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Electronics => Electronics => Topic started by: dell on February 05, 2009, 12:08:03 PM

Title: VNH3SP30 Trouble
Post by: dell on February 05, 2009, 12:08:03 PM

Hello,

I've been working with http://www.pololu.com/file/0J51/vnh3sp30.pdf (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?

Title: Re: VNH3SP30 Trouble
Post by: Soeren 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.

Title: Re: VNH3SP30 Trouble
Post by: Admin 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 . . .