DRV8803

Daniel Morley

Other Parts Discussed in Thread: DRV8803

I am drive this relay driver with a Arm Cortex M0. I am using one pin on this processor to control two ports. The spec says it only drains 100 uA at 3.3 V. I am using 5 V. When I try to drive this relay driver it works sparatically and the voltage of the pin drops to 2.5 V with it being turn on high. This voltage should be at 5 V or close to it. Do I need to respin this board with each of the pins being connected separately.

over 9 years ago

0 Casey McCrea over 9 years ago

TI__Guru** 103215 points

Hello Daniel,

Having one GPIO drive two digital input pins should not be a problem. Do you have any pull ups or pull downs on that line?

Best Regards,
Casey

0 Daniel Morley over 9 years ago in reply to Casey McCrea

Prodigy 150 points

I do not. There may be an internal Pull up that I am not aware of.

0 Casey McCrea over 9 years ago in reply to Daniel Morley

TI__Guru** 103215 points

Ok, what do your load and power supply look like? Do you have a schematic detailing the connections of the DRV8803?

Thanks,
Casey

0 Daniel Morley over 9 years ago in reply to Casey McCrea

Prodigy 150 points

The power supply of both the 5 V and the 12 V are both switching regulators

0 Daniel Morley over 9 years ago in reply to Daniel Morley

Prodigy 150 points

0 Casey McCrea over 9 years ago in reply to Daniel Morley

TI__Guru** 103215 points

Daniel,

You're going to have to be much more specific about the system components and connections for us to figure out the issue here. What specific part numbers are you using? What is your overarching power source (DC supply, battery, etc)? What are your load properties (voltage, current, transient current draw)? Do you have a schematic for the design?

Thanks,
Casey

0 Daniel Morley over 9 years ago in reply to Daniel Morley

Prodigy 150 points

I am trying to paste the schematic and not having any luck. but it has two decoupling caps. All four ports are being used to drive four relays. nFault is pull upto 5 V and VM and VClamp is tied to 12 V.

0 Casey McCrea over 9 years ago in reply to Daniel Morley

TI__Guru** 103215 points

Daniel,

Again, this is not enough information to troubleshoot. If you need to you can email me the schematic to: c-mccrea@ti.com

Most importantly, what kind of current is your load driving?

Thanks,
Casey

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DRV8803