The launch of the AAT1235 and AAT1236 research Nobel for cascaded LED driver

In lighting application of large panel, multi series series of white LED (WLED) application is not easy to reach the consistent illumination. Many existing solutions rely on pulse width modulation (PWM) technology, which makes use of a modulation DC input voltage and cause the screen flicker. In view of this, analogictech (AnalogicTech) days before the launch of AAT1235 and AAT1236 boost converter, let the designer through a single boost converter with digital interface, implementation of a cascade of 4 (series-connected) 5 20mA WLED series, and provides fixed and fluctuation forward current, provide uniform brightness for display, and at the same time reduce the number of components and simplify the design.

AAT1235 and AAT1236 AnalogicTech WLED designed for the application of large size LCD screen design, the boost converter in a single package with high efficiency, high voltage power supply. This component of the five series are divided into two groups, one group including two for backlighting applications current (current sink), the absorption end and the second group is composed of three auxiliary lighting function current absorption end, each series can be independent, or full closed or open.

Two boost converter allows designers to save the actual area of the circuit board through the integration for multiple series control line WLED and drive to a single circuit, this component from the external drive, inductance, capacitance, resistance and diode demand, but due to the high switching frequency which can be operated in 2MHz therefore, can use 2.2 Nanohenry inductance pins occupying the minimum.

AAT1235 and AAT1236 can operate in 2.7 to 5.5V input voltage, maximum boost output voltage up to 24V in 100mA. The two groups of backlight LED current absorption end and the output current of the three groups of auxiliary lighting, each group can be provided by the user can be set by the step of up to 30mA current.

AAT1235 control the open or close of each output through the AS2Cwire serial number AnalogicTech, and to adjust the current of the LED group. The AAT1236 boost converter provides the same functionality as AAT1235, but is equipped with a I2C interface for configuration and control. The two components have automatic soft start, over-voltage and over temperature protection. AAT1235 and AAT1236 for the -40 to +85 temperature range, can provide lead-free, heat strengthened type 16 pin TDFN34 package.

Source: EE