HALF-BRIDGE SELF-EXCITED OSCILLATOR Russian patent published in 2001 - IPC

FIELD: converter engineering; control systems for fluorescent, mercury, sodium (electronic ballast), and halogen lamps, secondary power supplies. SUBSTANCE: oscillator has power rectifier whose leads are connected to inputs of capacitive divider and also to plus and minus power buses of which one is connected to collector of one of power transistors and other, to emitter of other power transistor; switching transformer incorporating one feedback winding and two identical control windings each of them being connected through one lead to base of respective power transistor and through other, to emitter of respective transistor; current-limiting reactor one of whose leads is connected to output of self-excited oscillator and other one, to load; the latter is connected to center tap of capacitive divider. Control windings of switching transformer are connected in phase opposition to power transistors through diode-capacitor circuits; connected in parallel with feedback winding of switching transformer is blocking capacitor; additional shaping capacitor is inserted between midpoint of divider capacitors and that of power transistors; isolating diodes are inserted in addition into collector circuits of power transistors. Load is connected through current-limiting reactor. EFFECT: enhanced efficiency and safety in operation. 3 dwg