VCO tuning curve compensation method and module thereof

Abstract

The invention provides a VCO tuning curve compensation method. In the method, a negative resistance amplifier and an inductor are connected with both ends of a variable capacitor to form a parallel-connection structure, wherein the variable capacitor structure is a five-end AMOS capacitance network, and one end is a tuning curve compensation control end of the AMOS capacitance network, which changes the equivalent capacitance of the AMOS capacitance network by adjusting the DC voltage of a control end to obtain an approximate linearized change curve with respect to VCO output frequency and VCO control voltage, thereby realizing the VCO tuning curve compensation, improving the VCO stability and enabling a VCO circuit module to work in the area having a higher Q value. The invention also provides a VCO circuit module of a differential circuit structure formed by the method. The AMOS capacitance network comprises four AMOS varactors and one RC low-pass filter, wherein the four AMOS varactors are connected in series two by two and are symmetrically arranged, and the specific arrangement mode includes grid electrode series connection and substrate series connection. The VCO module performs voltage control on the AMOS varactors to change the oscillator frequency, and realizes the tuning curve compensation to enable the frequency tuning curve to be approximately linearized by changing the DC voltage of the compensation control end of the tuning curve, thereby realizing a larger frequency tuning range.

Description

technical field [0001] The invention relates to the technical field of wireless communication electronic circuits, relates to a voltage-controlled oscillator VCO, in particular to a tuning curve compensation VCO method and a module thereof. Background technique [0002] In the mobile handheld wireless transceiver terminal, the voltage-controlled oscillator VCO is one of the most critical modules. The phase noise performance of the VCO directly affects the receiving sensitivity and blocking performance of the transceiver. With the development of wireless communication technology, a single chip in a communication system is required to be compatible with many different frequency bands and modes. Therefore, as a multi-band and multi-mode transceiver, its voltage-controlled oscillator VCO is required to cover a certain frequency range, so the research and development of wideband VCO has become an important topic for wireless communication electronic circuits. [0003] There are ...

AI Technical Summary

Problems solved by technology

Although the VCO with this structure can be tuned in a large frequency range, it has major defects: First, the gain KVCO of the VCO varies greatly in the entire tuning range, and KVCO is large, and KVCO is very small in the low frequency band, which will seriously affect the stability of the entire frequency synthesizer; secondly, when there are many fixed capacitors, the MOS switch will make the resonant circuit, etc. The Q value of the effective capacitor decreases, especially in the low frequency band, which will not only lead to poor phase noise performance of the VCO, but also consume a lot of power

[0004]Compared with PN junction capacitors, traditional AMOS capacitors have a larger capacitance change ratio Cmax / Cmin, large Q value, and there is no forward bias conduction phenomenon, but the C-V curve of a single AMOS capacitor is steep, and the gate-substrate voltage V (Gate, Bulk) can only change within a small range, and the capacitance in this interval The Q value of the capacitor is the minimum value. Therefore, to achieve a wide tuning range for traditional AMOS capacitors, the gain value KVCO of the VCO is required to be relatively large. However, the control voltage variation range is small, and KVCO Too large will lead to poor phase noise performance, so it is difficult to achieve wide-band tuning of traditional AMOS capacitors

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