Dual +12V/-12V @ 400mA Regulated Linear Power Supply with AC input

  • Rajkumar Sharma
  • 572 Views
  • moderate
  • Tested

The project presented here is a dual output linear power supply. This power supply provides low ripple low noise DC regulated output. It is a very useful tool to power Audio, Video, OPAMP-based circuits, and projects. The circuit provides regulated +/-12V DC output @ 400mA + 400mA. The project supports AC input supply 230V or 115V. On-board jumpers are provided for AC230V or AC115V selection. Besides regulated output, the board also has provisions to output the unregulated supply using CN2.

Parts Explanation

  • Connector CN1: 230V/115V AC Input
  • Jumper J2:  230V Selection
  • Jumper J1, J3: 115V Selection
  • Transformer-Step Down T1: 230/115V AC IN, 12VAC-0V-12VAC 0.83A
  • Bridge Rectifier BR1: Bridge Rectifier
  • Capacitor C2, C5: DC Filter Capacitors
  • Connector CN2: Unregulated DC Output
  • Regulator U1: +12V Regulator
  • Regulator U2: -12V Regulator
  • C1,C3,C4, C6 : DC Filter Capacitors
  • LED D1: +12V LED
  • LED D2: -12V LED
  • Connector CN3, and CN4: +/-12V Regulated Output
  • Resistor R1, R2: Current Limiting Resistors for LEDs
Note1: This power supply supports 230V AC or 115V AC input, remove input power cable while changing Jumper selection.
Note 2: This power supply contains hazardous voltage at the input, PCB must be installed in an encloser that prevents accidental contact. Use Plastic screws to mount the power supply.
Note 3: Power supply also can be used as Dual Regulated +/-15V DC Output. In this case replace U1 LM7815, U2 LM7915

Note 4: Heatsink is a must for regulators U1 and U2 @ full load. The heatsink should be mounted with plastic screws and should not touch the ground plane of the PCB.

Input Voltage Selection

  • For 230V AC Input: Close Jumper J2 Jumper J1 and J3 Open,
  • For 115V AC Input: Close Jumper J1 and J3 Open Jumper J2

Other Similar AC to DC Power Supplies

Features

  • Input 230V or 115V AC (Use Jumpers to Select 230V or 115V AC)
  • Output +/-12V DC (Dual Output)
  • Unregulated Output Approx. +/-17V (CN2)
  • Output Ripple Approx. 5mV
  • Maximum Load Current 800mA ([email protected], [email protected])
  • 2 x Power LEDs, for 12V and -12V
  • Screw Terminal for AC Input
  • Screw Terminal for Regulated DC Output
  • 3 Pin Male Header Provides Unregulated DC Output
  • 4 Pin Male Header for Regulated DC Output
  • PCB Dimensions 99.06 x 58.74 mm

Schematic

Parts List

NOQNTY.REF.DESC.MANUFACTURERSUPPLIER SUPPLIER PART NO
11BR1BRIDGE GBL08 OR GBL06VISHAYDIGIKEYGBL06-E3/45GI-ND
21CN13 PIN SCREW TERMINAL PITCH 5.08MMPHOENIXDIGIKEY277-1248-ND
31CN23 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5316-ND
41CN34 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5317-ND
51CN43 PIN SCREW TERMINAL PITCH 5.08MMPHOENIXDIGIKEY277-1248-ND
62C1,C40.1uF/50V SMD SIZE 0805MURATA/YAGEODIGIKEY
72C2,C52200uF/25VRUBYCONDIGIKEY1189-3651-ND
82C3,C610uF/25V SMD SIZE 1206MURATA/YAGEODIGIKEY
91D1RED LED SMD SIZE 0805LITE ONDIGIKEY160-1427-1-ND
101D2GREEN LED SMD SIZE 0805DIALIGHTDIGIKEY350-2044-1-ND
113J1,J2,J3JUMPER 2 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
122R1,R21.5K 5% SMD SIZE 0805MURATA/YAGEODIGIKEY
131T1VPP24–830 TRANSFORMER 12V-0-12VACTRIADDIGIKEY237-1071-ND
141U1LM7812TIDIGIKEY296-50628-ND
151U2LM7912TIDIGIKEYLM7912CT/NOPB-ND
162SHUNTSHUNT FOR JUMPPERS J1,J2,J3SULLINSDIGIKEYS9001-ND
172HTHEATSINK AVIDDIGIKEYHS106-ND
182SCM3 SCREW X 10MM LIO AUDIODIGIKEY1937-IO-M3X10/M3HN-50-ND

Connections



Gerber View

Photos

Video

LM7812 Datasheet

LM7812-461970

PCB

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