin (a pin for performing a function such as a data pin for transmitting a signal, a status pin for detecting a plugged state, etc.).

Taking a Type-C connector as an example for illustration, 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- (differential data communication pin pair): the device comprises two pairs, namely an upper pair and a lower pair, which are used for high-speed data communication, and the transmission speed can reach 10Gbps;

4. CC1/CC2 (CC pin, positive and negative insertion detection pin): 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 the only pin supporting bidirectional signal transmission, wherein the CC2 pin is also named as a VCONN pin in some cases;

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.

The present embodiment configures protection circuits for certain critical pins in the connector, such as power pins, data pins, status pins, etc. For the Type-C interface, the power supply pin VBUS, the positive and negative plug detection pins CC1/CC2, the differential data communication pin pair D+ and the auxiliary communication pin SBU1/SBU2 which are sequentially adjacent to each other are used as selected functional pins to be connected with an anti-short circuit/micro-short circuit and anti-corrosion protection circuit.

First, the structural design and the working principle of the short-circuit/micro-short-circuit prevention protection circuit are introduced.

When a metal foreign matter enters the interface of the connector, according to the difference of the self impedance of the metal foreign matter, the interface pins contacted with the metal foreign matter can be in short circuit states with different degrees, such as a direct short circuit state, a micro short circuit state and the like.

Take Type-C interface as an example for illustration. If the impedance of the metal foreign matter falling on two adjacent pins of the Type-C interface approaches zero, the two pins are in a direct short circuit state. If a metal foreign matter with impedance of tens of ohms or hundreds of ohms between the power supply pins VBUS and the CC pins of the Type-C interface falls on the metal foreign matter, a micro-short circuit state is displayed between the power supply pins VBUS and the CC pins. For portable electronic devices configured with a Type-C interface, the Type-C interface is typically connected to a charging chip Charger IC inside the electronic device, as shown in fig. 2. The charging chip Charger IC can detect the direct short circuit state between the power supply pins VBUS and CC pins, but cannot detect the micro short circuit state. When the Type-C interface is externally connected with an adapter or a main device, the micro-short circuit position can continuously generate heat according to ohm law and Joule law until the plastic shell around the Type-C interface is burnt out, so that the damage is extremely high.

In order to solve the above-mentioned problem, the present embodiment connects a temperature sensing element to a selected functional pin of the connector interface, and identifies a micro-short circuit state between pins by sensing a temperature change on the selected functional pin.

In some embodiments, the temperature sensing element may be a thermistor connected to a selected functional pin of the connector interface and disposed in close proximity to the selected functional pin to increase sensitivity to temperature rise detection of the connector.

Taking a Type-C interface as an example, a plurality of negative temperature coefficient thermistors NTC 1-NTC 5 can be selected to be respectively connected among the power supply pin VBUS, the positive and negative plug detection pin CC1/2, the differential data communication pin pair d+, D-, the auxiliary communication pin SBU1/2 and the ground, as shown in fig. 2, and the layout positions are next to the selected function pins. When some selected functional pins are in a short circuit or micro short circuit state, the temperature of the selected functional pins is quickly increased or continuously increased, the resistance value of the thermistor connected with the selected functional pins is reduced, and the selected functional pins are in a certain proportional relation. The configuration detection circuit detects the resistance change of the thermistors NTC 1-NTC 5, and the temperature change of the pins can be converted according to the resistance change, so that the short circuit or micro short circuit faults of the selected functional pins can be judged.

In some embodiments, a low-power microprocessor MCU may be disposed in the detection circuit to detect the resistance change of the thermistors NTC1 to NTC5, so as to achieve the purposes of reducing the system power consumption and prolonging the endurance time of the electronic device.

Specifically, as shown in fig. 2, a plurality of analog-to-digital conversion pins ADC4 to ADC8 in the microprocessor MCU may be configured to be connected to a plurality of selected function pins in a one-to-one correspondence manner, and pull-up circuits are respectively configured on the analog-to-digital conversion pins ADC4 to ADC8, for example, connected to a dc power supply through pull-up resistors, which are not shown in the figure. The pull-up circuit can be connected with a thermistor NTC1/2/3/4/5 in an external or internal microprocessor MCU mode to form a voltage division network. When the resistance of the thermistor NTC1/2/3/4/5 decreases as the temperature of the selected functional pin increases, the voltage on the analog-to-digital conversion pin ADC4/5/6/7/8 of the microprocessor MCU decreases. When the voltage on a certain analog-to-digital conversion pin ADC4/5/6/7/8 decreases to a certain value, it indicates that the temperature rise of the selected functional pin connected to the analog-to-digital conversion pin exceeds the safety threshold, and a short circuit or micro-short circuit fault exists. In order to avoid further expansion of the influence caused by faults, a controllable switch can be additionally arranged in each circuit for transmitting power or signals of the selected functional pins, and the controllable switch is controlled to cut off the power transmission circuit or the signal transmission circuit connected with the selected functional pins so as to eliminate charges on the selected functional pins, namely, remove electricity, thereby achieving the purpose of protecting the connector and the electronic equipment where the connector is positioned.

Take Type-C interface disposed on the portable electronic device as an example for illustration. As shown in fig. 2, a controllable switch K1-K6 is respectively connected in series in a power supply or signal transmission line of the charging chip charge IC, wherein the two power supply pins VBUS, the positive and negative plug detection pin CC1/2, the differential data communication pin pair d+, D-and the auxiliary communication pin SBU1/2 of the Type-C interface are connected. The controllable switches K1-K6 can be electronic elements such as triodes, MOS tubes and thyristors, and the on-off states of the electronic elements can be changed by control signals. And the switch signals are output by the multiple paths of GPIO ports GPIO 1-GPIO 6 of the microprocessor MCU to control the on-off of each path of controllable switch K1-K6 so as to switch on or off the power transmission line or the signal transmission line where each path of controllable switch K1-K6 is positioned, thereby achieving the purpose of short circuit/micro short circuit protection.

The working principle is as follows: when the Type-C interface external adapter enters a charging process, if a direct short circuit or a micro short circuit is generated between a power supply pin VBUS and a CC pin of the Type-C interface due to the falling of foreign matters, the charging process can be directly detected and blocked by a charging chip Charger IC in the electronic equipment for the direct short circuit state, so that protection is realized. For micro-short conditions, the power pin VBUS will transfer current to the CC pin through the foreign body resistance and generate heat for a period of time (e.g., tens of minutes). Since the thermistors NTC1, NTC2 are close to the power supply pins VBUS and CC, a temperature change on the pins is sensed at the first time, and thus the resistance values of the thermistors NTC1, NTC2 are changed. After the microprocessor MCU detects the change, the controllable switches K1 and K2 connected with the power supply pins VBUS and CC are immediately cut off or all the controllable switches K1-K6 connected with the pins with the selected functions are cut off so as to protect the whole system.

Since the signal transmission channels of the adapter and the charging chip Charger IC are disconnected, the handshake communication cannot be performed normally. At this time, the adapter can prohibit the output of the charging power supply according to the PD protocol (rapid charging protocol) rule after the handshake protocol cannot be completed, thoroughly cut off the heating source, and end the charging process.

If the electronic equipment provided with the Type-C interface is in a starting-up state, prompt information can be displayed on a display screen of the electronic equipment, and a user is reminded to clean foreign matters in time and then work normally. Of course, a voice alarm mode can be adopted to remind the user of cleaning foreign matters in the interface.

In order to enable the protection circuit of the embodiment to complete the short circuit/micro short circuit protection function during the shutdown of the electronic equipment, the battery BAT in the electronic equipment can be utilized to supply power to the microprocessor MCU, so that the microprocessor MCU keeps an operation state during the shutdown of the electronic equipment, and the heating condition of the interface pins is continuously monitored. Since the direct short circuit between the pins also causes the pins to generate heat, the micro-short circuit protection measures of the embodiment are still suitable for short circuit protection.

If no foreign matter exists between the VBUS and CC pins of the power supply pins in the Type-C interface, the foreign matter only falls between other selected function pins, so that short circuit or micro short circuit occurs between other selected function pins, and in this case, as long as current flows between the pins, obvious temperature rise of the pins can be caused. The microprocessor MCU judges the temperature rise condition of the pin by detecting the resistance change of the thermistor connected with the pin. When the temperature of the pin exceeds a safety threshold, all the controllable switches K1-K6 are controlled to be disconnected, and the signal transmission channels of the adapter and the charging chip Charger IC are cut off, so that the adapter can not finish a handshake protocol to stop power output, the charging process is finished, the whole system is protected, and the aim of short circuit/micro short circuit protection is achieved.

The structural design and the working principle of the anti-corrosion protection circuit are described below.

When sweat or other liquid is dropped into the interface of the connector, the two adjacent pins are often connected through the liquid. When there is an electrical charge on the pin, it may occur that the electrical charge and the liquid coexist. If the condition exists for a long time, the pins are corroded, so that the functions are lost, and the normal use of the connector is affected.

In order to detect the liquid connection state between the adjacent pins, the embodiment bridges the differential resistor between every two adjacent selected functional pins, and bridges the differential operational amplifier at two ends of the differential resistor. As shown in fig. 3, when there is no liquid between the adjacent selected functional pins, the differential impedance connected between the non-inverting input terminal + and the inverting input terminal-of the differential operational amplifier U1 is the impedance of the differential resistor R1. At this time, the differential operational amplifier U1 outputs a fixed voltage value, i.e. a voltage value obtained by amplifying the voltage difference across the differential resistor R1. The analog-digital conversion pin ADC1 of the microprocessor MCU is utilized to receive the voltage value, and whether the differential impedance is abnormal can be judged according to the change condition of the voltage value. For example, if the change width of the output signal of the differential operational amplifier U1 exceeds a set threshold, it is considered that liquid drops.

As shown in fig. 4, when adjacent selected functional pins are connected by a fluid, the differential resistor R1 is shorted. At this time, the voltage output by the differential operational amplifier U1 will change obviously and be detected by the microprocessor MCU, if the change amplitude of the output voltage of the differential operational amplifier exceeds the set threshold, the microprocessor MCU controls the controllable switches K1 and K2 connected with the problem pins to be disconnected, or controls all the controllable switches K1-K6 to be disconnected, so as to eliminate charges on the problem pins and avoid coexistence of the charges and liquid, thus avoiding the pins from being corroded and achieving the protection purpose.

Taking the Type-C interface as an example, as shown in fig. 2, a differential resistor R1 may be bridged between the power supply pin VBUS and the positive and negative plug detection pin CC, a differential resistor R2 may be bridged between the positive and negative plug detection pin CC and the differential data communication pin d+, a differential resistor R3 may be bridged between the differential data communication pin pair d+ and D-, and a differential resistor R4 may be bridged between the differential data communication pin D-and the auxiliary communication pin SBU. Then, the non-inverting input end and the inverting input end of the differential operational amplifier U1 are connected across the two ends of the differential resistor R1, the non-inverting input end and the inverting input end of the differential operational amplifier U2 are connected across the two ends of the differential resistor R2, the non-inverting input end and the inverting input end of the differential operational amplifier U3 are connected across the two ends of the differential resistor R3, and the non-inverting input end and the inverting input end of the differential operational amplifier U4 are connected across the two ends of the differential resistor R4. And correspondingly connecting the output ends of the differential operational amplifiers U1-U4 to four analog-to-digital conversion pins ADC 1-ADC 4 of the microprocessor MCU, and judging whether liquid drops on the selected function pins in the Type-C interface by the microprocessor MCU through detecting the voltage values output by the differential operational amplifiers U1-U4.

The working principle is as follows: when the Type-C interface external adapter enters the charging process, if liquid is dripped between the VBUS and CC pins of the Type-C interface, the microprocessor MCU can detect that the differential impedance is obviously changed. At this time, the microprocessor MCU can output switch signals through GPIO ports GPIO1 and GPIO2 respectively, and control the controllable switches K1 and K2 connected with the power supply pins VBUS and CC to be disconnected, or control all the controllable switches K1 to K6 to be disconnected. Once the CC path between the adapter and the charging chip Charger IC is disconnected, handshake communication between the two cannot be performed normally. At this time, the adapter can prohibit the output of the charging power supply according to the PD protocol (fast charging protocol) after the handshake protocol cannot be completed, so that the charges on the power supply pins VBUS and CC disappear, and thus the corrosion on the power supply pins VBUS and CC caused by the coexistence of charges and liquid is avoided. The microprocessor MCU can monitor the state of the differential impedance in real time until the liquid is dried and the differential impedance is recovered to be normal, and then the controllable switches K1-K6 are controlled to be closed for normal charging and communication.

During the period, if the electronic equipment is in a starting-up state, a prompt message can be displayed through a display screen on the electronic equipment or a voice broadcasting mode is adopted to remind a user to unplug the adapter as soon as possible and to dry the adapter. If the electronic equipment is in a shutdown state, the built-in battery BAT of the electronic equipment can be configured to supply power for the differential operational amplifiers U1-U4 and the microprocessor MCU, so that the microprocessor MCU and the differential operational amplifiers U1-U4 still continuously operate during the shutdown period of the electronic equipment, and whether liquid drops in the connector interface is continuously monitored.

If no liquid exists between the VBUS and CC pins of the power supply pins in the Type-C interface, the liquid only drops between other selected function pins, so that the other selected function pins are short-circuited by the liquid. Under the condition, the microprocessor MCU can also detect the change of differential impedance, so as to control all the controllable switches K1-K6 to be disconnected, cut off the signal transmission channels of the adapter and the charging chip Charger IC, stop the power output of the adapter because the adapter cannot complete a handshake protocol, further end the charging process, protect the whole system and achieve the aim of anti-corrosion protection.

During the period that the Type-C interface is not plugged into the adapter, if liquid drops between the power supply pins VBUS and CC, the charging chip Charger IC can send out handshake voltage signals regularly, so that short circuit between the power supply pins VBUS and CC is caused, and the voltage of the analog-to-digital conversion pin ADC1 transmitted to the microprocessor MCU is obviously changed. After detecting the voltage change, the microprocessor MCU outputs a switching signal to control the controllable switches K1 and K2 to be disconnected, or controls all the controllable switches K1 to K6 to be disconnected, so that handshake voltage signals sent by the charging chip Charger IC are not transmitted to the CC pins, and the CC pins are prevented from being corroded.

Considering that the Type-C interface supports the forward and backward plugging function, the Type-C interface includes two rows of interfaces with the same definition of function pins, as shown in fig. 1. The protection circuits provided by the embodiment of the utility model can be configured in the electronic equipment and are respectively connected with the upper row of functional pins and the lower row of functional pins in the Type-C interface in a one-to-one correspondence manner, so that the effect of protecting the interface pins can be achieved no matter whether the plug of the adapter is inserted positively or reversely.

According to the embodiment, the protection circuit is additionally arranged in the electronic equipment provided with the Type-C interface, so that the use safety and reliability of the electronic equipment can be greatly improved on the premise of increasing smaller cost. Of course, the protection circuit of the embodiment is also applicable to a USB interface, a DP interface, an HDMI interface, etc. to realize the protection functions of short circuit/micro short circuit prevention and corrosion prevention of the interface pins.

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 protection circuit for preventing corrosion and short-circuiting of a connector, which is connected with at least two selected function pins in the connector; characterized by comprising the following steps:

a controllable switch connected in a line for transmitting power or signals to the selected function pin;

a temperature sensing element for sensing a temperature change of the connector;

differential resistors connected across adjacent selected functional pins;

the non-inverting input end and the inverting input end of the differential operational amplifier are connected with the two ends of the differential resistor in a crossing way and are used for amplifying the differential pressure of the two ends of the differential resistor;

and the detection circuit is connected with the temperature sensing element and the output end of the differential operational amplifier, and generates a switching signal when the temperature sensing element senses that the temperature of the connector rises above a safety threshold or the variation amplitude of the differential operational amplifier output signal exceeds a set threshold, so as to control the controllable switch to cut off a circuit for transmitting power or signals through the selected functional pin.

2. The protection circuit for preventing corrosion and shorting of a connector according to claim 1, wherein,

the temperature sensing element is a thermistor, is connected with the selected function pin and is arranged at a position close to the selected function pin;

the detection circuit converts the temperature change of the connector according to the resistance change of the thermistor.

3. The protection circuit for preventing corrosion and shorting of a connector according to claim 2, wherein,

the detection circuit is a low-power-consumption microprocessor and comprises an analog-to-digital conversion pin, and the analog-to-digital conversion pin is connected with the pull-up circuit;

one end of the thermistor is grounded, and the other end of the thermistor is respectively connected with the selected function pin and the analog-to-digital conversion pin of the low-power-consumption microprocessor.

4. The protection circuit for preventing corrosion and short-circuiting of a connector according to claim 1, wherein the controllable switch is a transistor, a MOS transistor or a thyristor.

5. The protection circuit for preventing corrosion and shorting of a connector as recited in claim 1, wherein said differential resistance is a kilo-ohm resistance.

6. The protection circuit for preventing corrosion and short-circuiting of connectors according to any of claims 1 to 5, wherein,

the connector is a Type-C interface, and the selected function pins are a power supply pin VBUS, a positive and negative plug detection pin CC, a differential data communication pin pair D+, D-and an auxiliary communication pin SBU in the Type-C interface;

and one differential resistor is respectively connected between the power supply pin VBUS and the positive and negative plug detection pin CC, between the positive and negative plug detection pin CC and the differential data communication pin D+, between the differential data communication pin pair D+ and D-, and between the differential data communication pin D-and the auxiliary communication pin SBU in a bridging manner, and two ends of each differential resistor are respectively connected with one differential operational amplifier in a bridging manner.

7. The connector corrosion and short circuit protection circuit of claim 6,

the Type-C interface comprises upper and lower rows of interfaces with the same definition of function pins;

the protection circuit comprises two groups, and the two groups are respectively connected with the upper row of functional pins and the lower row of functional pins in the Type-C interface in a one-to-one correspondence manner.

8. A portable electronic device comprising a housing having a connector disposed thereon for charging or data communication; a protection circuit for preventing corrosion and short-circuiting of a connector according to any one of claims 1 to 7 is enclosed in the housing, and is connected to the connector.

9. The portable electronic device of claim 8, wherein the portable electronic device comprises a portable electronic device,

a battery and a charging chip for controlling the charge and discharge of the battery are packaged in the shell;

and a selected functional pin in the connector is connected with the charging chip through the controllable switch.

10. The portable electronic device of claim 9, wherein the detection circuit and differential op-amp receive the battery power and remain operational during shutdown of the portable electronic device.