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LM3423: LED driver design for low side current sense

Satoshi
Guru 19645 points
Part Number: LM3423
Other Parts Discussed in Thread: TPS92690, LM3424, TPS92691

Can below LED driver IC use to design low side current sense? 

⇒LM3423, LM3424, TPS92690

If any IC yes, please let me know about reference design, application note, etc.

【Background】

・I want to design high Vout (over 100V) boost LED driver solution, it can not design on high side current sense.

・I considered TPS92691, but it was difficult because PWM dimming transient current became too high on very high Vout condition.

　I looking for the other LED driver matched low side current sense solution. 

Best regards,

Satoshi

  • 0
    TI__Expert 3640 points

    Hello,

    The application engineer who will support this question is currently out of office, and will reply when gets back next week.

    Thanks

    Sumeet

  • 0 in reply to Shashank Kulkarni
    TI__Mastermind 18890 points

    Hi

    The LM3423 and LM3424 will not work for your application because of input requirement for HSP and HSN.  The TPS92690 and TS92691 can be used for your application.

    I would recommend the TPS92691.  If designed properly with PWM dimming FET the TPS92691 is your best choice.

    Note:  The scope capture you gave above is from our data sheet and the inductor peak current on the first pulse is just a little higher than the normal running current and should not be an issue.

    You have previously posted this issue on E2E and the reason your first inductor current pulse is higher could be that you did not follow the design equations.

    Thanks Tuan

  • 0 in reply to Tuan Tran74
    Guru 19645 points

    Hi Tuan

    Thank you for reply,

    I will consider based on TPS92691.

    By the way, I think that TPS92690 is not occur peak current on the first pulse, correct?

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Mastermind 18890 points

    Santoshi,

    The TPS92691 does not have a true PWM dimming function so it behaves differently than the TPS92690. 

    Thanks Tuan