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# DRV8847: DRV8847

Part Number: DRV8847
Other Parts Discussed in Thread: DRV8210, DRV8833, DRV8220

Hi, I followed the EVM design. I have the following questions if you can reply. 1: In the EVM, a 300mOHM resistor is used to control current. If the shunt will install then both 300mOHM resistors will be in parallel otherwise, a single 300mOHM will be used. Now, what will be the current for 300mOHM(0.5A) and 150mOHM(1A) because I didn't understand the current setting formula i.e. Itrip = (Torque X Vtrip)/ Rsens 2: Can I use DRV8847 in the same configuration as DRV883? Like only IN1 to IN4 pins use as input and not connected to all other inputs pins as shown in the attached picture. Thanks

• Hello, ALi:

1. Itrip = (Torque X Vtrip)/ Rsens

Vtrip is a fixed voltage 150mV. Torque= 1 when TRQ pin = "0" (zero volt); Torque+0.5 when TRQ pin =1 (voltage higher than 1.6V).

When Rsens =300mohm, Itrip=0.5A when TRQ pin voltage is zero.

2. What is the part number? DRV8833? It has the nSLEEP pin. According to the requirement, would you use two DRV8220 or DRV8210?

Regards,

Wang Li

• Hi
Just to confirm, If I connect TRQ to GND then Torque will always equal 1, and as Vtrip is already fixed then so, the output current will depend on only resistor value i.e For 1A, 150mohm.

Yes, the part number is DRV8833. I am asking, can I use DRV8847 the same way that I can use DRV8833 with a microcontroller. The DRV8847 meets all my current and voltage requirements of a linear actuator. I just need to control a linear actuator forward and backward position. Its current rating is under 1A and Voltage 12V.
I can use nSleep pin to control the device in sleep mode and vice versa. I am confused about other pins functions.

1. Mode
2. nFAULT
3. TRQ
• Ali,

Yes. If you connect TRQ to GND then Torque will always equal 1, and as Vtrip is already fixed then so, the output current will depend on only resistor value i.e For 1A, 150mohm.

The mode pin is tri-level pin. It is in independent bridge mode if Mode pin is floating.

nFault is output pin which can be floated.

TRQ decides Torque value in Itrip = (Torque X Vtrip)/ Rsens.

Regards,

Wang Li

• Hi
One last question and after that, I will close it.
I have two dc linear actuators and they both will run together to pull a mechanical mechanism up and down. I also want to use fewer pins.
I think 2 pin interface will do the job because I just need to run the actuators forward and backward. Nothing more. Also, can I run both motors simultaneously and independently in 2 pin interface mode?
What do you think about it?

• Hi, Ali,

Yes. 2 pin interface will do the job because I just need to run the actuators forward and backward. Nothing more.

But, the "MODE" has to be "1".

Regards,

Wang LI

• I will follow this configuration to use it as a 2 pin interface

• Ali,

Thanks,

Wang Li