基于ADP2119设计的2A降压DC-DC电源转换技术

2011-05-09 20:03:07来源: 互联网
ADP2119/ADP2120是ADI公司的2A/1.25A低静态电流同步降压DC/DC电源稳压器,采用3 mm × 3 mm LFCSP_WD封装.两种器件采用恒流模式恒频PWM控制方案,具有极好的稳定性和瞬态响应.轻负载下可工作在脉冲频率调制(PFM)模式,以降低开关频率,节省功耗.输入电压从2.3V到5.5V,输出电压从0.6V到VIN,输出精度±1.5%,主要用在POL负载,通信和网络设备,工业和仪表,消费类电子和医疗设备.本文介绍了ADP2119/ADP2120主要特性, 功能方框图以及多种典型应用电路和所用元件.

The ADP2119/ADP2120 are low quiescent current, synchronous, step-down dc-to-dc regulators in a compact 3 mm × 3 mm LFCSP_WD package. Both devices use a current mode, constant frequency pulse-width modulation (PWM) control scheme for excellent stability and transient response. Under light load conditions, they can be configured to operate in a pulse frequency modulation (PFM) mode, which reduces switching frequency to save power.

The ADP2119/ADP2120 support input voltages from 2.3 V to 5.5 V. The output voltage can be adjusted from 0.6 V up to the input voltage (VIN) for the adjustable version, whereas the fixed output version is available in preset output voltage options of 3.3 V, 2.5 V, 1.8 V, 1.5 V, 1.2 V, and 1.0 V. The ADP2119/ADP2120 require minimal external parts and provide a high efficiency solution with their integrated power switches, synchronous rectifiers, and internal compensation. Each IC draws less than 2 μA current from the input source when it is disabled. Other key features include undervoltage lockout (UVLO), integrated soft start to limit inrush current at startup, overvoltage protection (OVP), overcurrent protection (OCP), and thermal shutdown (TSD).

ADP2119/ADP2120主要特性:

Continuous output current

ADP2119: 2 A

ADP2120: 1.25 A

145 mΩ and 70 mΩ integrated MOSFETs

Input voltage range from 2.3 V to 5.5 V

Output voltage from 0.6 V to VIN

±1.5% output accuracy

1.2 MHz fixed switching frequency

Synchronizable between 1 MHz and 2 MHz

Selectable PWM or PFM mode operation

Current mode architecture

Precision threshold enable input

Power-good flag

Voltage tracking

Integrated soft start

Internal compensation

Startup with precharged output

UVLO, OVP, OCP, and thermal shutdown

10-lead, 3 mm × 3 mm LFCSP_WD package

ADP2119/ADP2120应用:

Point of load conversion

Communications and networking equipment

Industrial and instrumentation

Consumer electronics

Medical applications

图1.ADP2119/ADP2120功能方框图

图2.ADP2119典型应用电路

图3.ADP2119典型应用电路:1.2V/2A降压稳压器, 强迫连续导通模式

图4.ADP2119典型应用电路:1.8V/2A降压稳压器,使能PFM模式

图5.ADP2119典型应用电路:2.5V/2A降压稳压器,外接时钟同步

图6.ADP21209典型应用电路:1.5V/1.25A降压稳压器,跟踪模式

图7.ADP21209典型应用电路:1.2V/1.25A降压稳压器,强迫连续导通模式

关键字:设计  降压  电源  转换

编辑:神话 引用地址:http://www.eeworld.com.cn/mndz/2011/0509/article_8414.html
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