Small power UPS power circuit and production

Small power UPS power circuit :

The picture below is a low-power online backup (UPS) power supply circuit. Its working principle is:

IC 1 constitutes a 50Hz clock generator, which outputs a symmetrical but square-phase square wave from pins 10 and 11. T1 and T2 form a power amplifier circuit, which are turned on in turn, forming a pulsating current with a frequency of 50Hz on the primary side of X2, and inducing a voltage of 220 volts with the same frequency on the secondary side of X2.

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Picture of small power UPS power supply circuit

Production and debugging:

When making, X2 can use a (9-12 volt) power transformer with a center tap, its low-voltage end is connected to T1 and T2, and the center tap is connected to the positive pole of the power supply. The power of the transformer is determined by actual needs, and the power of T1 and T2 must be considered. A radiator needs to be added to T1 and T2. In addition, pay attention to safety when making. C3, C4 and MOV at the output end can be canceled as needed. If the load is resistive, the oscillation frequency of IC 1 can be increased, and the transformer can be replaced with a ferrite transformer to achieve greater power.