Open Source Lab Power Supply
This project is to create an open source modular lab power supply. The power supply is designed to:
- Provide between 0-15V @ 5A and 15-30V @ 3A
- Provide current limiting
- Voltage to be settable to within 1mV and current limit to 1mA resolution.
- Voltage/current readback to 1mV and 1mA with low temperature drift.
- Limit heat loss through the use of a pre-regulator. The pre-regulator uses an SCR and MOSFET arrangement to reduce noise (switches at a low frequency)
- Digitally controllable via a Raspberry PI and touch-screen interface.
- Multiple channels (designed for 3).
- Each channel is isolated and can be paralleled or put in series.
- Each channel uses its own torroidal transformer.
A Blog documenting the development of the project can be found here http://wahz.blogspot.com.au/2015/03/lab-power-supply-project.html
The major components used in the project are:
- IRFP044N N-channel MOSFET as the pass device. http://www.irf.com/product-info/datasheets/data/irfp044n.pdf
- IRF5210 P-channel MOSFET used to switch the input in the pre-regulator http://www.irf.com/product-info/datasheets/data/irf5210.pdf
- MCR-100 SCR http://www.onsemi.com/pub_link/Collateral/MCR100-D.PDF
- LT1639 Op Amps used in the control loop. http://www.linear.com/product/LT1639
- LT1716 Comparator used in the pre-regulator http://cds.linear.com/docs/en/datasheet/1716fa.pdf
- LTC2050 Op Amp used for current sense amplifier. http://www.linear.com/product/LTC2050
- AD5689R DAC with built in 2ppm/degree reference as main output voltage/current DAC. http://www.analog.com/media/en/technical-documentation/data-sheets/AD5689_5687.pdf
- AD7705 ADC used to read output voltage/current http://www.analog.com/media/en/technical-documentation/data-sheets/AD7705_7706.pdf
- ATMEGA328P Used as the main controller
- ADUM1201 dual channel isolator used to isolate the USB interface from the rest of the module http://www.analog.com/media/en/technical-documentation/data-sheets/ADuM1200_1201.pdf
- MCP2200 USB to serial converter http://www.microchip.com/wwwproducts/devices.aspx?dDocName=en546923