Hey folks, I'm working on a precision voltage source platform. Not done yet, with much more left to do.
I'll probably make a handheld version of this, inspired by Ian's very excellent PDVS.
The architecture is modular, made of a DAC board, a reference board, analog supplies board and main board. The modularity is intentional and done for design flexibility as a top goal (reference, DAC, supplies can be replaced, improved or graded), and each board can be used separately in other designs by themselves as well.
Main board runs isolated digital supply, the digital electronics, battery charger, cal circuitry. A section of it will be dedicated to output buffering and output kelvin sensing. Main board, holds all other boards, on both sides, and is 100x70mm, smaller than most handheld instruments, a Fluke 57V is 150x70mm, Keysight U1272 is 170x80mm, Keysight U1733C is 140x70mm.
Reference board is based on LTC6655-5, it buffers and scales/inverts the reference to +10V and -10V. Reference board also contains an LDO supplied from the analog +15V supply.
The DAC board hosts some supply filtering, the AD5791 DAC IC, output buffer, and a small STM32 microcontroller which controls the DAC, keeps the cal constants, and communicates over UART.
The supplies board is based on ADP5070, with filters and with ADP7118 and ADP7182 as LDO post regulators.
Main board runs planned to run an STM32 micro, with an LTM8068 uModule isolated supply, for digital power.
The entire system runs on 3V, from which +15V and -15V is generated. The DAC is configured and can generate a 0 to +/-10V output. I plan to run the system from two independent 18650 cells, each independently powering the system. A charger will be built in to charge the cell that is not in use. Each cell should power the system for about 20hrs for a total of 40hrs. I do not plan to use an LM399 or LTZ1000 in a handheld version as simply they use too much power for handheld. However, the architecture can easily accommodate it with minimal or no changes to the mainboard and other modules.
If I ever experiment with an LTZ1000 version, it will be based on a 3458A reference module, with the buffering and scaling on the main board.
I plan to experiment at some point with an LT1533 regulator for lower noise. Of course the system can use any different supply scheme, like 2 x 9V batteries, and an 7815 regulator with an inverter to create the negative supply. Or external power from a dedicate low noise supply, like described above, but bigger, 2 x 7 x 18650 cells in an independent bank configuration. Such modification I'm considering for later not initial rev.