EL7900

Larkin nurses grudges. I don't get angry, I just remember ;-)

As you well know, I can stop on a dime. Larkin will _never_ stop. ...Jim Thompson

Charlieplexing is a way of multiplexing more display LEDs than a crossbar switch can manage, using their diode characteristics.

Cheers

Phil

I don't know the range of PD efficiencies that the XMOS process has. But it is a pretty small PD there. That could give reasonable bounds on the photo currents. Then compare output current for specified lux.

?-)

Aha! Didn't know it had a name :-)

I'm doing something similar, but the diodes are in series cathode-to-anode. Saves me half of the normally required H-bridges for the X-Y array. No meaningful power consequences, since switching is "occasional". ...Jim Thompson

didn't

that,

of

=A0 =A0 =A0...Jim Thompson

Thanks for the start langwadt. I fiddled the circuit some and i can get it do things like Marco' collapse. It is abruptly clear to me why a very large M (like my previous guess of 100) is not correct. It is probably not more than 4. Higher M seems to be more resistant to the collapse.

?-)

Version 4 SHEET 1 1744 680 WIRE 576 -80 448 -80 WIRE 768 -80 576 -80 WIRE 16 -64 -112 -64 WIRE 208 -64 16 -64 WIRE 576 -48 576 -80 WIRE 16 -32 16 -64 WIRE 448 48 448 -80 WIRE 768 48 768 -80 WIRE -112 64 -112 -64 WIRE 208 64 208 -64 WIRE 576 64 576 32 WIRE 720 64 576 64 WIRE 16 80 16 48 WIRE 160 80 16 80 WIRE 768 176 768 144 WIRE 896 176 768 176 WIRE 1040 176 896 176 WIRE 208 192 208 160 WIRE 336 192 208 192 WIRE 768 192 768 176 WIRE 896 192 896 176 WIRE 1040 192 1040 176 WIRE 208 208 208 192 WIRE 336 208 336 192 WIRE 832 208 816 208 WIRE 848 208 832 208 WIRE 992 208 848 208 WIRE 272 224 256 224 WIRE 288 224 272 224 WIRE 1040 288 896 288 WIRE 768 304 768 288 WIRE 832 304 832 208 WIRE 832 304 768 304 WIRE 208 320 208 304 WIRE 272 320 272 224 WIRE 272 320 208 320 WIRE 768 320 768 304 WIRE 896 320 896 288 WIRE 208 336 208 320 WIRE 336 336 336 304 WIRE 272 352 272 320 WIRE 832 352 832 304 WIRE 272 416 208 416 WIRE 768 416 768 400 WIRE 832 416 768 416 WIRE 768 432 768 416 WIRE 896 432 896 400 WIRE 208 448 208 416 WIRE 336 448 336 416 =46LAG 208 448 0 =46LAG 336 448 0 =46LAG -112 144 0 =46LAG 768 432 0 =46LAG 896 432 0 =46LAG 448 128 0 SYMBOL pmos 160 160 M180 SYMATTR InstName M1 SYMATTR Value BSS84 SYMBOL pmos 288 304 M180 SYMATTR InstName M2 SYMATTR Value BSS84 SYMBOL pmos 256 304 R180 SYMATTR InstName M3 SYMATTR Value BSS84 SYMBOL voltage -112 48 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 3.3 SYMBOL current 208 336 R0 WINDOW 3 -261 36 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value PULSE(0 10m 0 0.3 0 0.3) SYMATTR InstName I1 SYMBOL res 320 320 R0 SYMATTR InstName R1 SYMATTR Value 1k SYMBOL voltage 16 -48 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 2.4 SYMBOL pmos 720 144 M180 SYMATTR InstName M4 SYMATTR Value BSS84 SYMBOL pmos 848 288 M180 SYMATTR InstName M5 SYMATTR Value BSS84 SYMBOL pmos 816 288 R180 SYMATTR InstName M6 SYMATTR Value BSS84 SYMBOL voltage 448 32 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 3.3 SYMBOL current 768 320 R0 WINDOW 3 -261 36 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value PULSE(0 10m 0 0.3 0 0.3) SYMATTR InstName I2 SYMBOL res 880 304 R0 SYMATTR InstName R2 SYMATTR Value 1k SYMBOL voltage 576 -64 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V4 SYMATTR Value 2.5 SYMBOL pmos 992 288 M180 SYMATTR InstName M7 SYMATTR Value BSS84 SYMBOL diode 288 416 R180 WINDOW 0 24 72 Left 0 WINDOW 3 24 0 Left 0 SYMATTR InstName D1 SYMATTR Value 1N4148 SYMBOL diode 848 416 R180 WINDOW 0 24 72 Left 0 WINDOW 3 24 0 Left 0 SYMATTR InstName D2 SYMATTR Value 1N4148 TEXT -48 472 Left 0 !.tran 1

M=11 wasn't vague. Your comments about M sure were.

and

Same as I found, but doesn't fit with the IDD/IOUT calculation.

...Jim Thompson

OK, You mentioned substrate currents, complaint dropped.

How about some specifics ?:-) ...Jim Thompson

ohm.

I don't do silicon-level design, and I don't know what's inside this chip.

I wonder if the foldback has a finite slope, or is a Schmitt-type snap.

How could Intersil sell this?

ohm.

I suspect a really old process, might even be N-type wafer with all kinds of nasty interactions.

Pondering my navel, thinking that they might have made a photo-FET instead of a photo-DIODE, I found this....

I don't know, but perhaps Phil Hobbs does... could excessive light effectively short the channel of such a device?

I've not held an EL7900 in my hand. Could it be de-encapsulated? Take some high magnification photos, and trace the sucker. I used to do some of that for a living... chasing patent infringements. Used ICE's magnificent equipment, but no longer have access :-( ...Jim Thompson

ay

Jamie only hears what he wants to hear.

-- Bill Sloman, Nijmegen

Not really, I hear it all, and I mean I hear and have heard it all.

after a while it's like listening to the wife.

Maybe one day all of this will come full circle and some people are going to have egg on their face. You know what that is all about.

Jamie

may

You've heard it all, but you don't process much of it, and reject most of what you do condescend to process because it doesn't fit your prejudices.

Which suggests that she too is going to get tired to talking to you sometime soon.

As far as I'm concerned you got egg all over your face some time ago. You don't know enough to have noticed.

-- Bill Sloman, Nijmegen

No, the egg you see is what's falling off yours. You won't be embarrassed when it happens because you are always full of excrement any way, but there will be a few others that will be. I've been around long enough and seen the carnage.

Jamie

Il 02/09/2012 17:38, Marco Trapanese ha scritto:

I've just tried approaching slowly the led of my smartphone, because it's rainy here :)

Vsupply = 3.3V Rload = 10k Venv = 1.530V (voltage in room light)

It reaches gradually 3.175V, then it remain stable at this voltage (closing further the led) and goes to 0V suddenly after closing a bit further the led.

Vsupply = 5.0V Rload = 10k Venv = 1.550V (voltage in room light)

It reaches gradually 4.008V, then it remain stable at this voltage and goes to 0V suddenly after closing a bit further the led.

Marco

ay

not

ome

ue

Dream on.

xcrement

You like to think so, but - sadly - you can't tell shit from shinola.

One might wonder who? We've got some depressingly right-wing nitwits on this user-group, but none of them are as ignorant, silly and negligible as you are.

You've been around for a time, but since you don't learn from your experiences, this doesn't work to your advantage. The "carnage" you think you have seen - presumably people endorsing ideas that you don't understand and are consequently disinclined to take seriously - reflects the mess inside your head, rather than any problem in the real world.

-- Bill Sloman, Nijmegen

may

not

some

value

using

As much as i dislike agreeing with Bill, he is right on this one.

Thanks Phil, i knew something was missing from my holiday diet.

?-)

didn't

that,

of

=A0 =A0 =A0...Jim Thompson

first

get

very

Agreed. It seems that there are some bias currents running around and there may be an opamp servoing out some of the process variability.

?-)