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US 12,738,947 B2Granted
Phase locked loop having a filter with multiple amplifiers
AssigneeTexas Instruments Incorporated
InventorsDebapriya Sahu, Prakhar Agrawal, Rohit Chatterjee
Life of this patent
Estimating the term…
Abstract
A system includes a phase locked loop (PLL), which includes a filter. The filter may include a first amplifier and a second amplifier, where a feedback current from the first amplifier and the second amplifier is based on a parallel resistance of multiple parallel feedback resistors. The feedback current may be coupled to a noninverting input of the first amplifier.
Claims25
A circuit comprising:
- a first amplifier having a first input, a second input, and an output;
- a second amplifier having a first input, a second input, and an output;
- a first resistor having a first terminal and a second terminal;
- a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the output of the first amplifier, the second terminal of the first capacitor is coupled to the first terminal of the first resistor, and wherein the second terminal of the first resistor is coupled to the first input of the first amplifier;
- and
- a second resistor having a first terminal and a second terminal, wherein the first terminal of the second resistor is coupled to the output of the second amplifier, wherein the second terminal of the second resistor is coupled to the first input of the first amplifier, and wherein the second input of the second amplifier is coupled to the first terminal of the first resistor and the second terminal of the first capacitor, wherein the first input of the first amplifier is an inverting input and is coupled to an output of a charge pump.
3 more elements
A circuit comprising:
- a first amplifier having a first input, a second input, and an output;
- a second amplifier having a first input, a second input, and an output;
- a first resistor having a first terminal and a second terminal;
- a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the output of the first amplifier, the second terminal of the first capacitor is coupled to the first terminal of the first resistor, and wherein the second terminal of the first resistor is coupled to the first input of the first amplifier;
- and
- a second resistor having a first terminal and a second terminal, wherein the first terminal of the second resistor is coupled to the output of the second amplifier, wherein the second terminal of the second resistor is coupled to the first input of the first amplifier, and wherein the second input of the second amplifier is coupled to the first terminal of the first resistor and the second terminal of the first capacitor, wherein the output of the first amplifier is coupled to a voltage-controlled oscillator (VCO).
3 more elements
A circuit comprising:
- a first amplifier having a first input, a second input, and an output;
- a second amplifier having a first input, a second input, and an output;
- a first resistor having a first terminal and a second terminal;
- a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the output of the first amplifier, the second terminal of the first capacitor is coupled to the first terminal of the first resistor, and wherein the second terminal of the first resistor is coupled to the first input of the first amplifier;
- and
- a second resistor having a first terminal and a second terminal, wherein the first terminal of the second resistor is coupled to the output of the second amplifier, wherein the second terminal of the second resistor is coupled to the first input of the first amplifier, and wherein the second input of the second amplifier is coupled to the first terminal of the first resistor and the second terminal of the first capacitor, wherein the second amplifier comprises:
- a bias leg;
- a differential input first stage;
- and
- a common source second stage.
7 more elements
Dependencies are inferred from the claim text.