Starting circuit of self-excited inverter

摘要

When the power source voltage is charged to a capacitor between the source side of a MOSFET and a saturation reactor at the time of starting, the gate voltage of the MOSFET is caused to rise. When this charging voltage or the gate voltage exceeds the threshold voltage, the MOSFET is energized. The energization of this MOSFET induces a voltage in the tertiary self-excited oscillation winding through the primary winding, and a part of the induced voltage is applied to the gate of the MOSFET while some other part is applied to the reactor. This causes the magnetic flux of the saturation reactor to be set to the direction opposite that which had been set before. When the product of the voltages applied to the saturation reactor has reached the level for the allowable saturation magnetic flux density the saturation reactor is saturated and the gate voltage is discharged to turn off the MOSFET. When the MOSFET is energized once, the setting and resetting of the saturation reactor is repeated alternately due to the actions of the primary winding and the tertiary self-excited winding to enter the state of stable operation.