TPS4H000-Q1: Design Query

Abhishek Manoj

Part Number: TPS4H000-Q1

Hi Team,

We are planning to use the TPS4H000AQPWPRQ1 relay driver IC in our board design. The device will be powered from a +12 V supply, with 3.3 V logic-level input signals.

The datasheet specifies that the IC includes internal voltage clamp circuitry to suppress transients generated during relay coil switching. Could you please clarify the following:

What is the typical clamp voltage level during inductive flyback conditions?
Is there a specified clamping voltage range or tolerance?
Is the internal clamp sufficient to safely handle relay coil transients in a medical application, or is additional external protection (e.g., TVS diode at the output) recommended?

We would like to ensure that the output transient behavior will not cause damage or reliability concerns in our application.

Regards,

Abhishek

5 months ago

0 Filip Rados 5 months ago

TI__Expert 6710 points

Hi Abhishek,

I will have to get back to you tomorrow (3/3).

Thanks,

Filip

0 Abhishek Manoj 5 months ago in reply to Filip Rados

Intellectual 915 points

Hi Filip,

One more query:

For the TPS4H000, the input signals are of 3.3V IO level, the VDD supply is 12V, what is the required IO level of the DIA_EN signal to be provide to work in normal condition. Also what will the ST# pins output IO level.

Regards,

Abhishek

0 Filip Rados 5 months ago in reply to Abhishek Manoj

TI__Expert 6710 points

Hi Abhishek,

1) In section 8.3.4, it shows: V_DS(clamp) = V_VS - V_OUT

2) The V_DS(clamp) ranges from 46V to 65V as seen in the electrical characteristics.

3) We recommend using a blocking diode at the input to protect from reverse current from the sudden voltage spike. Similarly, we recommend a ground network diode to help for the same reason. This information can be seen in section 8.3.7.4 of the datasheet for this device.