RF voltage-controlled oscillator

Abstract

The invention relates to a RF voltage-controlled oscillator. The RF voltage-controlled oscillator comprises an adaptive bias circuit, an oscillation circuit and an LC resonant circuit; the oscillation circuit is connected with the adaptive bias circuit and the LC resonant circuit; the adaptive bias circuit outputs a bias voltage to the oscillation circuit; the oscillation circuit starts up the LC resonant circuit in a B type state to enable the LC resonant circuit to start oscillation based on the bias voltage, and the oscillation amplitude is increased gradually; and the oscillation circuit enters a C type state when the amplitude value of the bias voltage is smaller than a first threshold value, and increase of the oscillation amplitude is stopped when the amplitude value of the bias voltage is smaller than a second threshold value. As the adaptive bias circuit outputs the bias voltage to enable the oscillation circuit to start up the LC resonant circuit in the B type state, then the LC resonant circuit starts oscillation, and then the resonant circuit enters the C type state for oscillation along with the increase of the oscillation amplitude, the oscillation is easily started and high current utilization rate is obtained. As a compensatory resistor is added between the output ends of a first transistor and a second transistor and the ground, negative feedback stability is kept, and the stability within a wide working range is guaranteed.

Description

technical field [0001] The invention relates to the technical field of radio frequency oscillation control, in particular to a radio frequency voltage controlled oscillator. Background technique [0002] With the popularity of smart terminals, two radio frequency wireless connection technologies, Wi-Fi and Bluetooth, have been widely used as standard configurations. Due to the limitation of battery technology, the requirements for low power consumption of radio frequency chips are endless. A voltage-controlled oscillator (Voltage-Control Oscillator, VCO) is a key circuit module of a radio frequency chip, and has very strict requirements on its phase noise index. [0003] The usual RF VCO is Class B, which has a center-tapped inductor and two variable capacitors to form an LC resonant circuit. By changing the capacitance of the variable capacitor, the resonant frequency of the LC resonant circuit is controlled to the required value; two transistors are used as The oscillati...

AI Technical Summary

Problems solved by technology

Class B VCO has the advantages of easy and reliable start-up, but the disadvantages are also obvious: the conduction angle of the oscillation tube is 180 degrees, the current utilization rate is low, and the power consumption is very high

In order to meet the requirements of low power consumption, the industry proposes Class-C RF voltage-controlled oscillators. The conduction angle of the oscillation tube of Class-C RF voltage-controlled oscillators is small, and the current utilization rate is high, but it has the disadvantage of difficulty in starting oscillation.

Images