LP395: Building a Current Amplifier for Driver Needs

Any ideas are welcomed. I have been unable to make the 3.3v GPIO pins at 4mA test these drivers. I am using the AM674 quad-core processor in Linux to attempt findings.

I will test the GPIO pins that are outsourced to the headers some more to see if there is anything I can do to manually handle the DM332T drivers.

So, far...

Pin Function Details

PUL

Pulse signal: Pulse active at rising edge; 4-5V when PUL-HIGH, 0-0.5V when PUL-LOW.
Minimal pulse width of 2.5μs. Add a resistor for current-limiting at +12V or +24V input logic
voltage (1K for +12V, 2k for +24V). The same as DIR and ENA signals.

DIR

DIR signal: This signal has low/high voltage levels to represent two directions of motor
rotation.. Minimal direction setup time of 5μs. Also swapping the connection of two wires of a
coil (e.g. A+ and A-) to the drive will reverse motor direction.

OPTO

Opto-coupler power supply, and the typical voltage is +5V. Series connect resistors (at the
PUL, DIR, ENA terminals) for current-limiting when +12V or +24V used.

ENA

Enable signal: This signal is used for enabling/disabling the drive. High level +5V (NPN
control signal) for enabling the drive and low level for disabling the drive. PNP and
Differential control signals are on the contrary, namely Low level for enabling. By default it
is left UNCONNECTED (ENABLED).

That code are the levels needed to handle the driver in question. They are GPIO pins from my board to a ULN2002A Darlington Array chip with more than enough I/O, i.e. as I will only need three GPIO pins being used at any one time. 

I am using a level translator also. The level translator is not Open Source and there are barely any documents on it but I see in a photo, there is some documentation:

Here is a photo for now...

That is a level of their level translator that I am using...

Seth

P.S. I have tried a BC547, Darlington Array chip called the ULN2002A, and some op-amp tech but all have failed so far. I need to test the output of the GPIO pins again in case anyone has any questions. For instance, would you need to know 3.3v at 4mA and what else? Switching time and so on? I am wondering...I want to make sure I have some data to give back if questioned.

Oh and sorry but I forgot to mention this idea:

With the GPIO pins on the AM674, I tested the driver with two GPIO pins (only DIR and STEP) and the motor turned severely hot. Too hot to the touch. I have since changed motors. I tested with the same exact type of motor and it also turned hot to the touch. 

With three GPIO pins used (OPTO, DIR, and STEP) instead of just flowing voltage into the OPTO pin at 5v and GND at the ENABLE pin, my motor was not warm even. It was a success of sorts. Since then, I have tested all four inputs on the driver.

ENABLE = GND

DIRECTION = GPIO

STEP = GPIO

OPTO = GPIO (I am still unaware of if GPIO here is needed with ENABLE to GND or if I should keep it and translate the logic to 5v switching)

The continuity tests correctly on the motor(s) and the driver too. I am seeing about 1.4 to 1.6 of current listed on a DMM while testing the driver A +/- and B +/- with power off to the driver. 

Seth

P.S. If some people understand where I could be making a mistake in presentation, please let me know. I seem to just fail to make the driver adhere to commands no matter my stance and circuitry. I will keep testing and see if anyone replies one day!