LMZM33602: Dimmable LED Power Supply

Norbert Nestler

Part Number: LMZM33602

Dear all,

i want to use the LMZM33602 to create a 16V supply from a 24V source. The 16V shall be the working voltage for a PWM dimmable LED string (5 LED's a 2.9V in series with a linear CC regulator). The CC Regulator should be dimmed with a PWM frequency of 1KHz. Will there be any issues (noise, heat, oscillation....) switching the load of the LMZM33602 with 1KHz? The LED string current will be 1.05A. System power output: 16V x 1.05A = 16.8W

Kind regards

Norbert

over 5 years ago

0 Jimmy Hua over 5 years ago

TI__Guru 50120 points

Hi Norbert,

It is recommended to operate the LMZM33602 within the operating conditions of the SYNC pin based on Section 7.5.5. It is recommended to operate the clock between 200kHz and 1,2MHz range. Any frequency below the recommended range has not been tested for and may cause a combination of failures such as hitting current limit, derated maximum output current, potential oscillation and noise issue.

I believe TI has a portfolio for LED drivers. Perhaps this is where you can start.

http://www.ti.com/power-management/led-drivers/rgbw-led-drivers/products.html#p3212=Yes

Regards,

Jimmy

0 Jimmy Hua over 5 years ago in reply to Jimmy Hua

TI__Guru 50120 points

Hi Norbert,

If you are wondering about the load, I have done load transient tests on this device with signals as low as 1kHz from an e-load and did not observe any failure in output voltage regulation.

To my knowledge, you can run your LED lights at 1kHz and not have impact on the power module.

Regards,

Jimmy

0 Norbert Nestler over 5 years ago in reply to Jimmy Hua

Intellectual 340 points

Hi Jimmy,

thank you for your tests. This helps me a lot.

I will try a design with this component.

Kind regards

Norbert

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LMZM33602: Dimmable LED Power Supply