Integrated circuit stubs in a point-to-point system

Details Integrated circuit stubs in a point-to-point system Integrated circuit stubs in a point-to-point system

2001-02-28

2004-06-08

Phan, Trong (Department: 2818)

Electronic digital logic circuitry

Signal sensitivity or transmission integrity

C326S030000, C326S086000

Reexamination Certificate

active

06747474

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to integrated circuits and, more particularly, use of active integrated circuit stubs in a point-to-point system of integrated circuits.
2. Background Art
FIG. 1
illustrates a system
10
of integrated circuits including integrated circuits IC
0
, IC
1
, IC
2
. . . ICn. The integrated circuits are connected through a bus
16
. Integrated circuit IC
0
may be a controller to control IC
1
, IC
2
. . . ICn or can be the same as them or can be the same as other integrated circuits or can be different. System
10
may be a system that is referred to as multi-drop system in which one or more of integrated circuits IC
1
, IC
2
. . . ICn are selectively joined to bus
16
through stubs
18
-
1
,
18
-
2
, . . .
18
-n, respectively. Merely as an example, system
10
may be a memory system in which controller
14
is a memory controller (either joined with a processor on chip or in a different chip from the processor) and in which integrated circuits IC
1
, IC
2
. . . ICn are, for example, dynamic random access memory (DRAM) chips that are on one or more printed circuit boards (PCBs). They could also be in a multi-processor system.
Address, data, and control bits on bus
14
, may be on separate conductors of bus
14
or they may be, for example, time division multiplexed or packetized. For example, bus
14
may include some conductors used to carry only address bits, some conductors used only to carry only control bits, and some conductors used to carry only data bits. Or, some conductors may be used to transmit some combination of address, control, and/or data bits at different times or through a packetized or arrangement.
FIG. 2
illustrates a system
20
including integrated circuits IC
0
, IC
1
, IC
2
. . . ICn. The integrated circuits are connected through busses
24
-
1
,
24
-
2
, . . .
24
-n. IC
0
may be a controller to control the other integrated circuits or can be the same as them. System
20
is of the type that is sometimes referred to as point-to-point bus system. An optional conductor
28
completes the loop. System
10
, by contrast, is referred to as a radial bus system.
A disadvantage of radial bus systems is that they are slower do to the relatively large amount of capacitance associated with relatively long conductors and multiple receiving circuitry in IC
0
, IC
1
, IC
2
, . . . ICn. An associated disadvantage is that energy is dispersed through the stubs as well as through the bus. For example, in
FIG. 1
, at the junction of the bus
16
and stub
18
-
1
, some electrical energy passes through stub
18
-
1
and other electrical continues through bus
18
past stub
18
-
1
. This reduces the effective bus speed.
Another disadvantage of current point-to-point systems is that in many systems there is a set number of chips. Even if the number of chips can be added to by adding to the last chip, if a chip in the interior of the loop fails, the whole system is down. For example, in
FIG. 2
, if IC
2
is defective, the entire system may be nonoperational. By contrast, multi-drop systems are typically relatively easy to add to and in many such systems, if one of the chips fails, the system as a whole can still operate. For example, in
FIG. 1
, if IC
2
is defective, the rest of the system may be able to continue.
Bi-directional signaling refers to using the same conductors to transmit signals in both directions. For example, data may be transmitted either to or from an integrated circuit. If the same conductor is used in both directions, the signaling is bi-directional. The bi-directional signaling may be sequential or simultaneous. In the case of sequential bi-directional signaling, enable signals may be used to, for example, tri-state or turnoff unused drivers or receivers. In the case of simultaneous bi-directional signaling, the threshold voltage of the receiver may be changed depending on the state of the adjacent driver. For example, if the adjacent driver is transmitting a 0, the receiver threshold may be set to Vcc/4. If the remote driver is also 0, the threshold will not be met. If the remote driver is a 1, the Vcc/4 threshold will be met. If the adjacent driver is also transmitting a 1, the receiver threshold may be set to 3Vcc/4. If the remote driver transmits a 1, the threshold will be met and if it transmits a 0, the threshold will not be met.


REFERENCES:
patent: 4703198 (1987-10-01), Porter et al.
patent: 5604450 (1997-02-01), Borkar et al.
patent: 5955894 (1999-09-01), Vishwanthaiah et al.
patent: 5982192 (1999-11-01), Saito
patent: 6115318 (2000-09-01), Keeth
patent: 6437601 (2002-08-01), Borkar et al.
patent: 6502161 (2002-12-01), Perego et al.
J. Gabara, “Digitally Adjustable Resistors in CMOS for High-Performance Applications,” IEEE Journal of Solid-State Circuits, vol. 27, No. 8, Aug. 1992, pp. 1176-1185.
R. Farad-Rad, “A 0.4-um CMOS 10-Gb/s 4-PAM Pre-Emphasis Serial Link Transmitter,” IEEE Journal of Solid-State Circuits, vol. 34, No. 5, May 1999, pp. 580-585.
C. Smythe, “ISO 8802/5 token ring local-area networks,” Electronics & Communication Engineering Journal, Aug. 1999, pp. 195-297.
T. Starr, “Understanding Digital Subscriber Line Technology,” Chapter 7, pp. 202-205, Prentice Hall PTR, Upper Saddle River, NJ, 1999.

Affiliated with

Also associated with

Rating

Integrated circuit stubs in a point-to-point system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Integrated circuit stubs in a point-to-point system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrated circuit stubs in a point-to-point system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3365332