Connected in series or parallel

  • Thread starter Thread starter rineheart25
  • Start date Start date
  • Tags Tags
    Parallel Series
Click For Summary

Discussion Overview

The discussion revolves around the configuration of Zener diodes and LEDs as described in a U.S. Patent #7518158, specifically focusing on whether they are connected in series or parallel as illustrated in Fig. 4. The conversation explores the implications of this configuration for reverse breakdown protection and the functionality in forward direction applications.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that the back-to-back Zener diodes are connected in parallel with the LED, particularly for reverse breakdown protection.
  • Others question the function of the Zener diodes in the forward direction, suggesting that they may serve a protective role for the LED.
  • One participant mentions a two-way Zener diode that can protect the LED from electrostatic discharge (ESD) when connected in parallel.
  • Another point raised is that in LED lighting applications, well-matched LEDs are often connected in series, but this can lead to issues if one LED fails open, which could be mitigated by the presence of Zeners in the forward direction.
  • There is a suggestion that having Zeners allows current to continue flowing even if an LED fails open, enhancing the robustness of the lighting application.

Areas of Agreement / Disagreement

Participants generally agree that the Zener diodes are connected in parallel with the LED for reverse protection, but there is uncertainty regarding their function in the forward direction and the implications of series versus parallel configurations in practical applications.

Contextual Notes

The discussion includes assumptions about the behavior of Zener diodes and LEDs in different configurations, as well as the potential for failure modes in series connections. Specific details from the patent are not fully explored, leaving some aspects unresolved.

rineheart25
Messages
2
Reaction score
0
I am doing research on Zener diode and LEDs. I found a U.S. Patent #7518158.

http://www.google.com/patents?id=jlS_AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

With respect to Fig. 4: Is the LED and Zener diode connected in parallel or series?
Thanks
 
Engineering news on Phys.org
rineheart25 said:
I am doing research on Zener diode and LEDs. I found a U.S. Patent #7518158.

http://www.google.com/patents?id=jlS_AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

With respect to Fig. 4: Is the LED and Zener diode connected in parallel or series?
Thanks

It looks like the back-to-back zeners are connected in parallel with the LED. In the reverse direction they probably are for reverse breakdown protection. Do you know what function they would serve in the forward direction? I think I know (it may be in the patent also).
 
berkeman said:
It looks like the back-to-back zeners are connected in parallel with the LED. In the reverse direction they probably are for reverse breakdown protection. Do you know what function they would serve in the forward direction? I think I know (it may be in the patent also).

I agree with you. It looks like the LED and back-to-back zener diodes are in parallel with the LED. They are connected in the reverse/antiparallel direction direction. In your question above, about the forward direction: I know of a two-way Zener diode that when connected in parallel with LED---the two-way Zener diode has two-way breakdown voltage and the diode can protect the LED from being damaged by electrostatic discharge (ESD). What are you getting at in the "forward direction"?
 
rineheart25 said:
I agree with you. It looks like the LED and back-to-back zener diodes are in parallel with the LED. They are connected in the reverse/antiparallel direction direction. In your question above, about the forward direction: I know of a two-way Zener diode that when connected in parallel with LED---the two-way Zener diode has two-way breakdown voltage and the diode can protect the LED from being damaged by electrostatic discharge (ESD). What are you getting at in the "forward direction"?

In LED lighting applications, well-matched LEDs are often connected in series. But if one LED fails open, that opens the whole series string. Having the zeners in there in the forward direction let's the series current keep flowing in the forward direction, even if the LED fails open. That adds robustness to LED lighting applications. Neat idea.
 

Similar threads

  • · Replies 31 ·
2
Replies
31
Views
5K
Replies
4
Views
2K
  • · Replies 25 ·
Replies
25
Views
8K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 32 ·
2
Replies
32
Views
9K
Replies
12
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K