TRANSISTOR SWITCH CONTROL DEVICE Russian patent published in 2003 - IPC

FIELD: converter engineering; controlling power transistors of secondary power supplies. SUBSTANCE: device whose control circuits are transformer- isolated from power circuits has first transformer with primary and secondary windings, and pulse-width modulator, first lead of transformer secondary winding being connected to control lead of power transistor and to collector of first turnoff transistor. MIS transistor is used as power transistor; first transformer has three windings; newly introduced are control unit, second transformer with primary, secondary, and tertiary windings, second turnoff transistor, first through fourth diodes, and first through fifth resistors; first secondary-winding leads of first and second transformers are connected to anodes of first and second diodes, respectively, their cathodes being connected to common junction point of control lead of power transistor, collector of first turnoff transistor, and one of leads of first resistor; integrated second leads of secondary windings of first and second transformers are connected to first lead of first-transformer tertiary winding, to other lead of first resistor, to power transistor source, to emitters of first and second turnoff transistors, to anode of third diode, to one of leads of third resistor, and through second resistor, to second lead of second-transformer tertiary winding; second lead of first-transformer tertiary winding is connected through fourth resistor to base of first turnoff resistor, collector of second one, and cathode of fourth diode whose anode is connected through fifth resistor to second lead of second-transformer tertiary winding, its first lead being connected to other lead of third resistor, cathode of third diode, and base of second turnoff transistor; signal arriving from pulse-width modulator arrives at input of control unit whose control signal pulses y₁, y₂, applied to primary windings of transformers vary obeying logic expression , where x₁ is pulse-width modulator signal; x₂ is meander at clock frequency of pulse-width modulator master oscillator. Provision is made for introducing additional resistor to interconnect power transistor drain and first turnoff transistor base. EFFECT: enhanced efficiency. 2 cl, 3 dwg