Other Parts Discussed in Thread: DRV8801
Hello.
I applied motor driver, DRV8428PPWPR, to control output command for the servo valve circuit.
The servo valve specification of our system is that output current is range from +10mA to -10mA, and the impedance is 2kohm at 1kHz at reference pressure of 20bar.
The applied circuit is shown in the figure below.
I designed that Output current was set to +11.273mA ~ -11.273mA, and PWM off time was set to 7us with smart tune dynamic decay mode.
Here's what I'm curious about.
1) The datasheet states that the PWM duty cycle and polarity can be varied with both pins of the input.
If so, can you know what the output waveform will be like as the PWM duty cycle is changed to 0%, 25%, 50%, 75%, and 100% with the settings above?
The waveform for the example on page 25 of the datasheet shows a constant output, and the input is only for 1 pin, but it is assumed that the PWM duty is adjusted constant.
2) We want to control the output by varying it from +10mA to -10mA. In this case, how do we control the PWM input?
For other motor drivers such as the DRV8801, the PWM duty control method is shown as an example on the data sheet as shown in the following figure.
Can the DRV8428P driver also have PWM duty control with two inputs?
Can you please tell me how to do it if possible?
