Drv110: Solenoid Design

Hello Premankar,

For circuit design, the peak current, hold current and keep time are the main things to focus on for your application. The sense resistor must be chosen so that the voltage drop during the hold current is greater than 30 mV. Sometimes the SENSE pin needs a simple RC filter after the sense resistor. If your supply is greater the 15-V, the internal Zener diode helps to supply the DRV110 with an external current-limiting resistor. The gate charge of the FET should be ~10 nC or less.

The documentation for the DRV110EVM and TIDA-00284 show good examples of circuit design with the DRV110, and they explain some of these finer details.

If you have a specific technical question about your design, can you please share some more details?

I am trying to drive a solenoid with 167ohms DC resistance and inductance approx 322mH @10kHz. The minimum current that can be set with DRV110 is 35mA approx. I am unable to configure the same solenoid to consume 20mA.

Even if I increase to sense resistor to 2-3ohms from 1 ohm, the hold on current doesnt seem to reduce. Do I need to design a specific type of solenoid?

How are you measuring your current? If you have a current probe, could you please take some scope shots of the current? Also, please include SENSE pin voltage and OUT pin voltage in your scope shots.