Digipot Flex Module

Digital potentiometer Flex Module.

Similar projects worth following
Not so simple design to support 4 channel digital potentiometer. To utilize Wiper Lock the board has an on board boost power supply enabled by the WIPL pin. The power supply raises to 12V to enable EEPROM writing. The WP solder bridge will prevent writing.

Use as Microchip four digital potentiometers (or rheostats) with 100kOhm range with 256 positions on each - MCP4461T-104E/ML . Commonly used to calibrate analog sections of instrumentation.

The board utilizes a low cost TI power supply to boost from 3.3V-5V to 12V. It still is about half the BOM cost including the 4 layer design. Triple charge pumps have similar cost and are less available. Enabling the WIPL line turns on the power supply. This enables write commands for Wiper Lock which sets the potentiometer power on defaults. With the defaults programmed, calibration can be saved and i2c control maybe unnecessary. The WP solder bridge will also prevent overwrite of defaults.

The circuit should work well with a 3.3V-5V VDD. There may be noise on the A, B, W lines around the inductor when Wiper Lock is enabled. In calibration usage, I would recommend tuning before enabling it to write.

Any software related will be released under BSD or MIT license. SAAS or cloud based software will be AGPL.

Creative Commons License

  • 1 × MCP4461T-104E/ML Data Converters / Digital Potentiometers
  • 1 × TPS61046 28-V Output Voltage Boost Converter in WCSP Package
  • 1 × LPS4018-223MRB Inductors, Chokes, Coils and Magnetics / Fixed Inductors, Chokes and Coils

  • Digipot Application

    Chris Hamilton08/17/2015 at 16:51 0 comments

    The main reason we started working with it was to automate test jigs for our other Flex Modules. Hopefully there is general interest in the technology, but in general it is useful for calibration and analog automation.

  • Testing soon

    Chris Hamilton08/17/2015 at 16:48 0 comments

    We have the digipots, but not the power supply components. We will have them in stock soon though to test.

  • Wiperlock

    Chris Hamilton08/17/2015 at 16:46 0 comments

    The power supply for the wiper lock should be efficient, but is meant to only be enabled in special use cases. We may make it an optional set of components.

  • Almost 2 layer

    Chris Hamilton08/05/2015 at 06:07 0 comments

    This design was almost 2 layers. There were about 5 traces I could not route and so I converted to a standard 4 layer stack up. I might revisit this issue after confirming the circuit function.

View all 4 project logs

Enjoy this project?



Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates