NFC programming for LEDs using a PWM output to control analog LED-drivers: Page 5 of 5

September 04, 2019 //By Dr. Qi Zhu
NFC programming
In the LED market, more and more LED power suppliers to offer two novel functions: near-field communication (NFC) programming and constant lumen output (CLO). The NFC programming function is designed to replace the labor-intensive “plug-in resistor” current setting method to improve the flexibility across the value chain.

CLO implementation

The CLO is a quasi-control system (self-regulating system) that fights the natural degradation of the LEDs’ light output trying to maintain the luminous flux constant by regulating the LED current. The NLM0011 IC has an integrated 8-point CLO table to store the degradation curve of the LED module. Manufacturers can program this curve according to their needs. As soon as the CLO table is programmed, the duty cycle of the PWM sign The NLM0011 IC has an integrated 8-point CLO table to store the degradation curve of the LED module. Manufacturers can program this curve according to their needs. As soon as the CLO table is programmed, the duty cycle of the PWM signal is then automatically adjusted to compensate for the LED degradation. The actual duty cycle as a function of the actual runtime OTC is calculated by linear interpolation between two adjacent reference points. The IC is continuously counting the operation time (OTC function) and is continuously interpolating the dutycycle correction factor, which is then multiplied with the nominal duty-cycle value to get actual duty-cycle value.

Being compatible with existing analog LED-driver designs and the NFC programming specification from the Module-Driver Interface Special Interest Group (MD-SIG) makes this new NFCPWM concept a perfect fit for cost-sensitive segments.

An industry leader in power management, Infineon delivers solutions for next-generation LED lighting systems. For more information, please visit www.infineon.com/nfc-pwm

About the author :

Dr. Qi Zhu is Senior Business Development Manager at Infineon Technologies - www.infineon.com

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