Circuit arrangement and method for current measurement

Patent metadata

Field	Value
Publication number	US-10018655-B2
Application number	US-201415117511-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Feb 13, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

The invention relates to a circuit arrangement having a switching device ( 1 ) which is designed to provide a first voltage (U E ) and a first electrical current (I E ) in a power path and to provide a second voltage (U S ) and a second electrical current (I S ) in a measuring path for the duration of a switching period, wherein the first electrical current corresponds to the second electrical current; having a current measuring apparatus ( 2 ) which is arranged in the measuring path and is designed to provide an output signal (U M ) which corresponds to the first electrical current; and having a control circuit ( 3, 4 ) which is designed to activate the current measuring apparatus for the duration of a measuring period and to deactivate the current measuring apparatus again after the measuring period expires.

First claim

The invention claimed is:

1. A circuit arrangement comprising:
a switching device ( 1 ) configured, for the duration of a switching period (T B ), to provide a first voltage (U E ) and a first electric current (I E ) in a power path and also to provide a second voltage (U S ) and a second electric current (I S ) in a measurement path, wherein the second electric current (I S ) corresponds to the first electric current (I E );
a current measuring apparatus ( 2 ) arranged in the measurement path and configured to provide an output signal corresponding to the second electric current (I S ); and
a control circuit ( 4 ) configured to turn on the current measuring apparatus ( 2 ) for the duration of a measurement period (T M ) and to turn off the current measuring apparatus ( 2 ) again after the measurement period (T M ) has elapsed.

2. The circuit arrangement as claimed in claim 1 ,
wherein the switching device ( 1 ) comprises a BJT, a MOSFET, a JFET and/or an IGBT.

3. The circuit arrangement as claimed in claim 2 ,
wherein the switching device ( 1 ) is embodied as an IGBT having a sense terminal.

4. The circuit arrangement as claimed in claim 1 ,
wherein the duration of the measurement period (T M ) of the current measuring apparatus ( 2 ) is less than the duration of the switching period (T B ) of the switching device ( 1 ).

5. The circuit arrangement as claimed in claim 1 ,
wherein the control circuit ( 4 ) activates the current measuring apparatus ( 2 ) at the beginning of the switching period (T B ) of the switching device ( 1 ).

6. The circuit arrangement as claimed in claim 1 ,
wherein the control circuit ( 4 ) comprises a monostable multivibrator ( 5 ).

7. The circuit arrangement as claimed in claim 6 ,
wherein the control circuit ( 4 ) comprises a transistor ( 6 ) configured to activate and to deactivate the current measuring apparatus ( 2 ) and including a control terminal drivable by the monostable multivibrator ( 5 ).

8. The circuit arrangement as claimed in claim 1 ,
wherein the current measuring apparatus ( 2 ) is configured to provide a voltage signal (U M ) that is proportional to the first electric current (I E ).

9. The circuit arrangement as claimed in claim 1 , furthermore comprising:
a compensation circuit ( 3 ) configured to regulate the ratio of the first voltage (U E ) and the second voltage (U S ) of the switching device during the switching period (T B ).

10. The circuit arrangement as claimed in claim 9 ,
wherein the compensation circuit ( 3 ) includes an operational amplifier (OP) configured to regulate the first voltage (U E ) and the second voltage (U S ) of the switching device ( 1 ) by negative feedback.

11. A method for current measurement of an electric current in a measurement path of a circuit arrangement as claimed in claim 1 , comprising the following steps:
activating ( 110 ) the switching device ( 1 ) for the duration of a switching period (T B );
turning on ( 120 ) the current measuring apparatus ( 2 ) for the duration of a measurement period (T M ) by the control circuit ( 4 );
turning off the current measuring apparatus ( 2 ) following the measurement period (T M ) by the control circuit ( 4 ); and
outputting ( 130 ) an output signal by the current measuring apparatus ( 2 ),
said output signal corresponding to the second electric current (I S ) in the measurement path.

Assignees

• Bosch Gmbh Robert

Inventors

• Sievert Holger
• Butzmann Stefan

Classifications

• H03K17/56

  by the use, as active elements, of semiconductor devices (using diodes H03K17/74) · CPC title

• H03K2217/0027

  Measuring means of, e.g. currents through or voltages across the switch · CPC title

• H03K17/0828

  in composite switches · CPC title

• G01R19/0092 Primary

  Measuring current only · CPC title

• G01R15/146 Primary

  Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop (if no voltage isolation is involved G01R1/203 or G01R19/0092) · CPC title