A USB charging reverse connection short circuit protection circuit
By designing anti-reverse and short-circuit circuits in the vehicle charging circuit, and using components such as MOS tubes and relays, the problem of insufficient protection of existing vehicle charging circuits in the case of reverse connection and short-circuit is solved, and the security protection of protocol chips and the safety of car charging is improved.
Patent Information
- Application Number
- CN202421206510.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-29
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-05-29
AI Technical Summary
The existing car charging circuit may cause the protocol chip to burn when the USB interface and the in-car circuit are reversed, and it lacks effective short-circuit protection, affecting the safety of the car.
Design a USB charging anti-reverse short circuit circuit, including anti-reverse circuit and anti-short circuit circuit. The anti-reverse circuit uses MOS tubes and voltage-regulating diodes to achieve reverse connection protection, while the anti-short circuit uses relays and switches to achieve short circuit protection.
Effectively protect the protocol chip from being burned, and realizes the anti-reverse and short-circuit protection functions of USB charging lines, ensuring the safety of car charging, and is flexible in design and low in cost, without software algorithm control.
Smart Images
Figure CN222706280U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of automobile circuit design, in particular to a USB charging reverse connection short circuit prevention circuit. Background Art
[0002] At present, car chargers are widely used in cars, and the charging power is getting higher and higher. However, the car charger may be damaged during operation due to the reverse connection of the USB interface and the wiring in the car, or the load and the car charger may be damaged due to a short circuit of the connected load. If anti-reverse connection protection and short circuit protection are not added, it will seriously affect the safety of the car. Existing car charging circuits usually use dedicated protocol integrated circuits. This method uses a dedicated protocol chip. If a protection circuit is not added to the protocol chip, there may still be a risk of burning the protocol chip when the line is reversed. Therefore, it is necessary to design a low-cost anti-reverse connection short-circuit protection circuit that does not require software control to realize the protection function of car-related on-board charging. Utility Model Content
[0003] The utility model aims to add a protection circuit to a charging protocol chip of a car to prevent the protocol chip from being burned when a USB interface and a line in the car are reversely connected.
[0004] The technical solution adopted by the utility model to solve its technical problems is:
[0005] A USB charging reverse connection short circuit protection circuit, comprising a reverse connection protection circuit and a short circuit protection circuit:
[0006] The anti-reverse connection circuit includes: a MOS tube Q1, a second resistor R2, a third resistor R3, and a voltage-stabilizing diode ZD1. The drain of the MOS tube Q1 is connected to the power supply IGN, the source of the MOS tube Q1 is respectively connected to the first end of the third resistor R3, the cathode of the voltage-stabilizing diode ZD1, and the VIN pin of the fast charging protocol chip U1, and the gate of the MOS tube Q1 is respectively connected to the first end of the second resistor R2, the second end of the third resistor R3, and the anode of the voltage-stabilizing diode ZD1;
[0007] The anti-short circuit includes: a relay K1 and a switch S1. The common end of the relay K1 is respectively connected to the SW pin and the VOUT pin of the fast charging protocol chip U1. The normally closed end of the relay K1 is connected to the first end of the switch S1. The second end of the switch S1 is respectively connected to the VCC pin of the USB interface, the normally open end of the relay K1, and the positive pole of the relay K1 coil. The negative pole of the relay K1 coil is grounded.
[0008] Furthermore, the drain of the MOS tube Q1 is connected to the first end of the TVS tube Z1, and the second end of the TVS tube Z1 is grounded.
[0009] Furthermore, the drain of the MOS transistor Q1 is connected to a first end of a fourth filter capacitor C4, and a second end of the fourth filter capacitor C4 is grounded.
[0010] Furthermore, the source of the MOS tube Q1 is respectively connected to the first end of the second filter capacitor C2 and the first end of the third filter capacitor C3, the second end of the second filter capacitor C2 is grounded, and the second end of the third filter capacitor C3 is grounded.
[0011] Furthermore, the common end of the relay K1 is respectively connected to the first end of the seventh filter capacitor C7 and the first end of the sixth filter capacitor C6, the second end of the seventh filter capacitor C7 is grounded, and the second end of the sixth filter capacitor C6 is grounded.
[0012] Furthermore, a power inductor L1 is connected between the common end of the relay K1 and the SW pin of the fast charging protocol chip U1.
[0013] Furthermore, the USB charging anti-reverse short-circuit circuit also includes an RC circuit, and the RC circuit includes a first resistor R1 and a fifth capacitor C5. The first end of the first resistor R1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1, the second end of the first resistor R1 is connected to the first end of the fifth capacitor C5, and the second end of the fifth capacitor C5 is grounded.
[0014] Furthermore, the BST pin of the fast charging protocol chip U1 is connected to the first end of the first bootstrap capacitor C1, and the second end of the first bootstrap capacitor C1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1.
[0015] The beneficial effects of the utility model: the utility model has a simple circuit connection structure, and only a simple anti-reverse connection circuit and an anti-short circuit are added to realize the anti-reverse connection and short-circuit protection functions for the USB charging circuit, which can effectively protect the protocol chip from being burned, and the design is flexible, low-cost, and does not require software algorithm control.
[0016] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 The utility model discloses a USB charging reverse connection short circuit prevention circuit diagram. DETAILED DESCRIPTION
[0018] like Figure 1The USB charging reverse connection and short circuit protection circuit shown in the figure includes a reverse connection protection circuit and a short circuit protection circuit, and also includes an existing fast charging protocol chip U1 (used to identify the fast charging supported by the mobile phone and automatically adjust the output voltage and current, such as Yingjixin ip6525) and a USB interface at the lower right part of the circuit.
[0019] The anti-reverse connection circuit includes: a MOS tube Q1, a second resistor R2, a third resistor R3, and a voltage-stabilizing diode ZD1. The drain of the MOS tube Q1 is connected to the power supply IGN, the source of the MOS tube Q1 is respectively connected to the first end of the third resistor R3, the cathode of the voltage-stabilizing diode ZD1, and the VIN pin of the fast charging protocol chip U1, and the gate of the MOS tube Q1 is respectively connected to the first end of the second resistor R2, the second end of the third resistor R3, and the anode of the voltage-stabilizing diode ZD1;
[0020] The anti-short circuit includes: a relay K1 and a switch S1. The common end of the relay K1 is respectively connected to the SW pin and the VOUT pin of the fast charging protocol chip U1. The normally closed end of the relay K1 is connected to the first end of the switch S1. The second end of the switch S1 is respectively connected to the VCC pin of the USB interface, the normally open end of the relay K1, and the positive pole of the relay K1 coil. The negative pole of the relay K1 coil is grounded.
[0021] Preferably, in combination with the above solution, in order to achieve the surge protection function, the drain of the MOS tube Q1 is connected to the first end of the TVS tube Z1, and the second end of the TVS tube Z1 is grounded.
[0022] Preferably, in combination with the above solution, in order to play a filtering role, the drain of the MOS tube Q1 is connected to the first end of the fourth filter capacitor C4, and the second end of the fourth filter capacitor C4 is grounded.
[0023] Preferably, in combination with the above scheme, in order to play a filtering role, the source of the MOS tube Q1 is respectively connected to the first end of the second filter capacitor C2 and the first end of the third filter capacitor C3, the second end of the second filter capacitor C2 is grounded, and the second end of the third filter capacitor C3 is grounded.
[0024] Preferably, in combination with the above scheme, in order to play a filtering role, the common end of the relay K1 is respectively connected to the first end of the seventh filter capacitor C7 and the first end of the sixth filter capacitor C6, the second end of the seventh filter capacitor C7 is grounded, and the second end of the sixth filter capacitor C6 is grounded.
[0025] Preferably, in combination with the above solution, in order to filter the current and make the output voltage more stable, a power inductor L1 is connected between the common end of the relay K1 and the SW pin of the fast charging protocol chip U1.
[0026] Preferably, in combination with the above scheme, in order to play a filtering role in attenuating high-frequency signals, the USB charging anti-reverse short-circuit circuit also includes an RC circuit, and the RC circuit includes a first resistor R1 and a fifth capacitor C5. The first end of the first resistor R1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1, the second end of the first resistor R1 is connected to the first end of the fifth capacitor C5, and the second end of the fifth capacitor C5 is grounded.
[0027] Preferably, in combination with the above scheme, in order to achieve a voltage increase, the BST pin of the fast charging protocol chip U1 is connected to the first end of the first bootstrap capacitor C1, and the second end of the first bootstrap capacitor C1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1.
[0028] Principle of the utility model:
[0029] See also Figure 1 When the power supply is connected in the positive direction, the power supply voltage reaches the source S from the drain D through the body diode of the MOS tube Q1 (PMOS tube). At this time, Vgs meets the turn-on voltage of the MOS tube Q1, the source and drain of the MOS tube Q1 are turned on, current flows through, and the product works normally; when the power supply is connected in the reverse direction, Vgs does not meet the turn-on voltage of the MOS tube Q1. At this time, the MOS tube Q1 is turned off, the input voltage is 0, and the product does not work, realizing the anti-reverse connection function;
[0030] When the micro switch S1 is pressed, the voltage passes through the normally closed contact of relay K1 and then through the micro switch S1 to the USB interface and the coil of relay K1. When the coil of relay K1 is energized, the electromagnetic induction coil generates magnetic force to attract the armature, and the armature is attracted to the normally open contact. At this time, the current flows through the coil of relay K1 and the USB interface. After the current flows through the coil of relay K1, it continues to generate magnetic force, and the armature remains in the normally open contact. In this way, relay K1 forms a self-locking, and the USB port has normal output; when the output is short-circuited, the coil of relay K1 has no voltage drop, no electromagnetic induction, and the magnetic force disappears. At this time, the armature returns to the normally closed contact, the output is disconnected, and the short-circuit protection function is achieved. When the micro switch S1 is pressed again, the circuit works again.
[0031] The utility model is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the utility model is not limited to the above-mentioned method. For example, the input and output voltages are not limited to 24V and 5V, but can also be other voltages that meet the circuit form of the present invention. As long as various improvements are made using the method concept and technical solution of the utility model, or they are directly applied to other occasions without improvement, they all fall within the protection scope of the utility model.
Claims
1. A USB charging reverse connection short circuit protection circuit, characterized in that: Including anti-reverse connection circuit and anti-short circuit: The anti-reverse connection circuit includes: a MOS tube Q1, a second resistor R2, a third resistor R3, and a voltage-stabilizing diode ZD1. The drain of the MOS tube Q1 is connected to the power supply IGN, the source of the MOS tube Q1 is respectively connected to the first end of the third resistor R3, the cathode of the voltage-stabilizing diode ZD1, and the VIN pin of the fast charging protocol chip U1, and the gate of the MOS tube Q1 is respectively connected to the first end of the second resistor R2, the second end of the third resistor R3, and the anode of the voltage-stabilizing diode ZD1; The anti-short circuit includes: a relay K1 and a switch S1. The common end of the relay K1 is respectively connected to the SW pin and the VOUT pin of the fast charging protocol chip U1. The normally closed end of the relay K1 is connected to the first end of the switch S1. The second end of the switch S1 is respectively connected to the VCC pin of the USB interface, the normally open end of the relay K1, and the positive pole of the relay K1 coil. The negative pole of the relay K1 coil is grounded.
2. The USB charging reverse connection protection short circuit circuit according to claim 1 is characterized in that: The drain of the MOS tube Q1 is connected to the first end of the TVS tube Z1 , and the second end of the TVS tube Z1 is grounded.
3. The USB charging reverse connection protection short circuit circuit according to claim 1 is characterized in that: The drain of the MOS transistor Q1 is connected to a first end of a fourth filter capacitor C4 , and a second end of the fourth filter capacitor C4 is grounded.
4. The USB charging reverse connection protection short circuit circuit according to claim 1 is characterized in that: The source of the MOS transistor Q1 is connected to the first end of the second filter capacitor C2 and the first end of the third filter capacitor C3 respectively. The second end of the second filter capacitor C2 is grounded, and the second end of the third filter capacitor C3 is grounded.
5. The USB charging reverse connection protection short circuit circuit according to claim 1 is characterized in that: The common end of the relay K1 is connected to the first end of the seventh filter capacitor C7 and the first end of the sixth filter capacitor C6 respectively, the second end of the seventh filter capacitor C7 is grounded, and the second end of the sixth filter capacitor C6 is grounded.
6. The USB charging reverse connection protection short circuit circuit according to claim 1, characterized in that: A power inductor L1 is connected between the common end of the relay K1 and the SW pin of the fast charging protocol chip U1.
7. The USB charging reverse connection protection short circuit circuit according to claim 6 is characterized in that: The USB charging anti-reverse short-circuit circuit also includes an RC circuit, which includes a first resistor R1 and a fifth capacitor C5. The first end of the first resistor R1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1, the second end of the first resistor R1 is connected to the first end of the fifth capacitor C5, and the second end of the fifth capacitor C5 is grounded.
8. The USB charging reverse connection protection short circuit circuit according to claim 6 is characterized in that: The BST pin of the fast charging protocol chip U1 is connected to the first end of the first bootstrap capacitor C1, and the second end of the first bootstrap capacitor C1 is respectively connected to the SW pin of the fast charging protocol chip U1 and the first end of the power inductor L1.