LC voltage-controlled oscillator (LC-VCO) with wide frequency tuning range

Abstract

The invention provides an LC voltage-controlled oscillator (LC-VCO) with a wide frequency tuning range based on an equivalent resonant capacitor; and the equivalent resonant capacitor of a differential circuit structure module comprises an accumulated variable capacitor (AMOS) with the bias voltage being controlled by a switch and a plurality of fixed capacitors which are controlled by the switches. In a high-frequency band, the bias voltage which is controlled by the switch enables the AMOS variable capacitor to work in an area in which the capacitor is not sensitive to the voltage; the AMOS capacitor is equivalent to the fixed capacitors, the noise which is introduced by a bias circuit is reduced, and a higher Q value is realized. In a low-frequency band, the bias voltage which is controlled by the switch enables the AMOS variable capacitor to work in a variable capacity interval, the proportion of the variable capacitance in the loop of the equivalent resonant capacitor is increased, the gains or the low-frequency band VCO are increased, so that the LC-VCO with low noise and the wide frequency tuning range is realized. Compared with an existing broad-band VCO, the wide frequency tuning range is realized to a circuit module with an appropriate amount of switch capacitance, and the LC-VCO with wide frequency tuning range has the characteristics of low power consumption and small chip area.

Description

technical field [0001] The invention relates to the technical field of wireless communication electronic circuits, relates to an inductance-capacitance voltage-controlled oscillator VCO, and in particular to a method for realizing a wide-frequency tuning range LC-VCO and a circuit module thereof. Background technique [0002] Multi-mode, multi-band receivers require VCO to have a large frequency tuning range, but the tuning range of on-chip LC is limited. Therefore, it is of great significance to study wideband VCO technology. The simplest technology to realize wideband VCO is to integrate two or more VCOs on the same chip, and the output of these VCOs selects one output through a multi-channel switch. Therefore, only one VCO is working at any time. This method can realize any Range of frequency output, but need to use multiple on-chip inductors, so the chip area is large, not suitable for engineering. Furthermore, by increasing the VCO voltage gain K VCO Wider bandwidth c...

AI Technical Summary

Problems solved by technology

[0004] Capacitor-switched broadband VCO can achieve a wide range of frequency tuning range, but when there are many switch-controllable capacitor banks, the parasitic capacitance introduced by switch-controllable capacitors will increase and reduce the frequency tuning range. In addition, because the Q value of the on-chip inductor varies with The frequency will vary greatly, so the value range of the switch controllable capacitor is limited by the value of the on-chip inductor

The disadvantages of capacitive switching broadband VCO are: (1) The frequency range is limited by inductance and parasitic capacitance

(2) When there are many switch-controllable capacitor banks, the on-resistance of the switch will reduce the equivalent Q value of the switched capacitor, thereby reducing the phase noise performance

The phase noise is better than -100dBc / Hz100kHz, the main disadvantage of this circuit is that it occupies a large chip area

Images