LED devices are created by depositing two thin layers of materials onto a substrate, one with an excess of electrons and the other having holes and needing electrons to achieve a more stable state. When a potential is applied across the device, the electrons and holes move in the opposite directions. This causes light to be emitted with a wavelength and colour determined by the energy released when the electrons and holes combine. High brightness LED, often referred to as HBLED is a measure of LED that can produce over 50 lumens. The HBLEDs are mainly preferred due to its improved efficiency over other types of lamps. Some of the HBLED driver reference designs has been discussed along with their links, as shared below:
- ZMOTION enabled HBLED Driver Reference Design: The following high brightness LED reference design from Zilog helps in dimming control by using the buck converter topology and ZMOTION technology to control light intensity. The ZMOTION technology controls lighting through motion-sensing and relies on warm body motions to trigger a set of desired reactions apart from providing power saving. For reference design, please refer to the link as shared below. Click here for reference design.
- Current Controlled HBLED Design: The following reference designs of Maxim, refer to attaining long-life high brightness LEDs by regulating the flow of current in the circuit. The designs talk about three different methods of regulating current i.e. by using resistors, by active linear control-loop (a linear loop controlling LED current) or by switching regulator control (temperature compensation). To know more, click here.
- HBLED Design Based on EasyScale Protocol: The TPS61165 is a high-brightness LED driver from TI based on EasyScale protocol. It is a protocol that allows you to tell the driver to continuously output 32 levels of intensity, without having to provide a PWM signal there for saving battery power. Click here to know more about the reference design.
- PWM Based HBLED Reference Design: The uniquely designed RT8473 high brightness LED driver from Richtek, uses hysteretic control (time based dependence of a system’s output on current and past inputs) with a high side current sense resistor to set the constant output current (1A). The LED brightness control is achieved with PWM dimming from an analog or PWM input signal. To know more, click here.