Lighting Drivers and Controller ICs

Lighting drivers and controller IC is a device that provides the power and control to a number of different technologies, including light emitting diode (LED), florescent (CCFL) and electroluminescent (EL) solutions. These are not to be confused with ballast controllers, which are usually modules used in florescent lamps. They are used in architectural, industrial, emergency and ambient lighting.
A driver incorporates the step-down power regulator that provides constant power to the light. This usually requires a control loop, where the current and voltage are continually measured and controlled with negative feedback, adjusting the loop to provide a constant settable level of light emission. This is required because temperature and aging changes affect the characteristics of the lighting device. It is also important because unless the current and voltage are controlled— runaway conditions can happen that can lead to damage or destruction of the light.
A driver or controller will usually incorporate the ability to control the light level output. This can be achieved for LEDs by switching their current on and off at high frequency with a varying mark to space ratio. This is called a PWM waveform, and the control of intensity is called a dimmer circuit. This is also possible by directly controlling the current rather than the voltage. Drivers may also control the power-on and power-off voltage and current shapes – which can be required to protect the light from destruction (soft start up, soft power down).
A key parameter of these devices is efficiency. With the drive towards greenfield technology (technologies that conserve power), low power wastage is very important. Drivers can do this by having an efficient power supply conversion technology, which is usually referred to as a switch-mode. Drivers may be required to convert the voltage up from a main supply to a higher voltage (step-up, or boost regulator), or down from a higher AC or DC Voltage (step-down, or buck regulator). Efficiencies of power conversion of greater than 90% are possible with some drivers. Read more Read less