Principle of series anti reverse connection：
When V1 is directly connected, D1 is on, assuming that the on voltage drop of D1 is v_ FVF, the voltage applied to the load is v1-v_ Fv1 − VF. The disadvantage of this circuit is that there will be loss. The loss power is p = I * v_ FP = I * VF, if the output voltage is required, the conduction voltage drop V of D1 should be considered_ FVF size, high current circuit needs to consider the output current value of D1, so it is generally used in high voltage occasions;
When the power supply V1 is reversely connected, the reverse cut-off characteristic of the diode blocks the current flow and cannot form a loop with the load R1 to protect the load.
Diode series anti power reverse circuit
Principle of parallel anti reverse connection:
When V2 is in positive connection, D2 is in reverse cut-off, and the circuit works normally;
When V2 is reversely connected, D2 is conducting in the forward direction, and the reverse voltage is clamped at v_ FVF (diode conduction voltage drop), V_ FVF needs less than the maximum reverse voltage of the load; on the other hand, when PTC detects that the loop current is too large, it will disconnect to protect the back-end load. The disadvantage of this circuit is that there is one more fuse, which increases the cost of BOM. If V2 is followed by multiple loads, special attention should be paid to the use of the above circuit. The fuse can be recovered.
Diode parallel anti power reverse circuit