Renesas Electronics Announces Driver IC for High-Efficiency LED Lighting Applications

LED lighting systems combining low power consumption, high efficiency and long service life have gained considerable attention in recent years amid worldwide efforts to save power and reduce emissions of carbon dioxide. LEDs have come into widespread use in industrial and commercial equipment, as well as in lighting fixtures for outdoor and household use. The market for such products is expected to continue to grow substantially.

In 2011, Renesas started mass production of the high-efficiency R2A20134 LED driver IC, which features a high-power factor that performs functions such as LED on-off switching and is designed to be mounted inside LED lamps. The company further contributed to the compactness and high-performance of LED lighting systems with TRIAC dimming support with the new R2A20135SP device. Integrating the dimming function eliminates the need for a dedicated external circuit, reducing the required board space and bill of materials.

Main features of the new R2A20135SP LED driver IC:
(1) Reduction of external dimmable circuit mounting area by approximately 40 percent (compared with earlier Renesas products), contributing to more compact systems
The dimming function is a conduction angle detection circuit that detects information on the conduction angle, which adjusts the brightness, and reflects it in the output voltage for an LED light bulb. The function is built into the new R2A20135SP, which compared with designs using the earlier Renesas R2A20134 device enables a reduction of approximately 40 percent in the size of the external dimmable circuit. This integration results in greater system compactness and reduced system development costs, as fewer circuit components are needed.

(2) Reduce the numbers of current adjustment processes by lowering current variations
A change in the current is visible as a change in the brightness of the LEDs, so mass producing lighting systems that provide a stable level of luminance requires that current variations be reduced to a minimum. The new R2A20135SP device lowers the reference voltage used for current control to 0.2 V from the 0.6 V of previous comparable Renesas products. This has the effect of reducing inconsistency from 15 percent to 6 percent. A higher level of current control accuracy translates into more consistent LED brightness, reducing the number of processes required for current adjustment.
In addition, the new R2A20135SP uses a proprietary MOSFET high-side control technology to control the LED current value directly, which contributes to less inconsistency in the LED brightness.

(3) Availability of evaluation board to enable system designers to fully utilize the new R2A20135SP
Renesas will also provide an LED control circuit evaluation board with TRIAC dimming support as a development tool to support the design of systems incorporating the new R2A20135SP. With efficiency of 85 percent or better when using a TRIAC dimmer function, a power factor of 0.9 or above, and total harmonic distortion (THD) of 20 percent or less, this board delivers industry-leading performance and will contribute to more power-efficiency in LED lighting systems.

(4) Enables lower system cost with reduced voltage tolerance by adopting non-isolated method
When the new R2A20135SP device is adopted to an LED lighting system using non-isolated method, voltage tolerance (VDSS) can be reduced, which allows system designers to replace the 600 V power MOSFET with Renesas' low-cost, power MOSFETs, which feature a VDSS lower than 450 V, such as the RJK4532DPD, RJK4532DPH, RJK4002DJE.

In addition, the package is identical to that of the R2A20134, an earlier Renesas product with no on-chip dimming function, and it inherits its predecessor's high efficiency and high power ratio, two characteristics critical to power savings in LED lighting products. This makes it easy for lighting fixture manufacturers to extend their product lineups.

A leading supplier of analog and power devices, Renesas plans to provide a rich lineup including approximately 50 peripheral products with a focus on power MOSFETs in the range of 450V to 600V and diodes that can be best combined with the new LED driver IC, which will allow system designers to construct their systems easily.

Leveraging its strong signal chain expertise, Renesas focuses on bringing customers total solutions, including MCUs plus analog and power devices. For example, Renesas plans to provide evaluation boards that combine the new LED driver IC with the RL78 family of LED lighting control MCUs and power supply control IC to help customers with kit evaluation and product design.

Availability
Samples of Renesas Electronics' new LED driver IC will be available starting in March 2012. Mass production is scheduled to begin in June 2012 and is expected to reach 5,000,000 units per month in December 2012. (Availability is subject to change without notice.)