Numerically controlled oscillator working under near-threshold power voltage

Abstract

The invention relates to a numerically controlled oscillator working under near-threshold power source voltage. An LC cross coupling structured oscillator having high phase noise performance and a bootstrap type buffer based on a differential structure are adopted; the principle of a bootstrap circuit is utilized; bootstrap capacitors are charged and discharged through charging transistors; voltage superposition is carried out on the basis of the power source voltage; therefore, an output signal of a DCO oscillation circuit is amplified, so that the output oscillation amplitude reaches more than two times that of a power source voltage value; on the premise that low power consumption is ensured, the phase noise performance of the DCO oscillation circuit is improved; and the contradictory relation between the power consumption and the phase noise of the DCO oscillation circuit under the near-threshold power voltage can be solved.

Description

technical field [0001] The invention relates to a numerically controlled oscillator working under a near-threshold power supply voltage, belonging to the technical field of numerically controlled. Background technique [0002] DCO has a wide range of applications in integrated circuits, as an output signal generation module of a digital phase-locked loop, providing a local oscillator signal for a wireless transceiver system, and providing a clock signal for a system on chip (System on Chip, SoC). The DCO uses the digital control word to tune the frequency of the output signal. Compared with the traditional voltage-controlled oscillator (Voltage Controlled Oscillator, VCO), the digital control word is not easily disturbed by process deviation, power supply voltage and temperature changes, so the DCO has better noise immune properties. The noise performance of the DCO determines the out-of-band phase noise performance of the digital phase-locked loop, and then affects the per...

AI Technical Summary

Problems solved by technology

Although this structure can achieve better noise performance than the ring oscillator, the circuit based on transformer coupling technology has very high requirements on the matching of passive components. -Phase (AM-PM) modulation increases the phase noise of the loop

In addition, the structure requires a total of 4 inductors, which greatly increases the chip area and cost

Images