Noise cancellation circuit
AssigneeApple Inc.
InventorsTao Sun, Karthikeyan Reddy, Hyunsik Park
Life of this patent
Estimating the term…
Abstract
The present disclosure describes an apparatus, system, and method for cancelling noise (e.g., power supply noise). For example, the apparatus can include a load circuit, a sense resistor, and a current compensation circuit. The load circuit is configured to draw a first current (e.g., a load current). The sense resistor is configured to provide a voltage based on the first current. The current compensation circuit is configured to generate a second current (e.g., a compensation current) based on the voltage. A sum of the first current and the second current can be substantially constant.
Claims20
An apparatus, comprising:
- a load circuit configured to draw a first current;
- a sense resistor configured to provide a voltage based on the first current;
- and
- a current compensation circuit configured to generate a second current based on the voltage, wherein the second current is drawn away from the load circuit, and wherein the current compensation circuit comprises an amplifier circuit having a first input connected to a first terminal of the sense resistor and a second input connected to a second terminal of the sense resistor.
A system, comprising:
- a power distribution network configured to provide a supply voltage;
- a circuit electrically connected to the power distribution network and configured to receive the supply voltage;
- and
- a noise cancellation circuit between the power distribution network and the circuit, wherein the noise cancellation circuit is configured to generate a compensation current drawn away from the power distribution network by the circuit, wherein the noise cancellation circuit comprises:
- a sense resistor comprising a first terminal and a second terminal;
- and
- an amplifier circuit comprising a first input connected to the first terminal of the sense resistor and a second input connected to the second input of the sense resistor.
A method, comprising:
- drawing, with a load circuit, a load current from a power distribution network;
- providing a voltage based on the load current flowing through a sense resistor;
- generating a compensation current based on the voltage being received by a current compensation circuit that comprises an amplifier circuit having a first input connected to a first terminal of the sense resistor and a second input connected to a second terminal of the sense resistor;
- and
- setting a current level of the power distribution network substantially equal to a summation of the load current and the compensation current.
Dependencies are inferred from the claim text.