Modable dynamic terminator for high speed digital communications
First Claim
1. A terminator circuit for terminating an electrical connection, the terminator circuit comprising:
- at least one pull-up circuit connected between a higher-voltage supply rail and the electrical connection, wherein the at least one pull-up circuit turns on in response to a voltage at the electrical connection dropping below a lower threshold value;
at least one pull-down circuit connected between the electrical connection and a lower-voltage supply rail, wherein the at least one pull-down circuit turns on in response to the voltage at the electrical connection exceeding an upper threshold value;
biasing circuitry connected to the at least one pull-up circuit and the at least one pull-down circuit, wherein the biasing circuitry generates bias signals that determine the lower threshold value and the upper threshold value; and
logic circuitry connected to the biasing circuitry, wherein the logic circuitry receives as an input a designation of a mode for the terminator circuit selected from a plurality of modes, and wherein the logic circuitry directs the biasing circuitry to produce bias signals that correspond to the mode designated by the input to the logic circuitry.
1 Assignment
0 Petitions
Accused Products
Abstract
A terminator circuit for use on a pin of an integrated circuit (IC) is disclosed. A preferred embodiment of the present invention includes a clamp circuit that turns on when the voltage at the pin exceeds a threshold value (either an upper or lower bound). Logic and biasing circuitry are used to allow multiple modes of operation by adjusting the threshold values. A particular mode may be selected at any given time so as to strike an appropriate balance between signal quality and power consumption with respect to a particular terminator or set of terminators. This prevents excessive power consumption due to terminator circuitry at inactive or infrequently active IC pins.
-
Citations
15 Claims
-
1. A terminator circuit for terminating an electrical connection, the terminator circuit comprising:
-
at least one pull-up circuit connected between a higher-voltage supply rail and the electrical connection, wherein the at least one pull-up circuit turns on in response to a voltage at the electrical connection dropping below a lower threshold value;
at least one pull-down circuit connected between the electrical connection and a lower-voltage supply rail, wherein the at least one pull-down circuit turns on in response to the voltage at the electrical connection exceeding an upper threshold value;
biasing circuitry connected to the at least one pull-up circuit and the at least one pull-down circuit, wherein the biasing circuitry generates bias signals that determine the lower threshold value and the upper threshold value; and
logic circuitry connected to the biasing circuitry, wherein the logic circuitry receives as an input a designation of a mode for the terminator circuit selected from a plurality of modes, and wherein the logic circuitry directs the biasing circuitry to produce bias signals that correspond to the mode designated by the input to the logic circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A terminator circuit for use in an integrated circuit, comprising:
-
a first resistive element connected between a higher power supply rail and an integrated circuit pin;
a second resistive element connected between the integrated circuit pin and a lower power supply rail;
at least one biasing component, wherein the at least one biasing component limits current flow through the first resistive element and the second resistive element in accordance with a mode selected from a plurality of modes associated with the terminator circuit; and
mode-varying circuitry, wherein the mode-varying circuitry, in response to input, varies a degree to which current flow is limited by the at least one biasing component so as to make the plurality of modes selectable. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
Specification