Yutaka Electric Mfg. Co., Ltd.

Densetsukiki Industry Co., Ltd.

Nemic-Lambda K.d. and Densetsu Corporation

Nemic Lambda Co., Ltd.

Densetsu Co., Ltd

Rihei Hiramatsu

Kazushi Watanabe

Tokunari Inoue

Shigeo Watanabe

Seiji Imano

Ko Takeshita

Jun Maruyama

Yasuyuki Okumura

Shinzo Takeishi

A self-excited inverter circuit primarily includes a main transformer two switching elements e.g. the first and second (FET) switching elements, wherein capacitors at both ends of said first FET are charged during a time T.sub.1 -T.sub.2 when said first FET is turned off, and the voltage V.sub.g1 across said first FET is clamped by a charge voltage V.sub.c1 and then, a voltage V.sub.gs is applied across the gate and the source of said second FET for electrical continuity to cause the voltage to be clamped. The clamped state is maintained from T.sub.1 to T.sub.2, the saturation reactor is saturated at time T.sub.3, and V.sub.gs, which has been negative, starts to change toward O, thereby causing the first FET to change to ON; V.sub.q falls towards VPi at TP3 and further towards zero point. Thus, the voltage V.sub.q2 changes to zero to cause V.sub.gs of the second FET to become zero and the second FET to be shut off. When said voltage V.sub.q2 is clamped to a fixed value, a high -V.sub.sc (L) can be obtained in the case of Vi(L), whereas a low -V.sub.sc can be obtained in the case of Vi(H); and the continuity angle, or duty cycle, (T.sub.1 -T.sub.2)/(T.sub.1 -T.sub.3) of the first FET is naturally controlled to be kept in a desirable direction.

Continuity angle controlled self-excited inverter circuit

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.

Starting circuit of self-excited inverter

Disclosed is a full-wave output type forward converter wherein a main transformer having a primary winding connected in series with a switching element includes two secondary windings as winding halves divided by a center tap and electromagnetically coupled. A leakage self inductance can be reduced to obtain a high-frequency, high-power arrangement.

Full-wave output type forward converter

A device including a main circuit comprising a switching main transistor unit, a smoothing reactor, a smoothing condenser and a commutation diode. To control the conduction and nonconduction of said main transistor unit by means of the output obtained by detecting and amplifying the output voltage of said main circuit, the main transistor unit comprises at least two main transistors connected in parallel with each other. A secondary winding of a current transformer is connected between the bases of the main transistors. A parallel circuit comprising a diode and a condenser is connected between the neutral point of the secondary winding and the emitters of the main transistors. A control circuit comprises two transistors which are conductive and nonconductive alternately and outputs derived from the latter transistors are applied alternately to two primary windings of the current transformer and provision is made to short the ends of the primary winding of the current transformer while the two transistors of the control circuit are both nonconductive.

Switching regulator

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Tokyo, Japan

Rihei Hiramatsu