Circuit for stabilizing a high voltage

摘要

The circuit for stabilizing a high voltage for a picture tube comprises a high-voltage transformer (TR), which has a primary winding (W1) and a high-voltage winding (WH), a switch (SP), which is connected in series with the primary winding (W1), and a control loop for high-voltage stabilization. The control voltage (UR) of the control loop, with which the switch (SP) is driven, is derived from two signals (DC, AC) in this case. The first signal (DC) is tapped off from a secondary auxiliary winding (W4) at the transformer (TR) and supplies a static control voltage component, and the second signal (AC) is derived directly from the high voltage (HV) and supplies a measure of the dynamic loading on the high-voltage generator. The static control voltage component is, in particular, a measure of the value of the high voltage during the vertical line flyback, when the screen is black and the high-voltage transformer is minimally loaded. In this case, the auxiliary winding supplies a voltage which is proportional to the secondary flyback pulse. The second signal (AC) is a fast control signal, since it is derived directly from the high voltage (HV). Cost-effective standard components can be used for realizing the circuit. The stabilization circuit can be used in particular in high-voltage generators for high picture powers of picture tubes, as are used for example in large television sets and computer monitors.