Taking mobile device charging as an example, how should we design a reverse current protection scheme? If you are unfamiliar with reverse current protection, please refer to “What is Reverse Current?”.
Modern mobile devices have many power supply methods, such as the common TYPE-C DC 5V, internal battery power 4.2V, or power adapter power.
In the first case, when powered by a power adapter, a reverse connection protection diode can be used. This is the simplest and most cost-effective solution.
Circuit Principle:
The power adapter’s independent 5V input goes to J3, then through a 0-ohm short-circuit protection resistor R13, illuminating the LED indicator D4. After passing through a 10uF ceramic filter capacitor C5 to reduce power ripple, it passes through a reverse-connection protection diode to another 10uF filter capacitor C6. When current is generated at the load terminal, the SS34 diode is cut off and does not conduct, thus providing reverse current protection. The disadvantage of this solution is that the large diode voltage drop and high current lead to increased heat generation, causing product temperature rise and instability.
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
Related Parts: