I am driving 8 solenoids (low-side in common) with VN808-32. Normally, solenoids pulling 1.8A when powered by 24V. If I switch through VN808-32, I see around 1.6A. I control inputs of driver through 74HC4051. High side driver seems to be capable of drive solenoids even above maximum ratings but multiplexer is getting channel collision after a few try, two or more gates switching on together. If I place current limiter around 1A, circuit is working without any problem. I think VN808-32 pulling exceed switching current against multiplexer or reverse current when solenoid released damaging that.
I would be glad if someone could suggest possible problem point and protection from that.
Another confused details I stuck is, RGND resistor. There are diodes on every solenoid negative path to ensure current direction but I am thinking to add additional protection by adding RGND resistor. If I try to limit reverse current around 250mA at 24V, I need to use ~100 ohm resistor. According to calculation on datasheet, power dissipated through resistor at these values is P=V^2/R = 5.76W. Should I use high power rated resistor around this value? Is that sensible?
Best regards,
