TPS55010: TPS55010

Chin,
Anthony is on vacation. What update are you looking for? The original thread is closed and appears answered. If you need additional info on the transformer, you would need to contact the transformer vendor.

Hi John,

Thanks for  your replied.

I post another question about the output voltage two days ago, but it seems doesn't link to the thread.

Below is the quesion I need Anthony help, that we discussed before.

Thanks!

Hi Anthony,

We test add a 3K ohm resistor (See attached schematic of R658)on the output as we discussed before to keep the voltage about 5.5V.

But output voltage still keep in 6.5V with 3K ohm resistor when no load on the output.

The output will reduce to 5V when add a 33 ohm resistor.

But 33 ohm draw too much power and TPS55010.pdfthat is not a solution.

Do you have any idea about how to reduce the voltage ?

Thanks!

Chin

2705.TPS55010.pdf

Chin,
Try 200 ohm. It will get you past the steepest part of the line regulation curve.

Hi John,

The voltage change from 6.7 volt to 6.4 volt when add 200 ohm on the output load.

As I mentioned , the output voltage will change from 6.7 volt to 5 volt (what we want) if I add 33 ohm on the output load.

But 33 ohm  consume power very much and that is not a solution.

Sincerely,

Chin

Hi John,

Any update for the discussion?

Thanks!

Chin

Chin,

You can see the load characteristic as shown below.

You will need to bias your load current as appropriate.  If you are dissipating too much power, you may want to consider an LDO post regulator.

Hi John,

Yes, I also have the ciurve picture you provided.

But my question is why I add 200 ohm of resistor on the output load and the measure voltage is 6.4V?

The load current is  0.0325A(6.5V/200Ω) when add 200Ω on the output load  and according to the curve you provided, the voltage should be 5.1V rather than 6.4V of my measurement.

Thanks

Thanks

Chin

Chin,

I would need to see the load regulation curve for your actual circuit. Can you provide it?

Hi John,

Please see attachment of load curve of our circuit.

Thanks!

Chin

Hi Chin,

The output voltage could be tuned down using the resistor divider to VSENSE.

However I am surprised your performance is so much different than PMP4440. The transformer and resistor divider are the same. The schottky diode is similar. The main difference I see is the fsw. Can you check if adjusting the fsw to be the same as PMP4440 has any effect?

Best Regards,
Anthony