US 7,064,599 B1 · Apparatus and method for signal transmission

Abstract

A signal transmission gate includes a switch such as a transistor. The switch includes a gate terminal adapted to receive a control voltage, and a source terminal and a drain terminal. One of the source and drain terminals is adapted to receive an input signal, and the output signal is provided on the other terminal. A constant-voltage boosting circuit generates the control voltage such that it has a substantially constant value above a voltage of the input signal. In one embodiment, the constant-voltage boosting circuit is coupled between the gate terminal and the terminal that receives the input voltage, and generates a substantially constant voltage difference. In one implementation, a component is employed that exhibits a characteristic voltage behavior, such as a diode, for generating the substantially constant voltage difference.

Claims19

Dependent claims

A transmission gate, comprising:

a switch circuit including an input that is coupled to an input node, an output that is coupled to an output node, and a control input that is coupled to a control input node;
a boost circuit that is arranged to provide a boost voltage at a boost node responsive to a supply voltage;
a current source circuit that is coupled between the boost node and the control input node, wherein the current source circuit is arranged to provide a bias current during an on condition;
and
a constant voltage difference circuit that is coupled to the control input node, wherein the constant voltage difference circuit is arranged to provide a control input voltage at the control input node such that a voltage difference between the control input voltage and an input voltage at the input node is substantially constant during the on condition, wherein the constant voltage difference circuit includes a plurality of transistors, and wherein the constant voltage difference circuit is arranged such that the substantially constant voltage difference is substantially equal to the sum of the gate-to-source voltages of each of the plurality of transistors.

2 more elements

A transmission gate, comprising:

a switch circuit including an input that is coupled to an input node, an output that is coupled to an output node, and a control input that is coupled to a control input node;
a boost circuit that is arranged to provide a boost voltage at a boost node responsive to a supply voltage;
a current source circuit that is coupled between the boost node and the control input node, wherein the current source circuit is arranged to provide a bias current during an on condition, and wherein the on condition is an on condition for the switch circuit;
and
a constant voltage difference circuit that is coupled to the control input node, wherein the constant voltage difference circuit is arranged to provide a control input voltage at the control input node such that a voltage difference between the control input voltage and an input voltage at the input node is substantially constant during the on condition, wherein:
the boost circuit is a charge pump circuit that is arranged to provide the boost voltage such that the boost voltage is greater than the supply voltage;
and
wherein the current source circuit is a current mirror circuit that is arranged to provide the bias current such that the bias current is substantially constant.

5 more elements

A circuit for multiplexing, comprising:

a first transmission gate, including:
a switch circuit including an input that is coupled to an input node, an output that is coupled to an output node, and a control input that is coupled to a control input node;
a constant voltage difference circuit that is coupled to the control input node, wherein the constant voltage difference circuit is arranged to provide a control input voltage at the control input node such that a voltage difference between the control input voltage and an input voltage at the input node is substantially constant during an on condition of the first transmission gate, and wherein the constant voltage difference circuit includes at least one of a first transistor or a first diode;
and
a second transmission gate, including:
a second switch circuit including an input that is coupled to a second input node, an output that is coupled to the output node, and a control input that is coupled to a second control input node;
and
a second constant voltage difference circuit that is coupled to the second control input node, wherein the second constant voltage difference circuit is arranged to provide a second control input voltage at the second control input node such that a voltage difference between the second control input voltage and a second input voltage at the second input node is substantially constant during an on condition of the second transmission gate.

5 more elements

Dependencies are inferred from the claim text.

Apparatus and method for signal transmission

Life of this patent

Apparatus and method for signal transmission

Life of this patent

Abstract

Claims19