[sdiy] current sink idea

[Roman Sowa]

I could always slow down the slopes of PWM with just one capacitor so it 
would become really quiet.
Maybe direct PWM isn't such a bad idea. However the DAC was just asking 
to be used

Roman

W dniu 2024-11-30 o 17:37, Mike Bryant pisze:
> radiated emissions - possibly all over the audio band even if you 
> didn't care about EMC
>
> ------------------------------------------------------------------------
> *From:* grant musictechnologiesgroup.com 
> <grant at musictechnologiesgroup.com>
> *Sent:* 30 November 2024 16:36
> *To:* tom at electricdruid.net <tom at electricdruid.net>; Mike Bryant 
> <mbryant at futurehorizons.com>
> *Cc:* synth-diy at synth-diy.org <synth-diy at synth-diy.org>
> *Subject:* Re[2]: [sdiy] current sink idea
> Excuse my ignorance here,
>
> > I agree that would be asking for trouble.
>
> Are we talking about noise, LED destruction,  photosensitive epilepsy 
> (PSE) or what exactly?
>
> GB
>
>
> ------ Original Message ------
> From "Tom Wiltshire" <tom at electricdruid.net 
> <mailto:tom at electricdruid.net>>
> To "Mike Bryant" <mbryant at futurehorizons.com 
> <mailto:mbryant at futurehorizons.com>>
> Cc "synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>" 
> <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>>
> Date 11/30/2024 8:16:54 AM
> Subject Re: [sdiy] current sink idea
>
>     I think he meant instead of the DAC, not to drive the backlight
>     directly. I agree that would be asking for trouble.
>
>     Roman mentioned using a PWM pin as a basic DAC followed with a
>     simple RC and the current sink, and that should be fine.
>
>         On 30 Nov 2024, at 11:53, Mike Bryant
>         <mbryant at futurehorizons.com
>         <mailto:mbryant at futurehorizons.com>> wrote:
>
>         One problem is low cost displays aren't shielded so you'll
>         transmit the PWM frequency everywhere
>
>         ------------------------------------------------------------------------
>         *From:* Synth-diy <synth-diy-bounces at synth-diy.org
>         <mailto:synth-diy-bounces at synth-diy.org>> on behalf of
>         Gordonjcp <gordonjcp at gjcp.net <mailto:gordonjcp at gjcp.net>>
>         *Sent:* 30 November 2024 11:48
>         *To:* synth-diy at synth-diy.org
>         <mailto:synth-diy at synth-diy.org> <synth-diy at synth-diy.org
>         <mailto:synth-diy at synth-diy.org>>
>         *Subject:* Re: [sdiy] current sink idea
>         On Sat, Nov 30, 2024 at 09:17:13AM +0100, Roman Sowa via
>         Synth-diy wrote:
>         > with 2 days ago.
>         > Special needs require special solutions - I needed to
>         control display's
>         > backlit intensity from internal DAC of the microcontroller,
>         which
>
>         Immediate first question - why not use a PWM pin?
>
>         --
>         Gordonjcp
>
>         ________________________________________________________
>         This is the Synth-diy mailing list
>         Submit email to: Synth-diy at synth-diy.org
>         <mailto:Synth-diy at synth-diy.org>
>         View archive at: https://synth-diy.org/pipermail/synth-diy/
>         <https://synth-diy.org/pipermail/synth-diy/>
>         Check your settings at:
>         https://synth-diy.org/mailman/listinfo/synth-diy
>         <https://synth-diy.org/mailman/listinfo/synth-diy>
>         Selling or trading? Use marketplace at synth-diy.org
>         <mailto:marketplace at synth-diy.org>
>
>         ------------------------------------------------------------------------
>         *From:* Synth-diy <synth-diy-bounces at synth-diy.org
>         <mailto:synth-diy-bounces at synth-diy.org>> on behalf of
>         Gordonjcp <gordonjcp at gjcp.net <mailto:gordonjcp at gjcp.net>>
>         *Sent:* 30 November 2024 11:48
>         *To:* synth-diy at synth-diy.org
>         <mailto:synth-diy at synth-diy.org> <synth-diy at synth-diy.org
>         <mailto:synth-diy at synth-diy.org>>
>         *Subject:* Re: [sdiy] current sink idea
>         On Sat, Nov 30, 2024 at 09:17:13AM +0100, Roman Sowa via
>         Synth-diy wrote:
>         > with 2 days ago.
>         > Special needs require special solutions - I needed to
>         control display's
>         > backlit intensity from internal DAC of the microcontroller,
>         which
>
>         Immediate first question - why not use a PWM pin?
>
>         --
>         Gordonjcp
>
>         ________________________________________________________
>         This is the Synth-diy mailing list
>         Submit email to: Synth-diy at synth-diy.org
>         <mailto:Synth-diy at synth-diy.org>
>         View archive at: https://synth-diy.org/pipermail/synth-diy/
>         <https://synth-diy.org/pipermail/synth-diy/>
>         Check your settings at:
>         https://synth-diy.org/mailman/listinfo/synth-diy
>         <https://synth-diy.org/mailman/listinfo/synth-diy>
>         Selling or trading? Use marketplace at synth-diy.org
>         <mailto:marketplace at synth-diy.org>
>         ________________________________________________________
>         This is the Synth-diy mailing list
>         Submit email to: Synth-diy at synth-diy.org
>         <mailto:Synth-diy at synth-diy.org>
>         View archive at: https://synth-diy.org/pipermail/synth-diy/
>         <https://synth-diy.org/pipermail/synth-diy/>
>         Check your settings at:
>         https://synth-diy.org/mailman/listinfo/synth-diy
>         <https://synth-diy.org/mailman/listinfo/synth-diy>
>         Selling or trading? Use marketplace at synth-diy.org
>         <mailto:marketplace at synth-diy.org>
>
>
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org