Termination calibration scheme using a current mirror
AssigneeAdvanced Micro Devices, Inc.
InventorsAchal Kathuria, Pradeep Jayaraman
Life of this patent
Estimating the term…
Abstract
Systems, apparatuses, and methods for conveying and receiving information as electrical signals in a computing system are disclosed. A computing system includes multiple transmitters sending singled-ended data signals to multiple receivers. A termination voltage is generated and sent to the multiple receivers. The termination voltage is coupled to each of signal termination circuitry and signal sampling circuitry within each of the multiple receivers. Any change in the termination voltage affects the termination circuitry and affects comparisons performed by the sampling circuitry. Received signals are reconstructed at the receivers using the received signals, the signal termination circuitry and the signal sampling circuitry.
Claims20
A circuit comprising:
- a configurable calibration resistor;
- a load between a supply voltage and the configurable calibration resistor;
- a reference resistor;
- and
- a calibration controller;
- wherein the calibration controller is configured to:
- set the configurable calibration resistor to a first initial value;
- maintain a target voltage across the configurable calibration resistor, wherein the target voltage is less than or equal to the supply voltage;
- determine a first initial result by comparing a reference voltage to a given voltage across the reference resistor based at least in part on the configurable calibration resistor, wherein the first initial result indicates whether the given voltage is greater than the reference voltage;
- change a resistance of the configurable calibration resistor;
- and
- store a first value of the configurable calibration resistor, in response to determining a comparison of the given voltage and the reference voltage generates a first final result different from the first initial result.
A method, comprising:
- setting, by a calibration controller, a configurable calibration resistor to a first initial value, wherein a load is placed between a supply voltage and the configurable calibration resistor;
- maintaining a target voltage across the configurable calibration resistor, wherein the target voltage is less than or equal to the supply voltage;
- determining, by the calibration controller, a first initial result by comparing a reference voltage to a given voltage across a reference resistor based at least in part on the configurable calibration resistor, wherein the first initial result indicates whether the given voltage is greater than the reference voltage;
- adjusting, by the calibration controller, the configurable calibration resistor;
- and
- storing, by the calibration controller, a first value of the configurable calibration resistor, in response to determining a comparison of the given voltage and the reference voltage generates a first final result different from the first initial result.
An apparatus comprising:
- a plurality of receivers configured to receive signals;
- a plurality of transmitters configured to send a plurality of signals to the plurality of receivers;
- wherein a given receiver of the plurality of receivers is configured to receive a first signal of the plurality of signals from a given transmitter of the plurality of transmitters;
- wherein the given receiver comprises:
- a configurable calibration resistor;
- a load between a supply voltage and the configurable calibration resistor;
- a reference resistor;
- and
- a calibration controller;
- and
- wherein the calibration controller is configured to:
- set the configurable calibration resistor to a first initial value;
- maintain a target voltage across the configurable calibration resistor, wherein the target voltage is less than or equal to the supply voltage;
- determine a first initial result by comparing a reference voltage to a given voltage across a reference resistor based at least in part on the configurable calibration resistor, wherein the first initial result indicates whether the given voltage is greater than the reference voltage;
- adjust the configurable calibration resistor;
- and
- store a first value of the configurable calibration resistor, in response to determining a comparison of the given voltage and the reference voltage generates a first final result different from the first initial result.
Dependencies are inferred from the claim text.