About efficiency of TPS611941-Q

Koji Hayashi

Hello all,

I think the system efficiency is aggravated by influence of a switching loss.
When changing the frequency to 400kHz from 300kHz, how long does the system efficiency change?
About -1 %?

Regards,

Koji Hayashi

over 9 years ago

0 David Diaz Quintana1 over 9 years ago

TI__Intellectual 1235 points

Hi Koji,

Are you looking at regular boost configuration or SEPIC? Also, let me know if you are interested in particular duty cycle.

Kind Regards,
David D Quintana

0 Koji Hayashi over 9 years ago in reply to David Diaz Quintana1

Intellectual 955 points

Hi David,

I looking at regular boost.
Are you saying that the duty cycle is brightness?
Please tell us about the 100%.

Regards,

Koji Hayashi

0 David Diaz Quintana1 over 9 years ago in reply to Koji Hayashi

TI__Intellectual 1235 points

Hi Koji,

As you know efficiency is also dependent on switching frequency, input voltage, number of LEDs/string, and output_current/string.
Could you specify values of interest for these parameters?

Kind Regards,
David D Quintana

0 Koji Hayashi over 9 years ago in reply to David Diaz Quintana1

Intellectual 955 points

Hi David,

Input voltage is 5V.
Frequency is 400k.
LED 6 in the series connect to OUT1.
OUT2, OUT3, OUT4 is connected to the ground.
Output current is 80mA.

When changing an LED to OUT2 from OUT1, is there difference?

Regards,

Koji Hayashi

0 Takao Yamamoto over 9 years ago in reply to David Diaz Quintana1

Genius 4135 points

Hi David,

Thank you for your support.
I am working with Koji.

How is the progress?
I would appreciate if you teach us ASAP.

Best regards,

0 David Diaz Quintana1 over 9 years ago in reply to Takao Yamamoto

TI__Intellectual 1235 points

Hi Takao and Koji,

Thank you for your patience. I will send data soon.

Regarding your question about OUTPUTS: If you are asking whether results are dependent on the selected string the answer is no (results are independent on which active OUTx you select).

Kind Regards,
David D Quintana

0 Takao Yamamoto over 9 years ago in reply to David Diaz Quintana1

Genius 4135 points

Hi David,

Thank you for your reply.
We are thinking that the results depend on frequency, Vin, LEDs, and output current.
Therefore, we want to know how efficiency this device has at these condition.

Thank you for your data. We are looking forward hearing from you.

Best regards,
Takao Yamamoto

0 David Diaz Quintana1 over 9 years ago in reply to Takao Yamamoto

TI__Intellectual 1235 points

Hi Takao,

Yes, efficiency will depend on the parameters discussed above (Vin, # of LEDs, switching frequency, load). Thanks for providing specific conditions for which you need efficiency. For the conditions you specified boost efficiency is ~91.5% and system efficiency ~88.8% at room temperature.

Kind Regards,
David D Quintana

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About efficiency of TPS611941-Q