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 set 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.
Read More Source :http://members.tripod.com/michaelgellis/power4.html
Thank You.
Related Links
More circuit about switching power supply
More circuit about MJ2955
More circuit about 12V
More cirucit by IC CA3140
12 Volt Low Voltage Droput Precision Regulator with LM324
12V Switching Car PSU by UC3843 + 74LS02
12V 5A power supply Regulator with LM2678-12
power supply Switching Regulator 12V 3A by LM2576-12
LM2575 Regulator 1.2-12V for Solar
Power Supply 13.8V 30-40A with LM723 and BUZ24 or IRF150
This entry was posted on Thursday, August 16th, 2007 at 1:51 pm and is filed under high current power supply, Power supply, switching power supply.
