In addition to extending battery life, the ISL98611 also improves display brightness uniformity and colour consistency. It integrates a boost regulator, LDO and inverting charge pump for generating two output rails at +5V and -5V in a single device. It also includes a boost regulator with 3-channel current sinks for the LED backlight driver.
This single-chip solution offers designers four key benefits:
• Extended battery life: When used for web browsing and emails, a smartphone's backlight LEDs and display power consume the majority of its battery power. The ISL98611 backlight LED driver delivers 7% higher efficiency (up to 93%) than competitive multi-chip solutions and generates ±5V display power supplies with greater than 88% efficiency at 15 mA load using a 2.5 x 2 mm size inductor, compared to 85% efficiency of the nearest competitor.
• Improved display uniformity: The ISL98611 provides LED current matching at very low LED current: it achieves ±2.2% matching down to 1 mA and ±2.8% at 50 μA.
• Improved display colour consistency: The ISL98611 includes hybrid dimming to eliminate white LED colour shift issues at low LED current, which occur with DC dimming.
• It uses 24% less PCB area compared to the competition, while requiring only eight external components.
In a 2.33 x 2.61 mm 30-ball WLCSP package the part costs $1.50 (1000). An evaluation board, ISL98611EVAL1Z, is $100..