Current protection circuit for external load of terminal device and electronic device

Abstract

The utility model relates to the technical field of current protection. Especially, it relates to a current protection circuit for terminal equipment external load and electronic equipment, which comprises a load connector, an MCU module, an ADC acquisition module and a MOS switch control circuit. The load connector is used to connect a load device and feed back the connection state to the MCU module. The MOS switch control circuit is connected with the load connector and used to control the current output of the load connector. The ADC acquisition module is connected with the load connector and used to detect whether the current value of the load device exceeds a threshold. The MCU module is connected with the ADC voltage acquisition module and used to receive the signal of the ADC acquisition module and control the operation of the MOS switch control circuit according to the signal. The application improves the problem that the circuit is prone to overcurrent, short circuit and other faults and overcurrent protection is not timely when the product is connected with an external device.

Description

Technical Field

[0001] This utility model relates to the field of current protection circuit technology, and more specifically, to a current protection circuit and electronic device for an external load of a terminal device. Background Technology

[0002] With the continuous popularization of technology, the need for customized functions of terminal devices such as smartphones, tablets, and in-vehicle electronic systems is increasing. The market demand for specialized equipment such as in-vehicle intelligent terminals is showing a diversified trend, requiring the expansion of various functional modules through external interfaces such as micro-USB, TYPE-C, and DC external interfaces.

[0003] In existing technologies, when connecting external devices to terminal devices, faults such as excessive current and short circuits frequently occur due to factors such as inconsistent quality of the external devices themselves, differences in interface compatibility, and complex and variable operating environments. Therefore, there is a need for a circuit applicable to communication technology fields such as smartphones, tablets, and automotive electronic systems to solve the problems of untimely overcurrent protection and poor compatibility in existing technologies, and to improve the safety and reliability of terminal devices in complex application scenarios. Utility Model Content

[0004] The technical problem to be solved by this utility model is that when the product is connected to external equipment, it is prone to faults such as excessive current and short circuit, and the overcurrent protection is not timely. In view of the above-mentioned defects of the prior art, this utility model provides a current protection circuit and electronic equipment for the external load of terminal equipment.

[0005] The technical solution adopted by this utility model to solve its technical problem is: A current protection circuit for an external load of a terminal device includes a load connector, an MCU module, an ADC acquisition module, and a MOS switch control circuit. The load connector is used to connect the load device and feed back the connection status to the MCU module; The MOS switch control circuit is connected to the load connector and is used to detect whether the current value of the device exceeds the threshold. The MCU module is connected to the ADC voltage acquisition module and is used to receive signals from the ADC acquisition module and control the operation of the MOS switch control circuit according to the signals.

[0006] Preferably, the MOS switch control circuit includes a first control unit and a second control unit; The first control unit receives control signals from the MCU module and controls the operation of the second control unit; The second control unit is used to control the current output of the load connector.

[0007] Preferably, the first control unit includes a transistor Q16, a resistor R130, a resistor R132, and a resistor R133; the base of the transistor Q16 is connected to the MAIN_EN signal pin of the MCU module through the resistor R132, the emitter is grounded, and the collector is connected to the resistor R130; one end of the resistor R133 is connected to the base of the transistor Q16, and the other end is grounded.

[0008] Preferably, the second control unit includes a MOSFET Q15 and a resistor R128; the gate of the MOSFET Q15 is connected to the power supply terminal through the resistor R128, and is connected to the collector of the transistor Q16 through the resistor R130; the source of the MOSFET Q15 is connected to the power supply terminal; and the drain of the MOSFET Q15 is connected to the load connector.

[0009] Preferably, the ADC acquisition module includes a resistor R129, a sampling resistor R131, a Zener diode D11, and a filter capacitor C102; the resistor R129 is connected in series in the MAIN_CURRENT_ADC1 signal path; the anode of the Zener diode D11 is grounded, and the cathode is connected to the MAIN_CURRENT_ADC1 signal path; one end of the filter capacitor C102 is connected to the resistor R129, and the other end is grounded; the sampling resistor R131 is connected in series at the end of the MAIN_CURRENT_ADC1 signal path and is grounded.

[0010] Preferably, the load connector includes a VBUS pin, a DM pin, a DP pin, a USB_ID pin, and a G pin; wherein the VBUS pin is used to connect to the power supply voltage, the DM pin and the DP pin are used to transmit data signals, the USB_ID pin is used to identify the connection status, and the G pin is used to ground.

[0011] Preferably, the load connector is connected to diodes D8 and D9, rectifier diode D10, Zener diode D11, Zener diode D12, and filter capacitor C100. The anodes of diodes D8 and D9 are grounded, and the cathodes are connected to the VBUS pin of the load connector to suppress surge voltage on the VBUS pin and protect the circuit. The rectifier diode D10 has its anode grounded and its cathode connected to the VBUS pin of the load connector to prevent reverse voltage from damaging the circuit. The anode of the Zener diode D11 is grounded, and the cathode is connected to the relevant signal path of the load connector through resistor R129, etc.; the anode of the Zener diode D12 is grounded, and the cathode is connected to the signal path of the load connector such as USB_ID, which is used to stabilize the signal voltage and avoid voltage fluctuations from affecting detection and control. The filter capacitor C100 has one end connected to the VBUS pin of the load connector and the other end grounded, used to filter out high-frequency noise in the VBUS voltage.

[0012] on the other hand An electronic device that integrates a current protection circuit for any of the external load devices of a tablet computer.

[0013] The beneficial effects of this utility model are as follows: 1. It has overcurrent protection function. By comparing the load current with the threshold in real time, it quickly cuts off the circuit when the current is abnormal, preventing terminal equipment and external load from being damaged by overcurrent, and significantly improving system safety. 2. Two-stage control reliability: The hierarchical design of the MOS switch control circuit enhances anti-interference capability. The first control unit acts as a signal buffer, avoiding direct driving of the power MOS transistor by the MCU and reducing the risk of false triggering; the second control unit uses a MOS transistor with low on-resistance to reduce power consumption and heat generation. 3. Surge and reverse voltage protection: The multi-diode protection structure effectively suppresses voltage fluctuations at the VBUS pin, preventing damage to the circuit from surges and reverse voltages. It is suitable for complex electromagnetic environments and applications with frequent plugging and unplugging. 4. Signal stability optimization: The filtering and voltage regulation design of the ADC acquisition module ensures the accuracy of the current sampling signal and reduces noise interference; the status feedback of the USB_ID pin enables the MCU to dynamically adjust the control strategy, improving system adaptability; 5. Integration and compatibility: The circuit structure is compact and easy to integrate into terminal devices (such as mobile phones and tablets). It also supports a variety of external loads (such as headphones and chargers) and has good versatility and scalability. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is an overall circuit diagram of the current protection circuit for the external load of the terminal device in this embodiment of the application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, of the embodiments of this utility model. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0016] Example 1 The preferred embodiment of this utility model is as follows: Figure 1 As shown, a current protection circuit for an external load of a terminal device includes a load connector, an MCU module, an ADC acquisition module, and a MOS switch control circuit. The load connector is used to connect load devices and feed back the connection status to the MCU module. The load connector includes VBUS pin, DM pin, DP pin, USB_ID pin and G pin. Among them, the VBUS pin is used to connect the power supply voltage, the DM pin and DP pin are used to transmit data signals, the USB_ID pin is used to identify the connection status and the G pin is used to ground.

[0017] The MOS switch control circuit, connected to the load connector, is used to detect whether the current value of the device exceeds a threshold. The MOS switch control circuit includes a first control unit and a second control unit. The first control unit receives control signals from the MCU module and controls the operation of the second control unit. The second control unit is used to control the current output of the load connector.

[0018] The first control unit includes a transistor Q16, resistors R130, R132, and R133. The base of transistor Q16 is connected to the MAIN_EN signal pin of the MCU module through resistor R132, the emitter is grounded, and the collector is connected to resistor R130. One end of resistor R133 is connected to the base of transistor Q16, and the other end is grounded.

[0019] The second control unit includes a MOSFET Q15 and a resistor R128; the gate of the MOSFET Q15 is connected to the power supply terminal through the resistor R128, and is connected to the collector of the transistor Q16 through the resistor R130; the source of the MOSFET Q15 is connected to the power supply terminal; and the drain of the MOSFET Q15 is connected to the load connector.

[0020] The MCU module is connected to the ADC voltage acquisition module. It is used to receive signals from the ADC acquisition module and control the MOS switch control circuit to operate based on the signals.

[0021] The ADC acquisition module includes a resistor R129, a sampling resistor R131, a Zener diode D11, and a filter capacitor C102. The resistor R129 is connected in series in the MAIN_CURRENT_ADC1 signal path. The anode of the Zener diode D11 is grounded, and the cathode is connected to the MAIN_CURRENT_ADC1 signal path. One end of the filter capacitor C102 is connected to the resistor R129, and the other end is grounded. The sampling resistor R131 is connected in series at the end of the MAIN_CURRENT_ADC1 signal path and is also grounded.

[0022] The load connector has diodes D8 and D9 connected to it, with their anodes grounded and cathodes connected to the VBUS pin of the load connector. These diodes are used to suppress surge voltage on the VBUS pin and protect the circuit. A rectifier diode D10 has its anode grounded and its cathode connected to the VBUS pin of the load connector to prevent reverse voltage from damaging the circuit. Zener diodes D11 and D12 are also connected. Zener diode D11 has its anode grounded and its cathode connected to the relevant signal path of the load connector via resistor R129. Zener diode D12 has its anode grounded and its cathode connected to signal paths such as the USB_ID pin of the load connector to stabilize the signal voltage and prevent voltage fluctuations from affecting detection and control. A filter capacitor C100 has one end connected to the VBUS pin of the load connector and the other end grounded to filter out high-frequency noise in the VBUS voltage.

[0023] When an external device is plugged into the load connector interface, the USB_ID pin detection signal is fed back to the MCU module. When the MCU module detects that an external load device is connected, it pulls the MAIN_EN signal high, turns on the transistor Q16, and the collector level goes low, causing the gate potential of the MOSFET Q15 to go low and the MOSFET to turn on, thus powering on VBUS_5V. The USB communication protocol handshake is completed through the DP / DM pins, and the load works normally.

[0024] After the load starts working, the current is monitored by the voltage value across resistor R131 (Ohm's Law: I*R=U). The voltage value across resistor R131 is fed back to the MCU module via the current-limiting resistor R129 using the MAIN_CURRENT_ADC1 signal. The MCU module receives the MAIN_CURRENT_ADC1 signal, reads the voltage value across the load, and feeds it back to the MCU module for monitoring. When the ADC value is within the software preset range, the operation is normal.

[0025] When a short circuit or high current occurs in the load, the voltage across resistor R131 will continuously rise. When the MAIN_CURRENT_ADC1 signal value rises above the warning value set in the software, the MCU controls MAIN_EN to go low, resulting in a low base and high collector for Q16, thus cutting off transistor Q16. This causes the gate potential of MOSFET Q15 to rise, cutting off the MOSFET and shutting off the VBUS_5V output power, stopping the load from operating and completing the protection operation. The circuit can detect the presence of an external device based on the USB_ID pin detection signal of the load connector interface, and use the MAIN_EN signal in software to determine whether VBUS_5V output is needed, saving overall power consumption.

[0026] The implementation principle of a current protection circuit for an external load of a terminal device according to an embodiment of this application is as follows: the circuit consists of a load connector, an MCU module, an ADC acquisition module, and a MOS switch control circuit. The load connector connects to the external device and provides feedback on the connection status. The MOS switch control circuit detects the current, and the MCU module controls the MOS switch based on the signal acquired by the ADC.

[0027] The MOS switch control circuit adopts a two-stage control structure. The first control unit (transistor Q16 and resistor network) receives the MAIN_EN signal from the MCU and controls the conduction and turn-off of the second control unit (MOS transistor Q15), thereby controlling the current output of the load. When MAIN_EN is high, the transistor is turned on, pulling down the gate voltage of the MOS transistor to turn it on; conversely, it is turned off.

[0028] The ADC acquisition module converts the current signal into a voltage signal (MAIN_CURRENT_ADC1) through sampling resistor R131. After processing by resistor R129, filter capacitor C102, and Zener diode D11, the signal is input to the MCU for real-time monitoring. The MCU compares this signal with a preset threshold to determine whether the load power supply needs to be cut off.

[0029] The VBUS pin of the load connector is equipped with multiple protection components: diodes D8 and D9 suppress surge voltage; rectifier diode D10 prevents reverse voltage; Zener diodes D11 and D12 stabilize signal voltage; and filter capacitor C100 filters out high-frequency noise. The USB_ID pin is used to identify the load connection status and assist the MCU in decision-making.

[0030] Example 2 An electrical device, an electronic device, has an integrated current protection circuit for any terminal device's external load.

[0031] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A current protection circuit for an external load of a terminal device, characterized by Includes load connector, MCU module, ADC acquisition module and MOS switch control circuit; The load connector is used to connect the load device and feed back the connection status to the MCU module; The MOS switch control circuit is connected to the load connector and is used to control the current output of the load connector. The ADC acquisition module is connected to the load connector and is used to detect whether the current value of the load device exceeds the threshold. The MCU module is connected to the ADC acquisition module and is used to receive signals from the ADC acquisition module and control the operation of the MOS switch control circuit according to the signals.

2. The current protection circuit for external load of a terminal device according to claim 1, wherein The MOS switch control circuit includes a first control unit and a second control unit; The first control unit receives control signals from the MCU module and controls the operation of the second control unit; The second control unit is used to control the current output of the load connector.

3. The current protection circuit for external load of a terminal device according to claim 2, wherein The first control unit includes a transistor Q16, a resistor R130, a resistor R132, and a resistor R133; the base of the transistor Q16 is connected to the MAIN_EN signal pin of the MCU module through the resistor R132, the emitter is grounded, and the collector is connected to the resistor R130; one end of the resistor R133 is connected to the base of the transistor Q16, and the other end is grounded.

4. The current protection circuit for external load of a terminal device according to claim 3, wherein The second control unit includes a MOSFET Q15 and a resistor R128; the gate of the MOSFET Q15 is connected to the power supply terminal through the resistor R128, and is connected to the collector of the transistor Q16 through the resistor R130, the source is connected to the power supply terminal, and the drain is connected to the load connector.

5. The current protection circuit for external load of a terminal device according to claim 1, wherein The ADC acquisition module includes a resistor R129, a sampling resistor R131, a Zener diode D11, and a filter capacitor C102. The resistor R129 is connected in series in the MAIN_CURRENT_ADC1 signal path. The anode of the Zener diode D11 is grounded, and the cathode is connected to the MAIN_CURRENT_ADC1 signal path. One end of the filter capacitor C102 is connected to the resistor R129, and the other end is grounded. The sampling resistor R131 is connected in series at the end of the MAIN_CURRENT_ADC1 signal path and is also grounded.

6. The current protection circuit for external load of a terminal device according to claim 1, wherein The load connector includes a VBUS pin, a DM pin, a DP pin, a USB_ID pin, and a G pin; wherein the VBUS pin is used to connect to the power supply voltage, the DM pin and the DP pin are used to transmit data signals, the USB_ID pin is used to identify the connection status, and the G pin is used to ground.

7. The current protection circuit for external loads of a terminal device according to claim 6, characterized in that The load connector is connected to diodes D8 and D9, rectifier diode D10, Zener diode D11, Zener diode D12, and filter capacitor C100. The anodes of diodes D8 and D9 are grounded, and the cathodes are connected to the VBUS pin of the load connector to suppress surge voltage on the VBUS pin and protect the circuit. The rectifier diode D10 has its anode grounded and its cathode connected to the VBUS pin of the load connector to prevent reverse voltage from damaging the circuit. The anode of the voltage stabilizing diode D11 is grounded, and the cathode is connected with the signal path of the load connector through the resistor R129; the anode of the voltage stabilizing diode D12 is grounded, and the cathode is connected with the USB_ID signal path of the load connector, for stabilizing the signal voltage and avoiding the influence of voltage fluctuation on detection and control; The filter capacitor C100 is connected with the VBUS pin of the load connector at one end and grounded at the other end, for filtering the high-frequency noise in the VBUS voltage.

8. An electronic device, comprising: The electronic device is integrated with the current protection circuit of the external load of the terminal device in any of claims 1-7.

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