Maxim MAX1722x超低静态电流可穿戴电源解决方案

Maxim公司的MAX17220‒MAX17225系列是超低静态电流升压DC/DC转换器,具有225mA/0.5A/1A峰值电感限流和真关断.VOUT 0V到5V时没有反向电流,峰值效率95%, 400mV-5.5V输入,输出电压1.8V-5V,最低起动电压0.88V,主要用在光学心率监测(OHRM)LED驱动器,RTC/警报器超级电容备份,原电池手持系统,微型低功耗IoT传感器,二次电池便携式系统,可穿戴设备,电池医疗设备和低功耗无线通信设备.本文介绍了MAX17222主要优势和特性,框图和多种应用解决方案,评估板MAX17222EVK主要特性,电路图,材料清单和PCB设计图.

The MAX17220–MAX17225 is a family of ultra-lowquiescent current boost (step-up) DC-DC converters witha 225mA/0.5A/1A peak inductor current limit and TrueShutdown™. True Shutdown disconnects the output fromthe input with no forward or reverse current. The outputvoltage is selectable using a single standard 1% resistor.

The 225mA (MAX17220), 500mA (MAX17221/MAX17222/MAX17223), and 1A (MAX17224/MAX17225) peak inductorcurrent limits allow flexibility when choosing inductors. TheMAX17220/MAX17222/MAX17224 versions have　poststartupenable transient protection (ETP), allowing theoutput to remain regulated for input voltages down to400mV, depending on load current. The MAX17220–MAX17225 offer ultra-low quiescent current, small totalsolution size, and high efficiency throughout the entire load　range. The MAX17220–MAX17225 are ideal for batteryapplications where long battery life is a must.

MAX17222主要优势和特性:

●● 300nA Quiescent Supply Current Into OUT
●● True Shutdown Mode
• 0.5nA Shutdown Current
• Output Disconnects from Input
• No Reverse Current with VOUT 0V to 5V
●● 95% Peak Efficiency
●● 400mV to 5.5V Input Range
●● 0.88V Minimum Startup Voltage
●● 1.8V to 5V Output Voltage Range
• 100mV/Step
• Single 1% Resistor Selectable Output
●● 225mA, 500mA, and 1A Peak Inductor Current Limit
• MAX17220: 225mA ILIM
• MAX17221/MAX17222/MAX17223: 500mA ILIM
• MAX17224/MAX17225: 1A ILIM
●● MAX17220/MAX17222/MAX17224 Enable TransientProtection (ETP)
●● 2mm x 2mm 6-Pin μDFN
●● 0.88mm x 1.4mm 6-Bump WLP (2 x 3,0.4mm Pitch)

MAX17222应用:

●● Optical Heart-Rate Monitoring (OHRM) LED Drivers
●● Supercapacitor Backup for RTC/Alarm Buzzers
●● Primary-Cell Portable Systems
●● Tiny, Low-Power IoT Sensors
●● Secondary-Cell Portable Systems
●● Wearable Devices
●● Battery-Powered Medical Equipment
●● Low-Power Wireless Communication Products

图1.MAX17222功能框图

图2.MAX1722x/MAX30205温度传感器可穿戴解决方案

图3.MAX1722x/MAX30110/MAX30101/MAX30102光心率监视器(OHRM)传感器可穿戴解决方案(原电池)

图4.MAX1722x/MAX30110/MAX30101/MAX30102光心率监视器(OHRM)传感器可穿戴解决方案(二次电池)

图5.MAX1722x/MAX14575/DS1341 RTC备份解决方案

图6.MAX1722x/MAX14575告警哔声解决方案

图7.MAX1722x真关断零反向电流示图

图8.最小解决方案:0603电感-MAX17221/2/3 500mA ILIM(第一部分)

图9.最小解决方案:0603电感-MAX17221/2/3 500mA ILIM(第二部分)

图10.最高效率解决方案:4mmx4mm电感-MAX17221/2/3 500mA ILIM(第一部分)

图11.最高效率解决方案:4mmx4mm电感-MAX17221/2/3 500mA ILIM(第二部分)

评估板MAX17222EVK

The MAX17222 evaluation kit (EV kit) evaluates theMAX17220–MAX17225 IC family of ultra-low quiescentcurrent step-up DC-DC converters. The MAX17222 EVkit features two independent circuits to evaluate twodifferent IC packages of the MAX17220–MAX17225family. Both circuits on the EV kit operate over an inputrange of 400mV to 5.5V, depending on load, with 0.88Vtypical startup with 3k load. Each circuit provides resistorconfigurableoutput voltages from 1.8V to 5V in 100mV/step. Additionally, each circuit output on the EV kit deliversup to 100mA, 225mA, or 425mA of current, depending onthe input voltage to the output voltage ratio.The EV kit comes with the MAX17222ELT+ installed,while the MAX17225ENT+ is a future product.

评估板MAX17222EVK主要特性:

●● Two Independent Circuits on One Board
• Evaluates the MAX17220–MAX17225 IC Family ina 6-pin μDFN
• Evaluates the MAX17220–MAX17225 IC Familyin a 6-pin Wafer-Level Package (WLP) (FutureProducts)
●● 400mV to 5.5V Input Range
●● 1.8V to 5V Configurable Output Voltage in100mV/step
●● Up to 100mA/225mA/425mA Output Current
●● Proven 2-Layer 1oz Copper PCB Layout
●● Demonstrates Compact Solution Size
●● Fully Assemble and Tested

图12.评估板MAX17222EVK外形图

图13.评估板MAX17222EVK电路图

图14.MAX17222最少元件电路图
评估板MAX17222EVK材料清单:



图15.评估板MAX17222EVK PCB设计图(1)

图16.评估板MAX17222EVK PCB设计图(2)