Charge-Pump Drives White LEDs

Targeting white LED applications, the AQ9156 switched-capacitor regulator provides a regulated 4.5V output at up to 120 mA and can drive up to six parallel LEDs. Typical input voltage ranges from 3V to 6V. It features a 1.5X charge-pump circuit that uses two ceramic bucket capacitors and two small filters for VIN and VOUT. Other features include selectable switching frequencies of 8, 32, 262, or 650 kHz and efficiencies in excess of 80%. Brightness control is via a PWM signal on either the ENA or CLK2 pins. Available in MLP-10 or MSOP-10 packages, price is $0.98 each/1,000. ARQUES TECHNOLOGY INC., Santa Clara, CA. (408) 969-0868.