Renesas LED driver IC integrates dimming function for more compact systems
With the new R2A20135SP device, Renesas further contributes to the compactness and high-performance of LED lighting systems with TRIAC dimming support. 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 include reduction of external dimmable circuit mounting area by approximately 40 percent and reducing the number of current adjustment processes by lowering current variations.
The dimming function is based on a circuit that detects information on the conduction angle, which adjusts the brightness, and reflects it in the output voltage for an LED lamp. The function is built into the new R2A20135SP, which offers a reduction of approximately 40 percent in the size of the external dimmable circuit, compared with designs using the earlier Renesas R2A20134 device. This integration results in greater system compactness and reduced system development costs, as fewer circuit components are needed.
A current change is reflected 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.
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.
Renesas said it also will 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. The board offers an 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.
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.
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.
Refer to the separate sheet for the main specifications of Renesas Electronics’ new LED driver IC. Further information about Renesas Electronics Europe can be found at: www.renesas.eu.
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