Multi-phase Closed Loop LC Tank Circuits

Abstract

LC tank circuits can be coupled together to form closed loop oscillators. The interconnectivity of these LC tank circuits were performed by a physical connection such as a metal interconnect. The LC tank circuits may also comprise a plurality of inductors that are coupled together in parallel. These closed loop oscillators generate oscillations which have multi-phase components. Such circuits are useful for RF designs, clock generation for VLSI chips, adiabatic circuitry, analog circuitry, and high-speed digital circuitry.

1 . A closed loop oscillator, comprising: 
 a first terminal and a second terminal;    a plurality of oscillators; wherein, 
 each oscillator comprises: 
 a first input node and a second input node;  
 a first output node and a second output node; and,  
 and LC tank circuit coupled to the first and second output nodes; wherein 
 the LC tank circuit is comprised of a plurality of inductors connected in parallel;  
 
 
   the first terminal is coupled to the first input node of a first oscillator;    the second terminal is coupled to the second input node of the first oscillator; and,    the plurality of oscillators are coupled in series; wherein 
 the first output node of a previous oscillator is coupled to one of the input nodes of a next oscillator;  
 the second output node of the previous oscillator is coupled to the remaining input node of the next oscillator;  
 the first output node of a last oscillator is coupled to either of the first or second terminals; and,  
 the second output node of the last oscillator is coupled to the remaining terminal.  
   
     
     
         2 . The oscillator of  claim 1 , wherein: 
 the LC tank circuit further comprises at least one capacitor.    
     
     
         3 . The oscillator of  claim 1 , wherein: 
 each oscillator further comprises: 
 a regenerative circuit coupled to the first and second output nodes.  
   
     
     
         4 . The oscillator of  claim 1 , wherein: 
 each oscillator further comprises: 
 a first component coupling the first output node to a power supply node controlled by the first input node; and,  
 a second component coupling the second output node to the power supply node controlled by the second input node.  
   
     
     
         5 . The oscillator of  claim 4 , wherein: 
 the first and second components are MOS transistors.    
     
     
         6 . The oscillator of  claim 1 , further comprising: 
 at least one balanced pair of output signals.    
     
     
         7 . The oscillator of  claim 6 , wherein: 
 the balanced pair of output signals each drive a capacitor load.    
     
     
         8 . The oscillator of  claim 1 , wherein: 
 the first and second outputs of each oscillator provides the balanced pair of output signals.    
     
     
         9 . The oscillator of  claim 8 , wherein: 
 the collection of the balanced pair of output signals generates a multi-phase clock signal.    
     
     
         10 . The oscillator of  claim 1 , wherein: 
 the plurality of oscillators consist of an odd number of oscillators.    
     
     
         11 . The oscillator of  claim 10 , wherein: 
 the first and second output nodes of each oscillator cross each other an even number of times while forming the closed loop of the oscillator.    
     
     
         12 . The oscillator of  claim 1 , wherein: 
 the plurality of oscillators consist of an even number of oscillators.    
     
     
         13 . The oscillator of  claim 12 , wherein: 
 the first and second output nodes of each oscillator cross each other an odd number of times while forming the closed loop of the oscillator.    
     
     
         14 . A method of forming a closed loop oscillator, comprising the steps of: 
 selecting a plurality of oscillators where each oscillator comprises: 
 a first input node and a second input node;  
 a first output node and second output node; and  
 an LC tank circuit coupled to the first and second output nodes; wherein, 
 the LC tank circuit is comprised of a plurality of inductors connected in parallel;  
 
   connecting the plurality of oscillators in series to form the closed loop; wherein, 
 the first output node of a previous oscillator is coupled to one of the input nodes of a next oscillator; and,  
 the second output node of the previous oscillator is coupled to the remaining input node of the next oscillator;  
   coupling the first output node of a last oscillator to either of the first or second input nodes of a first oscillator; and,    coupling the second output node of the last oscillator to the remaining input node of the first oscillator; thereby, 
 forming the closed loop oscillator.  
   
     
     
         15 . The method of  claim 13 , wherein: 
 each oscillator further comprises: 
 a cross-coupled regenerative circuit coupled to the first and second output nodes.  
   
     
     
         16 . The method of  claim 13 , wherein: 
 each oscillator further comprises: 
 a first component controlled by the first input node that couples a power supply node to the first output node; and,  
 a second component controlled by the second input node that couples the power supply mode to the second output node.  
   
     
     
         17 . The method of  claim 13 , wherein: 
 the first and second output nodes of each oscillator can drive a capacitor load.    
     
     
         18 . The method of  claim 13 , wherein: 
 the first and second output nodes of each oscillator provides a balanced clock signal.    
     
     
         19 . The method of  claim 18 , wherein: 
 the collection of the balanced signals generates a multi-phase clock signal.    
     
     
         20 . A closed loop oscillator, comprising: 
 a plurality of oscillators; wherein, 
 each oscillator comprises: 
 a first input node and a second input node;  
 a first output node and a second output node;  
 a first component coupled between a power supply node and the first output node; wherein 
 the first component is controlled by the first input node;  
 
 a second component coupled between the power supply node and the second output node; wherein, 
 the second component is controlled by the second input node;  
 
 an LC tank circuit coupled to the first and second output nodes; and,  
 a regenerative circuit coupled to the first and second output nodes; and,  
 
   the plurality of oscillators coupled in series to form a closed loop; wherein, 
 the first output node of a previous oscillator is coupled to one of the input nodes of a next oscillator;  
 the second output node of the previous oscillator is coupled to the remaining input node of the next oscillator;  
 the first output node of a last oscillator is coupled to one of the input nodes of a first oscillator; and,  
 the second output node of the last oscillator is coupled to the remaining input node of the first oscillator.  
   
     
     
         21 . The oscillator of  claim 20 , wherein: 
 the LC tank circuit further comprises at least one capacitor.    
     
     
         22 . The oscillator of  claim 20 , wherein: 
 an inductance of the LC tank circuit is comprised of a plurality of inductors connected in parallel.    
     
     
         23 . The oscillator of  claim 20 , wherein: 
 each oscillator further comprises: 
 a regenerative circuit coupled to the first and second output nodes.  
   
     
     
         24 . The oscillator of  claim 20 , wherein: 
 the first and second components are MOS transistors.    
     
     
         25 . The oscillator of  claim 20 , further comprising: 
 at least one balanced pair of output signals.    
     
     
         26 . The oscillator of  claim 25 , wherein: 
 the balanced pair of output signals each drive a capacitor load.    
     
     
         27 . The oscillator of  claim 20 , wherein: 
 the first and second outputs of each oscillator provides the balanced pair of output signals.    
     
     
         28 . The oscillator of  claim 27 , wherein: 
 the collection of the balanced pair of output signals generates a multi-phase clock signal.    
     
     
         29 . The oscillator of  claim 20 , wherein: 
 the plurality of oscillators consist of an odd number of oscillators.    
     
     
         30 . The oscillator of  claim 29 , wherein: 
 the first and second output nodes of each oscillator cross each other an even number of times while forming the closed loop of the oscillator.    
     
     
         31 . The oscillator of  claim 20 , wherein: 
 the plurality of oscillators consist of an even number of oscillators.    
     
     
         32 . The oscillator of  claim 31 , wherein: 
 the first and second output nodes of each oscillator cross each other an odd number of times while forming the closed loop of the oscillator.