ON Semi’s New Switching Regulators Drive High Brightness LEDs In Low Voltage & Automotive Lighting
ON Semiconductor introduced the NCP3065 switching regulator designed to efficiently drive high brightness LEDs (HB-LED) typically used in, low voltage lighting, landscape path and solar lighting, Halogen bulb replacements, and automotive and marine lighting. Several reference designs are available that drive the industry’s latest HB-LEDs in various buck, boost and SEPIC applications.
The NCP3065 is a 1.5A monolithic switching regulator that features a low feedback voltage of 235mV. The feedback voltage is used to regulate the average current through the LED string in a constant current regulator configuration. The low feedback voltage also allows the use of a smaller and more cost competitive sense resistor. The company claims that the power dissipation in the sense resistor is reduced by 80% compared to competitive devices which utilize a standard 1.25V feedback voltage. It is said that this can result in up to 2% savings on the overall system efficiency. The internal reference voltage is trimmed to 2% to provide very accurate current regulation even with wide variations in input voltage, LED forward voltage and inductor tolerance.
The device has a wide input voltage range from 3 up to 40V to allow operation from 12Vac and 12Vdc supplies commonly used for lighting applications and unregulated power supplies such as Lead Acid batteries. The devices can be configured in a controller topology with the addition of an external transistor to support higher LED currents beyond the 1.5A rated switch current of the internal transistor. In a boost configuration, the external switch also enables the capability of higher output voltages.
The device also features thermal shutdown protection; cycle-by-cycle current limit; a 4mm x 4mm DFN package; and no external compensation components are needed.
The NCP3065 is also available in automotive grade as the NCV3065. The NCP3065 and NCV3065 are offered in a 4mm x 4mm DFN-8 package and priced at $0.32 per unit in 10,000 unit quantities. The devices are also offered in an SOIC-8 and a PDIP-8 package priced at $0.30 per unit in 10,000 unit quantities.
