Microchip's TB008 Reprise
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Posted by Phil Allison on May 13, 2008, 2:25 am
Please log in for more thread options On March 13 this year - poster " Hammy" raised a few valid questions about Tech Bulletin " TB 008 " on the Microchip web site ( and quoted widely elsewhere) on the subject of "Transformerless Power Supplies". http://ww1.microchip.com/downloads/en/AppNotes/91008b.pdf This prompted Mr Rod Elliot of ESP to contact Microchip with a view to having them retract and withdraw TB008 from publication. As feared but expected, this was not successful. The ESP site now has an outline of what happened when he complained and includes the email reply received from Microchip's Tech Support Group. http://sound.westhost.com/articles/power-supplies2.htm#s7 A second, even stronger worded email from Mr Elliot went unanswered. Microchip's anonymous tech support guy was clearly WAAAY out of his depth on the topic of AC mains and appliance electrocution hazards - as was that fool Stan D'Souza who wrote the infamous tech bulletin. D'Souza is now a "Technical Fellow " at Microchip - so I guess the dude walks on water and his word is Gospel round the place. IME - people like him will * NEVER * admit to even the most grievous of errors nor allow any error of theirs to be publicly corrected. Shame there appears to be no way to make direct contact. ..... Phil | |||||||||||||||||||||||||||||||
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Posted by David L. Jones on May 13, 2008, 7:16 am
Please log in for more thread options Unbelievable! There is a way to make direct contact though, and right to the TOP. Steve Sanghi is Microchip's CEO, his direct email address is (spambot friendly): steve DOT sanghi AT microchip DOT com Well, maybe his personal secretary vets every email first, but it should at least get that far. Dave. | |||||||||||||||||||||||||||||||
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Posted by David L. Jones on May 13, 2008, 7:36 am
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>
>> **Hi to all:
>> >> On March 13 this year - poster " Hammy" raised a few valid questions >> about Tech Bulletin " TB 008 " on the Microchip web site ( and quoted >> widely elsewhere) on the subject of "Transformerless Power Supplies". >> >> http://ww1.microchip.com/downloads/en/AppNotes/91008b.pdf >> >> This prompted Mr Rod Elliot of ESP to contact Microchip with a view to >> having them retract and withdraw TB008 from publication. As feared but >> expected, this was not successful. >> >> The ESP site now has an outline of what happened when he complained and >> includes the email reply received from Microchip's Tech Support Group. >> >> http://sound.westhost.com/articles/power-supplies2.htm#s7 >> >> A second, even stronger worded email from Mr Elliot went unanswered. >> >> Microchip's anonymous tech support guy was clearly WAAAY out of his depth >> on the topic of AC mains and appliance electrocution hazards - as was >> that fool Stan D'Souza who wrote the infamous tech bulletin. >> >> D'Souza is now a "Technical Fellow " at Microchip - so I guess the >> dude walks on water and his word is Gospel round the place. >> >> IME - people like him will * NEVER * admit to even the most grievous >> of errors nor allow any error of theirs to be publicly corrected. >> >> Shame there appears to be no way to make direct contact. >
> Unbelievable! > > There is a way to make direct contact though, and right to the TOP. > Steve Sanghi is Microchip's CEO, his direct email address is (spambot > friendly): > steve DOT sanghi AT microchip DOT com and tell him how much you love his book: http://www.drivingexcellence.biz/ Dave. | |||||||||||||||||||||||||||||||
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Posted by David L. Jones on May 13, 2008, 7:36 am
Please log in for more thread options
>
>> **Hi to all:
>> >> On March 13 this year - poster " Hammy" raised a few valid questions >> about Tech Bulletin " TB 008 " on the Microchip web site ( and quoted >> widely elsewhere) on the subject of "Transformerless Power Supplies". >> >> http://ww1.microchip.com/downloads/en/AppNotes/91008b.pdf >> >> This prompted Mr Rod Elliot of ESP to contact Microchip with a view to >> having them retract and withdraw TB008 from publication. As feared but >> expected, this was not successful. >> >> The ESP site now has an outline of what happened when he complained and >> includes the email reply received from Microchip's Tech Support Group. >> >> http://sound.westhost.com/articles/power-supplies2.htm#s7 >> >> A second, even stronger worded email from Mr Elliot went unanswered. >> >> Microchip's anonymous tech support guy was clearly WAAAY out of his depth >> on the topic of AC mains and appliance electrocution hazards - as was >> that fool Stan D'Souza who wrote the infamous tech bulletin. >> >> D'Souza is now a "Technical Fellow " at Microchip - so I guess the >> dude walks on water and his word is Gospel round the place. >> >> IME - people like him will * NEVER * admit to even the most grievous >> of errors nor allow any error of theirs to be publicly corrected. >> >> Shame there appears to be no way to make direct contact. >
> Unbelievable! > > There is a way to make direct contact though, and right to the TOP. > Steve Sanghi is Microchip's CEO, his direct email address is (spambot > friendly): > steve DOT sanghi AT microchip DOT com and tell him how much you love his book: http://www.drivingexcellence.biz/ Dave. | |||||||||||||||||||||||||||||||
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Posted by Paul E. Schoen on May 13, 2008, 5:55 pm
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>
>> **Hi to all:
>> >> On March 13 this year - poster " Hammy" raised a few valid questions >> about Tech Bulletin " TB 008 " on the Microchip web site ( and quoted >> widely elsewhere) on the subject of "Transformerless Power Supplies". >> >> http://ww1.microchip.com/downloads/en/AppNotes/91008b.pdf >> >> This prompted Mr Rod Elliot of ESP to contact Microchip with a view to >> having them retract and withdraw TB008 from publication. As feared but >> expected, this was not successful. >> >> The ESP site now has an outline of what happened when he complained and >> includes the email reply received from Microchip's Tech Support Group. >> >> http://sound.westhost.com/articles/power-supplies2.htm#s7 >> >> A second, even stronger worded email from Mr Elliot went unanswered. >> >> Microchip's anonymous tech support guy was clearly WAAAY out of his >> depth on the topic of AC mains and appliance electrocution hazards - >> as was that fool Stan D'Souza who wrote the infamous tech bulletin. >> >> D'Souza is now a "Technical Fellow " at Microchip - so I guess the >> dude walks on water and his word is Gospel round the place. >> >> IME - people like him will * NEVER * admit to even the most >> grievous of errors nor allow any error of theirs to be publicly >> corrected. >> >> Shame there appears to be no way to make direct contact. >
> Unbelievable! > > There is a way to make direct contact though, and right to the TOP. > Steve Sanghi is Microchip's CEO, his direct email address is (spambot > friendly): > steve DOT sanghi AT microchip DOT com > > Well, maybe his personal secretary vets every email first, but it should > at least get that far. Here is my thread in the Microchip forum. I posted it in their "Tips 'n Tricks", but under the development tools rather than a more hardware-oriented area. Still, it is usually read by their technical people, and I think it should be addressed. http://forum.microchip.com/tm.aspx?m=322529 Maybe someone should contact a lawyer and tell them they tried a circuit recommended by Microchip, and got a bad shock, and now they have neurological problems. It would be hard to disprove, if you actually built the circuit and just claim to have touched it. You could also offer to submit a design to Microchip for one of their contests as "The Next Killer App"! I like Microchip, but that App Note needs some major revision or retraction. There is also a bad circuit in: http://ww1.microchip.com/downloads/en/DeviceDoc/41283A.pdf. It is Tip #8, and it shows the AC line directly connected to the +5VDC supply, and the dropping capacitor and resistor on neutral! This sort of supply is reasonably safe if dropping resistors and capacitors are used in both legs (if line/neutral polarity cannot be guaranteed), or for 220 VAC applications, AND if the maximum current to ground (or into a person connected to ground) is less than about 10-20 mA. The 0.47 uF capacitor shown in their circuit will limit current to about 21 mA at 60 Hz, so if there were one on each leg, it would be reasonably safe. Paul | |||||||||||||||||||||||||||||||
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>
> On March 13 this year - poster " Hammy" raised a few valid questions
> about Tech Bulletin " TB 008 " on the Microchip web site ( and quoted
> widely elsewhere) on the subject of "Transformerless Power Supplies".
>
> http://ww1.microchip.com/downloads/en/AppNotes/91008b.pdf
>
> This prompted Mr Rod Elliot of ESP to contact Microchip with a view to
> having them retract and withdraw TB008 from publication. As feared but
> expected, this was not successful.
>
> The ESP site now has an outline of what happened when he complained and
> includes the email reply received from Microchip's Tech Support Group.
>
> http://sound.westhost.com/articles/power-supplies2.htm#s7
>
> A second, even stronger worded email from Mr Elliot went unanswered.
>
> Microchip's anonymous tech support guy was clearly WAAAY out of his depth
> on the topic of AC mains and appliance electrocution hazards - as was
> that fool Stan D'Souza who wrote the infamous tech bulletin.
>
> D'Souza is now a "Technical Fellow " at Microchip - so I guess the dude
> walks on water and his word is Gospel round the place.
>
> IME - people like him will * NEVER * admit to even the most grievous
> of errors nor allow any error of theirs to be publicly corrected.
>
> Shame there appears to be no way to make direct contact.