Hi there;
I'm trying to muddle my way through my first design with a motor driver that includes current sensing. This is for a battery-powered device, operating with an stm32f4 at 3.3v. My motor is a small gimbal-style motor, which I intend to run at 3.3v, and which I estimate will draw current ranging from 0.1-0.4A. I think I would like to run at a PWM that is at least 20kHz, though it would be nice to go faster to avoid switching frequencies that might be irritating to pets. Maybe that's 25-40kHz (center-aligned PWM)?
The STSPIN233 seems very appealing to me, but - because I'm new to this - I'm struggling a little navigating the ADC front end amplification necessary for this.
I'm aware I need amplification of some sort - I have several dozen tabs open in my web browser here to try to understand the differences between using an op-amp vs. a current sense amplifier for this. I am having trouble finding many specific resources for this in ST's library. TI has a ton of stuff, but they often seem to jump back and forth between high-speed op-amps (e.g. the OPA835) and current sense amplifiers (e.g. the INA303) without explaining why.
One thing I notice from browsing TI's parts is that the current sense amplifiers seem to have a notable Iq - it seems undesirable of me to choose a power-optimized part like the STSPIN233 and pair it with a sense amplifier that's not similarly designed for low-power use. But I'm finding it tricky to browse parts that would be good pairings for this device.
My question(s) then:
- Would anyone have advice as to what parameters I should be optimizing for when choosing an appropriate amplifier for the STSPIN233?
- What would be the reason(s) to prefer an op-amp solution vs. a current sense solution as it relates to this device?
- Are there any references or opinions about good amplifiers to consider for this device? (Stumbling around ADI's site, for example, I came across this device that seems to be intended for battery-powered devices, though it is not listed in stock on Digikey. But I found this totally by accident and wouldn't know how to look for 'similarly-categorized' parts)
I've had trouble finding example designs that use this device with properly-broken-out sense capabilities (there are a lot of hobbyist builds out in the world, almost all of them either forego current sensing entirely or wire all three sense outputs together and route them through a single shunt, which seems outright incorrect to me).
Thank you so much!
