OPTOELECTRONICS


mode capabilities. It dims with deep PWM by modulating the duty cycle of the constant current from 100 per cent to three per cent. However, under three per cent it transitions to an analogue dimming mode that produces the same functionality of CCR through programmable digital controls rather than a classic analogue CCR-only circuit.


With a built-in 16 MHz oscillator, the AL5887Q eliminates the need for an external clock, allowing for simplifi ed board design and layout, smaller printed circuit board footprints and a lower cost bill of materials (BOM). It uses a 12-bit PWM addressable register and a 30 kHz internal PWM generator for better colour mixing and reduced noise.


Controlling the colour of an RGB LED Controlling the colour of an RGB LED involves adjusting the current fl ow to each of the three different coloured die contained within the LED package (Figure 2). In simple terms, to produce a bright yellow colour, the red and green die are driven up to their specifi ed maximum, and the blue LED is dimmed or turned off. Similarly, a large range of colours can be produced by controlling the intensity of the individual LEDs.


FEBRUARY 2026 | ELECTRONICS FOR ENGINEERS


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