| 摘要 |
PURPOSE:To increase the voltage conversion efficiency and to set the dielectric strength of both switching sections higher, by positive-feeding back an output of a drive switching section to a control switching section and providing a constant voltage element for applied voltage restriction. CONSTITUTION:A smoothed DC output to make the potential of a bus 4 high is applied to a chopper type switching regulator 6 to drive, e.g., a reflection type photoelectric switch. A drive switching section 7 consisting of transistors (TRs) Q3, Q4 is turned on/off with a control switching section 9, and the chopper output is outputted 10 via a choke coil CL. the section 9 is constituted with TRs Q1, Q2 which are turned on/off with a comparator 11, and the base current for the TRs Q3, Q4 is supplied. The base of the TRs Q1, Q2 is positive-fed-back via resistors R6, R7, a zener diode (ZD)2 is connected to a bus 5 with the base of the TRQ2 and the Zener voltage of the ZD2 is set to almost 1/2 of the power supply voltage. |
