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Sci.Electronics.Basics -> Microchip's TB008 Reprise

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Author: Phil Allison
Date: 02:25 13-05-08

**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.

..... Phil

Author: David L. Jones
Date: 07:16 13-05-08

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:68sqj7F2uge06U1@mid.individual.net...
> **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.

Dave.

Author: David L. Jones
Date: 07:36 13-05-08

Author: default
Date: 17:20 13-05-08

On Tue, 13 May 2008 16:25:26 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>**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.
>
>
>
>..... Phil
>
That supply is very dangerous in the wrong hands. But I've been using
caps to run LED pilot lights on 120 with no problems. It is just not
suitable for any application where the user might come in contact with
the "low voltage" derived from a capacitive reactance power supply.

I've got one in my electric range - powers a microchip pic to modulate
the range heater - no more dangerous than the 240 VAC mechanical
switch it replaces.

The problem is in the application, not the circuit I'd recommend for
anyone just starting out in electronics. After a couple of "sit down"
shocks you gain the proper respect for mains.

I'm pretty sure he didn't become a technical fellow because of this
circuit - it appears in a 70's Fairchild publication.
--

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Author: Bob Monsen
Date: 17:20 13-05-08

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:68sqj7F2uge06U1@mid.individual.net...
> **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.
>
>
>
> ..... Phil
>

Well, they should clearly be more responsive about these kinds of things.
However, I'm still somewhat confused as to why the original tech note is
considered harmful.

It seems to be a fairly standard transformerless power supply. I've built
lots of them. The only problem with it is that it lacks a fuse (other than
the silly one between neutral and earth). The circuit needs to be isolated
from the user, of course.

I wonder if Australian and US standards are different in this respect?

Regards,
Bob Monsen

Author: Paul E. Schoen
Date: 17:55 13-05-08

"David L. Jones" <altzone@gmail.com> wrote in message
news:4829788b$1@dnews.tpgi.com.au...
>
> "Phil Allison" <philallison@tpg.com.au> wrote in message
> news:68sqj7F2uge06U1@mid.individual.net...
>> **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

Author: Phil Allison
Date: 18:04 13-05-08

"Bob Monsen"
> "Phil Allison"
>> **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.
>>
>
>
> Well, they should clearly be more responsive about these kinds of things.

** Yes - killing people is not a very nice thing to do, is it ?

> However, I'm still somewhat confused as to why the original tech note is
> considered harmful.

** You must be an utter moron.

> It seems to be a fairly standard transformerless power supply.

** No it ain't !!

Read the FUCKING link - you colossal jerk !!

You are JUST AS BAD as bloody Microchip.

...... Phil

Author: default
Date: 18:20 13-05-08

On Wed, 14 May 2008 08:04:46 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>** No it ain't !!
>
>Read the FUCKING link - you colossal jerk !!
>
>You are JUST AS BAD as bloody Microchip.
>
>
>
>...... Phil

What!!?? the world doesn't rotate at your colossal command, who's the
jerk, idiot.
--

----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.pronews.com The #1 Newsgroup Service in the World! >100,000 Newsgroups
---= - Total Privacy via Encryption =---

Author: Phil Allison
Date: 18:31 13-05-08

"default"

>
>>** No it ain't !!
>>
>>Read the FUCKING link - you colossal jerk !!
>>
>>You are JUST AS BAD as bloody Microchip.
>>
>
> What!!??

** Those words were NOT written to you - but you removed all the
context & altered the text to make it look as if they were.

Clearly - YOUR gross incomprehension of extreme electrocution hazard here
is just as bad as any of the fuckwits at Microchip.

Fuck off and die - you vile pile of shit.

..... Phil

Author: default
Date: 19:36 13-05-08

On Wed, 14 May 2008 08:31:01 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

>
>Fuck off and die - you vile pile of shit.
>
>
>
>..... Phil

The simpering wimp doth speak. Let me guess, you are one of the
children who never got to be playground monitor and it has affected
you this way. You'd probably be wetting yourself if you had to
confront some of these people in person.
--

----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.pronews.com The #1 Newsgroup Service in the World! >100,000 Newsgroups
---= - Total Privacy via Encryption =---

Author: Phil Allison
Date: 19:51 13-05-08

"default = some anonymous mental retard "

** Fuck off and die

- you vile, autistic pile of shit.

..... Phil

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