Using LEDs as photovoltaics

In AoE3, page 205, we have Figure 3.107, where we show and discuss the scene you're talking about. We used a TLP191B as an isolated voltage source. Comes in a small 4-pin pkg, $1.71, qty 100, at Digi-Key. It's rated for 5kV isolation for 1 minute, call it 2kV continuous. It provides 7V with a 10uA load, driving its LED with 10mA (we suggest 30mA drive to get 8V out). This compares to 10V at 2uA load, in your final blue-to-green LED setup.

You said you need more distance, a few mm, is that for a higher voltage rating? What rating do you need, and what do you think your LED-pair setup will be good for?

BTW, I assume you read our AoE x-Chapter, section 9x.23, posted here earlier? Sending Power on a Beam of Light

Endless goofy possibilities.

I have some high-voltage LEDs that are just a bunch of die in series.

It's a confidence thing. A few mm is clearly visible, a visible LED likewise, and a physical gap means a mechanical interlock is easy and visible.

If someone is going to handle a device which is normally powered form

I've used the photovoltaic devices elsewhere, they're very useful. I'm aiming for 10V 10uA or so and don't much care about efficiency. I'm going to try some narrow beam LEDs next, but not for a few days.

Cheers

Is this an educational thing? What LED p/n did you end up with?

Not edumicational. It's on hold for a few days thanks to pesky customers.

Cheers

If you are relying on a mechanical shutter as the interlock, you'd have to make sure that that the output LEDs acting as PV devices never get to be in sunshine, or the output will be powered whether or not the interlock is engaged. It might be tricky to make the interlock visible and keep the PV devices reasonably in the dark, both at the same time.

I wouldn't fancy relying on an optoelectronic HT safety interlock. The only HT interlock I trust is a grounding strap to a known good earth.

ht

ED

True.

This level-shifter --> doubler has 0VDC output under static illumination, 8V when illumination is alternated between LED1 and LED2.

C1 C3 D4 .-----+-----||-----+------------+-----||-----+---->|----+---> LED1 | | | | | | ~> V --- --- D2 V --- --- C4 --- ~>^ LED2 D1 ^ --- D3 ^ --- | | | C2 | | | === === .---+-----||-----+------------' === | ===

LED1 = LED2 = green D1-4 = BAT54

Cheers, James Arthur

Back-to-back PV led's is cute. Add a discharge resistor to turn off his mosfet.

I got some Broadcom ALMD-CM1F-34002 15 degree green LEDs and the blue equivalent. Five of each in series, blues running at 20mA.

With a 10mm gap between lenses (that's about 15mm die to die) I measure

It's the 15 degree beam angle that makes all the difference as you might expect.

Cheers