DRV110: Delay in closing the valve via ON.

Hello,

What PWM frequency are you switching at? 

The ROSC resistor will set the oscillation frequency for PWM control. The frequency should have an effect on the delay between EN and gate drive.

Best,

David

Hello David, Thank you for your reply. The PWM frequency is set to 20 kHz using a 0 ohm resistor. What resistor value can I use to minimize the delay?

Best regards

Eugen

Hello David,

I replaced the DOSC with a 215 kOhm resistor, but this had no effect on the delay.

Best regards

Eugen

Hi Eugen,

It's possible the inductance of the load is too high. The higher the inductance, the slower the current rise through the load, which leads to a longer delay. If possible, I would try a load with lower coil inductance to confirm if this is the issue. 

Best,

David

Hello David,

that's the problem. I don't have any other valve. What else can I do?

Best regards

Eugen

Hi Eugen,

The most effective ways of reducing high inductive loads would be to minimize the parasitic inductance in PCB layout, keep trace lengths (and wires) as short as possible, and use a fast recovery diode for the flyback path.

Are evaluating on our DRV110EVM or is this a new design?

If new design, what diode is being used?

Best,

David

Hello David,

I'm using an ON Semiconductor MBR0520LT1 and an IRLML6244TRPBF as a switch. I have four DRV110s on a board, and I switch them with 3.3V from the microcontroller. How can I send you the circuit diagram and layout?

Best regards

Eugen

Hi Eugen,

You can send them here. If they are confidential, let me know and I can send you an email offline. 

Best,

David