Hello. We are using the 2997 motor driver carrier board to drive a 12V Servo City motor p/n 638352. What will be the effect of motor regeneration EMF on the TB9051FTG driver IC when the carrier board is powered and not powered? Thanks.
Hello.
As with basically all H-bridges, the TB9051FTG has a diode bridge path from the motor to the supply. So if your motor is generating a higher voltage than the supply, current will try to flow into the supply. Of course, if you are additionally manipulating the MOSFETs, e.g. putting them in a brake configuration, then the current will just circulate through there.
- Patrick
Thanks Patrick. How about of there if the supply is not connected? What is the effect on the H bridge IC? Will it be damaged?
The motor voltage (minus the diode drops) will appear on the supply pins. As long as you are not violating any other ratings, that should be fine. For example, the maximum voltage is 40V; if you attach a motor that at 24V spins at 100RPM, and you force it to spin at 200 RPM, you would be generating roughly 48V, which is what would get routed to various nodes and could possibly destroy something.
- Patrick
Thanks Patrick. I understand and agree with all that. I kind of thought that’s what would happen. The motor runs at 12V. How about if I put a 16 V zener to clamp the supply voltage?
I’m not sure what the point is but it shouldn’t hurt as long as your zener can take the power your motor would be delivering in your scenario and you have thought out your tolerances. For instance, 16V nominal for the zener might be too close to what a 12V battery could get to.
- Patrick