MAX77503效率降压转换器解决方案

电子工程师 2019-05-01 1409

转换器

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描述

　　Maxim公司的MAX77503是同步1.5A 94%效率降压DC疍C转换器，工作输入电压3V到14V，输出电压在0.8V到5V间通过I2C串口可调，每步50mV，主要用在2电池／3电池高密度电源，手持锂+／锂离子电池供电设备，无人机，HD照相机和笔记本电脑。本文介绍了MAX77503主要特性和优势，框图和多种应用电路，以及评估板MAX77503 EVK优势和特性，电路图，材料清单和PCB设计图。

　　1.5A buck converter with 94% efficiency for 2-cell/3-cell battery applications

　　The MAX77503 is a synchronous 1.5A step-down DCDCconverter optimized for portable 2-cell and 3-cell battery-operated and USB-C applications. The converter operateson an input supply between 3V and 14V. Outputvoltage is adjustable between 0.8V and 5V in 50mV stepsthrough an I2C serial interface or 1.55V to 99% of the supplyvoltage with external feedback resistors. Factory-programmeddefault voltages of 1.2V， 1.8V， and 3.3V are offeredto reduce component count for common rails. Thedevice features a low-IQ SKIP mode which allows excellentefficiency at light loads.

　　Dedicated enable and power-OK pins allow simple hardwarecontrol. An I2C serial interface is optionally used forfull configuration and control for dynamic voltage scalingand system power optimization.

　　Built-in undervoltage lockout （UVLO）， output active discharge，cycle-by-cycle current limit， thermal shutdown，and short-circuit protection ensure safe operation underabnormal operating conditions.

　　The MAX77503 is available in a 12-bump， 0.4mmpitch wafer-level package （WLP）。

　　MAX77503主要特性和优势：

　　● 1.5A Single Channel Buck Regulator

　　● 3V to 14V Input Voltage Range

　　● 0.8V to 99%VSUP Output Voltage Range

　　• 0.8V to 5V I2C Programmable in 50mV Steps

　　• 1.55V to 99%VSUP with External FeedbackResistors

　　• 1.2V， 1.8V， or 3.3V Factory Preset Options

　　● High-Efficiency， Low-IQ Extends Battery Life

　　• 94% Peak Efficiency at 7.4VSUP， 3.3VOUT （2520Inductor）

　　• 9μA IQ （12VSUP， 1.8VOUT Internal FeedbackVersion）

　　• Selectable Light-Load SKIP and Forced-PWMModes

　　● 1MHz or 550kHz Fixed-Frequency Switching

　　● Hardware or Software Control

　　• Enable Input and Power-OK Output Pins

　　• Optional I2C Full Control Interface

　　● Protection Features

　　• Cycle-by-Cycle Inductor Peak Current Limit

　　• Short-Circuit Hiccup Mode， UVLO， and ThermalShutdown Protections

　　• 1ms Default Soft-Start

　　● Small Size

　　• 1.85mm x 1.4mm （0.7mm max. height） WLP

　　• 12-Bump， 0.4mm Pitch， 3 x 4 Array

　　MAX77503应用：

　　● 2-cell/3-cell High Power Density Supplies

　　● Portable Li+/Li-ion Battery Powered Devices

　　● Drones， HD Cameras， and Notebook Computers

　　● Space-Constrained Portable Electronics

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　　图1.MAX77503简化应用电路

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　　图2.MAX77503外部反馈电路

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　　图3.MAX77503内部反馈电路，3.3V工厂默认

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　　图4.MAX77503内部反馈电路，1.8V工厂默认

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　　图5.MAX77503内部反馈电路，1.2V工厂默认

　　评估板MAX77503 EVK

　　The MAX77503 evaluation kit （EV kit） is a fully assembled and tested PCB that demonstrates the MAX77503 synchronous step-down （buck） converter. The EV kit is a step-down voltage regulator circuit using MAX77503 that is capable of 3V to 14V input， 1.5A continuous load， and output voltage adjustable between 0.8V and 5V （internal feedback options） or 1.55V and 99% of the input voltage （external feedback option）。

　　The EV kit features a dual-range electronic load that allows easy evaluation of loading use cases for the buck converter circuit. Steady-state， transient， or random load profiles can be programmed.

　　A USB-to-I2C translator circuit allows a Windows®-based PC to run a graphical user interface （GUI） for easy control of the MAX77503 registers as well as the on-board electronic load.

　　评估板MAX77503 EVK优势和特性：

　　Proven PCB Reference Design and Layout

　　Easy to Use Simple Hardware Control： Jumpers and Test Points for EN， BIASEN， and POK

　　GUI Drives I2C Interface for Optional Software Control

　　Fully Assembled and Tested

　　USB to I2C Converter Allows for Easy Communication Windows-Based Software GUI Controls Registers

　　Level Translator （MAX3395） Allows for Adjusting I2C Bus Voltage from 1.8V to 3.3V

　　On-Board Electronic Load Emulates System Loading Steady-State， Transient， and Random Modes

　　图6.评估板MAX77503 EVK外形图

　　图7.评估板MAX77503 EVK顶层视图

　　图8.评估板MAX77503 EVK底层视图

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