App Notes

Front panel on/off without primary AC power

Applies to models:
BP1 (30W only)
– BP2 through BP7 (all models)

Most BP Series power converters feature an Enable pin that can be used to turn the converter on (open) or off (shorted to the “-” terminal).

This unique feature allows you to mount the power supply at the rear of the system chassis, near the AC line input, and control it from an ON / OFF switch on your system’s front panel without taking the primary AC power to the front panel.

The Enable pin is referenced to the output negative terminal (labeled “-“) and is thus isolated from the primary.

When left open, the Enable pin typically floats at about +4.4V.  The input impedance for this node is roughly 1Kohm.