Abstract: A DC power supply may use an input supply surge protection circuit that may be robust against positive and negative power surges. DC power may be provided through a first unidirectional circuit component such as a diode or selectively controlled MOSFET coupled in parallel with a transient voltage suppressor or Zener diode. The first unidirectional circuit component may have a first voltage rating and the transient voltage suppressor or Zener diode may have a second voltage rating lower than the first voltage rating. This may allow current to flow backward over the transient voltage suppressor or Zener diode to protect the first unidirectional circuit component from exposure to voltage beyond the first voltage rating in a power surge.

Abstract: A DC power supply may use an input supply surge protection circuit that may be robust against positive and negative power surges. DC power may be provided through a first unidirectional circuit component such as a diode or selectively controlled MOSFET coupled in parallel with a transient voltage suppressor or Zener diode. The first unidirectional circuit component may have a first voltage rating and the transient voltage suppressor or Zener diode may have a second voltage rating lower than the first voltage rating. This may allow current to flow backward over the transient voltage suppressor or Zener diode to protect the first unidirectional circuit component from exposure to voltage beyond the first voltage rating in a power surge.