Schematics power supply switching PCB

Posted on Feb 6, 2014

The switching power supply provides 12 volts, at 10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit. With reference to the schematic, the front panel power-on light is not shown. There is no adjustable current limiter in this unit, although R1, R2, R3, Q2, R8, R9, C5 and Q4 se

Schematics power supply switching PCB
Click here to download the full size of the above Circuit.

t the current limit to approximately 10 amps. As you can see, the design is very similar to that of a linear power supply, except that L1, and D1 have been added, and U1 operates in a switching mode as a comparator with a small amount of hystersis. The switching frequency of this unit varies with the output current drawn by the load. This is an undesireable feature, which is why PWM regulators are used today. With a PWM regulator, the switching frequency is constant and will produce spurs only at known discrete frequencies rather than spurs at all frequencies. The Darlington-connected pass transistor block in the schematic is there twice (in parallel) for robustness. R4 in an internal trim-pot that can set the output voltage anywhere between 5 to 15 volts.

Leave Comment

characters left:

New Circuits



Popular Circuits

Advanced Telephone Intercom
Flanger and Echo circuit
Window comparator
Regulated DC-to-DC converter
Audio/Video Switcher
easy build motocycle alarm
dual led flasher by 2n2907
fm radio jammer
pulse induction metal detector with DSP
Precision polarity switching circuit by conventional elements