Differential delay cell having controllable amplitude output
AssigneeSTMicroelectronics S.r.l.
InventorsSvilen Mintchev, Oleksiy Zabroda
Life of this patent
Estimating the term…
Abstract
A differential delay cell includes a current source for establishing an operating current and a differentially coupled transistor pair having a common node, two input nodes, and two output nodes. The common node is coupled to the current source, and the two output nodes are coupled to an impedance load. The impedance load establishes a time delay between each of the input nodes and a corresponding one of the output nodes. Differential output signals are generated at said two output nodes in response to input signals coupled to said two input nodes. An amplitude control device is coupled between the two output nodes for controlling an amplitude of the differential output signals being generated.
Claims28
A differential delay cell comprising:
- a cascade current source for establishing an operating current, wherein said cascade current source has a first input for controlling the magnitude of the operating current generated;
- a differentially coupled transistor pair having a common node, two input nodes, and two output nodes,
- said common node being coupled to said current source, and said two output nodes being coupled to load devices, wherein differential output signals are generated at said two output nodes in response to input signals coupled to said two input nodes, said load devices have a predetermined load impedance, and further wherein the operating current generated by said current source is divided between said differentially coupled transistor pair and said load devices in proportion to an input voltage applied to each of said two inputs nodes, and further wherein the predetermined load impedance varies in magnitude in response to the operating current applied thereto, and
- an amplitude control device coupled between said two output nodes for controlling an amplitude of the differential output signals being generated.
A differential delay cell comprising:
- a cascode current source for establishing an operating current,
- a differentially coupled transistor pair having a common node, two input nodes, and two output nodes,
- said common node being coupled to said current source, and said two output nodes being coupled to load devices, wherein differential output signals are generated at said two output nodes in response to input signals coupled to said two input nodes, said load devices have a predetermined load impedance, and further wherein the operating current generated by said current source is divided between said differentially coupled transistor pair and said load devices in proportion to an input voltage applied to each of said two inputs nodes, and further wherein the predetermined load impedance varies in magnitude in response to the operating current applied thereto, and
- an amplitude control device coupled between said two output nodes for controlling an amplitude of the differential output signals being generated,
- wherein said load devices comprise diode-connected transistors coupled to each of said cross-coupled transistors and ground.
A differential delay cell comprising:
- a cascode current source for establishing an operating current,
- a differentially coupled transistor pair having a common node, two input nodes, and two output nodes,
- said common node being coupled to said current source, and said two output nodes being coupled to load devices, wherein differential output signals are generated at said two output nodes in response to input signals coupled to said two input nodes, said load devices have a predetermined load impedance, and further wherein the operating current generated by said current source is divided between said differentially coupled transistor pair and said load devices in proportion to an input voltage applied to each of said two inputs nodes, and further wherein the predetermined load impedance varies in magnitude in response to the operating current applied thereto, and
- an amplitude control device coupled between said two output nodes for controlling an amplitude of the differential output signals being generated,
- wherein said load devices comprise diode-connected transistors coupled to each of said output nodes and ground.
A control circuit for controlling a differential delay cell having differential outputs generating differential output signals, and an amplitude control device for controlling an amplitude of the differential output signals in response to a control voltage applied thereto, the control circuit comprising:
- a replica differential delay cell having two inputs, two outputs, and a replica amplitude control device;
- and
- an amplifier having differential inputs and a control output, wherein said replica amplitude control device is coupled between said two outputs, and further wherein said two inputs are cross-coupled to said two outputs of said replica differential delay cell;
- and further
- wherein said differential inputs of said amplifier are coupled to said two outputs of said replica differential delay cell, and said control output is coupled to an input of said replica amplitude control device,
- said control output being further coupled to the amplitude control device of the differential delay cell for providing the control voltage for controlling the amplitude of the differential output signals being generated.
A ring oscillator comprising:
- a plurality of differential delay cells coupled into an oscillator ring, delay through each of said plurality of differential delay cells determining a frequency of oscillation of the ring oscillator,
- each of said plurality of differential delay cells having a pair of inputs which couple from a pair of outputs of a preceding differential delay cell, and having an amplitude control device coupled between said pair of outputs, said amplitude control device having an input responsive to a control voltage for controlling an amplitude of oscillation;
- and
- a control circuit including a replica differential delay cell for generating the control signal for controlling the amplitude of oscillation of the each of said plurality of differential delay cells.
Dependencies are inferred from the claim text.