EVAL6498L Evaluation Board

[arunrhpd88]

Moved from Feedback forum.

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I am exploring the possibility of using the EVAL6498L Evaluation Board to reverse the polarity of a DC bias in my circuit, and I would like to confirm whether it suits my application.

Application Details:

• Objective: To dynamically reverse the polarity of a DC bias voltage (80-120 V) supplied to a detector (GDD—Glow Discharge Detector).
• Requirements:

1. The ability to connect the DC supply terminals directly to the board and control polarity reversal.
2. Option to program and automate polarity reversal using a triggering circuit or an Arduino/microcontroller platform.

Specific Questions:

1. Can the EVAL6498L Evaluation Board handle the task of reversing the polarity of a DC bias by directly connecting the supply terminals to it?
2. Is an additional triggering circuit required to control the polarity change, or can this be achieved via programming (e.g., using an Arduino)?
3. Could you provide guidance on interfacing this board with an external control platform for polarity management?
4. Are there any limitations or specifications (voltage/current ratings) to be aware of in this configuration?

I would greatly appreciate any technical documentation, user guides, or application notes relevant to this use case. Please let me know if you need additional details about my setup or application.

Thank you for your support. I look forward to your response.

Best regards,

Arun

[Peter BENSCH]

Welcome @arunrhpd88, to the community!

I'm afraid that you won't be able to use the board for this. In order to be able to make a suggestion as to how you can realise this as an alternative, you should provide details about the GDD load in addition to the level of the voltage to be reversed, e.g. switching frequency, time sequences of the switching operations or the required current of the GDD.

Regards
/Peter

[arunrhpd88]

Thank you for your prompt response and for considering my inquiry. I appreciate your guidance and would like to provide the additional details requested regarding my application:

1. Voltage Range: 80–120 V DC
2. Current: Approximately 6–7 mA
3. Switching Frequency: Polarity changes are relatively slow; no high-frequency switching is required. The operation might involve switching polarity once every 2-3 minutes.
4. Time Sequences of Switching Operations: The application does not require rapid transitions. A stable and reliable polarity reversal is more important than speed.

[MasterT]

I don't think it'd work. Since L6498 has charge-pump circuitry to power up high-side driver, there is undocumented minimum switching frequency to generate enough power, to keep driver in "operational state".

It 'd be easier to build switching polarity circuits using solid state relays, like 

https://standexelectronics.com/wp-content/uploads/datasheets/55/5521308110e.pdf 

[Peter BENSCH]

The idea with the SSR is very good, alternatively you could also build a discrete full bridge. However, the effort with P-channel MOSFETs on the high-side and N-channel MOSFETs on the low-side (each at least 150V capable) is greater than with the SSRs mentioned by @MasterT, especially as you also have to control and protect the gates.