Circuit protection is a crucial measure for ensuring the safety of electronic systems. It prevents or limits abnormal conditions such as overcurrent, overvoltage, overtemperature, and short circuits, thereby avoiding equipment damage, fire, or electric shock. Let’s discuss one type of circuit protection, “Reverse Current”.
First, what is reverse current, and when does it occur?
Reverse current occurs when current flows from the load or secondary circuit back into the power supply, primary circuit, or other parts not intended to receive power. Simply put, the direction of current is opposite to that during normal operation. Many circuits can experience this type of reverse current, for example:
- Most common battery charging: After charging is complete, if the battery is not disconnected, it may discharge backwards into the charger.
- Systems connected to both a main power source and a backup battery: When the main power source loses power or its voltage falls below the battery voltage, the battery current may flow back into the main power circuit.
- Inductive loads such as motors and inductors: Reverse electromotive force is generated at the moment of power loss, which can also result in reverse current.
Reverse current protection methods vary. Based on circuit current, efficiency, and cost, we’ll share three reverse current protection solutions:
- Reverse Current Protection - Diode
- Reverse Current Protection - MOSFET
- Reverse Current Protection - Ideal Diode
- Reverse Current Protection - Simultaneous Use of Diode + MOSFET + Ideal Diode
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