Method and system for calibrating a shunt resistor

Patent metadata

Field	Value
Publication number	US-9632163-B2
Application number	US-201214125404-A
Country	US
Kind code	B2
Filing date	May 16, 2012
Priority date	Jun 29, 2011
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A shunt resistor includes: two measuring terminals for applying a measuring current flowing through the shunt resistor along a main flow direction; slot structures dividing the shunt resistor along the main flow direction to include two side flow areas of respective first widths and a main flow area of a second width; and two calibration terminals connected to the side flow areas. A circuit connected to the measuring terminals is designed to detect, and generate a signal based on, a measuring current flowing through the shunt resistor. A calibration device connected to the calibration terminals is designed to apply a reference voltage or current to the calibration terminals, and ascertain a calibration voltage based on a falling voltage across those terminals. A correction circuit connected to the calibration device and the detection circuit is designed to correct the signal generated by the detection circuit based on the detected calibration voltage.

First claim

What is claimed is:

1. A shunt resistor, comprising:
two measuring terminals configured for application of a measuring current that flows through the shunt resistor along a main flow direction;
slots that divide the shunt resistor along the main flow direction into (a) two side flow areas of respective first widths and (b) a main flow area of a second width, the flow of the measuring current being divided into three parallel flows, including respective flows in each of the two side flow areas and the main flow area; and
two calibration terminals that are connected to the side flow areas transversely with respect to the main flow direction.

2. The shunt resistor of claim 1 , wherein the second width is larger than each of the first widths, and the side flow areas and the main flow area are made of a same material.

3. A system for detecting a measuring current, comprising:
a shunt resistor that includes:
two measuring terminals configured for application of a measuring current that flows through the shunt resistor along a main flow direction;
slot structures that divide the shunt resistor along the main flow direction into (a) two side flow areas of respective first widths and (b) a main flow area of a second width; and
two calibration terminals that are connected to the side flow areas transversely with respect to the main flow direction;

a detection circuit that is:
connected to the measuring terminals of the shunt resistor;
configured to detect the measuring current flowing through the shunt resistor; and
configured to generate a measuring signal as a function of the detected measuring current;

a calibration device that is:
connected to the calibration terminals;
configured to apply one of a reference voltage and a reference current to the two calibration terminals; and
configured to ascertain a calibration voltage as a function of a falling voltage across the two calibration terminals; and

a correction circuit that is:
connected to the calibration device and the detection circuit; and
configured to correct the measuring signal generated by the detection circuit as a function of the ascertained calibration voltage.

4. The system of claim 3 , wherein the calibration device includes:
a source of one of a direct current and an alternating current, the source being connected to the calibration terminals of the shunt resistor; and
an operational amplifier configured to:
detect one of a falling direct voltage and a falling alternating voltage across the calibration terminals; and
ascertain the calibration voltage from the detected one of the falling direct voltage and the falling alternating voltage.

5. The system of claim 4 , further comprising:
a reference shunt resistor that is structurally identical to the shunt resistor and through which no measuring current flows;
a reference calibration device including a reference current source, which reference current source is connected to the calibration terminals of the reference shunt resistor; and
a reference operational amplifier configured to detect, and generate a reference calibration voltage based on, a falling voltage across the calibration terminals of the reference shunt resistor, wherein the correction circuit is connected to the reference calibration device and is designed to normalize the ascertained calibration voltage to the reference calibration voltage.

6. The system of claim 3 , wherein the calibration device includes:
an alternating voltage source configured to act on the calibration terminals with a reference alternating voltage;
two capacitors which are each connected to a respective one of the two calibration terminals;
two resistors which are each coupled between a respective one of the two capacitors and a respective ground terminal; and
an operational amplifier configured to tap a voltage difference between two nodes and ascertain the calibration voltage from the tapped voltage difference, each of the two nodes being between a respective one of the two capacitors and a respective one of the two resistors.

7. The system of claim 6 , further comprising:
a reference shunt resistor which is structurally identical to the shunt resistor and through which no measuring current flows;
a reference calibration device including a reference alternating voltage source which is connected to the calibration terminals of the reference shunt resistor;
two reference capacitors which are each connected to a respective one of the two calibration terminals of the reference shunt resistor;
two reference resistors which are each coupled between a respective one of the two reference capacitors and a respective ground terminal; and
a reference operational amplifier configured to tap a reference voltage difference between two reference nodes and generate a reference calibration voltage from the tapped reference voltage difference;
wherein:
each of the two reference nodes is arranged between a respective one of the two reference capacitors and a respective one of the two reference resistors; and
the correction circuit is connected to the reference calibration device and is configured to normalize the ascertained calibration voltage to the reference calibration voltage.

8. The system of claim 3 , wherein the calibration device includes:
a ring oscillator that is connected to the calibration terminals, and that is configured to generate a calibration voltage (a) which includes an alternating voltage and (b) whose frequency is a function of the resistance in the side flow areas of the shunt resistor.

9. A method for detecting a measuring current using a shunt resistor, the shunt resistor including (a) two measuring terminals configured for application of the measuring current which flows through the shunt resistor along a main flow direction, (b) slot structures which divide the shunt resistor along the main flow direction into (I) two side flow areas of respective first widths and (II) a main flow area of a second width, and (c) two calibration terminals that are connected to the side flow areas transversely with respect to the main flow direction, the method comprising:
detecting the measuring current flowing through the shunt resistor;
generating a measuring signal as a function of the detected measuring current;
applying one of a reference voltage and a reference current to the calibration terminals of the shunt resistor;
detecting a falling voltage across the two calibration terminals;
generating a calibration voltage from the falling voltage across the two calibration terminals; and
correcting the measuring signal as a function of the calibration voltage for ascertaining a corrected measuring current through the shunt resistor.

10. The shunt resistor of claim 1 , wherein, for each of the two side flow areas, the respective side flow area extends from a first respective end of the respective side flow area, at which the respective side flow area is connected to the main flow area, to a second end of the respective side flow area, at which the respective side flow area is connected to the main flow area.

Assignees

• Mueller Bernd
• Wieja Thomas
• Bosch Gmbh Robert

Inventors

• Mueller Bernd
• Wieja Thomas

Classifications

• G01R1/203

  Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts (resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R) · CPC title

• G01R35/005 Primary

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R35/00 Primary

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title