Low dissipation snubber for switching power transistor

摘要

A high efficiency switching power transistor uses the energy in a snubber circuit to drive the gate driver and the pulse-width-modulator (PWM). The snubber consists of a resistor and a capacitor connected in series between the drain and source of a field-effect-transistor (FET). A steering diode is connected from the junction between the capacitor and the resistor to the power supply of the gate driver and PWM. This diode steers current from the snubber and makes it flow into the power supply thereby lowering the power requirements of the power supply. This energy would have been dissipated in the snubber as heat if it were not used this way. Efficiency of the switcher is increased both by lowering heat loss in the snubber and by using recovered snubber energy to lower the power requirements of the power supply of the gate driver and PWM.