DRV8821: DC Solenoid driving

Hello Raj, 

Thank you for reaching out to us. 

The DRV8821 is a dual stepper motor driver, which is controlled by STEP/DIR pin. This driver is not appropriate for controlling solenoid.

Built-in indexer logic in the DRV8821 allows a number of different stepping configurations. The xUSM1 and xUSM0 pins are used to configure the stepping format as shown in the table below:

The following table shows the relative current and step directions for different settings of xUSM1 and xUSM0. At each rising edge of the xSTEP input, the indexer travels to the next state in the table. The direction is shown with the DIR pin high; if the xDIR pin is low the sequence is reversed. Positive current is defined as xOUT1 = positive with respect to xOUT2.

The DRV8243, DRV8873 can be a good candidate for controlling latching solenoid. To know how to implement, please read the following app note.

Using DRV to Drive Solenoids (Rev. A)

Best regards, 

Mojtaba.

Thanks Mojtaba,

So we can control the solenoid by making STEP & DIR pin high and ENB pin Low, the solenoid will latch and again after sometime 5-6 seconds, we can change the Step & DIR pin low and ENB pin Low, now solenoid will unlatch.

Or any other method to be followed for solenoid latch and unlatch operation.

Thanks & Regards,

S.Rajasekaran

Hi Raj, 

Thank you for your question. 

Rajasekaran S said:

So we can control the solenoid by making STEP & DIR pin high and ENB pin Low, the solenoid will latch and again after sometime 5-6 seconds, we can change the Step & DIR pin low and ENB pin Low, now solenoid will unlatch.

DRV8821 only support STEP/DIR control mode. The driver follows the microstepping indexer table by applying the step input. At each rising edge of the STEP input, the indexer travels to the next state in the table. Ie, the device is enabled under full step mode, and it goes to step #1 which in this state the Aout is 71% and Bout is 71 %. then by rising the Step pulse again it goes to next step (#2) and the Aout is  -71% and Bout is 71%. This continuous till step 4 to complete 1 rotation.

To reverse the Direction the DIR should be low and then step pulse should be applied to the driver. 

When you make STEP and DIR high and ENB low it means that the driver goes to step # 1 and the AOUT is 71% and Bout is 71%. When you make the step and DIR to low and ENB low, it will disable the output. and depending on the # of step pulse it will move from Step # 1 to #4 continuously. 

This method is implemented to control stepper motors and is not appropriate for solenoid driver. 

Rajasekaran S said:

Or any other method to be followed for solenoid latch and unlatch operation.

I would recommend using Full bridge BDC driver to control latching solenoid. The DRV8243, DRV8873 can be a good candidate for controlling latching solenoid. Following application note will help you how to implement the driver.

Using DRV to Drive Solenoids (Rev. A)

Best regards, 

Mojtaba