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Author Topic: VNH3SP30 Trouble  (Read 1571 times)

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Offline dellTopic starter

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VNH3SP30 Trouble
« on: February 05, 2009, 12:08:03 PM »
Hello,

I've been working with http://www.pololu.com/file/0J51/vnh3sp30.pdf I bought from Pololu. I bought only the ICs and not the boards. I made my own board and I'm facing some major issue:

While running the motor driver for smaller motors which consume close to 500 mA, I face no trouble at all. But as soon as I move into a larger range of 1 Ampere motors or above, my VNH stops responding altogether. It pulls my inputs low, which is something beyond me. This means that if my input voltage is 5 Volt at Input A and GND at Input B, both are pulled down to ground (-0.3 volt actually). The board doesn't heat up, doesn't indicate in any way that there is any kind of thermal shutdown, but thats it.

Now the 5 volt input I gave above was from an Atmega 16, when I give it an output from a SMPS, the motor suddenly starts running perfectly. I'm thoroughly confused here..Could anyone help me out with schematics of their own boards/anyone who has worked on this particular IC, could you please tell me what to do next?

Offline Soeren

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Re: VNH3SP30 Trouble
« Reply #1 on: February 06, 2009, 11:36:22 AM »
Hi,

Measure the input current of the driver and post it here - it should be 10mA max. but seems to be more than the conroller can handle.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline Admin

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Re: VNH3SP30 Trouble
« Reply #2 on: February 15, 2009, 04:39:02 AM »
Quote
This means that if my input voltage is 5 Volt at Input A and GND at Input B, both are pulled down to ground (-0.3 volt actually).
You mean 5V reads -0.3V? I don't understand what you mean . . .

 


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