Research And Design Of Ultra Low Power VCO

With the rapid development of wireless communication network and microelectronics technology,portable,low power consumption,low cost,high integration have become the current development trend in intelligent communication equipment.Voltage Controlled Oscillator(VCO),which provides the stable local oscillation signal,is the core module of the transceiver system.The performance of its phase noise,power consumption and tuning range almost determine the overall performance of the transceiver system,thus received extensive attention by scholars.On the basis of reading a large number of relevant literature,studying the theory of phase noise,low voltage low power consumption design methods,and summarizing several corresponding circuits,we proposed an ultra-low power wide range frequency tunable VCO and an ultra low power low phase noise QVCO.The main work and achievements are as follows:(1)A low power wide range frequency tunable VCO is presented.By using switched-capacitor array and variable capacitor,this new VCO can work in wide frequency range.In order to reduce the supply voltage,the traditional tail current source is replaced by an inductance,with the help of forward-body-bias and current multiplexing techniques,this structure draws very little power.Simulation results show that under 0.8V supply voltage,the power is 0.248 mW and the frequency tuning range is 2.21-3.33 GHz,and the phase noise is-112.7dBc/Hz@1MHz.The proposed VCO can be applied in wideband frequency synthesizer system.(2)An ultra low power low phase noise Quadrature Voltage Controlled Oscillator(QVCO)is presented.The circuit adopts single-layer PMOS tube to reduce the supply voltage and increase the outputs swing through capacitive feedback technique.The drain current switching speed has been improved to optimize phase noise by the way of direct substrate coupling.Simulation results show that under0.55 V supply voltage,the proposed circuit power consumption is just 0.535 mW.On the carrier frequency of 2.34 GHz,the phase noise is-128.2 dBc/Hz@1MHz,and the tuning range is 2.325-2.44 GHz.The proposed QVCO can be applied in zero intermediate frequency or low intermediate frequency transceiver systems.The proposed two circuits adopt TSMC 0.18 ?m RF CMOS technique,all the simulations and layout design are finished in Cadence IC5141.Compared with therelated literature at home and abroad,the proposed circuits have the advantages of simple structure,low power,wideband frequency tuning range,low phase noise etc.