Internal-Switch Boost Regulator and High-Voltage, Low-Dropout Linear Regulator for TFT LCDs

Active: In Production.

The MAX17115 includes a high-performance step-up regulator, a high-accuracy, high-voltage, low-dropout linear regulator (LDO), a high-performance buffer ampifier, and a logic-controlled high-voltage switch block.

The DC-DC converter is a high-frequency (1.2MHz/640kHz) current-mode step-up regulator with a built-in power MOSFET. It provides fast-transient response to pulsed loads while producing efficiencies over 88%. The built-in power MOSFET allows output voltages as high as 18V from inputs from 2.5V to 5.5V. A programmable soft-start function controls startup inrush currents.

The operational amplifier, typically used to drive the LCD backplane (VCOM), features high-output short-circuit current (200mA), fast slew rate (45V/µs), and wide bandwidth (20MHz). Its rail-to-rail input and output maximize application flexibility. The high-voltage LDO is adjustable and has a high accuracy of ±0.5%. It is typically used to drive a gamma reference divider string. The high-voltage switch control block modulates the shape of the gate-on supply and provides an adjustable delay for power-up sequencing.

The high-voltage stress (HVS) function is used to temporarily increase the source-driver supply voltage of the LCD panel for aging tests. The HVS digital input controls an open-drain internal switch, which is typically used to change the feedback divider of the step-up regulator.

The MAX17115 is available in a lead-free, 32-pin, thin QFN package. The package is a 5mm x 5mm square with a maximum thickness of 0.8mm for thin LCD panel design.

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