Very low voltage drop transistor

Click For Summary

Discussion Overview

The discussion centers around the construction of a fast-reacting current overload protection device using semiconductors, specifically focusing on the use of FETs with low voltage drops. Participants explore potential solutions and components relevant to this application.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, Cliff, seeks recommendations for off-the-shelf FETs with low voltage drops for a current overload protection device.
  • Another participant, Warren, suggests that Cliff may be referring to FETs with low on resistance and recommends conducting parametric searches on manufacturer and distributor websites.
  • A third participant mentions specific websites, such as analog.com and digikey.com, for finding suitable components.
  • QuantumCowboy expresses skepticism about Cliff's proposed solution and suggests consulting literature on ESD protection in ICs, referencing a circuit design involving a resistor across the gate and drain of an n-type MOSFET.
  • QuantumCowboy also notes the difficulty in finding individually-packaged ordinary MOSFETs and suggests using power devices for circuit protection, as well as the possibility of tying several FETs in parallel to reduce channel resistance.

Areas of Agreement / Disagreement

Participants present differing views on the best approach to constructing the overload protection device, with no consensus on the optimal solution or component choice. Some participants provide suggestions while others express doubts about the proposed method.

Contextual Notes

There are limitations regarding the availability of specific FETs and the assumptions about their performance in the proposed application. The discussion does not resolve the technical details of the circuit design or the effectiveness of the suggested alternatives.

Who May Find This Useful

Individuals interested in circuit design, particularly in overload protection mechanisms, as well as those looking for component recommendations in semiconductor applications.

Cliff_J
Science Advisor
Messages
789
Reaction score
7
I'd like to construct a fast-reacting current overload protection device. And rather than use a FET as a short to blow a fuse I'd rather just use a semiconductor in series that I can open on overload. This is similar in operation to some "intelligent circuit breakers" based on a Intra Technologies' MOSFET switch.

Anyone know of any common (cheap) off-the-shelf FETs that with really low voltage drops? Thanks in advance.

Cliff
 
Engineering news on Phys.org
I think you mean FETs with really low on resistance. You should be able to do parametric searches at both the manufacturers' websites and on distributor websites.

- Warren
 
...like analog.com and digikey.com
 
Cliff_J said:
I'd like to construct a fast-reacting current overload protection device. And rather than use a FET as a short to blow a fuse I'd rather just use a semiconductor in series that I can open on overload. This is similar in operation to some "intelligent circuit breakers" based on a Intra Technologies' MOSFET switch.

Anyone know of any common (cheap) off-the-shelf FETs that with really low voltage drops? Thanks in advance.

Cliff

I'm not sure that this is the right way to solve the problem. If I were you, I'd go to the library and get a book on ESD protection in ICs. As a matter of fact, when I worked as an IC design engineer, we had a circuit like this in our intellectual properties library. Essentially, there was a resistor across the gate and drain of an n-type MOSFET. When a sudden current surge rushed across this resistor, the channel activated... in other words the drain was shorted to the source and most of the current went straight to ground without damaging the circuit.

Individually-packaged, ordinary MOSFETs are almost impossible to come by... although I think you individually access the FETs of 500 series inverter. Most individually-packaged FETs are either power devices or RF devices. If you want circuit protection, then you're looking at power devices. If you want to reduce the channel (or source-to-drain) resistance, then I would just suggest tying several FETs in parallel.

QuantumCowboy
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
15K
Replies
3
Views
3K
  • · Replies 10 ·
Replies
10
Views
5K
Replies
4
Views
11K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 1 ·
Replies
1
Views
11K
  • · Replies 3 ·
Replies
3
Views
5K