Charge pump of source-end switch, phase-locked loop circuit and method for inhibiting feed-through effect

Abstract

The invention discloses a charge pump of a source-end switch, a phase-locked loop circuit and a method for inhibiting a feed-through effect. The charge pump of the source-end switch comprises a current source circuit in the output stage, wherein the current source circuit comprises a switching tube with the grid serving as the switch end of the charge pump, a current source tube with the source connected with the drain of the switching tube and with the drain serving as the output end of the charge pump, and a feed-through inhibiting capacitor, installed between the grid end of the switching tube and the grid end of the current source tube for inhibiting the feed-through effect. According to the charge pump of the source-end switch, the phase-locked loop circuit and the method for inhibiting the feed-through effect, the technical problem that in the prior art the feed-through effect of the charge pump of the source-end switch is very difficult to inhibit due to permanent overlap capacitances is solved.

Description

technical field [0001] The invention relates to the field of electronic circuits, in particular to a charge pump of a source switch, a phase-locked loop circuit and a method for suppressing the feedthrough effect. Background technique [0002] The charge pump is an important module in the phase-locked loop (PLL for short), which provides infinite gain for the entire loop, so that the phase difference between the input of the PLL and the output of the frequency divider is zero when the PLL is locked, so that Reduce the fluctuation of the voltage-controlled oscillator (VCO) control signal, and reduce the output spurious (Spur). Due to the non-ideality of the charge pump, the mismatch in time and amplitude of the charging and discharging current of the charge pump causes periodic fluctuations of the control voltage on the VCO, forming spurs, thereby affecting the quality of the output signal. [0003] Clock feedthrough (Feedthrough) is due to the gate-source and gate-drain ove...

AI Technical Summary

Problems solved by technology

[0011] The main purpose of the present invention is to provide a charge pump for source-side switching, a phase-locked loop circuit and a method for suppressing the feedthrough effect, so as to at least largely solve the problem of source-side switching caused by the fixed existence of overlapping capacitors in the above-mentioned related art. The feedthrough effect of the charge pump is difficult to suppress the problem of

Images