LED Temperature Coefficients When Used as Bias Sources

[mediatechnology]

"LED used as voltage reference provides self-compensating temp coefficient," Peter Lefferts, Electronic Design, February 15, 1975.


LED used as voltage reference provides self-compensating temp coefficient," Peter Lefferts, Electronic Design, February 15, 1975.

LED used as voltage reference provides self-compensating temp coefficient," Peter Lefferts, Electronic Design, February 15, 1975.
Full pdf: https://www.ka-electronics.com/images/p ... 5_1975.pdf


Interesting discussion here regarding Pete's circuit: http://www.electronicspoint.com/pete-le ... 21315.html

[mediatechnology]

I just checked a hunch that one of the reasons LEDs are used as voltage bias sources is that they have a sharper knee characteristic.
This seems to be the case.

The horizontal axis is 0.5V/div the vertical 100 uA/div.
The left trace is a red LED I-V curve.
The right trace is the I-V curve of three series-connected 1N4148 diodes.


LED Voltage Bias Source Knee vs 3 1N4148 Diodes

[emrr]

Cool hunch.