Maxim MAX8784 TFT-LCD电源解决方案

Maxim 公司的MAX8784是TV和监视器的TFT-LCD电源解决方案，包括升压稳压器，调整的正和负电荷泵，三个大电流运输放大器，以及双模式逻辑控制高压开关控制区块。输入电压4V-5.5V。效率高达90%，开关频率1.2MHz，主要用在LCD TV和LCD 监视器。本文介绍了MAX8784主要特性，方框图，典型工作电路图和所用元件列表，MAX8784评估板主要特性，电路图和评估板元件列表。
The MAX8784 generates supply rails for the thin-film transistor (TFT) liquid-crystal display (LCD) panels in TVs and monitors. It includes a step-up regulator, a regulated positive and a negative charge-pump, three high-current operational amplifiers, and Dual Mode™, logic-controlled, high-voltage switch control block. HVS mode automatically increases the output voltages of the boost regulator and the positive charge-pump to stress test display panels during production. The MAX8784 can operate from input voltages of 4V to 5.5V and is optimized for LCD TV panel and LCD monitor applications.
The step-up DC-DC regulator provides a regulated supply voltage for TFT source drivers. The step-up regulator is a high-frequency (1.2MHz), high-efficiency, currentmode regulator. The step-up regulator has a built-in 110m(typ) power MOSFET. The high-switching frequency allows the use of ultra-small inductors and ceramic capacitors. The current-mode architecture provides fast transient response and easy compensation.
The step-up regulator features output undervoltage protection, soft-start, internal current limit, and adjustable output voltage by an external resistive divider.
The three operational amplifiers drive the LCD backplane and the gamma-correction-divider string. Each operational amplifier has a fast slew rate (45V/μs), a wide bandwidth (20MHz), and a high-output short-circuit current (200mA). Each op amp has rail-to-rail input and rail-to-rail output operation.
The positive charge-pump regulator and the negative charge-pump regulator provide regulated supply voltages for the TFT gate drivers. The positi...