Difference between revisions of "Anchor"
From Hackstrich
(Modularize.) |
(Changing to an SPI ADC because having 2 will work better than 2 I2C versions.) |
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**** UI pot (if used) | **** UI pot (if used) | ||
**** 2 for touchscreen | **** 2 for touchscreen | ||
| − | |||
| − | |||
| − | |||
** '''Outputs''' | ** '''Outputs''' | ||
*** Digital | *** Digital | ||
**** CC/CV mode relay (if required) | **** CC/CV mode relay (if required) | ||
**** Scope trigger output | **** Scope trigger output | ||
| + | **** 2x SPI /SS outputs | ||
*** Analog/PWM | *** Analog/PWM | ||
**** Output drive (to op-amp) | **** Output drive (to op-amp) | ||
| + | ** '''Communication Busses''' | ||
| + | *** I<sup>2</sup>C | ||
| + | **** 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 | ||
* Want a graphical LCD for the output/UI, and the PIC chosen will drive a nice TFT | * 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 | ** WQVGA is a nice size, can get a menu/buttons on the side and still have room for the info display | ||
Revision as of 15:14, 28 December 2010
Anchor will be an electronic current/voltage sink, for testing/characterizing power supplies and other similar tasks.
- 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
- Ethernet could be cool, but that seems overkill here
- GPIB would be the traditional choice for test gear, but I've never done any work with it
- 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
- 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?
- 2 for UI quadrature encoder
- 2 for touchscreen
- MCU-integrated 10-bit ADC
- Heatsink temperature
- UI pot (if used)
- 2 for touchscreen
- Digital
- Outputs
- Digital
- CC/CV mode relay (if required)
- Scope trigger output
- 2x SPI /SS outputs
- Analog/PWM
- Output drive (to op-amp)
- 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
- 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
- Likely still want the critical UI bits to be physical controls (current/voltage mode/setting)
- The Newhaven NHD-43-480272MF-ATXI-T-1 from Mouser seems the best option for size/touch/resolution
