Method for compensating local oscillator frequency

摘要

An oscillator circuit includes a voltage-controlled oscillator configured to output an AC output signal having a predetermined frequency, which changes due to temperature and fabrication process variations and a control voltage generating circuit configured to provide a voltage signal to the voltage-controlled oscillator to maintain the predetermined frequency by compensating for the temperature and fabrication process variations.

主权项

1. An oscillator circuit, comprising:
a voltage-controlled oscillator configured to output an AC output signal having a predetermined frequency which changes due to temperature and process variations; and a control voltage generating circuit configured to provide a voltage signal to the voltage-controlled oscillator to maintain the predetermined frequency by compensating for the temperature and process variations, the control voltage generating circuit comprising an input unit configured to provide a PTAT (proportional to absolute temperature) current and a PTAR (proportional to absolute resistance) current and a compensation unit configured to generate the voltage signal in response to the PTAT current and the PTAR current, wherein: the input unit comprises:
a first current mirror circuit for outputting a mirrored PTAT current at a node, the first current mirror circuit comprising a first transistor having a terminal directly connected to a power supply terminal, and a second transistor having a terminal directly connected to the power supply terminal;a second current mirror circuit for outputting a mirrored PTAR current at the node, the second current mirror comprising a third transistor having a terminal directly connected to the power supply terminal, and a fourth transistor having a terminal directly connected to the power supply terminal; and the compensation unit comprises:
a third current mirror circuit comprising a fifth transistor having a terminal directly connected to the power supply terminal, and a sixth transistor having a terminal directly connected to the power supply terminal; and the first, second, third, fourth, fifth, and sixth transistor being all of p-type transistors.