Embed Size (px)
Citation preview
nA range Low power consumption testing challenges奈米電流波形及低功耗測試與挑戰
Keysight Technologies
Oct. 2016
Keysight CX3300 Series
Device Current Waveform Analyzer
Brian Chi 祁子年Keysight Technologies
Page
IoT market and trend
2
Low power design
Low power device
Technology trend 1:
How to reduce current
consumption
Technology trend 2:
How to fully study device
operation
IoT and M2M standards
Page
Case Study 1: Wireless Medical Device
Description
No cables to plug in. Take BP and store readings.
Support multiple users. Each user can track their data.
Timely reminders – remind users to take BP.
Pair with smart phone via bluetooth.
Free portal for doctor or coach for health record.
Wearable Device Power
Consumption
Characterization &
Optimization
Photo Courtesy: blipcare
Page
Battery powered devices adopt Power Management schemes to conserve energy
Applicable to a very wide variety of devices Long periods of sleep between bursts of activity
Resulting battery current drain is pulsed; high peak, low duty cycle, and
low average values – challenging to measure accurately!
Turn on:
Sleep 53 µA
Peak 95 mA
Avg 5 mA
sKeysight 14585A
4
BPM – Operation Start
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Pump activated – measure cycle started
peak 615 mA
16 s
To inflate the belt, the pump motor drain a peak current and start
rotating. At defined pressure the motor stops (~16 sec)
1.45 mAh
sKeysight 14585A
5
Wearable Device Power
Consumption
Characterization &
Optimization
Page
BPM deflating and measuring pressure, beeping
18.4 s
avg 77.5 mA
sKeysight 14585A
• Measurements are performed during the deflating.
• Heart pulses are detected, device beeps with heart pulses
6
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Wireless LAN transmission
Total TX 5s
avg 90 mA
peak 310 mA
pulses spaced 26 ms
• Measurement process is completed
by updating the online database.
• BPM connects over Wi-Fi and update
the database in the cloud with latest
measurements
sKeysight 14585A
7
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Ensure that BPM goes back to deep sleep
Timeout in 2 min
avg 9.64 mA
sleep 54 µA
• After the measurement finish, the device updates the information over internet.
• Result is displayed for 2 minutes. If nothing happen the device goes back to deep
sleep.
• Display is also turned off
deep sleepwait for timeout
sKeysight 14585A
8
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Test Challenge: Measuring Current Accurately
shunt
DUT
VDUT = Vbat – Vburden
Vbat
Vburden
VDUT
Ibat
Scope Ammeter
V meas
shunt
DUT
VDUT = Vbat – Vburden
Vbat
Vburden
VDUTIbat
Scopes
Good bandwidth for dynamic current
Advanced triggering
Time correlation with digital bus
Excellent update rate
Limited vertical accuracy
Selecting proper shunt is nearly impossible
to get good low current measurement and
tolerable burden voltage at high current
No long term measurements
DMMs/Ammeters:
Sufficient accuracy
Insufficient bandwidth for dynamic current
Imposes an unacceptable burden voltage
9
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Traditional Measurement Solutions for Battery Drain Test
DC source
or battery
Shunt
++
- -DUT current
Diff Amp MUX Gain Amp ADC
Data acquisition equipmentData
out+
-
PC to log
long-term
data
Most common: Shunt + DAQ equipment
Typical performance:
• ~14 to16 bits
• ~ 200K to 1M samples/sec
• ~ 0.2 to 1.0% gain error (both shunt and DAQ)
• ~ 0.02 to 0.1% of full scale offset error (mainly DAQ)
Commonly encountered issues:
• Peak voltage drop on shunt may be excessive
• Transient voltage drop at DUT when using a general purpose DC source can be excessive
• Large effort to configure and program
• Fixed offset error is 40 to 200 times greater than target of 0.0005%
The fixed offset error of most traditional test equipment limits their performance measuring battery current drain signals
10
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Innovation for Accurate Current Drain Measurements
N6705 DC Power Analyzer Mainframe
N6785A 2-Quadrant SMU
for Dynamic Current Drain Analysis
Integrates multiple instrument
functions into a single box:
• 1 to 4 advanced power supplies;
> 30 different models available
• Digital voltmeter and ammeter
• Arbitrary waveform generator
• Oscilloscope
• Long term data logger
• Output Sequencing
• Full functionality from front panel
Gain insights in minutes, not days!
Specialized DC power supply module for
current drain testing:
• Up to 200 kSa/s digitizing rate
• Fast transient response for pulsed loads
• Settable battery emulation characteristics
• Auxiliary DVM input port for battery run-down
testing
Innovation:
Seamless Measurement Ranging
for accurate measurement of battery
drain spanning wide dynamic ranges
11
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Keysight N6785A Seamless Current Ranging Innovation Performance
12
Range 8 A 100 mA 1 mAMeasurement
Accuracy±(0.04% + 1.5mA) ±(0.025% + 10µA) ±(0.025% + 100 nA)
Current
Seamless measurement between these 3 ranges
• Seamless ranging continually changes ranges without glitch nor lose readings
• 200 kHz, 18-bit digitizer, with seamless ranging, acts likes single range of ~30-bits
• 8 A range with an effective offset error as low as 110 nA (0.01 PPM)
• Measure ranges are independent from source ranges and don’t impact the output
voltage stability.
• Accurate measurements from Amps to sub-µA during a single scope sweep or data-log
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Seamless Dynamic Current MeasurementAccuracy and Speed with no wasted time during current ranging
13
RangeMeasurement
Accuracy
8 A ±(0.04% + 1.5mA) Pump / Wlan TX
100 mA ±(0.025% + 10 A) Measure
1 mA ±(0.025% + 110 nA) Sleep
Se
am
less R
an
ge C
ha
nge
s
Am
pere
s
= Seamless range change
200 kSa/s, 18-bits digitizers acts likes single range of ~30-bits
Wearable Device Power
Consumption
Characterization &
Optimization
Page
N678x Series SMU ModulesMeasurement Challenge: Long Term Datalog - Gapless
14
Keysight 14585A
Low Power Mode on TI MSP-430 Ultra Low Power microcontroller
100 m
A
nA nA nA nAnAnA nA
2s / div
Wearable Device Power
Consumption
Characterization &
Optimization
Page
N6785A SMU seamless measurement ranging performanceResults for standby current drain on Blood Pressure Meter
With fixed ranging we are limited to
the DC offset accuracy and noise
floor of the 8 A range
With seamless ranging we can measure
BPM at ~615 mA while having the DC
offset accuracy and noise floor of the 1 mA
range (110nA)
Standby: Sleep current base, 200 µA/div Standby: Sleep current base, 200 µA/div
The N6785A SMU is operating as a battery emulator powering the BPM while measuring its current drain
Fixed range measurement Seamless ranging measurement
sKeysight 14585AsKeysight 14585A
15
Wearable Device Power
Consumption
Characterization &
Optimization
Page
Thermometer
Glucose Meter
Pulse Oximeter
Heart Monitor
Blood Pressure
Infusion
Pumps
Body Gateway
Pacemaker,ICD
Access
Point
Bluetooth, WLAN,
ZigBee, ISM, LTE
Common Building Blocks
• Sensors, ADC’s,DAC’s.
• Microcontroller, Memory
• RF Power Amp/Antenna
• User Interface / Display, Speaker
• Battery and Power
Management
Smartphone
Tablet
Weight/Scale
Wireless Medical Devices
Wearable Device Power
Consumption
Characterization &
Optimization16
Page
Case Study 2: Wearable Fitband
Description
A polycarbonate body with a brushed aluminum
finish and three small LED lights.
Pair with smart phone via bluetooth 4.0.
It performs three main functions:
• step counter
• tracks sleep patterns
• Alert for alarm and incoming calls and messages
Wearable Device Power
Consumption
Characterization &
Optimization
Photo Courtesy: community.arm.com
Page
Case Study 2: Wearable FitbandComponent Arrangement
18
Wearable Device Power
Consumption
Characterization &
Optimization
Grid = 1 cm
Bluetooth Smart SoC / 32-Bit
ARM Cortex-M0 Processor
50 mA Step-Down
DC-DC Converter
3-Axis MEMS
Accelerometer (2-Die Pkg.)
Serial Flash
Memory - 256 KB
Single-Input, Single Cell
Li-ion/Li-Pol Battery Charger
4-Ch. LED Driver
Aluminum casing
Vibrator
Polycarbonate body
Circuit Board
Battery
Page
Case Study 2: Wearable FitbandConnection Diagram
19
Wearable Device Power
Consumption
Characterization &
Optimization
Page
34470A Key Specifications
Wearable Device Power
Consumption
Characterization &
Optimization 20
Meeting all your test need in your ever
changing test requirement !
DCV / ACV 100mV to 1,000V
DCV Accuracy 16ppm
DCI 1uA to 10A
ACI 100uA to 10A
2/4 wire resistance 100Ω to 1,000MΩ
Continuity, diode Yes, 5V
Frequency, period 3Hz to 300kHz
TemperatureRTD/PT100, thermistor,
thermocouples
Capacitance 1.0nF to 100.0uf
Page
Standby mode
21
nA pAuA
Wearable Device Power
Consumption
Characterization &
Optimization
Page
BenchVue Software: DMM
Supported Functionality• Measurement configuration
• Visualization & annotation
• Data Logging
• Exporting
• Screen shots
• Data
• Save/recall instrument state
• BenchVue Mobile app
Supported DMMs:34405A, 34450A, 34401A, 34410A, 34411A, 34460A, 34461A, 34465A, 34470A
Wearable Device Power
Consumption
Characterization &
Optimization 22
Page
23
Low Current
Measurement
Complex AC
Signals
Faster Data
Analysis
Enhanced
Measurement
Accuracy
Simultaneous
Measurement
Resolutions up to 7½ digits
Reading rates up to 50,000 readings/s
Memory up to 2 million readings
Voltage ranges from 100 mV to 1,000 V
Current ranges from 1 µA to 10 A
USB and LAN interfaces, optional GPIB
Introducing 34465A/34470A Performance DMMsMeasure with Unquestioned TruevoltConfidence!
Page
Case Study 3: Ultra Low current waveform analysis
Backgroud information:
• Measurement noise: Noise limits current sensing
• Limited dynamic range: Even 12-bit oscilloscopes
insufficient
• Bandwidth: Insufficient bandwidth to detect transients
• Multiple instruments: multimeter + oscilloscope
required
Wearable Device Power
Consumption
Characterization &
Optimization
Intermittent operation of low-power devices
Page
Existing current waveform measurement tools and the issues
25
Measurement tool Advantage Disadvantage
Shunt resistor & oscilloscope
> 1 mA
• Wide bandwidth
• Simple
• Low cost
• Large voltage drop
• High noise floor
• Limited dynamic range
Current probe & oscilloscope
> 1 mA• Simple
• Very common
• Degauss and adjustment
• High noise floor
• Limited dynamic range
IV amplifier & oscilloscope
< 1 μA
• Low-level current
measurement capability
• Limited flexibility
• Additional set up
DMM (Digital Multimeter)
< 1 μA
• General instrument
• Low-level static current
measurement capability
• Limited bandwidth
• No dynamic current
measurement capability
• No or poor GUI
Page
How to reduce current consumption?
26
Further reduction of low power devices operating intermittently
i
t
Sleep/standby
Active
(Average current)
Zoom in
Reduce sleep/standby current
(< 1 μA level)
Zoom in
Reduce active current and duration
(>10 mA level)
When more current
consumption
reduction is required
i i
i i
Current profile
Page
Trend 2: How to fully study device operation?
27
Measuring transient current when a short pulse is applied
Existing analyzers can
measure current here, but …Difficult to measure
transient current in this
short pulse
Difficult to measure
transient current in this
short pulse
< 100 ns
< 100 ns
Current transients in a short pulse provide customers with deeper
insights on the device or material behavior.
Voltage pulse for ReRAM evaluation
Page
Low-current waveform measurement dilemma
28
As a result, it was quite difficult to analyze current
profile or current transients in detail !!
Current
Time
Current
Time
Expected waveforms Always look like this !
Noise & limited bandwidth prohibit quantitative evaluation
Slow
Noisy
Page
CX3300A Device Current Waveform Analyzer
29
Mainframe
Current Sensor(w/ a Sensor Head)
Current Sensor (no Sensor Head type)
Digital Channel
Passive Probe
Interface Adapter
14.1” Multi Touch
GUI
Analysis
Capabilities
Benchtop Size
Page
CX3300 Series capabilities
30
Both mainframes and accessories are all dedicated to wideband
and low-level dynamic current measurements
Characteristic Value
Current measurement range 150 pA to 10 A
Maximum measurement bandwidth 200 MHz
Maximum sampling rate 1 GSa/s
Measurement dynamic range 14-bit or 16-bit
Maximum memory size 256 Mpts/ch
Number of channels 2 or 4
Page
Front view
31
Familiar and intuitive user interface enables everyone to start current
waveform measurements immediately.
Page
Current Sensors
32
HF noise suppression with low-burden current sensing
CX1101A Current Sensor,
Single Channel
100 MHz max bandwidth
40 nA to 10 A
+/- 40 V Common mode
voltage
CX1102A Current Sensor,
Dual Channel
100 MHz max bandwidth
40 nA to 1 A
+/- 12 V Common mode
voltage
CX1103A Current Sensor,
Low Side
200 MHz max bandwidth
150 pA to 20 mA
+/- 0.5 V Common mode
voltage
Sensor Head required
Sensor Head required
Basic current sensor
More dynamic range More BW & lower noise
Page
DUT connection examples
33
Sensor +
Sensor Head
SMA type connection
Test lead connection
Attach a Sensor Head to Current Sensors
Attach a Current Sensor to Mainframes
Sensor +
Sensor Head
Most wideband and
lowest noise
measurements
Often used for device
characterization on
wafer (semiconductor,
non-volatile memory)
Easy connection up to
~ 10 MHz bandwidth
Often used for
customer’s DUT
evaluation board
(Bluetooth, IoT device,
low power MCU, etc.)Battery
PGDUT (Single device)
DUT
(IC chip)
Gnd
Page
Waveform example #1: “Anywhere” Zoom (CX1101A)
34
Emulated BLE waveform by AWG (33662A)
“Anywhere” Zoom
You can move and
resize this area
anywhere on the
graph!
1.1 mA/div
2 mA/div
500 us/div
~ 20 us/div
Sharp and low
noise waveform
Page
Waveform example #2: Long duration measurement (CX1101A)
35
Emulated BLE waveform by AWG (33662A)
256 Mpts/ch memory by
10 MSa/s = 25.6 sec
Still high fidelity
waveforms due to high
speed sampling
5 mA/div
10 mA/div
2 s/div
1 ms/div
Page
Waveform example #3: Dual Channel Current Sensor (CX1102A)
36
100 uA/div
5 mA/div
1 ms/div
1 ms/div
Emulated BLE waveform by AWG (33662A)
200 mA range
2 mA range
200 uA pp
Simultaneous
measurement by two
different ranges
Page
Appendix: How to cover such a wide dynamic range?
Keysight
Confidential 37
1 A
1 mA
1 μA
200 mA
200 μA
Almost 100 dB
equivqlent
dynamic range
The dual channel current
sensor extends the
equivalent dynamic range.
< 3 μA
2 mA
A
The dual channel current sensor covers more than required
Channe 1
Channe 2
Page
Additional analysis capabilities
38
Statistical Analysis: CCDF (Complementary Cumulative
Distribution Function
Spectrum Analysis
（FFT)
Emulated BLE waveform by AWG (33662A)
Page
Waveform Example: 200 pA pp Waveform (CX1103A)
39
Sinusoidal waveform by AWG (33662A)
200 pA pp
200 pA/div
1 ms/div500 Hz
Page
The dilemma can be solved by the CX3300 Series
40
The CX3300 series allows:
• Engineers to quantitatively evaluate the current and power consumption
waveforms for low power device development.
• Researchers and engineers to measure fast transient currents required
for further study on advanced devices/materials.
Current
Time
Waveform by current solution Waveform by CX3300
Current
Time
Page
Summary
– N6705B is good source/ measurement solution to have seamless nA to 10A
waveform acquisition capability.
– With data logging, it can easily do the standalone post analysis without PC.
– 34470A 7.5 digits true mode performance DMM provided off the shelf benchtop
test solution from uA to 10A analysis tool.
– CX3300A 200 MHz bandwidth and a 1 GHz max sampling rate, with 14/16-bit
wide dynamic measurement ranges display clearly even very low-level current
waveforms.
– Ultra-low noise and low burden voltage current sensors enable you to measure
current waveforms from 10 A down to 100 pA level.
– A single instrument that provides a wide variety of current/power waveform
measurement and analysis capabilities that were previously impossible.
41
Page
Thank you for listening !
42
N6705B
http://www.keysight.com/find/N6705B
34470A
http://www.keysight.com/find/34470A
CX3300A
http://www.keysight.com/find/CX3300A
