SYNCHRONIZATION CIRCUIT FOR A RESONANT FLYBACK HIGH VOLTAGE SUPPLY

摘要

A synchronization circuit for a resonant flyback high voltage supply for use in providing a high voltage output for a CRT. The circuit includes driving circuitry including an input power filter providing power to a coupled inductor which transmits power to a four stage multiplier circuit. Power is switched on and off by a power FET. The synchronization circuit reduces power loss in the FET by using variations in operational frequency to meet varying loads. By reducing the frequency as load increases, the flyback wave--form is allowed to complete its resonant cycle before turning on the power FET. An anode resonant flyback regulator including a pulse width modulator controls the FET in response to signals provided by a negative slope detector circuit and feedback voltage. Over current shutdown capability is further provided by a current sensing latch.