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US 2004/0164802 A1Published application
Method of forming a variable propagation delay semiconductor device and structure therefor
AssigneeSemiconductor Components Industries, LLC
InventorJoseph Hughes
Life of this patent
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Abstract
A differential amplifier (10, 60) is formed to have a propagation delay that varied responsively to a control signal received on a differential control signal input. The propagation delay is varied by changing the bias current of a pair of differential input transistor (11, 13).
Claims20
A method of forming a differential amplifier with a variable propagation delay comprising:
- forming the differential amplifier to have an output voltage having a voltage swing;
- and
- coupling a differential input transistor pair of the differential amplifier to receive a first bias current that generates a first propagation delay and to receive a second bias current that generates a second propagation delay including forming the differential amplifier to maintain the voltage swing constant for receiving the first bias current and receiving the second bias current.
A method of forming a variable propagation delay for a differential amplifier comprising:
- providing a differential amplifier having a differential input pair;
- and
- varying a value of a bias current through the differential input pair over a first range of bias current values responsively to a delay control signal while maintaining a load current of the differential amplifier constant.
A variable propagation delay differential amplifier comprising:
- a first transistor having a control electrode coupled to a first data input, a first current carrying electrode coupled to a first output of the variable propagation delay differential amplifier, and a second current carrying electrode;
- a first load resistor having a first terminal coupled to the first current carrying electrode of the first transistor, and a second terminal coupled to a power input;
- a second load resistor having a first terminal coupled to the power input, and a second terminal coupled to a second output of the variable propagation delay differential amplifier;
- a second transistor having a first current carrying electrode coupled to the second output of the variable propagation delay differential amplifier, a control electrode coupled to a second to data input, and a second current carrying electrode coupled to the second current carrying electrode of the first transistor;
- a first current source having a first terminal coupled to the second current carrying electrode of the first transistor, and a second terminal coupled to a power return;
- and
- a variable current source having a first terminal coupled to the second current carrying electrode of the second transistor, and a second terminal coupled to the power return.
4 more elements
Dependencies are inferred from the claim text.