Hello.
I am looking for a dedicated IC which generates from a dc voltage a squared signal with fixed frequency and variable duty cycle. The duty cycle is changed in steps by pulses: for example with two push buttons, one for increasing and one for decreasing (inputs). So each time a (+) pulse is sent, the duty cycle increases in a step, for example: 0, 5, 10, 20, 40, 80,100 %. When the a (-) pulse is sent, the duty cycle decreases. An application example would be dimming a LED in steps.
The IC may be formed by:
1. A counter which increases or decreases its value depending on the 2 inputs. These being pulses.
2. A multiplexer which takes the counter output and depending on its value, sets its output signal level. This is "V reference".
3. A comparator that takes as input the multiplexer output (V reference, which sets the duty cycle value) and a RC (relaxation oscillator) or a crystal oscillator and outputs the PWM.
Can you help me to find this or something similar? Ideally would be a SOT23-6 package.
Regards,
Adrian
