OK,
I want to hook up a power led (RGB) to 3 mosfets, and drive each mosfet by a PWM circuit.
Each PWM circuit has to be driven by a voltage, from a capacitor charged by a logic output.
i.e. - the logic output goes HIGH for the RED channel - slowly charging a big capacitor at the output, which will make the fade in of the led.
so i need the PWM circuit to be controlled by that capacitor - 1% duty cycle when empty, and 99% duty cycle when full).
so if we look here:
R5 determinate the duty cycle ? (PWM brightness)
R1 only determinate the frequency ? (which should be above 33Hz)
did i get it right ?
in other words, the + of the comparator (between 1/3 and 2/3 Vcc) will set the led brightness ?
I want to hook up a power led (RGB) to 3 mosfets, and drive each mosfet by a PWM circuit.
Each PWM circuit has to be driven by a voltage, from a capacitor charged by a logic output.
i.e. - the logic output goes HIGH for the RED channel - slowly charging a big capacitor at the output, which will make the fade in of the led.
so i need the PWM circuit to be controlled by that capacitor - 1% duty cycle when empty, and 99% duty cycle when full).
so if we look here:
R5 determinate the duty cycle ? (PWM brightness)
R1 only determinate the frequency ? (which should be above 33Hz)
did i get it right ?
in other words, the + of the comparator (between 1/3 and 2/3 Vcc) will set the led brightness ?
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