Bypass switching circuit of direct-current uninterruptible power supply

The utility model discloses a bypass switching circuit of a direct-current uninterruptible power supply. Wherein the relay is connected with the mains supply input and the battery input to be used asa change-over switch; the operational amplifier circuit is used for voltage regulation; two ends of the operational amplifier circuit are connected with mains supply input and battery input; wherein the mains supply input outputs DC voltage AV + through AC/DC, the rear end of the mains supply input is provided with a first diode D1, the battery input outputs DC voltage BV + through DC/DC, the rearend of the battery input is provided with a second diode D2, and the operational amplifier circuit is arranged at the front end of the diodes. Compared with the prior art, the utility model has the advantages that: the time for switching the input circuit by the relay is short, a switching state close to zero is achieved, and the circuit cost is low; the setting of the electrolytic capacitor C2 compensates the drop of the