the up down control signal polarity of differential pair of charge pump ckt in fig 1 is error
and c1 and opamp of figure1 form positive feedback and perhaps it will cause oscillation on vc node
R1 and c1 and opamp of figure1 form positive feedback and perhaps it will cause oscillation on vc node
the sollution is to remove R1 and c1 and add compensation capacitor on unity gain buffer opamp output
to prevent oscillation