Circuit configuration for a gradiometric current sensor and a sensor chip equipped with this circuit configuration

• US 20040239322A1
• Filed: 03/10/2004
• Published: 12/02/2004
• Est. Priority Date: 09/15/2001
• Status: Active Grant

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Buchhold, Reinhard
• Granted Patent: US 7,030,601 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• CPC Class Codes: G01R 15/205 using magneto-resistance devices, e.g. field plates
• CPC Class Codes: G01R 33/022 Measuring gradient

Abstract

In order to create a circuit configuration for a gradiometric current sensor with a bridge circuit in the form of a Wheatstone bridge for measuring gradients of the magnetic field strength of a current-carrying conductor, with four magnetoresistive resistors, two of which resistors form a sub-bridge in each case, while the sub-bridges are arranged symmetrically in relation to sub-conductors of the current-carrying conductor, and with a compensating circuit associated with the bridge circuit, which compensating circuit comprises compensating conductors associated with the magnetoresistive resistors, to which compensating conductors a compensating current can be applied, by means of which circuit configuration mounting tolerances can be compensated in a simple manner, it is provided that the sub-bridges (22, 24) can each have a separate compensating current (I_comp1, I_comp2) applied to them.

Claims

1. A circuit configuration for a gradiometric current sensor with a bridge circuit in the form of a Wheatstone bridge for measuring gradients of the magnetic field strength of a current-carrying conductor, with four magnetoresistive resistors, two of which resistors form a sub-bridge in each case, whereby the sub-bridges are arranged symmetrically in relation to sub-conductors of the current-carrying conductor, and with a compensating circuit associated with the bridge circuit, which compensating circuit comprises compensating conductors associated with the magnetoresistive resistors, to which compensating conductors a compensating current can be applied, characterized in that the sub-bridges (22, 24) can each have a separate compensating current (I_comp1, I_comp2) applied to them.

2. A circuit configuration as claimed in claim 1, characterized in that the compensating circuit (36) comprises separately switched compensating conductors (38, 38′

), which are associated with resistors (14, 16) and with the resistors (18, 20), respectively.

3. A circuit configuration as claimed in claim 1, characterized in that the compensating conductor (38) is connected to an input terminal (40) and to a fixed voltage potential (GND), and the compensating conductor (38′

) is connected to an input terminal (42) and the fixed voltage potential (GND).

4. A circuit configuration as claimed in claim 1, characterized in that the separate compensating currents (I_comp1, I_comp2) can be applied to the input terminals (40, 42) as a function of the output voltage (V_OUT) of the bridge circuit.

5. A sensor chip characterized by a circuit configuration (12) as claimed in claim 1.