Patent ID: 8183947

Claim:
A horological quartz oscillator circuit including an inverter comprising two complementary MOS transistors, series-mounted with a first current source, between two terminals of a supply voltage source to define an active branch, a source terminal of the first MOS transistor being connected to the first current source, whereas a source terminal of the second MOS transistor is connected to one of the terminals of the supply voltage source, drain terminals of the two transistors of the inverter being together connected at output to a first electrode of the quartz, whereas gate terminals of said inverter transistors are together connected at input to a second electrode of the quartz, a first phase shift capacitor being connected to the first electrode of the quartz, whereas a second capacitor is connected to the second electrode of the quartz, the oscillator circuit including active polarisation means, arranged between the drain terminals and the gate terminals of the inverter transistors, the impedance value of said polarisation means being sufficiently high so as not to damage the transconductance of the active branch for generating an oscillation in the quartz, wherein the active polarisation means includes between the drain terminals and gate terminals of the complementary MOS transistors, an operational transconductance amplifier mounted as a voltage follower and stabilised by a stray capacitor of the horological quartz, or a pseudo-resistor made using a MOS transistor, whose source terminal is connected to the gate terminals of the complementary MOS transistors, a drain terminal is connected to the drain terminals of the complementary MOS transistors, and the gate terminal is polarised via a second polarising current source, whose the current is provided for passing through the second complementary MOS transistor in addition to the current of the first current source.