Dimming CCFL:s with PWM or amplified analog voltage
1.Normal DMX with 8 bit resolution does not create a nice enough effect with the dimmer I am using (it is in fact meant for dimming LEDs). The different steps are too noticeable. I have so far been able to get a nicer effect by using 16 bit PWM-drivers, but the desired dimming effect occurs just over a small portion of the resolution. Could I get the desired effect from a PWM-dimmer that uses a different dimming “range”?


The reason the range of steps is apparently small for the dimming range is that the response of the human eye to light intensity is non-linear.


To get this amount of drive current, you could use an op-amp with an emitter follower inside the feedback loop:








simulate this circuit &ndash; Schematic created using CircuitLab

The specific components are not what I would use (it will take me a little while to decide the specifics), but in the circuit above, you drive the V dimming control node from your DAC (or some other voltage source); the output voltage will be the same as the input voltage as this configuration is known as a voltage follower (provided you keep within the parameters of the datasheet such as the common mode range and Vout vs. V+ (at the opamp power pin) to name but two.

The transistor within the feedback loop provides a higher current path to your CCFL for dimming than the opamp itself could support.

I would suggest a new question if you need help with choosing components as more information will be required (the voltage range of dimming, power rail(s) available at least).