Variable gain electro-mechanical oscillator and method for starting balanced oscillations

Abstract

Methods and systems are provided for generating balanced oscillations in oscillators. An oscillator comprises a resonator input configured to receive, from an electro-mechanical resonator, a resonator signal; and an oscillator core comprising a first and a second complementary inverters forming a first loop and a second loop with the resonator input, respectively. The inverters are programmable to contribute to the resonator signal a first gain or a second gain to generate balanced oscillations in the oscillator, with the first gain being less than an upper threshold gain required to generate parasitic-mode oscillations when starting balanced oscillations, and the second gain being equal to or greater than a lower threshold, gain required to generate resonator-mode oscillations. Each inverter is configured to regulate gain contributed by the inventor based on regulating amount of power received to control the gain.

1 - 20 . (canceled) 
     
     
         21 . An oscillator, comprising:
 a resonator input configured to receive, from an electro-mechanical resonator, a resonator signal; and   an oscillator core comprising a first and a second complementary inverters forming a first loop and a second loop with the resonator input, respectively;   wherein:
 the inverters are programmable to contribute to the resonator signal a first gain or a second gain to generate balanced oscillations in the oscillator; 
 the first gain is less than an upper threshold gain required to generate parasitic-mode oscillations when starting balanced oscillations; 
 the second gain is equal to or greater than a lower threshold gain required to generate resonator-mode oscillations; and 
 each inverter is configured to regulate gain contributed by the inventor based on regulating amount of power received to control the gain. 
   
     
     
         22 . The oscillator of  claim 21 , further comprising an inverter controller configured to control the inverters. 
     
     
         23 . The oscillator of  claim 22 , wherein the inverter controller configured to program the inverters to contribute the first gain when starting the balanced oscillations. 
     
     
         24 . The oscillator of  claim 22 , wherein the inverter controller comprises a digital counter connected to a digital-to-analog converter configured to output a control voltage signal. 
     
     
         25 . The oscillator of  claim 22 , wherein the inverter controller is configured to increase a third gain contributed by the inverters by an amount less than a difference between the upper threshold gain required to generate parasitic-mode oscillations and the lower threshold gain required to generate resonator-mode oscillations. 
     
     
         26 . The oscillator of  claim 22 , wherein the first and second inverters comprise a bank of inverters, and the inverter controller is configured to enable a first set of inverters in the banks of inverters and disable a second set of inverters in the banks of inverters to program the inverters. 
     
     
         27 . The oscillator of  claim 21 , wherein the inverters are programmable to contribute to the resonator signal a third gain between the first gain and the second gain. 
     
     
         28 . The oscillator of  claim 21 , wherein each of the first gain and the second gain are less than a maximum amount of gain collectively contributable by all of the inverters. 
     
     
         29 . The oscillator of  claim 21 , wherein the first gain is equal to or greater than the lower threshold gain required to generate resonator-mode oscillations. 
     
     
         30 . The oscillator of  claim 21 , wherein second gain is equal to or less than an optimum power dissipation upper threshold gain amount. 
     
     
         31 . The oscillator of  claim 21 , wherein the first and second inverters comprise a first bank of inverters and a second bank of inverters, respectively. 
     
     
         32 . The oscillator of  claim 21 , further comprising a process monitor unit configured to detect manufacturing process corner parameters of the inverters, wherein the first gain and the second gain of the inverters are programmed based on the detected manufacturing process corner parameters. 
     
     
         33 . The oscillator of  claim 21 , further comprising an electro-mechanical resonator connected to the resonator input, the electro-mechanical resonator comprising a thin-film bulk acoustic resonator, a bulk acoustic wave resonator, a surface acoustic wave resonator, a micro-electro-mechanical system resonator, or a quartz crystal resonator. 
     
     
         34 . The oscillator of  claim 21 , wherein the oscillator comprises:
 a first and a second capacitors connected in series in the first and second loops to outputs of the first and second complementary inverters, respectively, for inhibiting the inverters from latching to a non-oscillatory direct-current stable state when starting balanced oscillations; and   a resistor connected to the capacitors and to the complementary inverters for creating a high-pass filter to inhibit relaxation-mode oscillations.   
     
     
         35 . A method for generating balanced oscillations in an oscillator, the method comprising:
 starting oscillations in the oscillator;   inhibiting the oscillator from latching to a non-oscillatory stable state;   inhibiting relaxation mode oscillations in the oscillator;   contributing a gain to the balanced oscillations, the gain being less than an upper threshold gain required to generate parasitic-mode oscillations; and   increasing the gain in increments, wherein each increment is configured such that it is sufficiently small to avoid parasitic mode oscillations.   
     
     
         36 . The method of  claim 35 , wherein the gain is greater than a lower threshold gain required to generate resonator-mode oscillations. 
     
     
         37 . The method of  claim 35 , comprising detecting a manufacturing process corner parameter for a component used in controlling the oscillations, and selecting the gain in response to the detected process corner parameter. 
     
     
         38 . The method of  claim 35 , comprising increasing gain every 0.1 milliseconds by an increment of no more than 20 percent of a maximum gain contributable in the oscillator. 
     
     
         39 . The method of  claim 35 , wherein the gain is contributed by programmable inverters, and comprising controlling gain contributed by each inventor based on regulating amount of power received to control the gain according to a control voltage signal. 
     
     
         40 . The method of  claim 39 , comprising:
 counting a number of balanced oscillations in a period of time during which the gain is increased; and   varying the control voltage signal according to the number of balanced oscillations.