Mosfet load board

16 07 2011

Three mosfets in parallel provide an adjustable load. Current is sensed with low side resistor. Reference is provided externally (DAC or pot).
Input voltage and current are fed into a PGA which is sent off board.
There is also an 8-bit i2c i/o expander and 18-bit i2c ADC available.

3D render:

Schematic:

PDF: mosfet_load.pdf

 

Main components:

#003





Atxmega base

16 07 2011

Connects to 128×64 LCD (sure electronics). Buffered DAC outputs. Some low side mosfets for fan/relay/LCD backlight control.

PCB render:

Schematic:

PDF:  xmega_base.pdf
BOM:  xmega_bom.xls (resistors not included, design not tested)

Main components:

Issues:

  • There is a problem when a 5V LCD is used as xmega i/o is not 5V tolerant. Will need 3k series resistors on pins LCD_D0-7.

#002





iGaging DRO to serial PCB

28 06 2011

Takes up to 3 igaging inputs (USB mini B connector), and outputs data via UART.

3D render:

Schematic:

PDF: DRO_Schematic.pdf

Main components:

#001