Monolithic clock generator and timing/frequency reference

摘要

A periodic signal generator includes a resonant LC tank circuit that generates a periodic reference signal at a first frequency at a differential output thereof. A temperature-responsive frequency compensation module is electrically coupled to the differential output of the resonant LC tank circuit. This module includes a temperature dependent voltage control module that generates a temperature dependent control voltage and an array of switchable capacitive modules that is electrically coupled to a first node of the differential output of the resonant LC tank circuit and responsive to the temperature dependent control voltage and a plurality of switching coefficients. The array of switchable capacitive modules includes a fixed capacitor having a first terminal electrically coupled to the first node and a voltage-controlled variable capacitor having a first terminal electrically coupled to the first node.

主权项

1. A periodic signal generator, comprising:
a resonant LC tank circuit configured to generate a periodic reference signal at a first frequency at a differential output thereof; and a temperature-responsive frequency compensation module electrically coupled to the differential output of said resonant LC tank circuit, said temperature-responsive frequency compensation module comprising:
first and second arrays of switchable capacitive modules that are electrically coupled to first and second nodes of the differential output of said resonant LC tank circuit, respectively, and responsive to a temperature dependent control voltage and a plurality of switching coefficients; anda temperature dependent voltage control module configured to generate the temperature dependent control voltage, said temperature dependent voltage control module comprising a temperature dependent current source electrically coupled to a first node of a current mirror and a bank of switchable resistive modules electrically coupled to a second node of the current mirror; wherein each of the first and second arrays of switchable capacitive modules comprises a respective binary-weighted array of fixed capacitors and a binary-weighted array of voltage-controlled variable capacitors that are responsive to the plurality of switching coefficients; wherein each of the fixed capacitors in the binary-weighted array of fixed capacitors is associated with a corresponding voltage-controlled variable capacitor in the binary-weighted array of voltage-controlled variable capacitors; wherein within each of the switchable capacitive modules, either the corresponding fixed capacitor or the corresponding voltage-controlled variable capacitor is active, but not both at the same time; and wherein when a voltage-controlled variable capacitor is active it has a first terminal responsive to the temperature dependent control voltage and when a voltage-controlled variable capacitor is inactive its first terminal is responsive to a fixed voltage.