Broadband numerical control oscillator based on on-chip transformer

Abstract

The invention discloses a broadband numerical control oscillator based on an on-chip transformer, and belongs to the technical field of integrated circuits. The broadband numerically-controlled oscillator comprises an on-chip transformer, a coarse adjustment switch capacitor, a fine adjustment switch capacitor, a digital-to-analog converter, a voltage-controlled varactor and a cross-coupled transistor, wherein the on-chip transformer comprises a first-stage coil and a second-stage coil; the fine adjustment switch capacitor is connected with the output end of the cross coupling transistor, the output end of a first-stage coil of the on-chip transformer and the output end of a second-stage coil of the on-chip transformer, the coarse adjustment switch capacitor is connected with the input end of the second-stage coil of the on-chip transformer, and the digital-to-analog converter is connected with one end of the voltage-controlled varactor. And the output ends of the voltage-controlled varactor and the cross-coupled transistor are connected with the output of the first-stage coil of the on-chip transformer. According to the invention, by introducing the on-chip transformer, the change rate of the output frequency of the DCO to the change of unit capacitance is increased, a larger bandwidth can be obtained, and the cost of a tape-out chip can be reduced.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and relates to a broadband numerically controlled oscillator, in particular to a broadband numerically controlled oscillator based on an on-chip transformer. Background technique [0002] DCO (Digital Controlled Oscillator, Digital Controlled Oscillator) is a general term for a type of oscillator whose output frequency is adjusted by a digital signal within a certain range. There are many application scenarios for broadband DCO, mainly including reconfigurable radio frequency transceivers, software defined radios and other broadband fields. Different from the DCO in narrowband communication, the wideband DCO needs to generate a local clock signal in a wider frequency range to cover the communication frequency bands specified by different wireless communication protocols. At the same time, the broadband DCO needs to be able to maintain good noise characteristics in a wide frequency ra...

AI Technical Summary

Problems solved by technology

Use multiple narrow-band DCOs to switch and synthesize through switches, and finally output the required broadband frequency signal. In actual use, this solution needs to use multiple DCOs, and additional switching circuits are required, which is difficult to implement, high power consumption, and takes up a large volume. ,high cost

Wideband DCO technology can directly output the desired wideband frequency signal, but because the phase noise of wideband DCO is generally poor (about 10dB worse than narrowband DCO), the phase noise of the final output wideband frequency signal is poor

Therefore, the traditional broadband DCO has the problems of large power consumption, large size and high cost

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