Embedded Systems Conference
Breaking News
Comments
Newest First | Oldest First | Threaded View
Page 1 / 2   >   >>
Rocket_G
User Rank
Author
re: X-rays and Photovoltaics
Rocket_G   12/30/2010 1:19:49 AM
NO RATINGS
Thanks Parity, ESD-protective encapsulation sounds really interesting. At what airspeed does triboelectric charge become significant? We would need something in liquid thermoset form that doesn't darken under UV (sunlight).

brightfiber
User Rank
Author
re: X-rays and Photovoltaics
brightfiber   12/29/2010 6:00:32 AM
NO RATINGS
Rich, to break this down to a finer level, 1) Do any of your tags work reliably time after time or do they all fail intermittently? Design issue? 2) If voltage spikes are suspect, inserting a zener diode in the circuit might be an interesting design revision. 3) Going back to electrostatic discharge, if your tags are encapsulated in any non-conductive plastic package like polycarbonate, they will develop charges on the order of 3-5 KV just from air friction leading to ESD events. Using PEEK or similar conductive plastic will dissipate charge collection and ESD events.

sharps_eng
User Rank
Author
re: X-rays and Photovoltaics
sharps_eng   12/24/2010 10:40:09 PM
NO RATINGS
Since the tags fail during deployment could we be seeing SEU problems due to solar radiation? What altitudes are you logging among similar tags that survive? It also is possible that your stripped-down ultra-light design allows more exposure to radiation than ordinary enclosures.

Jagdish Bisawa
User Rank
Author
re: X-rays and Photovoltaics
Jagdish Bisawa   12/24/2010 7:21:15 AM
NO RATINGS
Glad to know that Rich ! Would you also post the results of your findings once you are through with them ? It would be an interesting lesson for the design engineers around.

Rocket_G
User Rank
Author
re: X-rays and Photovoltaics
Rocket_G   12/23/2010 3:10:07 AM
NO RATINGS
Actually we're hoping for some help from the TSA folks at the airport across the street :-)

Rocket_G
User Rank
Author
re: X-rays and Photovoltaics
Rocket_G   12/22/2010 3:51:29 PM
NO RATINGS
Thanks, zman - the output of the PV cell goes through a 3V LDO regulator before going anywhere else, to prevent overcharging the battery.

zman_tekinsil
User Rank
Author
re: X-rays and Photovoltaics
zman_tekinsil   12/22/2010 3:23:21 PM
NO RATINGS
The cell is loaded during transit. With X-Ray this may "perhaps" lead to permanent traps that "may affect" the light to electricity conversion efficiency. Also the 0 instead of 1 logic you mensionned may be stuck bits that can be also due to ESD damage internally in addition to the I/O. Side question since the Voc is 4V, I assume the lithium battery is at least 2 diodes voltage-drop below the cell Voc?

zeeglen
User Rank
Author
re: X-rays and Photovoltaics
zeeglen   12/22/2010 2:15:53 AM
NO RATINGS
"these failures are observed after they've been in use" Possibly moisture getting into them? How are they sealed? Amendment to previous test - immerse some devices in salt water while at the beach. Your downhill ski idea is also a very valid test for simulating the shock and temperature extremes of a bird in flight.

Rocket_G
User Rank
Author
re: X-rays and Photovoltaics
Rocket_G   12/21/2010 11:46:01 PM
NO RATINGS
The PV cell Voc is 4V, Isc is 50 microamps. The cell is loaded during transit. A diode on the output of the LDO prevents reverse current flow through it. Checking output shorts and opens postmortem is a good idea. Thanks!

zman_tekinsil
User Rank
Author
re: X-rays and Photovoltaics
zman_tekinsil   12/21/2010 2:40:46 AM
NO RATINGS
You may have several problems that occured durang the cicuit build-up! ESD may be one of the culprits. You maybe able to see the I/Os quality with a voltmeter. ESD may create a short (metal melt from excessive zap). If that the case your data output maybe shorted after the ESD event. As for the X-ray, silicon based PV may survive X-ray pulses if not loaded. I am not sure what you have!. I assume the PV is not loaded (to generate electricity) during transit from FedEx for instance. Finally what is the output voltage spec of the PV (Open circuit voltage Voc, and other!). That diode may act as back to back scheme limiting current flow to the LDO!

Page 1 / 2   >   >>


Radio
NEXT UPCOMING BROADCAST
In conjunction with unveiling of EE Times’ Silicon 60 list, journalist & Silicon 60 researcher Peter Clarke hosts a conversation on startups in the electronics industry. One of Silicon Valley's great contributions to the world has been the demonstration of how the application of entrepreneurship and venture capital to electronics and semiconductor hardware can create wealth with developments in semiconductors, displays, design automation, MEMS and across the breadth of hardware developments. But in recent years concerns have been raised that traditional venture capital has turned its back on hardware-related startups in favor of software and Internet applications and services. Panelists from incubators join Peter Clarke in debate.
Flash Poll
Top Comments of the Week
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Special Video Section
The LT®3042 is a high performance low dropout linear ...
Chwan-Jye Foo (C.J Foo), product marketing manager for ...
The LT®3752/LT3752-1 are current mode PWM controllers ...
LED lighting is an important feature in today’s and future ...
Active balancing of series connected battery stacks exists ...
After a four-year absence, Infineon returns to Mobile World ...
A laptop’s 65-watt adapter can be made 6 times smaller and ...
An industry network should have device and data security at ...
The LTC2975 is a four-channel PMBus Power System Manager ...
In this video, a new high speed CMOS output comparator ...
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
10:29
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...
TE Connectivity's clear-plastic, full-size model car shows ...