Method for maintaining loop bandwidth of phase-locked loop circuit and phase-locked loop circuit debugging method

Abstract

The embodiment of the invention provides a method for maintaining the loop bandwidth of a phase-locked loop circuit, which comprises the steps of determining the reference charge pump current, the reference frequency gain and a reference frequency division average value of the phase-locked loop circuit when staying at a reference state; determining a value acquired by dividing the product of the reference charge pump current and the reference frequency gain by the reference frequency division average value to be a reference state value; determining a frequency curve of a voltage-controlled oscillator of the phase-locked loop circuit; setting the phase-locked loop circuit to be an integer frequency division mode, and respectively acquiring first control voltage and second control voltage ofthe voltage-controlled oscillator when an integer part of the reference frequency division average value adds or subtracts 1; determining the real-time frequency gain of the voltage-controlled oscillator; determining a real-time frequency division average value corresponding to the real-time frequency gain; and determining the real-time charge pump current according to the real-time frequency gain, the real-time frequency division average value and the reference state value. According to the method provided by the embodiment of the invention, the loop bandwidth of the phase-locked loop circuit can be maintained to be basically constant, and a problem of data loss caused by fluctuations in loop bandwidth is solved.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of electronic circuits, in particular to a method for maintaining loop bandwidth of a phase-locked loop circuit and a debugging method for a phase-locked loop circuit. Background technique [0002] Current wireless communication chips widely use frequency modulation technology for digital wireless communication, for example, common WIFI, Bluetooth and other communication chips. When the wireless communication chip adopts the frequency modulation technology, there are two ways to realize the frequency modulation from the baseband signal to the radio frequency signal: one way is to convert the digital baseband signal into an analog baseband signal through a DAC (Digital to Analog Converter), Then it is converted into a radio frequency modulation signal through the mixing operation of the analog baseband signal and the up-conversion mixer, and finally transmits it through the radio fre...

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Problems solved by technology

[0008] According to the above description, when the wireless communication chip works at different frequencies, if Icp maintains a fixed value, the loop bandwidth of the phase-locked loop will change due to the change of N and Kvco. If the bandwidth of the phase-locked loop is smaller than the transmission rate of the wireless signal, will result in loss of data

[0009] In order to solve the problem of data loss caused by the narrowing of the bandwidth of the PLL, the current practice is to design the loop bandwidth of the PLL to be much larger than the data transmission rate during chip design, so as to ensure that even if the bandwidth of the PLL is reduced, it will always be greater than Data transmission rate, but it brings waste of chip power consumption and area

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