Arduino Power Supply v18.08
Design
Requirements
- Up to 300 mA supply (200 mA would likely be enough)
- 7-12 V DC output
- 120 V ac input
- Stable voltage reference of less than 5V (not needed if Arduino's internal reference is accurate enough, TBD)
Research
Non-isolated design could waste more power if Arduino is drawing less than the designed maximum output current. Isolated could lose a small amount of efficiency to transformer but would waste less power when the Arduino is drawing less than the designed maximum output current.
Power requirements for Arduino Mega (usually <70 mA, 200 mA max) and RepRap Discount Smart Controller (40-100 mA?). 300 mA max to power control and display circuits.
Drawing Power from Grid without Transformer for *Low Power* Applications
Precise voltage measurement with the Arduino
High Efficiency 400W AC/DC Power Supply Reference Design
Calculations
QUCS-S Simulation
Simulation providing 9V at >250mA
Electronics Design
These designs are not guaranteed to be safe or functional. Use at your own risk.
Bill of Materials
Isolated
Fuse: FUSE GLASS 500MA 250VAC 5X20MM
Transformer: XFRMR LAMINATED 6VA THRU HOLE
Bridge rectifier: RECT BRIDGE 2A 40V 4SMDIP
Non-isolated
Fuse: FUSE GLASS 1A 250VAC 5X20MM
Cac: CAP FILM 10UF 5% 400VDC RADIAL
Cac discharge resistor: UPL1.064 RES SMD 1M OHM 1% 1/4W 1206
Bridge rectifier: RECT BRIDGE 2A 40V 4SMDIP or 4xUPL4.004 DIODE SCHOTTKY 40V 1A SOD123
Filter capacitor: CAP ALUM 680UF 10% 10V RADIAL
Output zener: DIODE ZENER 9.1V 5W AXIAL
Voltage reference: IC VREF SHUNT 4.096V TO92-3
Voltage reference resistor: RES 5.6K OHM 5W 5% AXIAL
Total cost of components ~$10