Voltage Regulation and Power Consumption Analysis of LED Driver using Switched String Method

This paper discusses an AC/DC buck converter-based LED driver to reduce the voltage from 230VAC to 12VDC with a few strings of LEDs. This led driver is designed with a cost-effective circuit because using a single inductor, single inductor multiple-output (SIMO) can reduce the number of components, control the current independently and precisely on each LED string simultaneously, compared to using an inductor on each LED string. To control current and voltage, PWM (Pulse Width Modulation) control is used as a MOSFET signal switch. This MOSFET calculates the duty cycle so that the desired DC output according to the LED specifications can be realized. The circuit was analyzed using PSpice software. The test based on the duty cycle shows that the highest output voltage is obtained with a work cycle of 10% resulting in a voltage of 5.9V and a current of 32.4mA. Meanwhile, achieving the output value based on the led specification with a voltage of 12V and a maximum current of 31mA has been achieved at a duty cycle of 4.7%. This AC/DC buck converter circuit not only lowers the voltage but can overcome dimming and provide a uniform light output on each LED with an output voltage of 12VDC. The experimental results show that this AC/DC buck converter circuit has been tested and can be applied to the Led driver system.