Author Topic: VNH3SP30 with 3.3V controller?  (Read 909 times)

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Offline silo_xtremeTopic starter

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VNH3SP30 with 3.3V controller?
« on: April 01, 2010, 12:26:16 PM »
Hi All,

I need a sanity check here.  Is it possible to use a 3.3V Atmel chip with the VNH3SP30?

http://pdf1.alldatasheet.com/datasheet-pdf/view/84563/STMICROELECTRONICS/VNH3SP30.html

I'm a little confused form their 3.25V test data and the other information in the data sheet.

I'd really appreciate your help!

Mike

Offline Razor Concepts

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Re: VNH3SP30 with 3.3V controller?
« Reply #1 on: April 01, 2010, 12:54:17 PM »
As long as the h-bridge itself is being powered by at least 5.5 volts, the 3.3v logic level high sent by the atmel chip should control it fine.

Offline silo_xtremeTopic starter

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Re: VNH3SP30 with 3.3V controller?
« Reply #2 on: April 01, 2010, 12:58:33 PM »
The INA , INB and PWM are at 5V

The Enable/Diag pins are at 3.3V

For some reason this doesn't turn on the motor.

The strange things is that when I cycle the VCC power, the motor starts to work.

Any ideas?

Offline Soeren

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Re: VNH3SP30 with 3.3V controller?
« Reply #3 on: April 01, 2010, 05:14:22 PM »
Hi,

The Enable/Diag pins are at 3.3V

For some reason this doesn't turn on the motor.

The strange things is that when I cycle the VCC power, the motor starts to work.
The 3.3V is in itself pretty close to the 3.25V. Add the hysteresis of 0.5V and it's going on one wing and a prayer.
You could use small signal transistors and pull ups, or a (6x or 8x) buffer/level translator circuit to get the voltages in check.
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

 


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