A large-current anti-backflow ideal diode circuit
Patent Information
- Application Number
- CN202423255949.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-29
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2034-12-29
AI Technical Summary
但在电流较大用电设备中，肖特基二极管存在约0.3V～0.5V电压降，在其上产生3W以上热损耗，需要选用封装较大的肖特基二极管和在电路板设计时考虑散热面积，且额外的热损耗对电池能量造成消耗
[0007]有益效果：本实用新型中由两只PMOS管、稳压二极管、电阻和电容等器件组成，结构简单、可靠性高、价格便宜、可便捷实现全国产化，可有效实现二极管的防反灌功能，且利用MOS管的导通内阻仅为0.0082mΩ，MOS管上产生的热损耗基本可忽略，不需要额外考虑散热。具有防反灌、防反接、尺寸小、可靠性高等优点。
Smart Images
Figure CN224909087U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of DC power supply equipment technology, specifically relating to a high-current anti-reverse-feed ideal diode circuit. Background Technology
[0002] In airborne platform missile-mounted DC electrical equipment, the onboard power supply is required when the equipment is mounted on the aircraft, and it needs to be switched to onboard battery power before launch. Therefore, a dual power supply is required. When using aircraft power, the onboard battery should not be affected by reverse power flow from the aircraft. When the battery is in operation and the equipment power supply is turned off, the stored voltage in the load capacitor should not flow back to the battery terminal.
[0003] The common approach is to use Schottky diodes for isolation and protection at the battery power supply front end. However, in high-current electrical equipment, Schottky diodes exhibit a voltage drop of approximately 0.3V to 0.5V, resulting in heat loss of over 3W. This necessitates the selection of larger packaged Schottky diodes and consideration of heat dissipation area in the circuit board design. Furthermore, the additional heat loss consumes battery power.
[0004] One existing ideal diode uses the LTC4359 dedicated chip from Analog Devices (ADI) to control the switching of a MOSFET, thus realizing the function of an ideal diode. However, this chip is several times more expensive than a MOSFET and is an imported chip, which is not conducive to the current demand for domestic production of products. Utility Model Content
[0005] This invention provides an ideal diode circuit for high-current anti-reverse current. The technical problem to be solved is to address the hazards of reverse current to batteries in the power supply switching circuit of aircraft-borne equipment and DC electrical equipment, and to improve the shortcomings of conventional Schottky diodes, such as high forward voltage drop and high heat loss.
[0006] To solve the above technical problems, this utility model provides a high-current anti-reverse-current ideal diode circuit, characterized by: including PMOS transistor Q1, PMOS transistor Q2, transistor Q3, Zener diode D1, resistors R1, R2, R3, R4, and capacitor C1; the sources of PMOS transistors Q1 and Q2 are connected, and their gates are connected; the drain of PMOS transistor Q1 serves as the power input, and the drain of PMOS transistor Q2 serves as the power output; one end of resistor R4 is connected to the power input terminal and the drain of PMOS transistor Q1, and the other end of resistor R4 is connected to resistor R2. One end of the resistor R2 is connected to one end of the capacitor C1, the base of the transistor Q3, and the anode of the diode D2. The other end of the resistor R2 is grounded, the other end of the capacitor C1 is grounded, the cathode of the diode D2 is connected to ground, the emitter of the transistor Q3 is grounded, the collector of the transistor Q3 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the gate of the PMOS transistors Q1 and Q2, the resistor R1 is connected between the common source and gate of the PMOS transistors Q1 and Q2, the anode of the Zener diode D1 is connected to the source of the PMOS transistors Q1 and Q2, and the cathode of the Zener diode D1 is connected to the gate of the PMOS transistors Q1 and Q2.
[0007] Beneficial effects: This invention consists of two PMOS transistors, a Zener diode, resistors, and capacitors, featuring a simple structure, high reliability, low cost, and easy domestic production. It effectively provides reverse current protection for the diodes, and due to the MOS transistors' on-resistance of only 0.0082mΩ, heat loss is negligible, eliminating the need for additional heat dissipation considerations. It offers advantages such as reverse current protection, reverse connection protection, small size, and high reliability.
[0008] This invention uses a CH120P04E type PMOS transistor, whose on-resistance R DS With an impedance of only 4.5mΩ, each MOSFET has a turn-on voltage of 0.045V and a power consumption of only 0.09W when a 10A current flows through it. Compared with the power consumption of Schottky diodes, which is over 3W, this significantly improves the power supply efficiency, reduces the circuit heat dissipation requirements, reduces the thermal stress of the devices, and improves the reliability of operation.
[0009] This invention can be widely used in DC power supply systems, especially portable battery power supply systems, which can effectively isolate the damage to battery voltage backflow during dual power supply switching and significantly improve battery efficiency. Attached Figure Description
[0010] Figure 1 This is a schematic diagram of a high-current anti-reverse-current ideal diode circuit according to the present invention. Detailed Implementation
[0011] To make the purpose, content and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below.
[0012] This invention proposes a high-current anti-reverse-current ideal diode circuit, which consists of two PMOS transistors in the main path and a MOS transistor switching control circuit. Specifically, it includes PMOS transistors Q1, Q2, Q3, a Zener diode D1, resistors R1, R2, R3, and R4, and a capacitor C1. The sources of PMOS transistors Q1 and Q2 are connected, and their gates are connected. The drain of PMOS transistor Q1 serves as the power input, and the drain of PMOS transistor Q2 serves as the power output. One end of resistor R4 is connected to the power input terminal and the drain of PMOS transistor Q1, while the other end of resistor R4... One end of resistor R2, one end of capacitor C1, the base of transistor Q3, and the anode of diode D2 are connected together. The other end of resistor R2 is grounded, the other end of capacitor C1 is grounded, the cathode of diode D2 is connected to ground, the emitter of transistor Q3 is grounded, the collector of transistor Q3 is connected to one end of resistor R3, the other end of resistor R3 is connected to the gates of PMOS transistors Q1 and Q2, resistor R1 is connected between the common source and gate of PMOS transistors Q1 and Q2, the anode of Zener diode D1 is connected to the source of PMOS transistors Q1 and Q2, and the cathode of Zener diode D1 is connected to the gate of PMOS transistors Q1 and Q2.
[0013] Working principle explanation: This utility model provides a circuit principle of an embodiment as follows: Figure 1 As shown, the ideal diode main path utilizes the source-to-source connection of two PMOS transistors. This connection method forms an anode-to-anode configuration for the parasitic body diodes within the two MOS transistors. The PMOS transistors will only turn on and form a path when the gate-drain voltage is below the threshold voltage. When there is a positive input voltage Vin, the input voltage is divided and current-limited by resistors R4 and R2, providing a turn-on voltage to the base of transistor Q3. This pulls down the gate voltages of PMOS transistors Q1 and Q2, causing them to conduct and completing the power supply operation.
[0014] The diode D2 is connected between the base and emitter of transistor Q3 to prevent current from flowing through resistor R4 when the input positive and input ground are reversed, thus protecting the base and emitter of transistor Q3 from breakdown. The capacitor C1 stabilizes the base voltage of the transistor, preventing malfunction of transistor Q3 caused by instantaneous input voltage fluctuations. Resistors R1 and R3 provide a path for the emitter current of transistor Q3, ensuring full conduction. Simultaneously, the voltage divided by resistors R1 and R3 is applied to Zener diode D1, which regulates the voltage to ensure it does not exceed the gate-drain voltage of PMOS transistors Q1 and Q2, providing a stable turn-on voltage for the PMOS transistors Q1 and Q2.
[0015] When the input and output voltages operate in the forward direction, the output voltage value follows the input voltage value, and the curves coincide. The losses on the MOSFET are negligible, achieving the advantage of low voltage drop of an ideal diode, which is especially suitable for high-current applications.
[0016] When the input and output voltages are reversed, there is no reverse voltage at the input terminal, thus achieving the reverse isolation function of the diode.
[0017] When the input positive and input ground are reversed, the input voltage passes only through the Zener diode D1 and resistor R4. Transistor Q3 is turned off, PMOS transistors Q1 and Q2 are not working, and there is no voltage at the output terminal.
[0018] For this utility model, the power supply Vin has a working voltage range of 5V to 32V, a working current of up to 30A, a working temperature of -40℃ to 85℃, a circuit area of 20mm×20mm×6mm, and a weight of no more than 10g.
[0019] Preferably, the PMOS models Q1 and Q2 are CH120P04E.
[0020] Preferably, the transistor Q3 is model BT2222.
[0021] Preferred: Zener diode D1 is model BZ5231.
[0022] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A high-current reverse-current protection ideal diode circuit, characterized in that: The system includes PMOS transistors Q1, Q2, Q3, Zener diode D1, resistors R1, R2, R3, and R4, and capacitor C1. The sources of PMOS transistors Q1 and Q2 are connected, and their gates are connected. The drain of PMOS transistor Q1 serves as the power input, and the drain of PMOS transistor Q2 serves as the power output. One end of resistor R4 is connected to the power input terminal and the drain of PMOS transistor Q1. The other end of resistor R4, one end of resistor R2, one end of capacitor C1, the base of transistor Q3, and diode D1 are also connected. The anode of diode D2 is connected to ground, the other end of resistor R2 is grounded, the other end of capacitor C1 is grounded, the cathode of diode D2 is connected to ground, the emitter of transistor Q3 is grounded, the collector of transistor Q3 is connected to one end of resistor R3, the other end of resistor R3 is connected to the gate of PMOS transistors Q1 and Q2, resistor R1 is connected between the common source and gate of PMOS transistors Q1 and Q2, the anode of Zener diode D1 is connected to the source of PMOS transistors Q1 and Q2, and the cathode of Zener diode D1 is connected to the gate of PMOS transistors Q1 and Q2.
2. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: PMOS transistors Q1 and Q2 are of model number CH120P04E.
3. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: The transistor Q3 mentioned is model BT2222.
4. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: The Zener diode D1 is model BZ5231.
5. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: A PMOS transistor will only turn on to form a circuit when the gate-drain voltage is lower than the threshold voltage.
6. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: When there is a positive input voltage Vin, the input voltage is divided and current limited by resistors R4 and R2, providing the turn-on voltage to the base of transistor Q3, pulling down the gate voltages of PMOS transistors Q1 and Q2, and then PMOS transistors Q1 and Q2 are turned on, and the circuit completes the power supply operation.
7. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: The diode D2 is used to prevent current from flowing through resistor R4 when the input positive and input ground are reversed, thus protecting the base and emitter of transistor Q3 from being broken down.
8. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: The capacitor C1 is used to stabilize the base voltage of the transistor and prevent the transistor Q3 from malfunctioning due to instantaneous fluctuations in the input voltage.
9. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: Resistors R1 and R3 provide the emitter current path for transistor Q3. At the same time, the voltage divided by resistors R1 and R3 is applied to Zener diode D1. Zener diode D1 regulates the voltage to ensure that it does not exceed the gate-drain voltage of PMOS transistors Q1 and Q2, thus providing a stable turn-on voltage for the gate-drain voltage of PMOS transistors Q1 and Q2.
10. The ideal diode circuit for high-current reverse-current protection according to claim 1, characterized in that: When the input positive and input ground are reversed, the input voltage passes only through the Zener diode D1 and resistor R4. Transistor Q3 is turned off, PMOS transistors Q1 and Q2 are not working, and there is no voltage at the output terminal.