Constant-current LED drivers are in low profile DFN package
Developed in response to demand for smaller LED lighting installations that also provide high efficiency and low EMI, Diodes extends its BCR420U and BCR421U families of linear LED drivers to include the BCR420UFD and BCR421UFD devices. Both are offered in the low profile DFN2020 package, making them suitable for 12 and 24V LED edge-lighting applications.
LED lighting offers benefits such as longer lifetime and higher efficiencies. As a result the less intrusive lighting is specified in fittings that emit light from the edges as opposed to vertically, which requires a thinner overall profile. The DFN2020 package of the BCR420UFD and BCR421UFD is suited to edge lighting, says Diodes.
Like other members of Diodes’ BCR4xxU series, the LED drivers can deliver an adjustable constant current between 10 and 200mA (BCR420UFD) or 350mA (BCR421UFD) with ±10 per cent tolerance, which in the case of the BCR421UFD can be controlled using a PWM signal of up to 25kHz and a duty cycle of one per cent to provide LED dimming functionality. Both devices include a negative temperature co-efficient, which lowers the LED driver current as the internal temperature rises, thereby protecting and extending the lifetime of the LEDs. In addition, the linear topology used is based on an NPN emitter-follower with emitter resistor, which means the devices exhibit virtually no EMI, making them well-suited for sensitive applications such as medical lighting.
Operating voltage range is between 1.4 and 40V, with total power dissipation up to 1.7W enable the devices to be used to drive longer strings of LEDs while still providing sufficient protection from transients in a 24V system.
Designed as monolithic solutions, the devices integrate transistors, diodes and resistors in a single package measuring just 0.6mm high. This is much thinner than the standard SOT26 package, allowing engineers, architects and lighting designers to develop LED fitments with a lower overall profile, for a wider range of applications. Edge lighting is specified in areas such as emergency, mood or decorative lighting, but is equally applicable in medical, industrial and commercial environments, points out Diodes.
The BCR420UFD and BCR421UFD linear constant current regulators for LED lighting are available in production volumes from Diodes now.
