NXP demonstrates "sensorless sensing" technology to improve LED light color quality

At the recently concluded CES 2013, NXP Semiconductors demonstrated a breakthrough solution through which LED lamps can maximize the mimicking of the warmer and more comfortable white light that traditional incandescent lamps can produce when they dim. In addition to the “sensorless sensing” technology developed and patented by NXP, the advantages of this solution include: eliminating the use of external temperature sensors reduces the cost of the LED system, reduces the size of the heat sink required for LED system cooling, and Significantly improve reliability.

The light color of an incandescent lamp becomes warmer and more emotional when it becomes darker and less bright. In contrast, today's LED lights are generally inferior to the light color experience of traditional bulb users in the entire dimming range.

To make LEDs mimic incandescent lamps when dimmed, the NXP solution integrates three key functions into the drive circuit:

1. Combine the white LED and amber LED as a cost-effective method to form the most pleasing light color (along the black body radiation curve)

2. Implement logarithmic correction of eye sensitivity with an analysis model that allows for the desired light color point when darkened

3. Using sensorless sensing technology to directly measure the temperature of the LED junction to achieve accurate and efficient real-time temperature correction, which is crucial for reliable control of LED performance under any conditions

No matter how long the LED is used, the smart LED driver developed by NXP can provide stable color and light output at any temperature through these functions. Sensorless sensing directly measures the LED junction temperature by connecting two existing wires of the LED, which solves the challenge of LED temperature drift and has more advantages than traditional LED temperature measurement methods. The use of sensorless sensing eliminates the need for external sensors or wiring, which reduces the total number of components and enables a more compact heat sink. In addition, sensorless sensing enables fast performance, accurate temperature measurement (~ 1 ° C res.), Dynamic light control, is not affected by heat sinks and operating conditions, does not require thermal modeling, and can compensate for use time through self calibration.

Michael Bruno, senior director of advanced technology and future innovative business development at NXP Semiconductors, said: "Our research team has uniquely set out to answer this question: What can motivate consumers to finally accept LED lighting with the same emotions as incandescent lamps? With sensorless Sensing technology, we have demonstrated a new way to achieve the warm light associated with incandescent lamps by using dimmable LED lights. Sensorless sensing also helps to reduce the total cost of the system and eliminate Another major obstacle to the widespread adoption of LEDs. This clever method significantly improves the reliability and lifespan of LEDs, so sensorless sensing has great potential in other fields such as automotive SSL and commercial LED applications.