Switchable high voltage generator for penetration-type color CRT

Claim 1

Very high voltage DC generator which can be switched between n levels for feeding a capacitative load, comprising a very high voltage power source capable of delivering at least two extreme levels of voltage straddling in the n DC voltage levels, at least two series assemblies of power transistors each connected to the power source via a current limiting resistor and to the load and defining respectively two opposite directions of conduction between the source and the load and a control circuit having a transistor control channel for each series assembly of transistors, means in each transistor control channel for elaborating an image signal of the error voltage between the voltage value at the terminals of the load and the required level, which causes, as a function of the direction of conduction of said assemblies, the transistors of one of the series assemblies to operate in the saturated state as a switching circuit, at least one of the control channels further comprising a modulator receiving the signal of an oscillator and ensuring the modulation thereof by said image signal to control the transistors of the corresponding series assembly in the saturated state and then in the non-saturated state, as a function of the value of said error voltage signal image, for ensuring operation of this assembly as a switching circuit and as a regulation circuit connected in series with the load.