原标题：Maxim MAX77827高效升压－降压6μA静态电流稳压器解决方案

　　Maxim公司的MAX77827是高效升压-降压稳压器,具有业界最低的6μA静态电流,目标用在单颗锂电池能源的设备.支持输入电压1.8V-5.5V,输出电压在2.3V-5.3V,提供两种不同的开关电流(1.8A和3.1A),以便基于已知负载电流条件来优化外接元件尺寸.1.8A开关电流限制工作,在降压模式支持高达1.0A负载电流,而升压模式支持900mA负载电流(VIN = 3.0V, VOUT = 3.3V).作为DC/DC转换器,峰值效率96%.器件具有可调输出电压,通过单个电阻可编程在2.3V到5.3V,GPIO引脚可支持PWM使能功能和电源良好(POK)指示器.它的独到控制算法具有高效率,杰出的线路/负载瞬态响应,并能在降压和升压模式中无缝转换.开关频率2.5MHz,器件具有UVLO,软起动,主动输出放电功能,过流和热关断保护等.主要用在单个锂电池电源设备,智能手机/手持设备/可穿戴,物联网设备(IoT)以及NB-IoT设备.本文介绍了MAX77827主要优势和特性,简化框图和功能框图,典型应用电路图以及评估板MAX77827 EVK主要特性和指标,电路图,材料清单和PCB设计图.

　　The MAX77827 is a high-efficiency buck-boost regulator targeted for one-cell Li-ion powered applications with the lowest typical quiescent current in the industry of 6μA. It supports input voltages of 1.8V to 5.5V and an output volt­age range of 2.3V to 5.3V. The IC provides two different switching current levels (1.8A and3.1A) to optimize exter­nal component sizing based on given load current require­ments.

　　With the 1.8A switching current-limit option, the IC can support up to 1.0A load current in buck mode and 900mA in boost mode (VIN = 3.0V, VOUT = 3.3V).

　　The peak efficiency of 96% makes the IC one of the best solutions as a DC/DC converter to supply a rail for battery-powered portable applications.

　　The IC features an adjustable output voltage, which can be programmed from 2.3V to 5.3V through a single resis­tor. Two GPIO pins are available to support force PWM enable function and power-OK (POK) indicator. A unique control algorithm allows high-efficiency, outstanding line/load transient response, and seamless transition between buck and boost modes.

　　These options provide design flex­ibility that allow the IC to cover a wide range of applica­ tions and use cases while minimizing board space.

　　The MAX77827 is available in a 1.61mm x 2.01mm, 12-bump wafer-level package (WLP).

　　MAX77827主要优势和特性:

　　● 1.8V to 5.5V Input Voltage Range

　　● 2.3V to 5.3V Single Resistor Adjustable Output Voltage

　　● 1.6A Maximum Output Current (3.1A ILIM Option, Buck Mode)

　　● 900mA Maximum Output Current (1.8A ILIM Option, Boost Mode 3.0VIN,3.3VOUT) ● 96% Peak Efficiency (3.3VIN, 3.3VOUT)

　　● SKIP Mode for Higher Light-Load Efficiency

　　● 6μA Ultra-Low Typical Quiescent Current (At TJ = +25℃ )

　　● 2.5MHz Nominal Switching Frequency

　　● Enable Pin

　　● GPIO Pins for System Design Convenience

　　• FPWM (Forced PWM) Mode Selection Pin

　　• POK Indicator Pin

　　● UVLO, Soft-Start, Active-Output Discharge, Overcurrent, and Thermal Shutdown Protections

　　● 1.61mm x 2.01mm, 12-Bump WLP

　　MAX77827应用:

　　● 1-Cell Li+ Battery Powered Equipment

　　● Smartphones/Portable/Wearables

　　● Internet of Things (IoT) Devices

　　● NB-IoT Devices

　　图1. MAX77827简化框图

　　图2. MAX77827功能框图

　　图3. MAX77827典型应用电路图

　　评估板MAX77827 EVK

　　The MAX77827 evaluation kit (EV kit) provides a proven design to evaluate the MAX77827, a 1.6A buck-boost converter. The IC is capable of 1.8V to 5.5V input and is output voltage adjustable between 2.3 to 5.3V (through SEL pin). The factory default output voltage of this EV kit is set at 3.3V. Output voltage can be adjusted by changing the SEL resistor value (R3). Two GPIO pins are available to support Force PWM and EN functions. The EV kit is compatible with any version of the MAX77827 WLP IC (MAX77827CEWC+ is the default).

　　评估板MAX77827 EVK主要特性和默认设定:

　　Sense Points for High-Accuracy Measurements

　　Accessible Test Points for EN, POK, and OUTS

　　Output Voltage Adjustable Through SEL

　　FPWM and Skip Mode Configurable (Skip Mode Default)

　　UVLO Rising = 2.6V, UVLO Falling = 1.9V (MAX77827CEWC+)

　　评估板MAX77827 EVK主要指标:

　　图4.评估板MAX77827 EVK外形图

　　元件列表:

　　图5.评估板MAX77827 EVK电路图

　　评估板MAX77827 EVK材料清单:

　　图6.评估板MAX77827 EVK PCB设计图:左:顶层元件放置图;右:顶层布局图

　　图7.评估板MAX77827 EVK PCB设计图:层2

　　图8.评估板MAX77827 EVK PCB设计图:左:层3;右:底层

　　图9.评估板MAX77827 EVK PCB设计图:底层丝印