Temp and Voltage Variation of Ceramic Capacitors, or Why 4.7µF Becomes a 0.33uF

[Old_but_Alive]

I just found this interesting article on Maxims web site.


Temperature and Voltage Variation of Ceramic Capacitors, or Why Your 4.7µF Capacitor Becomes a 0.33µF Capacitor


http://www.maximintegrated.com/app-notes/index.mvp/id/5527

[solutions]

Sorry - I can't take anyone seriously that uses a critical RC time constant in a LED driver circuit.

Looks, to me, like everything he "learned" came from the TDK guy.

[Old_but_Alive]

thats a minor point, and doesnt take away anything from his findings, even if they are TDK's

[Faros]

Sorry - I can't take anyone seriously that uses a critical RC time constant in a LED driver circuit.

@Solutions
what would you use for LED driving other than RC or let us say C depended time constant/OSC ?

[solutions]

A linear current source, a resistor, or a SMPS with current feedback.

There are many excellent on-chip oscillators these days, to where an RC for "critical timing" is the silliness that only dinosaurs like Maxim and National can come up with to squeeze every penny for profit while making the system designer's life miserable.

[Old_but_Alive]

wow, feel the heat, anger and the prejudice.

Most of the linear tech led drivers use an RC for timing, the actual frequency is not that critical

[solutions]

NO...I worked with these guys. I know how they think...worse, I know the STUPID idiots that were their managers and the really DUMB, mostly political, cultural and technology constraints they put them under.

The author did day "critical". For non-critical, RC is fine, in some cases preferred.