Patent ID: 8193785

Claim:
A switching regulator for regulating an ac signal, the regulator comprising: input terminals for receiving an input ac signal; output terminals for providing an output signal; an inductor and a capacitor arranged to smooth the output signal appearing at the output terminals; a positive half-cycle part and a negative half-cycle part arranged to regulate the positive and negative half-cycles respectively of the input ac signal; each of the positive and negative half-cycle parts comprising: a modulating transistor operable to modulate the respective half-cycle of the input ac signal and having an associated modulator diode arranged to allow current flow through the modulating transistor during that modulating transistor's respective half-cycle and to resist current flow through the modulating transistor during the other half-cycle; and a clamping diode arranged to protect the modulating transistor from reverse-bias voltages and having an associated clamp switch operable to cause the clamping diode to conduct during that modulating transistor's respective half-cycle and to cause the clamping diode to be bypassed during the other half-cycle; the regulator further comprising: a first switching controller operable to cause the modulating transistors to switch, comprising a first power supply operable to take power from one half-cycle of the input ac signal; and a second, separate switching controller operable to cause the clamp switches to switch, comprising a second power supply operable to take power from the other half-cycle of the input ac signal.