Fairchild semiconductor’s new energy-efficient LED driver

Citation

(2010), "Fairchild semiconductor’s new energy-efficient LED driver", Microelectronics International, Vol. 27 No. 2. https://doi.org/10.1108/mi.2010.21827bad.008

Fairchild semiconductor’s new energy-efficient LED driver

Article Type: New products From: Microelectronics International, Volume 27, Issue 2

Fairchild semiconductor has been selected by one of the world’s largest lighting manufacturers, OSRAM^®, to supply LED driver solutions. The FSEZ1016A was developed by Fairchild to meet and exceed the stringent performance benchmarks set by OSRAM.

Fairchild’s FSEZ1016A fits OSRAM’s 1W-4W LED products. OSRAM is also considering deploying Fairchild’s FAN6300 LED driver for its 12-60 W products. The new FSEZ1016A and FAN6300 are designed for lighting manufacturers seeking energy-efficient LED driver solutions.

Lighting applications consume nearly 22 percent of electrical energy generated worldwide. Reducing wasted energy in these applications can have a significant impact on energy conservation. As the industry moves from standard incandescent light bulbs to CFL, LFL and LED lighting, a 75 percent energy saving can be realized. Fairchild provides solutions for all lighting applications including linear fluorescent ballast, compact fluorescent ballast, LED, and high-intensity discharge (HID). The company’s extensive product portfolio ranges from discrete to integrated solutions that contain PFC controllers, ballast control ICs, high voltage gate drivers, and MOSFETs.

About FSEZ1016A

The FSEZ1016A is a primary side regulation (PSR) PWM controller, addressing a critical need in the high brightness (HB) LED market by simplifying design, reducing board space and providing important performance advantages. The FSEZ1016A is an EZSWITCH™ device that integrates a PSR PWM controller with a power MOSFET. Through this integration, this controller achieves the most accurate constant current (CC) through built-in proprietary TRUECURRENT™ technology and tight constant voltage (CV) without using secondary-side feedback circuitry. By tightening the constant current over a wide voltage range, the same circuit can accommodate different numbers of LED units in a string, increasing design flexibility, accelerating time-to-market and stretching the lifetime of HB LEDs. With this high level of integration, this PSR PWM controller conserves board space, accommodating the form factor of lamp cases that continue to diminish in size.

To minimize the standby power consumption, the proprietary green-mode function provides off-time modulation to linearly decrease PWM frequency under light-load conditions. This green mode function assists the power supply in meeting power conservation requirements.

About FAN6300

The highly integrated FAN6300 PWM controller provides several features to enhance the performance of flyback converters. A built-in HV startup circuit can provide more startup current to reduce the startup time of the controller. Once the V_DD voltage exceeds the turn-on threshold voltage, the HV startup function is disabled immediately to improve power consumption. An internal valley voltage detector ensures the power system operates at quasi-resonant operation in wide-range line voltage and any load conditions, and reduces switching loss to minimize switching voltage on drain of power MOSFET.

To minimize standby power consumption and light-load efficiency, a proprietary green-mode function provides off-time modulation to decrease switching frequency and perform extended valley voltage switching to keep to a minimum switching voltage.

The FAN6300 controller also provides many protection functions. Pulse-by-pulse current limiting ensures the fixed peak current limit level, even when a short circuit occurs. Once an open-circuit failure occurs in the feedback loop, the internal protection circuit disables PWM output immediately. As long as V_DD drops below the turn-off threshold voltage, the controller also disables PWM output. The gate output is clamped at 18 V to protect the power MOSFET from high gate-source voltage conditions. The minimum t_OFF time limit prevents the system frequency from being too high. If the DET pin reaches OVP, internal OTP is triggered, and the power system enters latch-mode until AC power is removed.