Hi to all in the Forum,
That is now my first post here, but I got a lot of good information and read interesting discussions
I want to use two or more VNH5019 for a submarine ROV unit. To prevent the whining sound coming from the motors, I want to use them all in ultrasonic PWM mode. (I think you can imaging who horrible it would be underwater for divers near by)
Okay, due to some limitations it is not possible to get them all in ultrasonic PWM by the pololu library. To use them as stackable shields is also not possible.
But I did not find any shield or breakout which will be usable. So I think it is time to talk about to use some external parts to solve this problem.
First idea was to use a TLC5940 Breakout.(like sparkfun.com/products/10616?)
Advantage: It has 16 channels, there is a ready to use library and can handle up to 30MHz grayscale clock frequency.
Disadvantages: Need several connections and some Timers for grayscale frequency and blanking the output.
My second Idea was to use the PCA9685 (a 16 channel 12bit PWM/Servo driver) like the one from Adafruit. (adafruit.com/products/815)
Advantage: Use a I2C bus connection and therefore it needs only 2 connections for the PWM scale for up to 16 channels.
Disadvantages: Adjustable frequency PWM only up to about 1.6 KHz, so not enough for ultrasonic.
Now I would like to discuss with you about your experiences or ideas. Has any of you ever run multiple motors with VNH5019 at 20kHz? How do you have solved this.
Sorry for my spelling errors, I do not write in English so often.