美芯(Maxim)公司的MAX17014A是多输出电源控制器,它能从12V输入电压中产生用于TFT LCD TV和监视器的所有电源. MAX17014A包括一个降压和升压稳压器,一个正电荷泵和一个负电荷泵,两个运算放大器,一个Dual Mode逻辑思维控制高压开关控制区块.工作电压从8V到16.5V,输出电压精度1%,内部的软起动时间3毫秒.本文介绍了MAX17014A的主要特性,方框图以及典型应用电路.

      The MAX17014A multiple-output power-supply controller generates all the supply rails for thin-film transistor (TFT) liquid-crystal display (LCD) panels in TVs and monitors operating from a regulated 12V input. It includes a step-down and a step-up regulator, a positive and a negative charge pump, two operational amplifiers, and a Dual Mode™ logic-controlled highvoltage switch control block. The MAX17014A can operate from 8V to 16.5V input voltages and is optimized for LCD TV panel and LCD monitor applications running directly from 12V supplies.

      The step-up and step-down regulators feature internal power MOSFETs and high-frequency operation allowing the use of small inductors and capacitors, resulting in a compact solution. Both switching regulators use fixed-frequency current-mode control architectures, providing fast load-transient response and easy compensation.

      A current-limit function for internal switches and output-fault shutdown protect the step-up and step-down power supplies against fault conditions. The MAX17014A provides soft-start functions to limit inrush current during startup. The MAX17014A provides

      adjustable power-up timing.

      The positive and negative charge-pump regulators provide TFT gate driver supply voltages. Both output voltages can be adjusted with external resistive voltage-dividers. The switch control block allows the manipulation of the positive TFT gate driver voltage.

      The MAX17014A includes two high-current operational amplifiers designed to drive the LCD backplane (VCOM). The amplifier features high output current (±150mA), fast slew rate (100V/μs), wide bandwidth (20MHz), and rail-to-rail inputs and outputs. A series

      p-channel MOSFET is integrated to sequence power to AVDD after the MAX17014A has proceeded through normal startup, and provides True Shutdown.

      The MAX17014A is available in a small (7mm x 7mm), low-profile (0.8mm), 48-pin thin QFN package and operates over a -40°C to +85°C temperature range.

      MAX17014A 主要特性:

      _Optimized for 10.8V to 13.2V Input Supply

      _8V to 16.5V Input Supply Range

      _Selectable Frequency (600kHz/1.2MHz)

      _Current-Mode Step-Up Regulator

      Built-In 20V, 3.7A, 110mn-Channel MOSFET

      High-Accuracy Output Voltage (1%)

      True Shutdown

      Fast Load-Transient Response

      High Efficiency

      3ms Internal Soft-Start

      _Current-Mode Step-Down Regulator

      Built-In 20V, 2.5A, 120mn-Channel MOSFET

      Fast Load-Transient Response

      Adjustable Output Voltage Down to 1.25V

      Skip Mode at Light Load

      High Efficiency

      3ms Internal Soft-Start

      _Adjustable Positive and Negative Charge-Pump Regulators

      _Soft-Start and Timer-Delay Fault Latch for All Outputs

      _Logic-Controlled High-Voltage Integrated Switches with Adjustable Delay

      _Two High-Speed Operational Amplifiers

      ±150mA Short-Circuit Current

      100V/μs Slew Rate

      20MHz, -3dB Bandwidth

      _120mp-Channel FET for AVDD Sequencing

      _Input Undervoltage Lockout and Thermal-

      Overload Protection

      _48-Pin, 7mm x 7mm Thin QFN Package

      MAX17014A 应用:

      LCD TV Panels

      LCD Monitor Panels

图1. MAX17014A方框图

图2. MAX17014A典型应用电路图

图3. 简化的MAX17014A应用电路