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We are getting the current from Charge pump and then we converted it into voltage and the again into current. What is the use of this procedure. Are there any advantages.
Design a PLL circuit that operates exclusively with current signals and see how it works. Not impossible in principle, but probably inconvenient. Would use inductors as current storage elements.
A charge pump in current mode, integrates nicely to a control
voltage with a shunt cap (1-pole filter) or integrator amplifier.
A voltage pulse output, bare, would need a couple of extra
passives (perhaps inconveniently large for integrating).
We are getting the current from Charge pump and then we converted it into voltage and the again into current. What is the use of this procedure. Are there any advantages.
Normally a digital PLL has a phase comparator and an integrator with lead/lag compensation RC network to drive the VCO.
Using a charge pump with a PWM pulse voltage and open circuit when in phase or between pulses to a storage cap accomplishes the same. RC lead/lag functions are necessary to improve this second order system with optimal speed, capture range and/or jitter.
This refers to the "type I" phase comparators which are often XOR gates with analog switch.
Your final current conversion must be a special VCO designed using current control or the Norton equivalent.
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