DC-based uninterruptible power system and method for detecting abnormal voltage

摘要

A direct current (dc) uninterruptible power system is disclosed. The dc-based uninterruptible power system includes a multiplexer, a battery unit, a linear regulator, a switch-transistor, a voltage comparator and micro controller. The multiplexer receives a first control signal, a first reference voltage and a second reference voltage and outputs a control voltage according to the first control signal. The switch-transistor has a body diode and the body diode has a conduction voltage. When the dc-based uninterruptible power system is non-discharge mode, the switch-transistor is switched-off and the linear regulator receives the first reference voltage, so that the subtraction of the output voltage and the power-supply voltage is smaller than the conduction voltage to cutoff the body diode.