POWER SUPPLY CIRCUIT

PURPOSE:To provide a power supply circuit constituted only of circuits formed on a semiconductor substrate in which the voltage can be boosted efficiently and AC power as well as DC power can be outputted. CONSTITUTION:A positive phase output signal from an oscillation circuit 12 is fed to an output buffer 16 and an inverter 14 and both outputs are utilized in a power supply circuit. An inverted negative phase output signal is fed to an output buffer 20 thence fed to a transformer 24 through a switching circuit 22. Output signal from the output buffer 16 is also fed to the transformer 24 through a switching circuit 18. A transformed AC signal is outputted from the secondary of the transformer 24. The transformed AC signal is rectified through a rectifying circuit 26 which produces a DC output. Since a large number of diodes are not required to be connected in series like a charge pump circuit, a power supply circuit having high conversion efficiency can be obtained.