Current detection device and method for sensing an electric current

Patent metadata

Field	Value
Publication number	US-10031162-B2
Application number	US-201415117754-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Feb 13, 2014
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

The invention relates to a method and a device for detecting a current in a measuring path, the current in said measuring path corresponding to a current in a power path. An electric current is detected by a current measuring instrument in the measuring path, while simultaneously part of the electric current is conducted parallel to the current measuring instrument by a bypass device, in order to reduce the load on the current measuring instrument.

First claim

The invention claimed is:

1. A current detection device ( 10 ) for detecting an electric measuring current (I s ) on a measuring path, the electric measuring current (I s ) corresponding to an electric current (I E ) on a power path, the current detection device comprising:
a current measuring device ( 11 ) which is arranged on the measuring path and which is designed to provide an output signal which corresponds to an electric current which flows through the current measuring device ( 11 ), and
a bypass device ( 12 ) including a current mirror circuit arranged in parallel with the current measuring device ( 11 ) and a resistor (R 0 ) arranged in series with the current measuring device ( 11 ), wherein the bypass device ( 12 ) is designed to adjust an electric bypass current (I B ) in dependence on the electric measuring current (I s ) by activating the current mirror circuit when the voltage drop across the resistor (R 0 ) is greater than a predetermined reference voltage.

2. The current detection device ( 10 ) as claimed in claim 1 , wherein the bypass device ( 12 ) is designed so that no electric bypass current flows through the bypass device ( 12 ) when the electric measuring current (I s ) drops below a predetermined first threshold value.

3. The current detection device ( 10 ) as claimed in claim 1 , wherein the bypass device ( 12 ) is designed to adjust an electric bypass current (I B ) in parallel with the current measuring device ( 11 ) when the electric measuring current (I s ) exceeds a predetermined second threshold value.

4. The current detection device ( 10 ) as claimed in claim 1 , wherein the bypass device ( 12 ) is designed to adapt the electric bypass current (I B ) in dependence on the output signal of the current measuring device ( 11 ).

5. The current detection device ( 10 ) as claimed in claim 1 , wherein the bypass device ( 12 ) is designed to limit the electric current through the current measuring device ( 11 ) to a predetermined maximum limit value.

6. The current detection device ( 10 ) as claimed in claim 1 , wherein the bypass device ( 12 ) further includes a reference voltage source (U Ref ) which is designed to provide the predetermined reference voltage and the bypass device ( 12 ) is designed to compare the voltage drop across the resistor (R 0 ) with the predetermined reference voltage provided by the reference voltage source (U Ref ) and to adjust the electric bypass current (I B ) in parallel with the current measuring device ( 11 ) in dependence on the comparison.

7. A circuit arrangement ( 1 ) for providing an electric current (I E ), comprising:
a current control device ( 20 ) which is designed to provide an electric current (I E ) on a power path and to provide an electric measuring current (I s ) corresponding to the provided electric current (I E ) on a measuring path, and
a current detection device ( 10 ) as claimed in claim 1 .

8. The circuit arrangement ( 1 ) as claimed in claim 7 , wherein the current control device ( 20 ) comprises a bipolar transistor having an insulated gate, IGBT.

9. A method ( 100 ) for detecting an electric current on a measuring path, the electric current corresponding to an electric current on a power path, the method comprising:
arranging ( 110 ) a current measuring device ( 11 ) on a measuring path,
arranging ( 120 ) a bypass device ( 12 ) on the measuring path, the bypass device including a current mirror circuit arranged in parallel with the current measuring device ( 11 ) and a resistor (R 0 ) arranged in series with the current measuring device ( 11 ), wherein the bypass device is designed to adjust an electric bypass current (I B ),
adjusting ( 130 ) an electric current (I B ) which flows through the bypass device ( 12 ) in dependence on the electric current which flows on the measuring path by activating the current mirror circuit when the voltage drop across the resistor (R 0 ) is greater than a predetermined reference voltage, and
detecting ( 140 ) an electric current which flows through the current measuring device ( 11 ).

10. The current detection device ( 10 ) as claimed in claim 1 , wherein the output signal is scaled in order to compensate for the bypass current not detected by the current measuring device ( 11 ) and to infer the electric current (I E ) on the power path by means of a suitable transfer factor.

Assignees

• Bosch Gmbh Robert

Inventors

• Sievert Holger
• Butzmann Stefan

Classifications

• G01R19/16571 Primary

  comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52) · CPC title

• G01R19/0046

  characterised by a specific application or detail not covered by any other subgroup of G01R19/00 · CPC title

• G01R19/0092 Primary

  Measuring current only · CPC title

• G01R15/08

  Circuits for altering the measuring range · CPC title

• G01R15/09

  Autoranging circuits · CPC title