Wide DC Supply Shield

Overview

Most Arduino base boards only support a narrow input voltage range of 7 to 12V DC. While they usually have components rated for more than this (typically up to 20V), the voltage regulators are linear and therefore generate large amounts of heat to regulate down from high voltages to 5V.

This shield provides a reverse-polarity protected DC input which can be used instead of the DC input jack on your Arduino, and works with a wide voltage range of 12-37V DC while producing almost no heat. It supports automatic power input selection, just like the existing DC jack, and supplies power to any shield that draws from the VIN pin. All other pins on the shield are passed-through as is. And it includes a power switch and LED for convenience.

The shield is supplied as a kit which requires a basic familiarity with soldering, however all components are through-hole making it suitable for beginners and the board is marked clearly with values, polarity, and component types.

Specifications

  • Supports both Uno R3 shield format and original shield format (includes stackable headers for both options)
  • Can power shields which draw power from VIN pin
  • Does not interfere with power selection logic
  • Power LED and switch
  • Reverse-polarity protected input
  • Input: 12-37V DC (screw terminal block)
  • Output: 7.98V DC (on VIN shield pin), 1000mA
  • Kit includes the following components:
    • 1 x Shield PCB
    • 1 x LM2672 switchmode voltage regulator IC
    • 2 x 1k ohm resistors
    • 1 x 5.6k ohm resistor
    • 1 x 68uH inductor
    • 1 x 3mm green superbright LED
    • 1 x switch
    • 2 x 180uF 50V aluminium electrolytic capacitors
    • 1 x 10uF 50V aluminium electrolytic capacitor
    • 1 x 120uF 16V aluminium electrolytic capacitor
    • 1 x 100nF ceramic capacitor
    • 2 x Schottky diode 2A
    • 1 x terminal block, 2 pin
    • 2 x 6-pin stackable header, 2 x 8-pin stackable header, 1 x 10-pin stackable header

Current Build

Version 1.1 improved the PCB layout so that large components lie flat, and improved the silk screen to make component values and polarity clearer.

Version 1.0 was successfully built and tested.

Resources

Schematics and PCB Layout

To be provided.

License

Schematics and PCB layout are released under the Creative Commons BY-SA license.

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