DRV8837C: Driving a Pump 12V 1A, voltage drops

Dharmesh Joshi

Part Number: DRV8837C

Hi All

I am working on a new design where I need to control a water pump rated to 12V 0.8A.

If I am correct, as a pump is an inductive load, I need to be careful how I connect this to the power supply, even if the power supply has a control switch.

I don't need a H-Brdige to control this pump but as i have a lot of DRV8837C on PCB as module, so to experiment the concept i have used them. The aim is to switch on / off the pump using this device.

When I measure the voltage at the +(OUT 1) of DRV8837C it shows 10.71V and the negative -(OUT 2)it is 0.774V, does this seem correct?

Is this an expirmentaly design, but is there better device to use to control a low powered 12V pump?

4 months ago

0 Keerthivasan Kumanan 4 months ago

TI__Expert 8435 points

Hi Joshi,

Can you tell me what your input signals look like (in1 and in2). If you are just looking for a new device that fits your requirements then you can check out DRV8234 data sheet, product information and support | TI.com. Can you also send me how you are planning on connecting the pump as If you are using this device as just a switch then there could be a huge voltage spike if there is no recirculation path for the current.

Best,

Keerthi

0 Dharmesh Joshi 4 months ago in reply to Keerthivasan Kumanan

Expert 1815 points

Hi Keerthi

The input signals are GPIO from my uC, so at the moment, IN2 is low, and In1 goes high every time I want to switch on the pump. I need a suitable device that is not an H-Bridge but simply provides power to the 12V 1.2A pump, ideally with the protection circuit.

0 Jacob Thompson 4 months ago in reply to Dharmesh Joshi

TI__Mastermind 21780 points

Hey Dharmesh,

Those voltages don't seem right when powered at 12V/GND, OUT1 should be 12V and OUT2 should be 0V or very close. Can you try repeat the test without a load, and with a resistor as the load?

Also consider ordering an EVM to test it on so you can easily determine if it is your PCB/schematic that is the issue or the part.

I second Keerthi's suggestion - I think DRV8220 is a much newer device that fits your goals better. You can easily use it's EVM to test it out -https://www.ti.com/tool/DRV8220EVM

Regards,

Jacob

0 Dharmesh Joshi 4 months ago in reply to Jacob Thompson

Expert 1815 points

Hi Jacob

Well, I used DRV8837C purely because i had previously made some PCB with this components for H-Bridge Latching Solenoids, and when i connected my motor pump directly to my power supply, i noticed a massive voltage drop to protect my existing PCB i experimented with DRV8837C .

Without a load, we get 12V and close to 0V.

But we don't not really need an H-Bridge circuit as my the pump operates in one direction only. Could you suggest more suitable part?

0 Keerthivasan Kumanan 4 months ago in reply to Dharmesh Joshi

TI__Expert 8435 points

Hi Joshi,

The voltage dip in the power supply might be due to insufficient bulk capacitance. This App note is a good guide on sizing your bulk capacitance:

PTHxxxxx.pdf (ti.com)

We have a couple low side drivers in our portfolio. I would reccomend: DRV8803.

Best,

Keerthi

0 Keerthivasan Kumanan 3 months ago in reply to Keerthivasan Kumanan

TI__Expert 8435 points

Any updates

Regards,

Keerthi

Motor drivers

Motor drivers forum

DRV8837C: Driving a Pump 12V 1A, voltage drops