RF1 Wire-wound resistor alternative
Posted by: mgcorr
on
I am using the LNK304 reference design found in the LinkSwitch-TN datasheet for a universal AC input to single 12V output.
The reference calls for a wire-wound 2W resistor for RF1. This is a fairly obscure part that has a 10-week lead time.
Is there an alternative design option for providing circuit protection? Would a slow-blow fuse work?
thanks
Michael
Comments
Better use resettable fuse or slow blow fuse.
Hi,
The purpose of the resistor RF1 is dual. It acts as a inrush limiting resistor which limits inrush current darwn by the power supply input capacitors. The other purpose is to protect by fusing in case of a catastrophic failure in the circuit.
The fusible resistors are designed to open in a safe manner without creating a safety hazard.
You could substitute the resistor with a combination of a NTC Thermistor which is commonly used for inrush limiting and a fuse that will protect the circuit in case of a fault.
Regards
PI-Sarek
