TPS54231: Stability for feedback source

Thank you for your reply, and sorry too late.

Please refer to attached concept of using the current source of the load as the feedback.

The structure that converts the current flowing from the load to the corung into a voltage level and applies it to the feedback.

The key is to obtain a constant current output regardless of load changes.

Thanks.

Hi,

R17 and R18 are zero, C29 and C30 are very large, dose the circuit operate as you expected?

Shawn

Hi,

1) PH switching frequency output abnormally. Is this a problem with this output?

2) Vsense uses the current source of the product as a feed back (FB) and mixes AC components (30kHz).

* Vout has confirmed improvements when adding caps.

How can I improve if I have a problem?

or Is this not a problem if you use it like this?

Thanks.

Hi,

What is the load? From the waveform, the FB voltage is ringing.

Shawn

Hi,

Please refer to the graphic below for more information.

The final load is a vacuum tube (filament) for the X-ray, and the final voltage is driven through two transformer.

The filament inside the cacuum tube gradually changes over time, and thus the application deeps the current constant.

The current is output as an AC component with a frequency of 30kHz, which is due to the oscillation freq. of the transformer.

Thanks.

Hi,

What is the function of C29 and C30? For TPS54231, it is operational transconductance amplifier.
If the current is AC, the system would not stable, it looks like a dynamic tuning.
There is on issue for operating this application, right?

Shawn

Hi,

In case of C29 & C30, if configured like dataheet, TPS54231 output does not work and it is changed.

There is no problem in operation of the product during the development stage.

however, due to mass prodution of the product, we will ask about stability later.

Thanks.

Hi,

Is there any theoretical basis for the using of C29 & C30?

Shawn