Anchor
From Hackstrich
Anchor will be an electronic current/voltage sink, for testing/characterizing power supplies and other similar tasks.
Status
- 2911-10-12: Parts for Anchor PSU and logic board have been received.
- 2011-10-09: Anchor PSU PCB received, order placed for all PSU and logic board parts.
- 2011-09-22: Tagged as rev. 1 and sent to Laen for PCB manufacturing. Parts still need to be ordered.
- 2011-09-21: Added speaker and completed the rest of the routing. Added silkscreen to all connectors/test points/button/etc. One final check tomorrow, then will be sent to Laen.
- 2011-09-19: Completed rev. 1 schematic, started working on board layout and got about 80% completed, remaining to complete are the USB port, one of the two expansion slots, and GND.
- 2011-09-18: Worked on schematic, completed the two ADC sections and the DAC section for measurement and load driving.
- Pre-September 2011: Put together majority of desired specs and started putting BOM together, put together UI part of the schematic.
Specs/Brainstorming
- Desired features/specs:
- Constant current and constant voltage options
- Maybe constant power too?
- Ramp-up/down automatically and track outputs
- Pulse load to test transient response
- 5A/100V maximums
- 500W dissipation in a FET is a bit nuts, so it won't be 5A *at* 100V
- 100W continuous, 500W pulse might be reasonable? Would be nice anyway.
- Some kind of computer interface for more complicated tests/more detailed data analysis
- USB would be easy to implement
- Implemented on rev. 1
- RS232 would be even easier to implement
- Implemented on rev. 1
- Ethernet could be cool, but that seems overkill here
- The LXI standard seems useful for this, could be implemented on an expansion card
- GPIB would be the traditional choice for test gear, but I've never done any work with it
- Could be implemented on an expansion card later if there is any need
- USB would be easy to implement
- Add-on module system for adding extra monitoring channels for things that might be expensive to implement or not commonly used
- Temperature monitoring (a couple channels worth) would be good, as you often want to monitor chips/pass elements/etc. while load testing supplies
- Everything to do with thermocouples is expensive, so making this an add-on module would be good
- Temperature monitoring (a couple channels worth) would be good, as you often want to monitor chips/pass elements/etc. while load testing supplies
- Direct connection to mains, as power bricks are annoying in hackerspaces where gear is moved around a lot
- Constant current and constant voltage options
- PIC24FJ256DA210 will be used as it has all the graphics/LCD drive/acceleration built in to enable a nice colour TFT display
- Inputs
- Digital
- Load On/Off
- Event trigger switch
- CC/CV mode?
- 3 for UI quadrature encoder
- 2 for touchscreen
- MCU-integrated 10-bit ADC
- Heatsink temperature
- 2 for touchscreen
- Digital
- Outputs
- Digital
- CC/CV mode relay (if required)
- Scope trigger output
- Load disconnect relay
- 3x SPI /SS outputs
- Digital
- Communication Busses
- I2C
- AR1020 I2C resistive touchscreen controller (will try to eliminate it and do it in the PIC for revision 2)
- SPI
- 2x LTC2450 SPI 16-bit ADC for current and voltage measurement
- 1x MCP4921 12-bit DAC for driving the MOSFET
- I2C
- Inputs
- Want a graphical LCD for the output/UI, and the PIC chosen will drive a nice TFT
- WQVGA is a nice size, can get a menu/buttons on the side and still have room for the info display
- The Newhaven NHD-43-480272MF-ATXI-T-1 from Mouser seems the best option for size/touch/resolution
Revision 1 Issues
PSU
- Fuse holder pins are bigger than holes
