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ADM8845EB-EVALZ: Charge Pump Driver for 6 White LED LCD Backlights

The ADM8845 provides the power required to drive up to 6 white LEDs from a 2.6 V to 5.5 V (li-ion) input supply, using charge pump technology. The white LEDs are used for backlighting a color LCD display. To maximize power efficiency, a charge pump that can operate in either of a 1x, 1.5x or 2x mode is used. The Charge Pump automatically switches between 1x/1.5x/2x modes based on the input voltage, to maintain correct output levels at a high power efficiency.

Improved brightness matching of the white LEDs is achieved by the use of a feedback pin to sense each individual LED current with a maximum matching accuracy of 1% and ISET to ILED maximum matching of 1%.

The ADM8845 provides two digital input control pins, CTRL1 and CTRL2, which control the shutdown operation and the brightness of the LEDs. The LEDs are arranged into two groups, main and sub display options, the main display refers to 4 of the 6 LEDs (FB1 -FB4) and the sub display refers to the remaining 2 LEDs (FB5 - FB6). Brightness control of the white LEDs can be achieved with a digital PWM signal applied to CTRL1 and/or CTRL2 to provide brightness control on the main and/or sub displays. The duty cycle of the applied digital PWM signal determines the brightness of the backlight white LEDs. Also brightness control of the white LEDs can be controlled using a DC voltage or a PWM signal applied to the ISET pin with a few external components added.

The ADM8845 also has soft-start circuitry to limit inrush current flow at power up.

The ADM8845 is fabricated using CMOS technology for minimal power consumption. The part is packaged in a 16-pin LFCSP package.

ADM8845EB-EVALZ 特点
ADM8845EB-EVALZ 功能框图

ADM8845 芯片订购指南
产品型号 产品状态 封装 引脚 温度范围
ADM8845ACP-REEL 量产 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 工业
ADM8845ACP-REEL7 量产 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 工业
ADM8845ACPZ-REEL 量产 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 工业
ADM8845ACPZ-REEL7 量产 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 工业
ADM8845EB-EVALZ 量产 评估板 - 待定
ADM8845EB-EVALZ 应用技术支持与电子电路设计开发资源下载
  1. ADM8845 数据手册DataSheet 下载 . PDF
  2. ADI 模拟器件公司比较器产品选型指南 . PDF
  3. Analog Devices, Inc. 美国模拟器件公司产品订购手册 .PDF