US 9,755,496 B2Granted

Solid state wideband high impedance voltage converter

AssigneeNational Instruments Corporation

InventorsMark Whittington, Mohammadreza Samadiboroujeni

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Abstract

A front-end converter circuit may allow devices, e.g. oscilloscopes and digitizers, to receive input signals having a wide range of possible amplitudes while maintaining a high standardized input impedance. The converter may selectively couple, using low-voltage switches, a selected input network of two or more input networks to a virtual ground node, and a selected feedback network of two or more feedback networks to a transconductance stage input. The selected input network and selected feedback network together define a respective input signal amplitude range. The converter may also controllably adjust an AC gain of the converter to match a DC gain of the converter, and selectively couple non-selected input networks to signal ground. Output referred integrated resistor thermal noise may be reduced to a desired value by lowering the value of the transconductance stage coupled across the input of the converter (through an input resistance) and the virtual ground node.

Claims23

Dependent claims

An input circuit for establishing a switchable voltage converter, the input circuit comprising:

two or more input terminals, each input terminal of the two or more input terminals configured to couple to a respective input network, each input network comprising a respective input pathway;
two or more feedback terminals, each feedback terminal of the two or more feedback terminals configured to couple to a respective feedback network, each feedback network comprising a respective feedback pathway;
a switching network comprising:
a first set of low-voltage switches configured to selectively couple the respective input pathway of a selected respective input network across an input of the voltage converter and a first node;
and
a second set of low-voltage switches configured to selectively couple the respective feedback pathway of a selected respective feedback network across a second node and an output of the voltage converter, wherein the selected respective input network and the selected respective feedback network together define an input signal value range of the voltage converter;
an output configured to provide an output signal having a value within an output signal value range according to the defined input signal value range;
and
a control circuit configured to controllably adjust an AC gain of the voltage converter to match a DC gain of the voltage converter.

6 more elements

A voltage converter comprising:

an input configured to receive an input voltage;
an output configured to provide an output voltage according to the input voltage;
two or more input networks, each input network of the two or more input networks comprising a respective first terminal coupled to the input and further comprising a respective input pathway;
two or more feedback networks, each feedback network of the two or more feedback networks comprising a respective first terminal coupled to the output and further comprising a respective feedback pathway;
a switching network comprising:
a first set of low-voltage switches configured to selectively couple the respective input pathway of a selected respective input network across the input and a first node through a respective second terminal of the selected respective input network;
and
a second set of low-voltage switches configured to selectively couple the respective feedback pathway of a selected respective feedback network across a second node and the output through a respective second terminal of the selected respective feedback network, wherein the selected respective input network and the selected respective feedback network together define an input voltage range of the voltage converter;
and
a control circuit configured to controllably adjust an AC gain of the voltage converter to match a DC gain of the voltage converter.

7 more elements

A measurement system comprising:

a device configured to operate on an incoming signal;
and
a converter circuit having an input configured to receive an input signal, and having an output configured to provide the incoming signal according to the input signal, wherein the converter circuit is configured to:
selectively couple, by a first set of low-voltage switches, a respective input pathway of a selected respective input network of two or more input networks across the input and a first node configured to operate as a virtual ground node;
and
selectively couple, by a second set of low-voltage switches, a respective feedback pathway of a selected respective feedback network of two or more feedback networks, across a second node and the output, wherein the selected respective input network and the selected respective feedback network together define an input signal value range of the input signal;
and
controllably adjust an AC gain of the converter circuit to match a DC gain of the converter circuit.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/086,047Filed 21 Nov 2013
Published: US 2015/0137840 A121 May 2015
Granted: 5 Sep 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G05F 1/46
Regulating voltage or current: wherein the variable actually regulated by the final control device is DC
G06F 1/00
Details not covered by groups g06f3/00 - g06f13/00 and g06f21/00
Y02B 70/10
Technologies for an efficient end-user side electric power management and consumption: technologies improving the efficiency by using…
G05F
Systems for regulating electric or magnetic variables