D C TO D C VOLTAGE CONVERTER Russian patent published in 1995 - IPC

FIELD: power supply sources. SUBSTANCE: enabling pulses are sent to bases of transistor keys 2 and 3 at starting time moment. Rate of increase of collector currents of transistor keys 2 and 3 is limited by small inductance of choke 14. When collector current reaches working state it is kept at this level the help of choke 16 and voltage across commutating capacitor 10 equals voltage across collector-emitter of open transistor key 3. After termination of pulse transistor key 3 blanks and current flowing through capacitor 10 charges it up to supply voltage thanks to presence of chokes 14 and 15. Process of drain of remaining energy from chokes 14 and 15 is conducted through backward diodes 8 and 9. In this case voltage across capacitor 11 equals voltage across open diode 8. During pause voltage across capacitors does not change and transistor keys 4 and 5 are switched on under zero voltage. EFFECT: improved operational reliability. 2 dwg