DRV8832 Help

Lee Olson

Other Parts Discussed in Thread: DRV8832, DRV8816, DRV8800, DRV8837, DRV8801, DRV8832EVM

I am trying to take PWM signal from a 555 timer and put it into a DRV8832 to control a DC brush gear-motor to remotely adjust a variable butterfly capacitor on a amateur radio antenna. I'll be using forward, reverse and braking and using the 555 timer for variable speed. I have been looking all over the internet for a diagram of something similar. The gear-motor is surplus from a battery power display sign and draws 50ma under load. Do I have to put a .25 ohm resistor at ISENSE or can it be left out or bypassed? I would like to share this info with a Yahoo Antenna Group. Thank you for your assistance.

Lee

over 11 years ago

0 Nicholas Oborny over 11 years ago

TI__Mastermind 21320 points

Hi Lee,

The current sense resistor can be removed if you do not require current limiting. Simply connect the ISENSE pin directly to GND. This is stated on page 9 of the datasheet.

0 Lee Olson over 11 years ago in reply to Nicholas Oborny

Prodigy 40 points

Thank you for the quick reply.. I looked over that section but missed that line. I cannot see how I would put my PWM signal in or is there a way to use the internal PWM to adjust the motor speed. Would a potentiometer voltage divider to VSET do it? I do not want to smoke my IC doing something wrong.

Lee

0 Nicholas Oborny over 11 years ago in reply to Lee Olson

TI__Mastermind 21320 points

The inputs for the H-Bridge are IN1/IN2. This part also provides a closed loop speed control incase of varying supply voltage. Are you just looking to move a DC motor back and forth? We have a few simpler chips such as DRV8837, DRV8800, DRV8801, and DRV8816 for basic DC motor control.

0 Lee Olson over 11 years ago in reply to Nicholas Oborny

Prodigy 40 points

So IN1 and IN2 are not just for logic inputs for direction and braking but also for PWM input? Braking is needed because this gear-motor coasts and when the antenna gets tuned for the loudest volume it cannot coast by. Another user in the Yahoo Group sells a motor controller and I zoomed in on a picture of it and he uses this chip. I already purchased 10 of these and would like to get this chip going instead of buying others.

Lee

0 Nicholas Oborny over 11 years ago in reply to Lee Olson

TI__Mastermind 21320 points

Hi Lee,

The control logic for IN1/IN2 is shown on page 7 of the datasheet. We also have an EVM you can purchase to evalutate the part PN = DRV8832EVM.

For forward you would hold IN1 High and PWM IN2 (opposite for reverse).

0 Lee Olson over 11 years ago in reply to Nicholas Oborny

Prodigy 40 points

Thank you for all your help, Nick.

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DRV8832 Help