Match line control circuit for content addressable memory
AssigneeNetLogic Microsystems, Inc.
InventorBindiganavale S. Nataraj
Life of this patent
Estimating the term…
Abstract
A match line control circuit includes a weak, static pull-up transistor and a strong, dynamic pull-up transistor coupled between a match line of an associated CAM and a supply voltage. Prior to compare operations, both the static pull-up transistor and the dynamic pull-up transistor are in a conductive state and thereby quickly charge the match line to the supply voltage. During compare operations, the dynamic transistor is turned off to reduce current flow between the supply voltage and the match line. In some embodiments, the static pull-up transistor and the dynamic pull-up transistor are configured to match the parasitics of the CAM cells 10 coupled to the match line, thereby increasing performance of the associated CAM.
Claims15
A control circuit for coupling to an associated match line of a content addressable memory (CAM) having a row of CAM cells, comprising:
- a static pre-charge circuit coupled between the match line and a power supply terminal;
- and
- a dynamic pre-charge circuit coupled between the match line and the power supply terminal, wherein the static pre-charge circuit and the dynamic pre-charge circuit are operative to simultaneously pre-charge the match line.
A method of controlling the state of a match line of a content addressable memory (CAM), comprising:
- pre-charging the match line simultaneously with a static pre-charge circuit and a dynamic pre-charge circuit when the CAM is not performing a compare operation;
- and
- disabling the dynamic pre-charge circuit from charging the match line when the CAM is performing a compare operation.
A control circuit for coupling to an associated match line of a content addressable memory (CAM) having a row of CAM cells, comprising:
- a static pre-charge circuit coupled to the match line;
- and
- a dynamic pre-charge circuit coupled to the match line and having more current carrying capacity than the static pre-charge circuit.
Dependencies are inferred from the claim text.