H-bridge

[billskip]

I am trying to use the NMIH-0050 H-bridge to run a small DC motor. I am using a OOpic micro-controller to send the logic signals to the ttl compatible inputs of the H-bridge, which determine the direction of the motor. For some reason it seems to be drawing an unusual amount of current through these logic level inputs, and will not spin the motor unless there is an adequate amount of current going to the logic inputs. I cannot supply enough current with the micro-controller signal to turn the motor. Can anyone tell me if this is normal?
Thanks.

[nmitech]

Bill,

Per spec,

H-input current (Vin=5V), Min: -2uA Max: 2uA
L-Input current (Vin=0V), Min: -10uA Max: 0uA

FYI, here is the Bridge spec sheet,
http://www.infineon.com/cmc_upload/documents/026/691/tle5206-2_20010619.pdf

You should be able to drive it with any microcontroller.

chris
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[RMDumse]

Ah! nmitech asked me about this earlier today, and I couldn't imagine why there would be high current needed into these inputs. Now I have one idea how this could be. There is a jumper on the board to allow the IN1 signal to be inverted and applied to the IN2 signal. This is so you can use just the IN1 signal to create a locked anti phase drive. If you drove the IN2 signal in as well, with that jumper in place, you would experience excessive drive currents. Any chance something like that is happening?

[billskip]

No, I am not using the jumper. However, I beleive I am connecting something wrong. Sorry to ask a dumb question, but what is the recommended way to connect the h-bridge. Is it necessary to connect ground and VDD to J3 and J2. Is it best to connect IN1 at J2 or J3 or both? Also, is it possible to have speed control by applying a pwm signal at IN1 and IN2?

[billskip]

I realy like this H-bridge ckt. I hope I can get it to work.

[nmitech]

Is it necessary to connect ground and VDD to J3 and J2. Is it best to connect IN1 at J2 or J3 or both?

J3 is the best connector to connect the input/output and power signals from your microcontroller system.

uP<--------------------------->J3
+5V--------------------------->VDD
GND--------------------------->GND
OUTA-------------------------->IN1
OUTB-------------------------->IN2
No Connection==============IN1'
IN<------------------------------EF

For Locked Anti Phase option, insert a jumper from IN2 to IN1' on J3.
uP<----------------------------->J3----------J3
+5V----------------------------->VDD
GND----------------------------->GND
OUTA---------------------------->IN1
No Connection================IN2<---->IN1'
No Connection================IN1'<---->IN2
IN<--------------------------------EF

Please see the schematic link below for proper wiring,

http://www.newmicros.com/store/product_schematics_pdf/NMIH-0050.pdf

For Speed control application, please see the data sheet page 15 from the link below for detail,

http://www.infineon.com/cmc_upload/documents/026/691/tle5206-2_20010619.pdf

[billskip]

Thanks, I realy appreciate the help.