I am building a trigger circuit for my monostable multivibrator ( op-amp design) where the pulse width has to be varied from 0.1ms to 10s and also provision needs to be given for varying the duty cycle from 25% to 75 % .
The trigger circuit essentially takes care of my duty cycle path and i am using a RC passive differentiator ( to which a square wave i/p is given) to give triggers at required time period. Since i have to vary my pulse width up 10s , my R , C values of the trigger ckt is enormous . So i fixed my R at 470k and tried to vary my capacitance . I tried doing this using a capacitance multiplier ( since my design specifications says i cant use capacitors greater than 1u) .
The problem i am facing now is how i can connect the capacitance multiplier in place of my capactior of the trigger ??? ( Suppose the +ve of capacitor is connected to i/p square wave and -ve side connected to R , then how do i do the same using a capacitance multiplier, which terminals do i connect to the i/p and which to the resistor ???)
Another question is will the frequency of the input or any other frequency component affect my capacitance multipliers' problem ?? Will it cease to work as the one i originally designed for ??? If so what can be a solution to this problem ??? I ask this because , in order to satisfy my pulse width and duty cycle conditions, i may have to give square pulses of frequency from hz - Mhz( upto approx. 5Mhz , if am not mistaken) range .
The trigger circuit essentially takes care of my duty cycle path and i am using a RC passive differentiator ( to which a square wave i/p is given) to give triggers at required time period. Since i have to vary my pulse width up 10s , my R , C values of the trigger ckt is enormous . So i fixed my R at 470k and tried to vary my capacitance . I tried doing this using a capacitance multiplier ( since my design specifications says i cant use capacitors greater than 1u) .
The problem i am facing now is how i can connect the capacitance multiplier in place of my capactior of the trigger ??? ( Suppose the +ve of capacitor is connected to i/p square wave and -ve side connected to R , then how do i do the same using a capacitance multiplier, which terminals do i connect to the i/p and which to the resistor ???)
Another question is will the frequency of the input or any other frequency component affect my capacitance multipliers' problem ?? Will it cease to work as the one i originally designed for ??? If so what can be a solution to this problem ??? I ask this because , in order to satisfy my pulse width and duty cycle conditions, i may have to give square pulses of frequency from hz - Mhz( upto approx. 5Mhz , if am not mistaken) range .