I'm looking for a solution to control the direction of a powerful DC Motor (http://micro-motor-warehouse.com/collections/all/products/cl-0820-17). I came up with the idea to use a H-Bridge. Since the motor uses up to 3.2A the amount of possible H-Bridges is quite limited. The supply voltage on my quad is 3.7V. Since my outputs are limited I want to control the position using only one Digital Output. Which does work in one direction if set to 0 and other direction if set to 1. The PWM output should control the velocity. Is that even possible? I found this one http://www.newark.com/texas-instrum...r-h-bridge-8a-vqfn/dp/36X2964?ost=DRV8850RGYR but I have absoultely no clue if this one can be controlled only with 2 inputs per motor (1 PWM , 1Digital Output).

Thx for your help

 

Factory lifetime rating: 5-6 Hrs?
Is this a DC or BLDC motor?
Max.

 

I don't know about the lifetime rating, but that may be right. But the motors are much easier to exchange than a H-Bridge that is soldered onto a PCB... It is a DC motor with brush.

 

I have built several big DC motor reversing drives using only two port-pins from an Arduino or PIC. I use one port-pin to drive a DPDT relay, where the contacts of the relay are wired as an H-Bridge to reverse the current through the motor. The other port-pin generates PWM to the Gate of a large (heatsinked) NFET, which is connected in-series with the 0V side of the H-bridge.

The code in the controlling micro takes care of accelerating the motor, de-accelerating it, dead-time to allow it to coast to a stop before reversing it, etc. via the PWM. I never switch the relay while I think the motor may be moving... Actually, I can measure the motor current using an A/D input to the micro, so I can tell what the motor is doing...

Send me a PM if you want the schematic of my project, from which you can see how to wire the relay and the PWM NFET.

 

Here is the data sheet for the DRV8850RGYR
That will tell you everything you need to know about the chip.
The chip has 4 inputs, one for each of the 4 transistors in the bridge.
You can drive the chip with a PMW signal to turn on the diagonal MOSFETs for the motor direction you want. The other diagonal MOSFETs in the bridge must both be OFF.
Two AND gates (such as a CD4081), one for each opposite pair of MOSFETs) and one inverter (CD4049) for the direction signal, will generate the proper signals so it will operate with one PWM signal and one direction signal as you want. (Make sure you tie all unused gate inputs to ground).
The maximum PWM frequency is 50kHz.
(Make sure you get the chip with through hole pins (DIP) unless you want surface-mount).

 

Here is the data sheet for the DRV8850RGYR
That will tell you everything you need to know about the chip.
The chip has 4 inputs, one for each of the 4 transistors in the bridge.
You can drive the chip with a PMW signal to turn on the diagonal MOSFETs for the motor direction you want. The other diagonal MOSFETs in the bridge must both be OFF.
Two AND gates (such as a CD4081), one for each opposite pair of MOSFETs) and one inverter (CD4049) for the direction signal, will generate the proper signals so it will operate with one PWM signal and one direction signal as you want. (Make sure you tie all unused gate inputs to ground).
The maximum PWM frequency is 50kHz.
(Make sure you get the chip with through hole pins (DIP) unless you want surface-mount).

I found the data sheet as well. But what you wrote about the AND gates and inverter was what I was looking for, since I was not sure how to adapt it.

 

Here's a simulation of the logic that should do what you want.
Power and ground connections are not shown and must be added.
Tie all unused inputs (not outputs) to ground.

 

thank you very much for the simulation. What program did you use? Or what do I need to open that .asc file?

 

thank you very much for the simulation. What program did you use? Or what do I need to open that .asc file?

I used the free LTspice program from Linear Technology.
Note that you have to add the CD4000 models from the Yahoo LTspice users group to run my file.