Help
Hello!
Can anyone tell me which voltage to put on the PWM pins of the h-bridge?
I've tried 0V to 5V, but in the datasheet the range is -5V to 5V. Is that important?
Thanks for your answers!
Best regards,
Sonja
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Controlling Simple H-Bridge
#1
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Posted 20 November 2007 - 03:40 AM
#2
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Posted 20 November 2007 - 10:33 AM
Sonja,
The -5V to 5V are the absolute maximum ratings. 0 to 5VDC is what you should apply to the H-bridge PWM control lines.
Lon
The -5V to 5V are the absolute maximum ratings. 0 to 5VDC is what you should apply to the H-bridge PWM control lines.
Lon
#3
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Posted 20 November 2007 - 08:52 PM
Hello Lon,
thanks for your answer, that's also what I thought. But the problem is that it does not work properly.
Can you please tell me which frequency I should use for the PWM?
Thank you very much for your support.
Sonja
thanks for your answer, that's also what I thought. But the problem is that it does not work properly.
Can you please tell me which frequency I should use for the PWM?
Thank you very much for your support.
Sonja
#4
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Posted 21 November 2007 - 07:23 AM
Sonja,
A frequency between 15KHz-20KHz would be optimal. You can use higher or lower frequencies. Ideally you only PWM the low side switches, and the high sides are held at a logic state.
Page 7 of the datasheet shows appropriate drive signals for operation. Using a resistor (like 1K ohm) as a test load you can monitor the voltage across the load with a multimeter or preferably with an oscilloscope. You do need to avoid shoot through conditions where both the low and high sides on the same side of the "H" are turned on. This will cause a short circuit. You also need to provide a 5V signal to the Simple Bridge to power the low side MOSFET driver.
You can test the control lines with non-pwm signals (0VDC or 5VDC) to determine correct operation. All grounds should be common.
Lon
A frequency between 15KHz-20KHz would be optimal. You can use higher or lower frequencies. Ideally you only PWM the low side switches, and the high sides are held at a logic state.
Page 7 of the datasheet shows appropriate drive signals for operation. Using a resistor (like 1K ohm) as a test load you can monitor the voltage across the load with a multimeter or preferably with an oscilloscope. You do need to avoid shoot through conditions where both the low and high sides on the same side of the "H" are turned on. This will cause a short circuit. You also need to provide a 5V signal to the Simple Bridge to power the low side MOSFET driver.
You can test the control lines with non-pwm signals (0VDC or 5VDC) to determine correct operation. All grounds should be common.
Lon
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