Breaking News
Comments
Newest First | Oldest First | Threaded View
Chuck Sampson
User Rank
Author
Why no PDF?
Chuck Sampson   2/28/2015 11:59:28 AM
NO RATINGS
This is a very interesting and informative article. Why isn't there a PDF option so I can keep it for reference?

ABMorley
User Rank
Author
Re: IR losses in connectors and variable cable lengths still an issue
ABMorley   10/11/2013 4:18:46 AM
NO RATINGS
Whilst everything Teno says is true, quite a common scenario is a USB charger with captive cable - in which case the designer does control the cable resistance.  And if you don't have a captive cable then remote sensing isn't an option anyway.

Entirely true about not being able to rely on much more than 3.3v + LDO drop-out voltage.

Teno
User Rank
Author
IR losses in connectors and variable cable lengths still an issue
Teno   10/10/2013 9:47:18 PM
This isn't a derogatory comment about this tip but one shouldn't think they are getting accurate voltages to the load when remote sensing is not used, even with this tip.

This method only correctly compensates for static cable losses when the cable and contact resistance are known and constant. Unfortunately, especially in USB applications, the cable resistance is typically not constant because different length cables with varying quality can be interchanged. Furthermore, USB applications are often used in mobile applications where the cable is flexed and the contacts have varying strain and therefore varying resistance. 

This point doesn't critisize the tip or make it any less valid. It should serve as a warning to USB device designers to avoid pushing the designs to the limit because USB has very poor power regulation because it doesn't use remote sensing. I would design devices powered by USB to run from a 3.3V or less power supply regulated off the 5V USB voltage or if 5V is required use a buck/boost regulator to keep the voltage at 5V. Don't depend on having 5V at the end of a USB cable.



Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Radio
NEXT UPCOMING BROADCAST

What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.
Like Us on Facebook
Special Video Section
The quality and reliability of Mill-Max's two-piece ...
01:34
The quality and reliability of Mill-Max's two-piece ...
LED lighting is an important feature in today’s and future ...
05:27
The LT8602 has two high voltage buck regulators with an ...
05:18
Silego Technology’s highly versatile Mixed-signal GreenPAK ...
The quality and reliability of Mill-Max's two-piece ...
01:34
Why the multicopter? It has every thing in it. 58 of ...
Security is important in all parts of the IoT chain, ...
Infineon explains their philosophy and why the multicopter ...
The LTC4282 Hot SwapTM controller allows a board to be ...
This video highlights the Zynq® UltraScale+™ MPSoC, and sho...
Homeowners may soon be able to store the energy generated ...
The LTC®6363 is a low power, low noise, fully differential ...
See the Virtex® UltraScale+™ FPGA with 32.75G backplane ...
Vincent Ching, applications engineer at Avago Technologies, ...
The LT®6375 is a unity-gain difference amplifier which ...
The LTC®4015 is a complete synchronous buck controller/ ...
10:35
The LTC®2983 measures a wide variety of temperature sensors ...
The LTC®3886 is a dual PolyPhase DC/DC synchronous ...
The LTC®2348-18 is an 18-bit, low noise 8-channel ...