change LED brightness

[yassin.kraouch]

Hi,
I have an LED board where i want to add a circuit to control the brightness,
input parameter of the LED board DC voltage ( 12V, 350mA),
i want to add a circuit in such a way that when the voltage turns from 12V to 0V and again 12V ( low pulse of few ms) the current decrease ( for example from 350mA to 200mA),
and when again i do the same pulse the current decrease more ( for example from 200mA to 100mA)
can anybody help me and propose idea?
thanks.

 

[KlausST]

Hi,

there are LED controllers. With dimmer input (push button).
And others with a 1..10V control input.

You could build your own.
Maybe linear current controlled (adjust voltage to decrease power dissipation)
Maybe digital with a microcontroller, and PWM output.

Klaus

 

[yassin.kraouch]

Hi,

there are LED controllers. With dimmer input (push button).
And others with a 1..10V control input.

You could build your own.
Maybe linear current controlled (adjust voltage to decrease power dissipation)
Maybe digital with a microcontroller, and PWM output.

Klaus

i want to build my own, i don't want to use existing driver, do you have proposal ?

 

[Easyrider83]

i want to build my own, i don't want to use existing driver, do you have proposal ?

Maybe linear current controlled (adjust voltage to decrease power dissipation)
Maybe digital with a microcontroller, and PWM output.

This was his proposal. And my also.

 

[yassin.kraouch]

This was his proposal. And my also.

yes how to supply the microcontroller when the switch is OFF for few seconds.

 

[KlausST]

Hi,

yes how to supply the microcontroller when the switch is OFF for few seconds.

1) you talked about "a few ms" before, so a capacitor could do the job. Now there are "a few seconds". A factor of 1000. But no problem for a goldcap. In sleep mode even a standard capacitor should do.
2) is there a need to supply the controller? Why not power it OFF? (I did a very low power application, where I save the last "operating state" in EEPROM. --> nonvolatile memory)

Klaus

 

[yassin.kraouch]

Hi,



1) you talked about "a few ms" before, so a capacitor could do the job. Now there are "a few seconds". A factor of 1000. But no problem for a goldcap. In sleep mode even a standard capacitor should do.
2) is there a need to supply the controller? Why not power it OFF? (I did a very low power application, where I save the last "operating state" in EEPROM. --> nonvolatile memory)

Klaus

i was not aware that saving the last operating state in the EEPROM can solve the problem when there is no power, i will see in details the microcontroller solution, if the problem can be solved