TPS631000: Issues with supply for controlling a solenoid

Vivek Bhageria

Part Number: TPS631000
Other Parts Discussed in Thread: DRV8210, , TPS63805

I am using the TPS631000 for my circuit. I am trying to control a solenoid using the DRV8210.

What I observed is that if the input to the TPS is less than 3.2V, I get a jittery signal as shown below. The below image is with 2.9V input. The yellow signal is the TPS output and the blue signal is the signal output of the DRV8210

However, with 3.2+ V input, the signal is clean. Shown below:

I am not sure what the issue is here. The design of the TPS circuit is as suggested in the datasheet. The inductor is one from Murata as suggested in the datasheet.

Also, the spike in voltage in the TPS output is about 6v. This seems very high. How do I correct the behavior?

over 2 years ago

0 Tao Zhang over 2 years ago

TI__Mastermind 32350 points

Hi,

is it possible current limit triggered when Vin is 2.9V? is it possible you can capture the waveform of inductor current?

Regards

Tao

0 Vivek Bhageria over 2 years ago in reply to Tao Zhang

Intellectual 270 points

Hello Tao

It is a bit difficult to get the current waveform because we do not have the instruments to measure that. I am looking at ways to get it done.

Meanwhile, I tried a resistive load - about 14.5 ohms, 227 mA current.

Here the signal remains ok till 2.7V input.

Decreasing the input voltage further starts showing those fluctuations. Following capture is at 2.45v input

0 Tao Zhang over 2 years ago in reply to Vivek Bhageria

TI__Mastermind 32350 points

Hi Vivek,

The input volatge is measured at the Vin Pin of device or just the output voltage of power supply?

can you capture a waveform about the Vin at input cap when this fluctuations happen?

Regards

Tao

0 Vivek Bhageria over 2 years ago in reply to Tao Zhang

Intellectual 270 points

Hello Tao

The input voltage was the output of the power supply.

Following are the measurements of the input cap:

1) Yellow signal - At the input cap

2) Yellow signal - At the output cap

3) Blue - At input cap, yellow - at output cap

0 Tao Zhang over 2 years ago in reply to Vivek Bhageria

TI__Mastermind 32350 points

Hi Vivek.

is it possible UVLO_off triggered? could you help to double check？

Regards

Tao

0 Vivek Bhageria over 2 years ago in reply to Tao Zhang

Intellectual 270 points

Hi Tao

Could you please let me know how to check for UVLO_off?

0 Tao Zhang over 2 years ago in reply to Vivek Bhageria

TI__Mastermind 32350 points

Hi Vivek,

You can measure the minimum value of input to check if this voltage is smaller than 1.6V. if yes, mostly, UVLO_off is triggered and the device restart repeatdely.

Regards

Tao

0 Vivek Bhageria over 2 years ago in reply to Tao Zhang

Intellectual 270 points

Hi Tao

I am supplying it through a regulated power supply. The minimum input voltage is the one that I supply from the regulated power supply. The minimum that I am supplying is 2.4v. However, the signal starts fluctuating below 3.2v

0 Tao Zhang over 2 years ago in reply to Vivek Bhageria

TI__Mastermind 32350 points

Hi Vivek,

First, we should confirm if the UVLO_OFF triggered or not. By measure the minimum voltage at input cap.

If UVLO_OFF triggered, we should check if the capability of power source is too weak to support or if the cable from power supply to board is too long which make the impedence too high.

Second, if everything is ok, mostly, it should be caused by the current limit of device itself. May be you need another device with higher current limit, such as TPS63805/6/7

Regards

Tao

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TPS631000: Issues with supply for controlling a solenoid