Maxim MAX17017 UMPC四输出电源控制方案

Maxim公司的MAX17017是低功耗超移动手提电脑(UMPC)的确四输出电源控制器,采用固定频率和恒流模式控制,输入电压5.5V到28V(降压)或3-5V(升压)有四个独立的稳压器:一个升压或降压转换器,一个5A峰-峰值升降压稳压器, 一个3A峰-峰值升降压稳压器,以及一个2A源/吸线性稳压器.主要用于UMPC,手提游戏机,笔记本和亚笔记本电脑,PDA和移动通信器以及以1-4节Li+电池为能源的设备.本文介绍了MAX17017主要特性,方框图和标准应用电路.

The MAX17017 is a quad-output controller for ultramobile portable computers (UMPCs) that rely on a lowpower architecture. The MAX17017 provides a compact, low-cost controller capable of providing four independent regulators—a main stage, a 3AP-P internal stepdown, a 5AP-P internal step-down, and a 2A source/sink linear regulator.

The main regulator can be configured as either a stepdown converter (for 2 to 4 Li+ cell applications) or as a step-up converter (for 1 Li+ cell applications). The internal switching regulators include 5V synchronous MOSFETs that can be powered directly from a single Li+ cell or from the main 3.3V/5V power stages. Finally, the linear regulator is capable of sourcing and sinking 2A to support DDR termination requirements or to generate a fixed output voltage.

The step-down converters use a peak current-mode, fixed-frequency control scheme—an easy to implement architecture that does not sacrifice fast-transient response. This architecture also supports peak currentlimit protection and pulse-skipping operation to maintain high efficiency under light-load conditions.

Separate enable inputs and independent open-drain power-good outputs allow flexible power sequencing. A soft-start function gradually ramps up the output voltage to reduce the inrush current. Disabled regulators enter high-impedance states to avoid negative output voltage created by rapidly discharging the output through the low-side MOSFET. The MAX17017 also includes output undervoltage, output overvoltage, and thermal-fault protection.

The MAX17017 is available in a 48-pin, 6mm x 6mm thin QFN package.

MAX17017主要特性:

_ Fixed-Frequency, Current-Mode Controllers

_ 5.5V to 28V Input Range (Step-Down) or 3V to 5V Input Range (Step-Up)

_ 1x Step-Up or Step-Down Controller

_ 1x Internal 5AP-P Step-Down Regulator

_ 1x Internal 3AP-P Step-Down Regulator

_ 1x 2A Source/Sink Linear Regulator with Dynamic REFIN

_ Internal BST Diodes

_ Internal 5V, 50mA Linear Regulator

_ Fault Protection—Undervoltage, Overvoltage, Thermal, Peak Current Limit

_ Independent Enable Inputs and Power-Good Outputs

_ Voltage-Controlled Soft-Start

_ High-Impedance Shutdown

_ 10μA (typ) Shutdown Current

MAX17017应用:

1to-4 Li+ Cell Battery-Powered Devices

Low-Power Architecture

Ultra-Mobile PC (UMPC)

Portable Gaming

Notebook and Subnotebook Computers

PDAs and Mobile Communicators

图1.MAX17017方框图


图2.PWM比较功能方框图

图3.MAX17017标准应用电路(1)

图4.MAX17017标准应用电路(2):稳压器A配置成升压转换器