Dynamic Load Correction for EHT Voltage Regulation
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
In an EHT regulation system for a CRT display, a primary winding of an EHT transformer is driven by a pulse-width modulation circuit controlled by an error amplifier. A diode split secondary winding generates an EHT output voltage. An auxiliary transformer winding is used to generate a sense voltage which is fed back to the error amplifier. The EHT current is monitored by a resistor controlling a circuit whose output modifies the sense voltage to provide dynamic load correction. In a regulated EHT generation system the problem arises of reliably sensing EHT. This may be achieved by direct sensing of EHT using a dropper resistor, but high voltage resistors have wide tolerance, aging and drift characteristics and susceptibility to static discharges.