Magnetic field pulse current sensing for timing-sensitive circuits

Patent metadata

Field	Value
Publication number	US-10901011-B2
Application number	US-201916674665-A
Country	US
Kind code	B2
Filing date	Nov 5, 2019
Priority date	Nov 6, 2018
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A current measurement circuit for determining a start time t START , an end time t END , and/or a peak time t MAX for a current pulse passing through a current conductor. The current measurement circuit includes a pickup coil and a threshold crossing detector. The pickup coil generates a voltage V SENSE ′ proportional to a magnetic field around the conductor, which is proportional to a change in current over time. The threshold crossing detector compares V SENSE ′ and a threshold voltage and generates an output signal indicative of a transition time and whether a slope of V SENSE ′ is positive or negative. The current measurement circuit can also include an integrator and a sample and hold circuit. The integrator integrates V SENSE ′ over time and generates an integrated signal V SENSE . The sample and hold circuit compares V SENSE to t MAX and generates a second output signal which can be used to measure the pulse current.

First claim

What is claimed is:

1. A current measurement circuit for measuring characteristics of a current pulse passing through a current conductor, comprising:
a pickup coil for generating a voltage V SENSE ′ proportional to a magnetic field around the current conductor, wherein the magnetic field is proportional to a change in current through the current conductor over time;
an amplifier connected to the pickup coil for amplifying V SENSE ′ to generate an amplified V SENSE ′; and
at least one threshold crossing detector for comparing the amplified V SENSE ′ to at least one threshold voltage and generating an output signal based on the comparison, wherein the output signal is indicative of a transition time for the current pulse, and whether a slope of V SENSE ′ is positive or negative.

2. The current measurement circuit of claim 1 , wherein the at least one threshold voltage is ground.

3. The current measurement circuit of claim 2 , wherein the output signal is indicative of a start time of the current pulse when the output signal is indicative of a first transition time for the current pulse and the slope of V SENSE ′ changes from positive to negative in a first case or from negative to positive in a second case.

4. The current measurement circuit of claim 3 , wherein the output signal is indicative of a peak amplitude time of the current pulse when the output signal is indicative of a second transition time after the first transition time for the current pulse and the slope of V SENSE ′ remains positive or remains negative.

5. The current measurement circuit of claim 3 , wherein the output signal is indicative of an end time of the current pulse when the output signal is indicative of a third transition time after the first transition time for the current pulse and the slope of V SENSE ′ changes from negative to positive in the first case or from positive to negative in the second case.

6. The current measurement circuit of claim 1 , wherein the pickup coil comprises a single loop configured to be arranged near the current conductor.

7. The current measurement circuit of claim 1 , wherein the pickup coil is configured to not encircle the current conductor.

8. The current measurement circuit of claim 1 , wherein the pickup coil comprises a Rogowski-type coil.

9. The current measurement circuit of claim 1 , wherein the current measurement circuit is integrated on a single semiconductor chip.

10. The current measurement circuit of claim 9 , wherein the single semiconductor chip further comprises the current conductor.

11. A current measurement circuit for measuring characteristics of a current pulse passing through a current conductor, comprising:
a pickup coil for generating a voltage V SENSE ′ proportional to a magnetic field around the current conductor, wherein the magnetic field is proportional to a change in current through the current conductor over time;
at least one threshold crossing detector for comparing V SENSE ′ to at least one threshold voltage and generating an output signal based on the comparison, wherein the output signal is indicative of a transition time for the current pulse, and whether a slope of V SENSE ′ is positive or negative;
an integrator for integrating V SENSE′ over time and generating an integrated signal V SENSE based on the integrated voltage; and
a sample and hold circuit for comparing V SENSE to a peak amplitude time of the current pulse and generating a second output signal which can be used to measure the pulse current.

12. A current measurement circuit for measuring characteristics of a current pulse passing through a current conductor, comprising:
a pickup coil for generating a voltage V SENSE ′ proportional to a magnetic field around the current conductor, wherein the magnetic field is proportional to a change in current through the current conductor over time; and
at least one threshold crossing detector for comparing V SENSE ′ to at least one threshold voltage and generating an output signal based on the comparison, wherein the output signal is indicative of a transition time for the current pulse, and whether a slope of V SENSE ′ is positive or negative;
wherein the pickup coil comprises one or more turns, and wherein the one or more turns are arranged to increase a total magnetic flux resulting from the current pulse and reduce a total magnetic flux resulting from other sources.

13. The current measurement circuit of claim 12 , further comprising an amplifier for amplifying V SENSE ′ and connected to the pickup coil and to the at least one threshold crossing detector, wherein the at least one threshold crossing detector compares the amplified V SENSE ′.

14. A current measurement circuit for measuring characteristics of a current pulse passing through a current conductor, comprising:
a pickup coil for generating a voltage V SENSE ′ proportional to a magnetic field around the current conductor, wherein the magnetic field is proportional to a change in current through the current conductor over time; and
at least one threshold crossing detector for comparing V SENSE ′ to at least one threshold voltage and generating an output signal based on the comparison, wherein the output signal is indicative of a transition time for the current pulse, and whether a slope of V SENSE ′ is positive or negative;
wherein the at least one threshold crossing detector and a first portion of the pickup coil are integrated on a semiconductor chip, and wherein a second portion of the pickup coil is formed by at least two die terminals and an external conductor.

15. The current measurement circuit of claim 14 , wherein the external conductor forms part of a mounting substrate.

16. The current measurement circuit of claim 15 , wherein the mounting substrate further comprises a portion of the current conductor.

Assignees

• Efficient Power Conversion Corp

Inventors

• Glaser John S
• De Rooij Michael A

Classifications

• G01R29/02

  Measuring characteristics of individual pulses, e.g. deviation from pulse flatness, rise time or duration · CPC title

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G01R33/063

  Magneto-impedance sensors; Nanocristallin sensors · CPC title

• G01R33/028 Primary

  Electrodynamic magnetometers · CPC title

• G01R29/027

  Indicating that a pulse characteristic is either above or below a predetermined value or within or beyond a predetermined range of values · CPC title