Do you find errors often as I do ?

Thread Starter

Externet

Joined Nov 29, 2005
1,816
Hi.
First, need to confirm if it is wrong... Texas Instruments, a first class company document shows these as symbols for IGBTs :

1640628796407.png

Aren't they supposed to be
1640628905077.png
I see these kind of errors daily everywhere including tutorials, do you ? Or does not matter, or nobody cares, or what ?

And is 'BUS' a standard wording? Seen also VCC, V+, VDD, Vwhatever the publisher wants... just because of habit.:rolleyes: What are correct norms ?
 

MrChips

Joined Oct 2, 2009
25,918
This is the schematic circuit symbol of an NPN transistor which is a BJT (bipolar junction transistor).

1640630272862.png



This is the symbol of a FET (field effect transistor).
1640630358969.png

This is the symbol of a insulated gate FET.
1640630432285.png

This is the symbol of an IGBT.

1640631178138.png

Hence, technically you are correct. I wouldn't lose sleep over it.
 

MrChips

Joined Oct 2, 2009
25,918
Technically speaking, VBE represents the voltage at the base with respect to the emitter.
VCE is the voltage at the collector with respect to the emitter.

By this reasoning, VCC would be 0V. However, it is generally accepted to represent the supply voltage in a circuit containing BJTs.

Similarly, VDS is the voltage at the drain with respect to the source.
VDD has come to represent the supply voltage of CMOS circuitry where FETs, CMOS, or MOSFETs are employed.
VSS commonly is connected to GND.

Sometimes VCC and VDD are used to refer to the same thing. For example, how would you label the positive supply bus in a circuit containing BJTs, FETs, CMOS components in the same drawing?

BUS can be used to represent any common signal or supply lines. For example, there is address bus, data bus, positive supply bus, ground bus.
 

crutschow

Joined Mar 14, 2008
29,466
I see these kind of errors daily everywhere including tutorials, do you ? Or does not matter, or nobody cares, or what ?
Yes, the common IGBT symbol is as you show.
They apparently copied a bridge with BJTs and didn't bother to change the symbols.
 

dl324

Joined Mar 30, 2015
14,302
Texas Instruments, a first class company
They've gone downhill. The quality of their datasheets isn't what it used to be. In the 70's and 80's, their databooks were a must have on the benches of engineers and technicians.

But they're not alone. MCU datasheets from Atmel and others (e.g. Allwinner) seem to gloss over electrical specs. Some are clearly written by people who don't know English well.

TI couldn't even be bothered to clean up datasheets from their acquisitions. They just put their logo on them and call it good.
1640631777327.png
 

MisterBill2

Joined Jan 23, 2018
11,556
For the complaint about symbols that are not quite right, consider that not all programs contain all of the current symbols, and that sometimes symbol libraries are not kept up for writers. And not even every engineer knows every new symbol. Fortunately by simply adding an actual correct part number the problem is reduced. The far worse errors are sticking ground symbols on common wires when it is not even desirable to have them. The critical comments come across a bit like being critical of an individual because their English is not perfect.. If we know a device is an insulated Base Bipolar thransistor then the important information is which wire is collector and which is emitter. , and is it P or is it N..
Connections that are in the wrong place bother me a lot more.
 

Ian0

Joined Aug 7, 2020
4,821
Vdd and Vss on CMOS has always puzzled me. Both power supplies connect to the source (one to a P-channel FET and one to an N-channel FET) and neither connects to a drain.
 
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