US 2019/0245382 A1 · Current Sense Apparatus and Method

Abstract

A device comprises a positive current sense apparatus having two inputs connected to a drain and a source of a power switch respectively, the positive current sense apparatus comprising a first amplifier, a first sense switch and a second sense switch, a negative current sense apparatus having two inputs connected to the drain and the source of the power switch respectively, the negative current sense apparatus comprising a second amplifier, a third sense switch and a fourth sense switch and a current sense processing apparatus connected to the positive current sense apparatus and the negative current sense apparatus respectively.

Claims20

Dependent claims

A device comprising:

a positive current sense apparatus having two inputs connected to a drain and a source of a power switch respectively, the positive current sense apparatus comprising a first amplifier, a first sense switch and a second sense switch;
a negative current sense apparatus having two inputs connected to the drain and the source of the power switch respectively, the negative current sense apparatus comprising a second amplifier, a third sense switch and a fourth sense switch;
and
a current sense processing apparatus connected to the positive current sense apparatus and the negative current sense apparatus respectively.

1 more element

A method comprising:

through a positive current sense apparatus comprising a first sense switch and a second sense switch, mirroring in a positive current sense processing circuit a current passing through a power switch when the current flows from a drain of the power switch to a source of the power switch, wherein a ratio of the current passing through the power switch to a sense current flowing through the positive current sense processing circuit is equal to a ratio of a drain-to-source on-resistance of the first sense switch to a drain-to-source on-resistance of the power switch;
and
through a negative current sense apparatus comprising a third sense switch and a fourth sense switch, mirroring in a negative current sense processing circuit the current passing through the power switch when the current flows from the source of the power switch to the drain of the power switch, wherein a ratio of the current passing through the power switch to a sense current flowing through the negative current sense processing circuit is equal to a ratio of a drain-to-source on-resistance of the fourth sense switch to the drain-to-source on-resistance of the power switch.

A system comprising:

a power switch coupled between an input power source and a coil;
a positive current sense apparatus having two inputs connected to a drain and a source of the power switch respectively;
a negative current sense apparatus having two inputs connected to the drain and the source of the power switch respectively;
and
a current sense processing apparatus connected to the positive current sense apparatus and the negative current sense apparatus respectively, wherein the positive current sense apparatus and the negative current sense apparatus are configured such that:
a ratio of a current flowing through the power switch to a current flowing from the positive current sense apparatus to the current sense processing apparatus is equal to a ratio of a drain-to-source on-resistance of a sense switch of the positive current sense apparatus to a drain-to-source on-resistance of the power switch;
and
a ratio of the current flowing through the power switch to a current flowing from the negative current sense apparatus to the current sense processing apparatus is equal to a ratio of a drain-to-source on-resistance of a sense switch of the negative current sense apparatus to the drain-to-source on-resistance of the power switch.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application

15/891,950Filed 8 Feb 2018

Published

8 Aug 2019

Term ends

Not estimatedThe source records don’t support an estimate.

Classification11 codes

G01R 19/0092
Arrangements for measuring currents or voltages or for indicating presence or sign thereof: measuring current only
G01R 31/302
Testing of electronic circuits, e.g. by signal tracer: contactless testing
H02J 7/62
Including safety or protection arrangements: against overcurrent
H02J 50/10
Circuit arrangements or systems for wireless supply or distribution of electric power: using inductive coupling

Current Sense Apparatus and Method

Life of this patent

Current Sense Apparatus and Method

Life of this patent

Abstract

Claims20