• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 285 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS61196: Can TPS61196 connect IFBx pins together?

Paul Yeh
Genius 14385 points
Part Number: TPS61196
Other Parts Discussed in Thread: TPS61500

Hi Team,

Due to my customer only has one string LED and the specification is 6S/700mA. And we propose TPS61196 to them.

So my question is can we use 4 channels connected together (tie IFB1/2/3/4 together) to sink 700mA continuous current?

And unused IFB pin, how to deal with them?

Thanks

  • 0
    TI__Genius 13001 points

    Hi Paul,

    Yes, and the unused pins can be left floating.

    One question: How about input voltage range? If it's not too low, how about single channel device, such as tps61500?

    BR,

    Robin

  • 0 in reply to Yuting Shao
    TI__Genius 14385 points

    Robin,

    Customer’s input voltage is 13V typical.

    Thanks

  • 0 in reply to Paul Yeh
    TI__Genius 13001 points

    Hi Paul,

    As I mentioned before, TPS61196 can satisfy your requirements. And if the Vin is 13V, then TPS61500 is also a proper device considering of lower price.

    Please contact me if you have any concern.

    Robin

  • 0 in reply to Yuting Shao
    TI__Genius 14385 points

    Robin,

    Thanks for suggestion, but due to there is no MCU in their system, so they can't produce PWM signa for TPS61500.

    So they will still use TPS61196. but there is IFBV setting questions would like to consult with you.

    They have two level LED current setting by hardware switch and they will use ISET pin to program, see below picture.

    But we don't know how to design IFBV resistor value, which ISET resistor we should reference to calculate? please advise.

    Thanks

  • 0 in reply to Paul Yeh
    TI__Genius 13001 points

    Hi Paul,

    Please refer to section 7.3.7 of datasheet. FBV is used to set minimum headroom voltage at the IFB pin, and the recommended minimum headroom voltage can be found in the Figure 5.

    As for your design requirements, each channel current is 700mA/4=175mA and the recommended headroom voltage is about 480mV.

    According to above schematic, Iled=1.229Vx3992/R11=175mA, so R11 is 28kOhm.

    VIFBV=R10X307.3mV/R11=480mV, so R10 is about 43,7kOhm.

    Please chose the nearest value of R10, R11.

    BTW, the unused IFB is suggested to connect to ground with a resister between 20kOhm and 36kOhm.

    Robin

  • 0 in reply to Yuting Shao
    TI__Genius 14385 points

    Robin,

    Thanks and so far there is no question from customer.

    Thanks