Design Of Low Power Bluetooth RF Receiver Front-End

With the the development of the wireless communication technology,the Bluetooth technology is gradually applied to mobile terminals,such as the Internet,the smart dressing equipment and the intelligent household.The Implementation of low power consumption Bluetooth has a crucial significance on realizing the wireless terminal of various efficient systems.The RF frond end is the key module of Bluetooth.Its power consumption occupies the main part of the Bluetooth system,thus reducing the power consumption of the RF front end has an extremely important significance on Bluetooth system and wireless terminal system.The thesis has designed a model application of bluetooth in the RF front-end circuit with low consumption.Paper introduces the domestic and foreign research status of RF front-end circuit,combined with the requirements of the application of bluetooth to confirm the design index.After comparing the merits and demerits of the RF front-end solutions,combined with the application of bluetooth transceiver,the paper confirms the overall low intermediate frequency scheme of two levels of mixing and selects the respective module circuit structure at the same time.To reduce the contribution of noise level from the behind circuit,it is added the active mixing circuit on the traditional IQ passive mixer structure to provide a certain amount of conversion gain.The CG LNA is used with the technology of cross coupling capacitance to improve the noise performance.The output of LNA has a switch control capacitor array,then it can be tuned within the Bluetooth frequency.Using the parallel resistance to change the gain of LNA can introduce larger noise.Then it uses the parallel MOS to change the gain,the RF front-end overall gain can be adjustable in four gain and more suitable for the system.It uses the saturated MOS to consist the load of active mixer,making it more suitable for the work under low voltage.The bias of the load MOS is controlled by the common-mode feedback circuit.In order to obtain good linearity and low dc power consumption,the second mixer of IQ adopts passive mixer structure.In order to avoid the problem of IQ crosstalk,the second mixer uses the 25%duty cycle local oscillator signal to drive.The frequency of the second local signal is a quarter of the first local signal.It consists a sliding-IF RX architecture to reduce the power consumption of the local oscillator signal circuit.In order to obtain high output swing and linearity,the transimpedance amplifier uses the op-amp with negative feedback to constitute.The schematic and layout of the proposed low-power RF front-end is designed in TSMC 55nm CMOS technology.It works under the 1V voltage.The post simulation results show the conversion gain of RF front-end can be adjusted among the OdB?12dB?24dB and 36dB.The double sideband noise figure can be 7.3dB under the highest gain mode.The IIP3 can be-7dBm under the lowest gain mode.The whole RF front-end only consumes 2.2 mA current.The RF front-end circuit can achieve a low power and is suitable for the low-power Bluetooth system.