Is there a shield out there that will give me 0 - 70 vdc at 0.05a max, control able by pwm or other mechanism? Ideally with h bridge output for polarity reversal.
I just don't want to design it if it already exists.
:~ Crickets chirping...
Sounds like it's time to roll my own.
Search for "arduino motor shield".
I would say not, that is a voltage higher than the norm. While it is possible to do it is not a natural thing, that is you have to specifically design it to do that. You also have to have a 70V supply or use an expensive DC to DC converter.
Have you read this...
Regulated Positive Voltage Booster
A simple regulated DC-DC booster for up to 60V 1/4W. It uses no special ICs, just basic components and two pins from the Arduino.
Outputs 1/4 Watt, up to +60V DC Max
Voltages exceeding 60V may be possible
If you're trying to get more than one watt, then use a darlington pair. With BJT power transistors, the most you'll get is about 4 watts, efficiently. With N-Channel power MOSFETs, it's possible to get 25 watts at about 70% efficiency with a good power inductor (it's very difficult). To get past 30 watts, you'll lose efficiency, need a different frequency PWM, or an elaborate/expensive switch.
70 vdc at 0.05A = 3.5W
Ouch, 70V! (Hint to me: next time pay more attention...)
I hadn't seen that one yet, and 60V is close enough even though this isn't government work.
I can work with that, especially if I can use one of the less popular pins for PWM, since I'm already having conflicts between the motor shield and SD card interfaces.
Thanks!
Have you read this...
Regulated Positive Voltage Booster
That's just the power supply, it is not the switching circuits.