Abstract: An uninterruptible power supply provides internal connection to an auxiliary power to provide continuous device power without duplicating regulation and switching circuits. The power supply includes an AC to DC converter, a transformer and a switch applying DC power from converter to the transformer. A pulse width modulation control circuit assures a regulated output voltage while application of auxiliary power is controlled by a fixed time interval one-shot that assures a smooth transition to AC utility power upon resumption of such power following a failure. An auxiliary AC power output signal is maintained for a video monitor or other device even while operating on auxiliary power.
Type:
Grant
Filed:
March 22, 1993
Date of Patent:
February 22, 1994
Assignee:
National CSF Corporation
Inventors:
James V. Lavin, Loy L. Spears, Neil S. Symonds