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Question about LD Driver(ONET11x1L) APC Loop function.

Go
Genius 4155 points
Other Parts Discussed in Thread: ONET1141L

Hi,

Regarding the APC Loop function integrated in ONET11x1L,

Is it possible that only use APC Loop function independently?

(means, don't use Equalizer, output driver)

If yes, does anyone have the reference circuit or something?

Thanks,

Go 

  • 0
    Genius 4155 points
    Hi,

    Does anyone have information about the question?

    Any advice would be very much appreciated.

    Regards,

    Go
  • 0 in reply to Go
    TI__Genius 16150 points

    Hi Go,

    Sorry for the delay. In my understanding is not possible since APC is an analog loop and it is not adjusting the register settings. The register setting sets the initial point of operation and then the APC loop adjusts the bias current through analog control to try and keep the photodiode current constant, is an automatic feature to protect the laser driver, please let me verify with the team. ASAP I will be back with the answer.

    Best Regards,

    Luis Omar Moran

    High Speed Interface

    SWAT Team

  • 0
    TI__Intellectual 1715 points

    Hello,

    ONET11xL is essentially a Laser driver that has the added EQ function and APC loop feature. The EQ function can be disabled through I2C by setting the Equalizer enable bit (EQENA) to 0, while setting the Open loop enable bit (OLENA) to 0 to have the device operate in APC loop/closed loop mode. Please refer to the Figure 1 in the Datasheet of ONET1141L for circuit details.

    However, the output pins OUT+/- and the BIAS pins will still output the modulation current and bias currents respectively to drive the laser. You can disable this function only by setting DISMODE register bit to 1 but that that will disable the output stage altogether. I'm not sure if this is what you want. Please let us know for any further questions.

    Hope that helps.

    Thanks,

    Sri

  • 0 in reply to Sriharsha Kota Pavan
    Genius 4155 points

    Hi, Sri

    Thank you for your comment.

    I'd like to know that if I compose the signal circuit(enclosed by the red line in the attached file) externally,

    Can I combine the ONET11x1 APC Loop function and the external signal circuit?

    Thanks,

    Go