Micro-phase adjusting and micro-phase adjusting mixer circuits designed with standard field effect transistor structures

Abstract

Disclosed herein are embodiments of a programmable phase adjusting circuit, a programmable phase adjusting mixer circuit and design structures for these circuits. These circuits comprise a variable delay device connected between input and output nodes. The device includes multiple FETs with input diffusion regions that are connected to a voltage rail via switches so that they can be selectively biased, gates that are connected in series to the input node so that a periodic input signal can be propagated sequentially through each of the gates and output diffusion regions that are connected in parallel to the output node. A current source is connected between the output node and another voltage rail for biasing the output node when the variable delay device is off. The variable delay device enables a circuit in which small increments of selectable phase adjustments can be made to the periodic input signal as a function of propagation delay.

1 . A phase adjusting circuit comprising:
 an input node for receiving a first signal;   an output node;   a variable delay device comprising a plurality of field effect transistors comprising input diffusion regions adapted to be selectively biased, gates connected in series to said input node such that said first signal is propagated to said gates sequentially and output diffusions regions connected in parallel to said output node; and   a current source connected to said output node and adapted to bias said output node when all of said field effect transistors are off,   wherein, when an input diffusion region of said selected field effect transistor is selectively biased and when an active edge of said first signal is propagated from said input node to a gate of said selected field effect transistor, a second signal is transmitted through a selected field effect transistor to said output node, and   wherein a phase difference between said first signal and said second signal is based on delay in propagation of said first signal from said input node to said gate.   
   
   
       2 . The circuit of  claim 1 , wherein said variable delay device further comprises switches corresponding to said field effect transistors and connected between said input diffusion regions and a first voltage rail so as to allow selective biasing of said input diffusion regions. 
   
   
       3 . The circuit of  claim 2 , wherein said switches comprise field effect transistors. 
   
   
       4 . The circuit of  claim 1 , wherein, if only one input diffusion region is selectively biased, when an inactive edge of said first signal reaches said gate, transmission of said second signal through said selected field effect transistor to said output node is broken. 
   
   
       5 . The circuit of  claim 1 , wherein, if multiple input diffusion regions are selectively biased:
 when said active edge of said first signal reaches a first gate of a first selected field effect transistor, said second signal is transmitted through said first selected field effect transistor to said output node,   when an inactive edge of said first signal reaches said first gate, said second signal is transmitted through a next selected field effect transistor to said output node, and   when said inactive edge of said first signal reaches a last gate of a last selected field effect transistor, transmission of said second signal to said output node is broken.   
   
   
       6 . The circuit of  claim 1 , wherein said field effect transistors have one of uniform sizes and varying sizes. 
   
   
       7 . The circuit of  claim 1 , wherein said variable delay device comprises at least one resistor connected in series with said gates. 
   
   
       8 . The circuit of  claim 1 , wherein said variable delay device comprises at least one capacitor connected at a node in the series connection of said gates. 
   
   
       9 . The circuit of  claim 1 , wherein said variable delay device comprises a mixture of silicide regions and non-silicide regions on said gates and connections between said gates. 
   
   
       10 . The circuit of  claim 1 , wherein said current source is constant and connected between said output node and a second voltage rail and wherein said output node is adapted to combine said second signal and a load from said current source. 
   
   
       11 . The circuit of  claim 1 ,
 wherein said current source comprises at least one additional delay device connected to said input node and said output node,   wherein said additional delay device is adapted to receive and phase adjust said first signal simultaneously with said variable delay device, and   wherein said output node is adapted to combine phase-adjusted signals from both said variable delay device and said at least one additional delay device.   
   
   
       12 . The circuit of  claim 11 , wherein said at least one additional delay device comprises a second variable delay device. 
   
   
       13 . A phase adjusting mixer circuit comprising:
 an input node for receiving a first signal;   an output node;   a variable delay device comprising a plurality of field effect transistors comprising input diffusion regions adapted to be selectively biased, gates connected in series to said input node such that said first signal is propagated to said gates sequentially and output diffusions regions connected in parallel to said output node,   wherein, when an input diffusion region of said selected field effect transistor is selectively biased and when an active edge of said first signal is propagated from said input node to a gate of said selected field effect transistor, a second signal is transmitted through a selected field effect transistor to said output node, and   wherein a phase difference between said first signal and said second signal is based on delay in propagation of said first signal from said input node to said gate; and   a current source connected to said output node,   wherein said current source is non-constant, independent of said first signal and is adapted to transmit a third signal to said output node, and   wherein said output node is adapted to combine said second signal and said third signal.   
   
   
       14 . The circuit of  claim 13 , wherein said variable delay device further comprises corresponding switches between said input diffusion regions and a first voltage rail so as to allow selective biasing of said input diffusion regions. 
   
   
       15 . The circuit of  claim 13 , wherein, if only one input diffusion region is selectively biased, when said active edge of said first signal reaches said gate, said second signal is transmitted to said output node through said selected field effect transistor and, when an inactive edge of said first signal reaches said gate, transmission of said second signal to said output node is broken. 
   
   
       16 . The circuit of  claim 13 , wherein, if multiple input diffusion regions are selectively biased:
 when said active edge of said first signal reaches a first gate of a first selected field effect transistor, said second signal is transmitted through said first selected field effect transistor to said output node,   when an inactive edge of said first signal reaches said first gate, said second signal is transmitted through a next selected field effect transistor to said output node, and   when said inactive edge of said first signal reaches a last gate of a last selected field effect transistor, transmission of said second signal to said output node is broken.   
   
   
       17 . A design structure embodied in a machine readable medium used in a design flow process, said design structure comprising a phase adjusting circuit comprising:
 an input node for receiving a first signal;   an output node;   a variable delay device comprising a plurality of field effect transistors comprising input diffusion regions adapted to be selectively biased, gates connected in series to said input node such that said first signal is propagated to said gates sequentially and output diffusions regions connected in parallel to said output node; and   a current source connected to said output node and adapted to bias said output node when all of said field effect transistors are off,   wherein a second signal is transmitted through a selected field effect transistor to said output node when an input diffusion region of said selected field effect transistor is selectively biased and when an active edge of said first signal is propagated from said input node to a gate of said selected field effect transistor, and   wherein a phase difference between said first signal and said second signal is based on delay in propagation of said first signal from said input node to said gate.   
   
   
       18 . The design structure of  claim 17 , wherein said design structure comprises a netlist, which describes said phase adjusting circuit. 
   
   
       19 . The design structure of  claim 17 , wherein said design structure resides on a geographically dispersed sites (GDS) storage medium. 
   
   
       20 . The design structure of  claim 17 , wherein said design structure comprises at least one of test data files, characterization data, verification data and design specifications.