Variable frequency dimmable multi-channel LED driver

This paper presents a variable frequency dimmable multi-channel LED Driver with 12-channels, each channel supplying a stable current of 30mA. This circuit design can be used in indoor plant cultivation for dimming and illumination purposes, simulation of sunlight source and optical inspection system. Operating at a frequency of 133 kHz to 233 kHz using PWM control, this chip is fabricated and simulated by Taiwan Semiconductor Manufacturing Company using the 0.35μm 2P4M CMOS 5V process and the chip size is 0.76mm². External inputs, as well as a multiplexer control with a fixed external input voltage, can be used to control the brightness. Using a multiswitch sawtooth generator, the LED can be switched on or off, and the duty cycle can be changed to 25%, 35%, 50 %, and 75% to vary the brightness.