Rca Inc.

Thomson Consumer Electronics Inc.

Sammy S Henig

Wolfgang F Dietz

Enrique Rodriguez-Cavazos

Lawrence E Smith

Steven C Wetta

An SCR switch of a switch mode power supply is coupled between an unregulated supply voltage and a filter capacitor. A regulator oscillator generates trigger pulses for controlling a switching operation of the SCR switch of the power supply to produce an output supply voltage that energizes a deflection circuit. The regulator oscillator produces trigger pulses that are applied to the SCR switch during both power-up and power-off operation. A resistor coupled between the unregulated supply voltage and the filter capacitor maintains the filter capacitor charged during power-off operation to prevent the trigger pulses from causing the latching operation in the SCR switch throughout the power-off operation. In this way, an audible parasitic vibration sound is not being generated by the power supply during the power-off operation.

Television apparatus power supply

A phase-lock loop circuit of a television apparatus is synchronized by a horizontal synchronizing input signal. The phase-lock loop circuit includes a frequency-to-voltage converter that is responsive, during vertical trace, to the synchronizing input signal for generating a control voltage indicative of the frequency of the synchronizing input signal. During vertical trace, the control voltage varies the free running frequency of a controlled oscillator of the phase-lock loop circuit such that the free running frequency of the oscillator is directly related to the frequency of the input signal. During vertical retrace, the frequency-to-voltage converter is responsive to the oscillator output signal for generating the control signal that maintains the free running frequency of the oscillator substantially unchanged during vertical retrace. The phase of the output signal of the oscillator is controlled by a signal that is indicative of the phase difference between the oscillator output signal and the synchronizing input signal.

Growing community of inventors

Secaucus, NJ, United States of America

Sammy S Henig