cordless phone charger 120v to 230v (repair)

Roderick Young

Joined Feb 22, 2015
Even though the designation U1 suggests an integrated circuit, it seems the pins are all wired together on each side. I'm not really sure what it is.

This simple power supply resembles a cheap one I worked on here. In theory, the input voltage should not matter for the design, as the output voltage is not dependent on a turns ratio in the transformer. Many power supplies have a flexible input voltage from 100 - 250 volts. At one time in the past, there might have been a circuit to double the 100 volts to charge the high-voltage capacitor, but nowadays, I think the supply just uses whatever high voltage is connected directly.

Unfortunately, in practice, I suspect your supply won't work at a high voltage than it was designed for because of real world limitations, the transformer primary winding not the least of them. I know you came here for help, and this is not what you want to hear, but my suggestion would be to get a 220 to 110 step down transformer, and use that with your existing supply. Either that or find a 220 volt power brick of similar output voltage and current, and splice on the connector from your phone.