On Wed, 13 Dec 2023 12:22:43 -0800, John Larkin <jl@997PotHill.com>
wrote:
>I might use an LED+mosfet type SSR to switch a voltage divider at the
>input of an isolated ADC.
>
>The ON resistance of the switch is an error contributor, and a
>super-low Ron is expensive. 1 or 2 ohms is affordable.
>
>I'm thinking that driving the LED side from the proper Thevenin source
>might temperature compensate the ON resistance of the mosfets. Or even
>program the LED supply with a DAC.
>
>LT Spice dosn't seem to have any led-mosfet SSR models. I guess I'll
>have to try it.
On Wed, 13 Dec 2023 12:39:30 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
>onsdag den 13. december 2023 kl. 21.23.40 UTC+1 skrev John Larkin:
>> I might use an LED+mosfet type SSR to switch a voltage divider at the
>> input of an isolated ADC.
>>
>> The ON resistance of the switch is an error contributor, and a
>> super-low Ron is expensive. 1 or 2 ohms is affordable.
>>
>> I'm thinking that driving the LED side from the proper Thevenin source
>> might temperature compensate the ON resistance of the mosfets. Or even
>> program the LED supply with a DAC.
>>
>> LT Spice dosn't seem to have any led-mosfet SSR models. I guess I'll
>> have to try it.
>
>TLP3905 or similar and two low Ron fets ?
Reply by Lasse Langwadt Christensen●December 13, 20232023-12-13
onsdag den 13. december 2023 kl. 21.23.40 UTC+1 skrev John Larkin:
> I might use an LED+mosfet type SSR to switch a voltage divider at the
> input of an isolated ADC.
>
> The ON resistance of the switch is an error contributor, and a
> super-low Ron is expensive. 1 or 2 ohms is affordable.
>
> I'm thinking that driving the LED side from the proper Thevenin source
> might temperature compensate the ON resistance of the mosfets. Or even
> program the LED supply with a DAC.
>
> LT Spice dosn't seem to have any led-mosfet SSR models. I guess I'll
> have to try it.
TLP3905 or similar and two low Ron fets ?
Reply by John Larkin●December 13, 20232023-12-13
I might use an LED+mosfet type SSR to switch a voltage divider at the
input of an isolated ADC.
The ON resistance of the switch is an error contributor, and a
super-low Ron is expensive. 1 or 2 ohms is affordable.
I'm thinking that driving the LED side from the proper Thevenin source
might temperature compensate the ON resistance of the mosfets. Or even
program the LED supply with a DAC.
LT Spice dosn't seem to have any led-mosfet SSR models. I guess I'll
have to try it.