King Fahd University of Petroleum and Minerals

King Abdulaziz City for Science and Technology

Alaa Hussein

Munir A Al-Absi

Zainulabideen Jamal Khalifa

Hesham M Al Bar

Muhammad T Abuelma'Atti

The capacitor-less LED drive is an LED drive circuit having a design based on the utilization of the internal capacitance of the LED to replace the smoothing capacitor in a conventional buck converter in a power supply. LED lighting systems usually have many LEDs for better illumination that can reach multiple tens of LEDs. Such a configuration can be utilized to enlarge the total internal capacitance, and hence minimize the output ripple. Also, the switching frequency of the buck converter is selected such that minimum ripple appears at the output. The functionality of the present design is confirmed experimentally, and the efficiency of the drive is 85% at full load.

Capacitor-less LED drive

A current-mode analog computational circuit can be controlled to produce multiplying, squaring, divider and inverse functions and corresponding current outputs. The current-mode analog computational circuit is based on an implementation using MOSFETs operating in a sub-threshold region as can provide relatively ultra-low power dissipation. Furthermore, the current-mode analog computational circuit can be operated from a &#xb1;0.75 V DC supply. Tanner simulation results conducted using a 0.35-&#x3bc;m TSMC CMOS process confirmed the functionality of the multiplying, squaring, divider and inverse functions of the circuit. The current-mode analog computational circuit advantageously can have a total power consumption of 2.3 &#x3bc;W, a total harmonic distortion is 1.1%, a maximum linearity error of 0.3% and a bandwidth of 2.3 MHz.

Growing community of inventors

Dhahran, Saudi Arabia

Alaa Hussein