AnalogicTech has developed two 4-channel, charge pump-based LED drivers for larger LCD screens in portable systems.

Available in compact 2x2.1mm packages, the devices offer designers 16-step, 32-step or PWM current control.

To deliver uniform brightness and excellent matching between adjacent LEDs, the AAT3104 provides common current sinks for command anode configurations, while the AAT3195 supports common sources for common cathode configurations.

It provides the required compliance voltage to forward bias the LED as well as a means to control and set the desired current for both common anode and common cathode configurations with four LEDs.

The AAT3104 is a current-source LED driver capable of driving up to four LEDs at up to 30mA each. The charge pump-based device automatically switches between a 1x and 2x mode to maximise efficiency and optimize LED current accuracy and matching.  LED output current accuracy is +/-10%.  LED output current matching is +/-3%.

The device operates at a 1MHz switching frequency and comes in two versions that offer either 16-step (AAT3104-1) or 32-step (AAT3104-2) control of LED brightness via a patented single-wire S2Cwire interface. A PWM version, the AAT3105, will be available shortly.

More information: www.analogictech.com