NXP 低功耗LCD点阵驱动方案 PCF8579

NXP公司的PCF8579 是低功耗CMOS LCD点阵驱动器,能以1:8,1:16,1:24或1:36多路复用速率驱动点阵图像显示器. PCF8579有40个输出,可级联32个器件,驱动多达40960个点阵的显示器.逻辑电压范围从2.5V到6V,LCD最大电源为9V,I2C总线接口. PCF8579主要应用在汽车信号系统,通信系统,POS终端,工业计算终端和仪器仪表.本文介绍了PCF8579的主要特性,方框图, 不同多路复用速率的LED驱动器系统以及1:32多路复用速率的单屏配线案例.

The PCF8579 is a low power CMOS1 LCD column driver, designed to drive dot matrix graphic displays at multiplex rates of 1:8, 1:16, 1:24 or 1:32. The device has 40 outputs and can drive 32.40 dots in a 32 row multiplexed LCD. Up to 16 PCF8579s can be cascaded and up to 32 devices may be used on the same I2C-bus (using the two slave addresses). The device is optimized for use with the PCF8578 LCD row/column driver.

Together these devices form a general purpose LCD dot matrix driver chip set, capable of driving displays of up to 40960 dots. The PCF8579 is compatible with most microcontrollers and communicates via a two-line bidirectional bus (I2C-bus). To allow partial VDD shutdown the ESD protection system of the SCL and SDA pins does not use a diode connected to VDD. Communication overhead is minimized by a display RAM with auto-incremented addressing and display bank switching.

PCF8579主要特性:

LCD column driver

Used in conjunction with the PCF8578, this device forms part of a chip set capable of driving up to 40960 dots

40 column outputs

Selectable multiplex rates; 1:8, 1:16, 1:24 or 1:32

Externally selectable bias configuration, 5 or 6 levels

Easily cascadable for large applications (up to 32 devices)

1280-bit RAM for display data storage

Display memory bank switching

Auto-incremented data loading across hardware subaddress boundaries (with PCF8578)

Power-On Reset (POR) blanks display

Logic voltage supply range 2.5 V to 6 V

Maximum LCD supply voltage 9 V

Low power consumption

I2C-bus interface

Compatible with most microcontrollers

Optimized pinning for single plane wiring in multiple device applications (with PCF8578)

Space saving 56-lead small outline package and 64-pin quad flat pack

PCF8579应用:

Automotive information systems

Telecommunication systems

Point-of-sale terminals

Industrial computer terminals

Instrumentation



图1.PCF8579方框图



图2.PCF8579 LED驱动器系统(1:32多路复用速率)



图3.PCF8579 分立屏应用(1:16多路复用速率,改善对比度)



图4.PCF8579 分立屏应用(1:32多路复用速率)



图5.单屏配线案例:单屏,1:32多路复用速率(PCF8578在行驱动器模式)