Phase-locked loop frequency synthesizer

Abstract

The invention provides a phase-locked loop frequency synthesizer comprising a phase detection discriminator and a charge pump, wherein the charge pump comprises an upper power supply and a lower powersupply; the phase-locked loop frequency synthesizer also comprises a first extended circuit and a second extended circuit; the first extended circuit provides a trigger signal for the second extendedcircuit according to the output of the phase detection discriminator; and the second extended circuit provides current together with the upper power supply and the lower power supply under the control of the trigger signal. The phase-locked loop frequency synthesizer broadens the lineal working area by extending the phase detection discriminator / the charge pump, achieves dynamic switch of the charge pump current in a locking process, and accelerates locking process.

Description

technical field

[0001] The present invention generally relates to the technical field of wireless transceivers, and more specifically, relates to a phase-locked loop frequency synthesizer. Background technique

[0002] The phase-locked loop frequency synthesizer is a key module in the design of the wireless transceiver. It outputs a series of high-precision frequency signals to provide local oscillator signals for the frequency conversion of the transceiver. The commonly used phase-locked loop frequency synthesizer structure is as follows figure 1 As shown, the phase and frequency detector 101, the charge pump 102, the loop filter 103, the voltage controlled oscillator 104 connected in sequence and between the input terminal of the phase frequency detector 101 and the output terminal of the voltage controlled oscillator 104 The frequency divider 105 constitutes.

[0003] The working principle of the phase-locked loop frequency synthesizer is: the phase-frequency detector 1...

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