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US 6,664,804 B2Granted

Transmission circuit, data transfer control device, and electronic equipment

AssigneeSeiko Epson Corporation

InventorsAkira Nakada, Akira Abe, Shoichiro Kasahara

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Abstract Drawings Claims Description

Abstract

There are provided a transmission circuit capable of stabilizing high-speed data transfer by driving current, a data transfer control device, and electronic equipment. An HS current driver (transmission circuit) included in a data transfer control device has a current source connected between a first power supply AVDD and a node ND, and switching devices SW1 to SW3, one ends of which are connected to the node ND. The other end of the switching device SW1 is connected to a DP terminal. The other end of the switching device SW2 is connected to a DM terminal. The other end of the switching device SW3 is connected to a DA terminal. The DA terminal is connected to a second power supply AVSS inside or outside the transmission circuit. The transmission circuit is configured so that impedances of each current path from the node ND through the switching devices SW1 to SW3 become substantially equal when the switching device is turned on. This prevents an increase in the voltage of the node ND in a non-signal-transmission period.

Claims39

Dependent claims

Claim 1A transmission circuit which transmits a signal through first and second signal lines forming a differential pair · 128 words3 dependent Claim 5A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 184 words8 dependent Claim 13A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 287 words12 dependent Claim 27A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 329 words2 dependent Claim 30A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 356 words2 dependent Claim 33A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 349 words1 dependent Claim 35A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 387 words2 dependent Claim 38A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0 · 333 words1 dependent

A transmission circuit which transmits a signal through first and second signal lines forming a differential pair, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
a first switching device inserted between the node and the first signal line;
a second switching device inserted between the node and the second signal line;
and
a third switching device inserted between the node and a second power supply,
wherein one of the first and second signal lines is driven by current from the current source through one of the first and second switching devices in a signal-transmission period, and
wherein the node is connected to the second power supply through the third switching device in a period other than the signal-transmission period.

4 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
a first transistor which is inserted between the node and the first signal line and has an impedance substantially equal to an impedance Z0 when the first transistor is turned on;
a second transistor which is inserted between the node and the second signal line and has an impedance substantially equal to the impedance Z0 when the second transistor is turned on;
and
a third transistor which is inserted between the node and a second power supply and has an impedance twice the impedance Z0 when the third transistor is turned on;
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period, and
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period.

4 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a third connection terminal connected to a second power supply outside the transmission circuit;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is inserted between the node and the third connection terminal and has an impedance substantially equal to an impedance Z0 when the third transistor is turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period, and
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period.

8 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a third connection terminal connected to a second power supply outside the transmission circuit;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is inserted between the node and the third connection terminal and has an impedance substantially equal to an impedance Z0 when the third transistor is turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0,
wherein at least one of the first to third transistors is an n-type MOS transistor,
wherein a signal transmitted through the first and second signal lines, which form the differential pair, is a signal conforming to the Universal Serial Bus (USB) standard,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period, and
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period.

10 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a third connection terminal connected to a second power supply outside the transmission circuit;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is inserted between the node and the third connection terminal and has an impedance substantially equal to an impedance Z0/2 when the third transistor is turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a third load element which is connected between the third transistor and the third connection terminal and has an impedance substantially equal to the impedance Z0/2,
wherein at least one of the first to third transistors is an n-type MOS transistor,
wherein a signal transmitted through the first and second signal lines, which form the differential pair, is a signal conforming to the Universal Serial Bus (USB) standard,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period, and
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period.

12 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a third connection terminal connected to a second power supply outside the transmission circuit;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is inserted between the node and the third connection terminal and has an impedance substantially equal to an impedance Z0/2 when the third transistor is turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0,
wherein at least one of the first to third transistors is an n-type MOS transistor,
wherein a signal transmitted through the first and second signal lines, which form the differential pair, is a signal conforming to the Universal Serial Bus (USB) standard,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period,
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period, and
wherein the third connection terminal is terminated at an impedance substantially equal to the impedance Z0/2 outside the transmission circuit.

11 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a third connection terminal connected to a second power supply outside the transmission circuit;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is inserted between the node and the third connection terminal and has an impedance substantially equal to an impedance Z0/2 when the third transistor is turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a third load element which is connected between a third transmission signal line connecting the third transistor with the third connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0,
wherein at least one of the first to third transistors is an n-type MOS transistor,
wherein a signal transmitted through the first and second signal lines, which form the differential pair, is a signal conforming to the Universal Serial Bus (USB) standard,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period,
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period, and
wherein the third connection terminal is terminated at an impedance substantially equal to the impedance Z0 outside the transmission circuit.

13 more elements

A transmission circuit which transmits a signal through a differential pair of first and second signal lines which are terminated at a given impedance Z0, the transmission circuit comprising:

a current source connected between a first power supply and a given node;
first and second connection terminals connected to the first and second signal lines;
a first transistor which is inserted between the node and the first connection terminal and has an impedance substantially equal to an impedance Z0/2 when the first transistor is turned on;
a second transistor which is inserted between the node and the second connection terminal and has an impedance substantially equal to the impedance Z0/2 when the second transistor is turned on;
a third transistor which is connected to the node and has an impedance substantially equal to the impedance Z0/2 when turned on;
a first load element which is connected between a first transmission signal line connecting the first transistor with the first connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a second load element which is connected between a second transmission signal line connecting the second transistor with the second connection terminal and the second power supply, and has an impedance substantially equal to the impedance Z0;
and
a third load element which is inserted between the third transistor and the second power supply and has an impedance substantially equal to the impedance Z0/2,
wherein at least one of the first to third transistors is an n-type MOS transistor,
wherein a signal transmitted through the first and second signal lines, which form the differential pair, is a signal conforming to the Universal Serial Bus (USB) standard,
wherein one of the first and second signal lines is driven by the current source through one of the first and second transistors in a signal-transmission period, and
wherein the node is connected to the second power supply through the third transistor in a period other than the signal-transmission period.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/142,066Filed 10 May 2002
Priority: JP 2001-14363314 May 2001
Published: US 2002/0172151 A121 Nov 2002
Granted: 16 Dec 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G06F 13/4072
Electrical coupling: drivers or receivers
H04L 7/033
Speed or phase control by the received code signals, the signals containing no special synchronisation information: using the transitions of the…
G06F
Computing and data processing
H04L
Digital communication

Family

US 2002/0172151 A1Pre-grant publication · published 21 Nov 2002
US 6,664,804 B2This patent

From the US filing history. Foreign family members aren’t listed.

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