I have a circuit which input voltage shouldn't exceed 50 V, I can't use neither of available overvoltage protection circuits because of the limits each have;
Crowbar circuit. While this is a good approach, the fuse in the circuit is 10 A. What if overvoltage condition occurred but the source supply can't provide 10 A to blown the fuse? For example if the input voltage is 60 V and supply can only provide a maximum current of 5 A, that's 300 W on the SCR and fuse is not going to open.
P-channel MOSFET based overvoltage protection. This circuits working condition is depended on the gate voltage and is not a sharp cut off like crowbar circuit. assuming the mosfet have 50 mΩ RDSon with 10 A over it, that's 5 W of power loss, not to mention the price on low RDSon p-channel MOSFETs.
- How do I protect the input from overvoltage condition and overcome the problems described? is there a better approach?
Input source can be a battery or power supply of any kind (DC), input voltage shouldn't exceed 50 V and maximum current is limited to 10 A both by a fuse and design.