US 12,273,973 B2
Automatic compensation method based on temperature characteristics of RGB LEDs
YunFeng Li, Fujian (CN); JunHao Li, Fujian (CN); Hui Zhang, Fujian (CN); MingChi Huang, Fujian (CN); and KunFu Lu, Fujian (CN)
Assigned to LUMISSIL MICROSYSTEMS LIMITED, Fujian (CN)
Filed by LUMISSIL MICROSYSTEMS LIMITED, Fujian (CN)
Filed on Sep. 5, 2023, as Appl. No. 18/242,008.
Claims priority of application No. 202211303845.9 (CN), filed on Oct. 24, 2022.
Prior Publication US 2023/0422369 A1, Dec. 28, 2023
Int. Cl. H05B 45/28 (2020.01); H05B 45/325 (2020.01)
CPC H05B 45/28 (2020.01) [H05B 45/325 (2020.01)] 4 Claims
OG exemplary drawing
 
1. An automatic compensation method based on temperature characteristics of RGB LEDs, comprising the following steps:
obtaining current temperatures of a red LED, a green LED, and a blue LED of the RGB LEDs respectively; and
adjusting a corresponding pulse width modulation (PWM) duty cycle of each LED according to the current temperature of each LED so as to change drive currents of the red LED, the green LED, and the blue LED, thereby achieving compensation for the RGB LEDs; wherein,
a PWM duty cycle of the red LED is adjusted according to the following formula: PWMOUT_R=PWMIN_R×TCR=PWMIN_R×[1+(T_ADC_R−TADC@25_R)/KR×NR %];
a PWM duty cycle of the green LED is adjusted according to the following formula: PWMOUT_G=PWMIN_G×TCG=PWMIN_G×[1+(T_ADC_G−TADC@25_G)/KG×NG %];
a PWM duty cycle of the blue LED is adjusted according to the following formula: PWMOUT_B=PWMIN_B×TCB=PWMIN_B×[1+(TADC_B−TADC@25_B)/KB×NB%];
wherein PWMOUT_R, PWMOUT_G, and PWMOUT_B represent adjusted PWM values for the red LED, the green LED, and the blue LED respectively;
PWMIN_R, PWMIN_G, and PWMIN_B represent original PWM values for the red LED, the green LED, and the blue LED respectively before adjustment;
TCR, TCG, and TCB represent temperature adjustment coefficients for the red LED, the green LED, and the blue LED respectively;
T_ADC_R, TADC_G, and TADC_B represent the current temperatures of the red LED, the green LED, and the blue LED respectively;
TADC@25_R, TADC@25_G, and TADC@25_B represent temperatures of the red LED, the green LED, and the blue LED respectively at room temperature;
KR, KG, and KB represent temperature adjustment step sizes for the red LED, the green LED, and the blue LED respectively, and values of KR, KG, and KB are identical;
NR%, NG%, and NB% represent temperature adjustment percentages for the red LED, green LED, and the blue LED respectively.