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Recommended LED Driver for 1cell Li-Ion

S.Satoshi
Guru 21675 points
Other Parts Discussed in Thread: TPS63000, TPS63030, TPS63030EVM-658, TINA-TI

Hi,

Please introduce your recommended LED driver for following two requirement.

(1)

Input : Li-Ion 1cell

# of Ch :1ch (WLED 1s1p)

LED current : 500mA

PWM dimming : Yes

(2)

Input : Li-Ion 1cell

# of Ch : 3ch (WLED 1s1p, Green 1s1p, UV-LED 1s1p)

LED current : 500mA for each channel

PWM dimming : Independent PWM dimming is needed for each channel

Best Regards,

Sonoki / Japan Disty

  • 0
    TI__Guru*** 145650 points

    Since your battery voltage will likely go both above and below the LED's forward voltage, a buck-boost converter is needed to drive the LED properly over the entire voltage range of your battery.  Our TPS630xx devices are designed to do with this app note: http://www.ti.com/lit/an/slva419b/slva419b.pdf  There are a few TPS630xx LED driving EVMs available as well.

    For the second application, I think you still need a buck-boost.  Your power is high for each LED, so 3 separate circuits are likely needed, one for each LED.

    PWM dimming is accomplished as shown in Figure 3 in the app note.  Just replace Vref with your RC filtered PWM signal to create the analog voltage used for dimming.

  • 0 in reply to Chris Glaser
    Guru 21675 points

    Hi Chris-san,

    Thank you for proposing TPS630xx. I believe that TPS63000 or TPS63030 will meet their requirement. I also found TPS63030EVM-658 which is supporting to drive WLED, so I'll show this EVM to our customer.

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    Guru 21675 points

    Hi Chris-san,

    Our customer need to dim control with PWM signal by using the circuit described in SLVA419B. And they would like to control as following PWM signal.

    • PWM frequency, 60Hz
    • Contrast ratio, 1000 : 1 (16usec minimum pulse width)

    Can you verify the RC value to achieve this requirement?

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    TI__Expert 7110 points

    I'd suggest to run a simulation with TINA-TI. Just add a rectangular source and put the Filter as a load.

    You need to design the filter depending on the acceptable ripple (brightness accuracy). Please check especially the corner cases, like when you have the lowest modulation value. That could mean you have to use a smaller crossover frequency (higher R, bigger C)