UNINTERRUPTIBLE POWER SUPPLY

In the uninterruptible power supply, when the input switch is connected between the input terminal and the AC node of the converter and the fourth operation mode is selected, the input switch is turned off and the bypass switch is turned on, and the converter is controlled to convert the DC power of the battery into AC power and supply the AC power to the load via the bypass switch. Thus, even if the inverter is failed when the commercial AC power source is failed, it is possible to drive the load.