Panasonic Develops Four-channel LED Driver LSI-based on 190V Voltage Process
Osaka – Semiconductor Company of Panasonic Corp. has developed a four-channel LED driver LSI (model number: AN37010) that can drive multiple LEDs connected in series for edge-type LED backlight LCD TVs, thanks to the adoption of 190V voltage processing technology. Samples will be available in March 2011 at a cost of 200 yen each. Building on the development of this new chip, Panasonic will further develop a series of LED driver LSIs that support applications for displays with high picture quality across a wide range of sizes.
A single chip of the AN37010 LED driver LSI can drive up to 228 LEDs (for 42-inch TV) in four light bars, each of which consisting of 57 LEDs, in a backlight of an LCD display and also incorporates four current sources with a 190V voltage, a boost converter, and various protection circuits. This technology contributes to the down-sizing and cost-reduction of LED backlight modules. Furthermore, this LSI supports ON-OFF control, which the LED backlight in LCD TVs uses to improve the picture quality and reduce power consumption.
Conventional LSIs drive multiple serially connected LEDs by providing each channel with external MOSFETs that protect the LSI from high voltages. However, this has been one of the factors of increased system cost of edge-type LED backlight which is expected to be the mainstream in the near future. Driving multiple LEDs in series by a single LSI free from the external MOSFETs has been eagerly awaited.
Panasonic’s new LED driver LSI was developed based on the following technologies.: analog LED driver circuit technologies adaptable to a 190V voltage process; analog circuit technologies for a boost converter, error detection circuits and false-detection-prevention circuits; and LED-dimming-control technologies supporting PWM (pulse-width modulation) pulse input-based LED current duty-cycle control and external voltage application-derived current value control.
Panasonic’s LED driver LSI has the following new features: a single LSI can drive up to 228 pieces (for 42-inch TV) of LEDs in a backlight of an LCD display; reduction of four external MOSFETs for protection against high voltages; and drives four LED light bars, in each of which 57 LEDs (approximately five times more than conventional LSI ) are connected in series at VF = 3.2 V.
