Abstract: In a conventional voltage conversion circuit, a switching control unit for controlling a pumping operation to be alternately performed is decided by a delay of an inverter, and thus a switching timing is inefficiently considerably varied according to the delay. Also, a well bias is applied to prevent a switch from being latched up. However, a large layout area is required in order to generate the well bias. A voltage conversion circuit according to the present invention can reduce a layout area and power consumption and improve conductivity and reliability, by efficiently driving a pumping capacitor by receiving an oscillation signal during a voltage pumping operation and using transitions from high to low and from low to high without overlapping each driving signal through a flip-flop switching structure, and by solving reduction of a threshold voltage of an NMOS transistor by controlling a precharge and switching transistor with a PMOS transistor.

Abstract: A method of controlling the switching transistor in the switch mode power supply of a television receiver includes the steps of selectively operating the transistor in a stand-by state, a start-up state and an ON-state. During the stand-by state the switching transistor is rendered conductive by applying bursts of pulses at a frequency above, and unsynchronized with, the line frequency of the television receiver. The pulses are separated by changing intervals. During the start-up state the frequency of said bursts of the pulses is continuously reduced and pulses and the duration of the on time of the transistor is determined using a regulation voltage. During the ON-state, line synchronizing pulses are applied and the switching transistor is regulated to the line frequency.