Power Challenges for IoT devices Wireless signaling test/ DC Power consumption Solution Architect/ Keysight General Electronic Measurement Soluiton R&D Brian Chi 祁子年
Agenda IOT Signaling Test Solution -- X8711A Event Based Current Consumption -- X8712A Battery Self Discharge Solution -- BT2152A 2
The Internet of Things T H I R D P H A S E O F T H E I N T E R N E T R E V O L U T I O N Fixed Internet +1 Billion Mobile Internet +2 Billion Internet of Things +50 Billion 1990 2000 2010-2020 3
Challenges of IoT Device Manufacturers Integrating IoT into my product opens up a multitude of capabilities. However, I do need to test them to ensure it works and that includes areas that are not my core competencies. Connected medical devices Consumer devices Industrial / smart city Challenges Lack of RF knowledge Maintain low cost Ensure quality Fast time-to-market 4
Typical Test Solutions (Current State) G O L D E N R A D I O O R S I M P L E P H O N E PA I R I N G Or Simple pairing method (e.g. smartphone) Golden radio (chipset / reference radio) Simple and Low Cost! 5
Interface Bd Commonly Used Test Solutions G O L D E N R A D I O O R PA R A M E T R I C T E S T S O L U T I O N S 1 Current state Use basic golden radio + software recommended by RF module vendor Gap Accuracy & test coverage issues (subjective testing) Underestimate the complexity of RF tests Why the readings keep changing? Why I couldn t get the results I am expecting? Metal shielded enclosure DUT Ref unit PC SW How to reduce cost of test? How to streamline test process? Why it passed my production test but failed at customer s side? 2 Parametric test solution Gap Too expensive, only a subset of functions is used, complex to setup How to balance cost of test & test coverage? Why there is no spec? How to do MSA? 6
IoT Device Functional Test Solution I D E A L F O R E N D - OF- L I N E M A N U F A C T U R I N G T E S T Chipset/ Module Manufacturing Parametric Test Parametric Test IoT Devices Functional Test Lvl Integration Chipset/ Module Material Assembly Testing Assembly Testing Product 1 <SoC> Comprehensive Testing Parametric Test Final Assembly Functional Test 2 Chip>Product Critical parameters testing Parametric Test Final Assembly Functional Test 3 Module>Product Just enough testing Parametric Test Final Assembly Functional Test 4 Board>Product Only if needed Functional Test Reduced test complexity, time and cost Test Coverage 7
The IoT Device Functional Test Solution C O M P L E T E T X A N D R X T E S T S I N L E S S T H A N 3 0 S Cost-effective OTA signaling test Simplified quantitative measurements Complete solution with hardware and software Test device in actual operating mode and in its final form Reduce production test time Eliminate test firmware flashing Lower capital investment Objectively test transmitter with Tx power measurement Receiver quality testing with PER and Sensitivity test Shorten test development time Simplify after sales support and calibration Expandable to cover more radios, and static voltage and current measurements A Solution IoT device functional test solution 8
How Keysight can help? I O T D E V I C E F U N C T I O N A L T E S T Core Values 1. Streamlining test processes Reduce test development time Reduce production test time Eliminate test firmware flashing 2. Quantitative Measurements Objectively test transmitter with Tx power measurement Receiver quality testing with PER and Sensitivity testing 3. Cost effective Lower capital investment Expandable to cover more radios, and static voltage and current measurements. How Keysight deliver? Signaling test methodology (no chipset control) Over-the-air (OTA) testing Test only the core parameters Calibrated front-end for traceable output and measurements. Proprietary measurement synchronization techniques Compact form factor Built on popular 34972A platform 9
Why do we need OTA signaling test? Small DUT, no connector or interface for wire connections Internet of Things Wearables, smart home devices Automotive connectivity Chipset specific control / driver is not required don t have expertise for DUT chipset control Measure with final commercial firmware Measure actual performance of DUT Test mode can t be available in the firmware of shipped product Final production test / go-no-go test 10
BLE / WLAN Signaling Test solution -- X8711A 11
BLE Signaling Measurement Suite S A M P L E S C R E E N S H O T Setting configurations Initial configurations Device discovery & connection Active Scan PER test Connect Request PER test TX power measurement Test results Data logging Test log 12
Agenda IOT Signaling Test Solution -- X8711A Event Based Current Consumption -- X8712A Battery Self Discharge Solution -- BT2152A 13
How To Characterize Battery Life Industrial sensors/ gateways Consumer devices Medical devices Challenges: 1. How to define the battery life? 2. What are the critical events that contribute to the power consumption and how frequently do those events happen? 3. What design changes or tradeoffs should I make to optimize battery life? 14
Common way to measure battery life (current state) P O W E R S U P P LY, D M M O R O S C I L L O S C O P E Digital Multimeter Power supply Scope & Probe Inaccurate & poor visibility Limited dynamic range and resolution Easily available, easy to use, flexible and low cost 15
IoT Battery Drain Measurements Are Challenging 1. Extremely low levels during sleep mode 2. Large amplitude shifts in active mode 3. Narrow pulses require high bandwidth 4. Connections to DUT can impact results 5. Complexity in power consumption analysis (events vs power consumption) sagilent 14585A Fast, frequent transitions between multiple levels Current draw by a wireless Blood Pressure Monitor N6705C/ N6781A Current draw by a wearable fitness band CX3300A/ CX1101A 16
Other Power Consumption Test Solutions DC power analyzer and SMU module CX3300 device current waveform analyzer Scope and N2820A probe B2900 SMU 34465/70A Truevolt DMM 17
Seamless Range Changes Amperes Seamless Current Measurements Range Measurement Accuracy = Seamless range change 3 A ±(0.03% + 250 µa) TRANSMIT MODE DUT 100 ma ±(0.025% + 10 µa) STANDBY MODE 1 ma ±(0.025% + 100 na) SLEEP MODE 10 µa ±(0.025% + 8 na) FIXED RANGE See the complete current waveform you ve never seen before from na to A in one pass and one picture What does this current profile means? To understand you need to manually correlate measurements and events from multiple instruments. 18
N6781A SMU operation behavior To simplify using the new N6781A module, select one of the modes below Keeps operation in quadrant and behavior that is best fit for the application V V Battery with programmable R Used as Battery V I Battery Charger V I A AMM meter Other events detection Standard DC Supply I Electronic Load/ Battery Discharger (CV, CC) I V Voltage meter 19
An IoT device battery life optimization solution Sourcing & current measurements RF Cable DC Cable Digital Trigger Shielding Box Companion device IoT Device Functional Tester 2 Channels of Source Measurement Unit (SMU) OR DUT TX RX Add Ch3 and Ch4 for additional event monitoring (V or I channels) RF events monitoring RF Event Detector Synchronize and correlate current consumption with RF events. Identify critical events that contribute to the most power consumption. 20
IoT Device Battery Life Optimization Solution 21
A new solution to maximize IoT device battery life K E Y S I G H T I O T D E V I C E B AT T E R Y L I F E O P T I M I Z AT I O N S O L U T I O N Synchronous RF and/or DC event and current consumption monitoring Easily correlate current consumption to critical RF events Pinpoint critical events consuming the most current In-depth current consumption analysis to estimate battery life Calculate RF or DC event s occupancy time and current consumption contribution in percentage to get the estimated battery life in hours according to the measured event Statistical current consumption CCDF analysis by user defined time span Easy data logging Simplify report creation Log event occupied time, current consumed and estimated battery life Online instrument control or off-line data record for real time comparison and future post analysis DC event RF event Current drawn 22
Event Correlation A/h % Time domain current waveform Up Limit Low Limit Current consumption with TX ON Up Limit Low Limit Current consumption with LED ON Total Current consumption 23
Current consumption by correlated events 10 9 8 7 6 5 4 3 2 1 A/h % dbm dbm Tips: 1. Scan once, use XY marker to define the level we interest as set as upper/ lower threshold. 2. Then perform the Acquire with suitable time span and verify conditions. 3. Live Demo with Sensor tag Color is consisted as the N6705C front panel. And unit consisted from the original events, the label can be changed. 24
Estimate long term current consumption How to estimate long term current consumption result by short period? time Analysis Repetitive events into segments, should have similar results if the events are homogeneous. Tips: 1. The homogeneous result should be very close. 2. Use 3X record length (time span) to capture 2 events we interested. 3. Using Trigger function to capture if the events hit the level criteria. 25
Signaling performance verification with data sheet. The Orion can easily separate the RF events by RF detector. And other events can be counted as MCU processing by zone definitions. Then others could be standby or sleep 26
4 channel current Consumption Analysis Concept DUT Current RF Burst (dbm) Request Prepare DUT Current Profile Response Display TX (Pair Device) TX (DUT) Time CH1 CH2 IoT Device/ DUT 5% N6705C + N6781A*4 LED Battery pack 3% up Pump 20% 20% Display RF Radio Peripheral Drivers 40% 10% IoT Device Functional Tester Companion device Voltage LED Turns ON OR CH3 RF Event Detector 27
Example -- LoRa module measurements E X A M P L E A P P L I C AT I O N The battery life of LoRa module varies depending on the signaling condition it is operating in. We can vary the spreading factor and measure the changes in maximum current and battery life. We can also use this info to help us choose the appropriate battery capacity to meet the battery life specification. 28
Example BLE Sensor B L E / W L A N S E N S O R T A G E V E N T M O N I T O R I N G Yellow:DUT Current consumption Green:RF Transmissions between DUT companion device BLUE: LED supply voltage Waveform Zoom & Analysis Events Tags Occupied Time by event Event based analysis (Max current, cycle time, charge energy, battery life, occupied time, current consumption, and more) Current CCDF 29
Agenda IOT Signaling Test Solution -- X8711A Event Based Current Consumption -- X8712A Battery Self Discharge Solution -- BT2152A 30
電池自放電對工作壽命的影響 18650 電池工作耗電的粗略計算 Iwake-up Isleep Wake-up=2.67ms 200mA Connection interval=10s sleep Target average 0.05mA 目標平均電流 - 工作 10 年 =5000mAh / 87600h (10 year) = 0.057mA 但是, 即便高品質的電池, 自放電率在 10uA, 將使產品壽命只有 設計壽命的 80% 如果您選用的電池自放電率是 50uA, 5 年就可能需要更換電池 篩選出市場上自放電率低的電池非常重要 是德科技自放電測試應用手冊 https://literature.cdn.keysight.com/litweb/pdf/5992-2354enn.pdf?id=2871162 31
電池的自放電率自放電率 : 又稱電荷保持能力, 是指電池在開路狀態下, 電池所儲存的電量在一定條件下的保持能力 主要受電池製造工藝 材料 儲存條件等因素影響, 是衡量電池性能的重要參數 下表列出了正常儲存條件下自放電的近似值 : 類型 自放電率 / 月 Cell Assembly/Forming 鋰離子紐扣電池 1% 堿錳圓形電池 2 % 鋅碳圓形電池 4% Charging Charge redistribution/rest 5-15 days 鉛蓄電池 20-30% 鎳鎘 / 鎳氫電池 35% Measure OCV Suspect Pass Ship WIP storage 4-12 weeks Measure OCV Pass Ship Fail Recycle/discard 32
是德科技創新型自放電測試方案 一種全新的測試方案可以大大縮減測試時間, 保證新品上市 該方案的核心是 : 直接測量自放電電流, 與測試開路電壓 OCV 不同, 測試系統可以直接測量電芯內部的自放電電流 DMM Traditional 相比開路電壓 OCV 變化太慢, 而直接測量電流要快的多 Self-Discharge Analyzer New 33
自放電測試原理 ISDM Self Discharge Measurement Isd 電芯開路時, 等效的內部電阻 Rp 構成的放電回路 Isd. 自放電測試系統保持電芯電壓 /Soc, 因此, 電芯沒有被充電 (Soc 減少 ), 也沒有被放電 (Soc 增加 ), 此時測試系統提供的電流 ISDM 就等於 Isd 假設用一個水杯代替電芯, 水杯的高度對應電芯電壓 Ocv (nv), 該水位對應的容積代表電芯電量 Soc(n%) 雖然水杯依然有一個很小的洞, 但由於外部補充的速度 (ISDM) 與漏水速度 ( 自放電電流 Isd) 一樣, 且電芯電壓 OCV 和 SOC 均保持不變, 所以測量 ISDM 就等於 Isd. 是德科技鋰電池自放電測試應用手冊 https://literature.cdn.keysight.com/litweb/pdf/5992-2517en.pdf?id=2911018 34
BT2191A SDM 測試系統介面及即時結果 -- Good Cell 良品 18650 電芯, 測試時間約 1. 5 小時, 自放電電流 9. 1 5 U A 35
BT2191A SDM 測試系統介面及即時結果 -- Bad Cell 高自放電率 18650 電芯, 測試時間 1. 5 小時, 自放電電流 1 4 9 U A, 2 小時約 1 5 9 U A 36
Keysight BT2152A Self-Discharge Analyzer- 32 channels Digital I/O for control lines (emergency off, fixture open/close, etc) USB for service LAN for control 425mm width of instrument body 88.9 mm 1 2 3 4 5 6 7 8 Rear air exit Connection to cells 8 connectors for 32 ch 4 cells per RJ45 connector Temperature sensor input Calibration port AC line in 100Vac-240Vac 50/60 Hz < 200W 37
256 通道電芯自放電產線應用案例 BT2152A Self-Discharge Analyzer 不良或待確認 良品 0 5 10 15 20 25 30 分鐘 批量生產的目的是對電芯的一致性進行篩選 從上圖可以得到的結論和建議 : 1. 該 256 個電芯同時開始測試, 絕大部分曲線重合 ; 2. 在很短 ( 約 5 分鐘 ) 的時間後, 電流開始分開, 大約 10-15 分鐘後明顯區分 ; 3. 針對分離後的電芯可以再進行完整的電芯自放電驗證 https://literature.cdn.keysight.com/litweb/pdf/5992-2450en.pdf?id=2891867 38
Cell and Battery Applications Mat l R&D Cell R&D Cell Mfg Small cells Cell End User -- Manufacturer of Small Devices Large cells Module (+ BMS) Battery Battery End User -- Manufacturer of Large Devices Material Research Cell R&D In-situ thin film analysis Cell design characterization Cell Mfg Process Quality (e.g., weld quality) Forming Self Discharge Modules/Batteries Cell evaluation to determine suitability in battery Cell simulation to test BMS BMS functional test Battery Powered Devices Battery simulation for functional test of device Battery Drain Analysis BT2151A BT2152A N6705C 39
Summary Signaling test solution for WLAN/ BLE Event based power consumption Self discharge measurement for battery evaluation. 40
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