ADI 公司的ADP1874/ADP1875" title="DP1874/ADP1875">DP1874/ADP1875是电流模式同步降压电源控制器，提供优异的瞬态响应，最佳的稳定性和限流保护，输入电压2.95V-20V，输出电压最低可达0.6V，开关频率有300 kHz, 600 kHz和1.0 MHz三种选择，不需要电流检测电阻，主要用在通信和网络系统，中高端服务器，STB和DSP核电源。本文介绍了ADP1874/ADP1875主要特性，方框图以及多种12A输出电流应用电路图，大电流评估板电路图和布局图。

The ADP1874/ADP1875 are versatile current mode, synchronous step-down controllers. They provide superior transient response, optimal stability, and current-limit protection by using a constant on-time, pseudo fixed frequency with a programmable current limit, current control scheme. In addition, these devices offer optimum performance at low duty cycles by using a valley, current mode control architecture. This allows the ADP1874/ADP1875 to drive all N-channel power stages to regulate output voltages to as low as 0.6 V.

The ADP1875 is the power saving mode (PSM) version of the device and is capable of pulse skipping to maintain output regulation while achieving improved system efficiency at light loads (see the ADP1875 Power Saving Mode (PSM) section for more information).

Available in three frequency options (300 kHz, 600 kHz, and 1.0 MHz, plus the PSM option), the ADP1874/ADP1875 are well suited for a wide range of applications that require a single-input power supply range from 2.95 V to 20 V. Low voltage biasing is supplied via a 5 V internal low dropout regulator (LDO).

In addition, soft start programmability is included to limit input in-rush current from the input supply during startup and to provide reverse current protection during precharged output conditions. The low-side current sense, current gain scheme, and integration of a boost diode, along with the PSM/forced pulse-width modulation (PWM) option, reduce the external part count and improve efficiency.

The ADP1874/ADP1875 operate over the −40℃to +125℃ junction temperature range and are available in a 16-lead QSOP package.

ADP1874/ADP1875主要特性：

Power input voltage range: 2.95 V to 20 V

On-board bias regulator

Minimum output voltage: 0.6 V

0.6 V reference voltage with ±1.0% accuracy

Supports all N-channel MOSFET power stages

Available in 300 kHz, 600 kHz, and 1.0 MHz options

No current-sense resistor required

Power saving mode (PSM) for light loads (ADP1875 only)

Resistor programmable current limit

Power good with internal pull-up resistor

Externally programmable soft start

Thermal overload protection

Short-circuit protection

Standalone precision enable input

Integrated bootstrap diode for high-side drive

Starts into a precharged output

Available in a 16-lead QSOP package

ADP1874/ADP1875应用：

Telecom and networking systems

Mid- to high-end servers

Set-top boxes

DSP core power supplies

图1。ADP1874/ADP1875方框图

图2。ADP1874/5大电流评估板电路图（蓝色为大电流通路）

图3。ADP1874/5大电流评估板布局图

图4。ADP1874/5应用电路图：12V输入，输出1.8V/12A,300kHz（Q2/Q4不连接）

图5。ADP1874/5应用电路图：5.5V输入，输出2.5V/12A,600kHz（Q2/Q4不连接）

图6。ADP1874/5应用电路图：13V输入，输出1.8V/12A,300kHz（Q2/Q4不连接）

详情请见：
http://www.analog.com/static/imported-files/data_sheets/ADP1874_1875.pdf