Automatic-tracking current type charge pump for phase-locking loop

Abstract

The invention discloses an automatic-tracking current type charge pump for a phase-locking loop, comprising an pull-up circuit, a pull-down circuit and a feedback control circuit, wherein the pull-up circuit comprises a P-channel metal oxide semiconductor (PMOS) pull-up switch transistor used for receiving control command signals output by a phase frequency detector (PFD), a PMOS current mirror used for supplying charge current, and a PMOS switch transistor used for supplying a discharge path when the pull-up switch transistor is shut off; the pull-down circuit comprises a N-channel metal oxide semiconductor (NMOS) pull-down switch transistor used for receiving control command signals output by the PFD, an NMOS current mirror used for supplying charge current, and an NMOS switch transistor used for supplying a charging path when the pull-down switch transistor is shut off; and the feedback control circuit comprises a PMOS transistor and an NMOS transistor and is used for dynamically controlling the magnitude of charge and discharge current. The automatic-tracking current type charge pump for the phase-locking loop realizes the dynamic tracking and matching of non-const current, the charge current and the discharge current, and has advantages of simple structure and easiness for realization.

Description

technical field [0001] The invention relates to the technical field of analog integrated circuit design, in particular to a self-tracking current type charge pump for a phase-locked loop, which can be applied to a charge pump phase-locked loop (Charge Pump Phase-Locking Loop CPPLL). Background technique [0002] The phase-locked loop (PLL) circuit was first proposed by H. de Bellescize in 1932, because of its excellent diversity, it has been widely used in the fields of electronics and communication. As an important application example, a phase-locked loop can be used to generate an output signal whose frequency is programmable, equal to a rational fractional multiple of a fixed input frequency. This kind of frequency synthesizer based on phase-locked loop is widely used in wireless terminal products. The diversity of the phase-locked loop also makes it applied to the digital system for the recovery of the clock signal and the generation of the clock signal. [0003] figu...

AI Technical Summary

Problems solved by technology

(2) The structure is complex, and the traditional charge pump structure needs to provide bias current and feedback amplifier to meet the performance requirements

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