浅析汽车TFT-LCD显示器升压电源的解决方案

Maxim公司的MAX16928是高度集成的汽车TFT-LCD显示器电源,器件集成了一个升压转换器(高达6W,输出高达18V),一个1.8V/3.3V稳压控制器(500mA电流)和两个栅极电压稳压器,其中的正栅极电压稳压器能在28V时提供20mA电流,高频2.2MHz工作,提供软起动和超温关断等功能.主要用在汽车仪表盘,汽车中心信息显示器和汽车导航系统.本文介绍了MAX16928主要特性,方框图, 正输出和负输出电压的多级电荷泵电路以及典型应用电路.

Automotive TFT-LCD Power Supply with Boost Converter and Gate Voltage Regulators

The MAX16928 is a highly integrated power supply for automotive TFT-LCD applications. The device inte­grates one boost converter, one 1.8V/3.3V regulator controller, and two gate voltage regulators. The device comes in several versions to satisfy common automotive TFT-LCD power-supply requirements.

The boost converter uses spread-spectrum modulation to reduce peak interference and to optimize EMI performance.

The sequencing input (SEQ) allows flexible sequencing of the positive-gate and negative-gate voltage regulators. The power-good indicator (PGOOD) indicates a failure on any of the converters or regulator outputs. Integrated thermal shutdown circuitry protects the device from over­heating.

The MAX16928 is available in a 20-pin TSSOP pack­age with exposed pad and operates over the -40NC to +105NC temperature range.

MAX16928主要特性:

High-Power (Up to 6W) Boost Output Providing Up to 18V

1.8V or 3.3V Regulator Provides 500mA with External npn Transistor

One Positive-Gate Voltage Regulator Capable of Delivering 20mA at 28V

One Negative-Gate Voltage Regulator

High-Frequency 2.2MHz Operation

Flexible Stand-Alone Sequencing

True Shutdown™ Boost Converter

Internal Soft-Start

Overtemperature Shutdown

-40NC to +105NC Operation

AEC-Q100 Qualified

MAX16928应用:

Automotive Dashboards

Automotive Central Information Displays

Automotive Navigation Systems

图1.MAX16928升压转换器功能框图

图2.正输出电压的多级电荷泵电路

图3.负输出电压的多级电荷泵电路

图4.MAX16928应用电路图