ADI ADP2118高效同步降压DC-DC转换方案

ADI 公司的ADP2118是3A高效同步降压DC-DC转换器,采用电流模式恒定频率PWM控制方案,有极好的稳定性和瞬态响应,输入电压丛2.3V到5.5V,输出电压从0.6V到输入电压(VUN),可连续输出3A电流,广泛应用在DSP/FPGA/ASIC内核电源,通信和网络设备,PDA和掌上电脑以及音频/视频消费类电子产品.本文介绍了ADP2118的主要特性,方框图和典型应用电路,包括强迫连续导通模式, 使能PFM模式, 和1MHz外接时钟的相位同步以及和1MHz外接时钟的180度相位同步的降压稳压器电路图.

ADP2118: 3A, 1.2 MHz/600 kHz High Efficiency Synchronous Step-Down DC-to-DC Converter

The ADP2118 is a low quiescent current, synchronous, step-down, dc-to-dc converter in a compact 4mm × 4mm LFCSP_WQ package. It uses a current mode, constant frequency pulse-width modulation (PWM) control scheme for excellent stability and transient response. Under light loads, the ADP2118 can be configured to operate in pulse frequency modulation (PFM) mode that reduces switching frequency to save power. The ADP2118 runs from input voltages of 2.3 V to 5.5 V. The output voltage of the ADP2118ACPZ-R7 is adjustable from 0.6 V to input voltage (VIN), and the ADP2118ACPZ-x.x-R7 are 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 ADP2118 requires minimal external parts and provides a high efficiency solution with its integrated power switch, synchronous rectifier, and internal compensation. The IC draws less than 3 μA 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).

ADP2118主要特性:

3 A continuous output current

75 mΩ and 40 mΩ integrated FET

±1.5% output accuracy

Input voltage range from 2.3 V to 5.5 V

Output voltage from 0.6 V to VIN

600 kHz or 1.2 MHz fixed switching frequency

Synchronizable between 600 kHz and 1.4 MHz

Selectable synchronize phase shift: 0o or 180o

Selectable PWM or PFM mode operation

Current mode architecture

Precision enable input

Power good output

Voltage tracking input

Integrated soft start

Internal compensation

Starts up into a precharged output

UVLO, OVP, OCP, and thermal shutdown

Available in 16-lead 4mm × 4mm LFCSP_WQ package

ADP2118应用:

DSP/FPGA/ASIC core power

Telecommunication/networking equipment

PDAs and palmtop computers

Audio/video consumer electronics

图1.ADP2118功能方框图



图2.ADP2118典型应用电路


图3. 1.2 V, 3 A, 1.2 MHz降压稳压器(强迫连续导通模式)


图4.2.5 V, 3 A, 1.2 MHz 降压稳压器(使能PFM模式)


图5.1.8 V, 3 A降压稳压器(和1MHz外接时钟的相位同步)


图5.1.5 V, 3 A降压稳压器(和1MHz外接时钟的180度相位同步)

图6.3.3 V, 3 A, 1.2 MHz降压稳压器(跟踪模式)