Is the linear change in LED brightness difficult? PWM duty cycle helps you

First of all, it needs to be clear that the LED driver is constant current, and the PWM only changes the time ratio of the constant current to the current interruption, so the duty ratio and the output of the luminous flux are linear. As a luminaire, its output luminous flux changes linearly with time, but the human eye does not feel linear. The performance is that in the light-bright area, the small change of luminous flux also makes the light flux change greatly, and the luminous flux is compared. In a large area, a large luminous flux jumps, and the luminous flux perceived by the human eye does not change much.

In this set of drawings, all scales are evenly distributed. Figure 1 shows the relationship between the actual duty cycle and the luminous flux, which is linear; its corresponding human eye perception is shown in Figure 2, and the relationship between Figure 3 and Figure 4 is reversed.

To get the effect of Figure 4, the PWM duty cycle adjustment mode is like Figure 3. This is troublesome in the software processing of the microcontroller. There is a mathematical formula in the software processing to describe this curve, which may result in calculation. The duty cycle of a certain moment, taking up a lot of CPU resources to calculate; of course, there are other ways, such as using a large table to put the curve in the table, how much brightness is needed to go to the table to check the corresponding duty value Yes.

It should be noted here that the human eye like Figure 4 cannot be measured by the instrument. Therefore, the graphic given in the text is only a rough reference, and then adjusted according to the actual experience, until the brightness on the controller is added and the brightness is reduced. From the brightest to the darkest, the human eye feels that it is stepless and uniform. .

This article gives a way to adjust the PWM duty cycle from a software perspective to ensure that the brightness is linear. It is an article that is more biased towards the basic class. I hope everyone can gain something after reading this article.

Solar panels are a central part of solar power systems and are the most valuable part of solar power systems. Its role is to convert solar energy into electricity, or to be stored in a Storage Battery, or to drive load work. The quality and cost of solar panels will directly determine the quality and cost of the entire system. As long as there is light, can produce voltage, between is negative electricity for dc solar panels, and according to different requirements, can create a 2 v, 3 v, 6 v, 9 v, 12 v, dc voltage. Now the voltage of the photovoltaic panels is generally 18V, which can charge a 12V battery. Power generation plate generation, as long as the power and voltage can reach, can supply the same power and the same voltage to use the electric appliance.

Poly 100W Solar Panel

Poly 100W Solar Panel,100W Solar Panel,Poly Solar Panel,100 Watt Solar Panel

Yangzhou Bright Solar Solutions Co., Ltd. , https://www.solarlights.pl