LED Strip
09/10/2013 08:58
Knowledge of linear algebra shows that when xc ≠ xw and yc ≠ yw equation has a unique solution when . It can be seen , given the expectations of color, luminosity values of the duty cycle is determined, and is unique. In this case, calculate the duty cycle and calculate the amount of light and color mixed light is a reversible process .
1.2 two -channel PWM dimming color limitations
Theoretically, mixed light color coordinates xm ranges [xc, xw] ( Let xc <xw), light mixed light measurement Ym ranges [0, Yc + Y w]. Mixed light measurement and light color measure all possible values of the area enclosed by the theory known as domains. In fact , two -channel PWM dimming method does not achieve color theory all values of the domain , and only some specific area can be achieved . Achievable region is called the feasible region , the boundaries of the feasible region mainly determined by the power constraints .
1.2.1 Power Constraints
Starting from a practical sense , the duty cycle of the two channels should satisfy 0 ≤ Dc ≤ 1, 0 ≤ Dw ≤ 1, the formula ( 5 ) solution obtained Dc, Dw Substituting this inequality , obtained by the simplified two -channel PWM mix light power constraints are as follows:
Said power constraints expressed by Figure 1 , the figure x0 = (Rc xc + Rwxw) / (R c + Rw), are two LED duty ratio of 1:1 mixed light color coordinate x. Figure entire rectangular area is shown in two -channel PWM mixing the theoretical domain ,
