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TPS61165: Consultation on led chips using in laser tubes

Weihao Li
Prodigy 70 points
Part Number: TPS61165
Other Parts Discussed in Thread: LM3643, LM3644

I want to power 4 lasers in series using TPS61165. The lasers characteristics is like a LED, but we need continuous current here. For each laser, the maximum current is 170mA, and the forward voltage of laser is 1.6V-1.7V. I want to know whether the output current is continuous or not? Can I reduce the output current ripple by increasing the value of the output capacitance if the current is continuous? And is it possible to reduce the current ripple into 1mA?

  • 0
    TI__Mastermind 22745 points
    Hi ,
    1.The output current of TPS61165 is continuous. The current ripple is depend on the input voltage , output voltage, output current and the value of inductor and capacitor.
    2. For your application, the output current is 170mA, difficult to achieve 1mA current ripple. The increase of output capacitor can decrease the output voltage ripple and current ripple. You need a very large output capacitor to achieve 1mA current ripple. Please refer to TPS61165 Datasheet 9.1.5 to choose the value.
    3. You can look at the LM3643/LM3644 , those device has very good current accuracy. Thanks.
    Sean