Integrated Silicon Solution, Inc. (ISSI) announced its IS32BL3552 and IS32BL3554 solutions, two highly integrated multi-string LED drivers for LCD backlighting applications. These new high performance devices integrate a boost converter with multiple current sinks for cost-effective automotive infotainment displays and instrument clusters, as well as applications in industrial displays, TVs and monitors. ISSI’s new LED drivers include a dc-dc boost switching controller with outputs up to 60V to drive multiple strings of LEDs as well as regulated current sinks with string-to-string current matching accuracy of ±1.5% to ensure uniform LCD display brightness. The IS32BL3552 supports two parallel strings of up to 360mA each, while the IS32BL3554 supports four strings of up to 180mA. For added flexibility, the sinks can be paralleled together to achieve even higher LED currents.
“These new LED driver products represent our ongoing efforts to expand our content and penetration of the automotive industry,” said Ven Shan, vice president of analog products at ISSI. “Industry analysts forecast double digit growth for automotive LED lighting over the next five years, driven by its widespread use in both interior and exterior lighting applications for safety, durability and aesthetics. We are well positioned to leverage our current leadership position in memory solutions to address this exciting growth opportunity in the automotive market.”
Both products incorporate multiple protection features to prevent damage during a fault condition. An internal soft-start circuit prevents a high inrush current during startup, and thermal shutdown protection shields the IC from thermal damage. Both devices monitor the LED string condition for open or shorts and automatically disable any faulty current sinks.
Designers will benefit from smaller PCB footprints and lower BOM costs due to the high frequency operation of the boost converter. The addition of an external resistor allows for frequencies up to 1MHz. The device can be PWM modulated over a wide frequency range from 20Hz to 20kHz to provide a high contrast ratio. In addition, the lower external component count will enhance system reliability. No additional external circuitry is required to implement advanced functions such as open and short LED protection and high contrast PWM dimming.
The IS32BL3552 and IS32BL3554 are fully specified over the -40Â°C to +125Â°C automotive temperature range, while operating over a wide input-voltage of 4.5V to 33V. The devices are offered in low profile 16-pin thermally enhanced TSSOP packages with an exposed thermal pad. Prices start at $1.29 for IS32BL3552 and $1.39 for IS32BL3554 in 1,000 piece quantities.