BLOCKING OSCILLATOR TYPE CHOPPER POWER SUPPLY

摘要

PURPOSE:To simplify the circuitry by connecting a power supply switching transistor directly between a power supply and a load, and connecting the primary winding of a transformer directly between the power supply and the other end of the load thereby inducing a blocking oscillation. CONSTITUTION:A transistor Tr 13 for turning a power supply ON/OFF is connected directly between the positive terminal of a power supply 11 and one end of a load 12. Primary winding 14 of a transformer is connected directly between the negative terminal of the power supply 11 and the other end of the load 12. The Tr 13 is energized by a starting resistor 16 and the auxiliary winding 17 of the transformer is connected between the emitter of the Tr 13 and the gate of the Tr 13 through a resistor 18 and a capacitor 19 thus realizing positive feedback of the voltage induced in the primary winding 14 of the transformer to the gate of the Tr 13. The feedback current is controlled by means of a Zener diode 20. Energy stored in the primary winding 14 is discharged through a diode 15 to the load 12 thus inducing blocking oscillation. By such arrangement, a considerably simplified power supply can be obtained.