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I'm using the DRV8836 (datasheet here) from Texas Instruments and can't seem to get it to work. Does it require a PWM (pulse from the signal generator) or am I able to drive it with only the DC power supply? I'm a bit confused with how this chip works in terms of what type of input the PHASE pin expects. I know that the ENABLE pin can just be pulled high by a DC power supply. I am using the PHASE/ENABLE mode, but what is the difference between this mode and the IN/IN mode?

What I want to do is to control a DC motor with this H-bridge and a microcontroller, but for now I just want to test if I have the chip soldered onto its adapter board properly, which I have on a breadboard.

enter image description here

Here is my set-up: second

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The difference between PH/EN mode and IN/IN mode can be understood by looking at the truth table given in the data sheet (pg 7). When Under IN/IN mode you are essentially controlling each output port individually. Hence energizing one output port and leaving the other open will operate the motor in a particular direction.

Under PH/EN mode what you are doing is allowing the logic circuit inside to control the direction of movement, instead of energizing and de-energizing each coil individually. Hence the truth table for PH/EN mode is much smaller. For driving a DC motor PH/EN mode is sufficient.

To check if the board is working Give VCC and ground as usual.

1) set mode to 1

2) AIN1 = 0

3) AIN2 = 1

4) nsleep = 1

With the motor connected across AOUT1 and AOUT2 the motor should run in the forward direction.

If you wish to provide PWM to control the speed of the motor send a pwm signal to AIN2 which is the enable pin (AIN2 is the phase/direction pin). By changing the Duty cycle you may vary the speed.

You can also confirm that this method works by looking at the timing diagram given in page 6.

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  • \$\begingroup\$ I would like to drive the motor at a constant speed. From your answer my understanding then is that I don't need the signal generator at all for PWM. I can simply use the DC power supply? I have connected the circuit as you suggested but what happens is the motor does not run and the chip heats up very quickly (so I disconnect it immediately as soon as this happens). \$\endgroup\$ – Christina Apr 29 '15 at 8:42
  • \$\begingroup\$ What could the problem be? I tested for shorts between the leads of the adapter board but since the chip itself has no leads on the package (DFN), I can't tell if the chip is soldered onto the board correctly. \$\endgroup\$ – Christina Apr 29 '15 at 8:43
  • \$\begingroup\$ Can we see a picture of the set up? Make sure Vcc is powered by a 5V source. And provide an input capacitor. Would'nt know why it would overheat, sounds weird. \$\endgroup\$ – Sada93 Apr 29 '15 at 8:47
  • \$\begingroup\$ What's the motor rating? \$\endgroup\$ – Sada93 Apr 29 '15 at 8:53
  • \$\begingroup\$ It's a 13 V motor and I've attached an image to the post now. Red and black are what you would expect, but I don't use the red rails on the edge of the breadboard because I have another circuit connected to the same board. They share the same ground but I only power the one pictured. However I only tried supplying 2V to the chip - I'm afraid 5V might blow something if I did wire something wrong. \$\endgroup\$ – Christina Apr 29 '15 at 9:35

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