US 10,862,480 B2Granted

Controlled active resistance

AssigneepSemi Corporation

InventorChristopher C. Murphy

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Abstract

A controlled active resistance. The active resistance is implemented on an integrated circuit. In some embodiments, the active resistance includes a MOSFET. In alternate embodiments, the active resistance includes a MOSFET and a resistor. The control for the active resistance includes a reference resistor and an operational amplifier. The control for the active resistance further includes two current sources: i) a current source producing a current that is proportional to absolute temperature, and ii) another current source that is produced by a bandgap voltage reference. In one aspect, the active resistance generates an effective resistance that is proportional to thermal voltage. In another aspect, the active resistance generates an effective resistance that is proportional to inverse of the thermal voltage. In an alternate aspect, the current sources have various dependencies, and the active resistance generates an effective resistance that is proportional to those dependencies.

Claims13

Dependent claims

A floating active resistance circuit, comprising:

a first resistive element;
a first active element having an input terminal, a control terminal and an output terminal;
a second active element having an input terminal, a control terminal and an output terminal;
a first operational amplifier, having a first input connected to the first resistive element, a second input connected to the input terminal of the first active element, and an output connected to the control terminal of the first active element;
a second operational amplifier, having a first input connected to a reference voltage, a second input connected to the first resistive element and the output terminal of the first active element, and an output connected to the control terminal of the second active element;
and
a first current source connected to the first active element and a second current source connected to the first resistive element,
wherein the first resistive element, the first operational amplifier, the first current source and the second current source are configured, in combination, to control the first active element, and cause the first active element to act as an active resistance, and
the second operational amplifier and the second active element are configured to create a floating node for the active resistance.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/276,482Filed 14 Feb 2019
Published: US 2020/0266815 A120 Aug 2020
Granted: 8 Dec 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

H03F 3/45475
Characterised by the way of implementation of the active amplifying circuit in the differential amplifier: using IC blocks as the active…
H03K 17/687
By the use, as active elements, of semiconductor devices: the devices being field-effect transistors
H03F 3/45071
Differential amplifiers: with semiconductor devices only
G01K 7/16
Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using…: using…