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1. (WO2002027333) TRANSFORMER CURRENT SENSOR

Pub. No.:    WO/2002/027333    International Application No.:    PCT/US2001/029252
Publication Date: Apr 4, 2002 International Filing Date: Sep 19, 2001
IPC: G01R 19/25
Applicants: MTS SYSTEMS CORPORATION
Inventors: WEGGEL, Craig, R.
Title: TRANSFORMER CURRENT SENSOR
Abstract:
A dual totem (or H-bridge) power stage has four power devices (Q1, Q2, Q3, Q4), at least two of which are controlled by pulse width modulation (PWN) control signals (Vg1?, Vg3?, Vg4?, Vg4?) to change current paths of the load current flowing through he driven load (110). A current sensor (130) for measuring the load current includes a transformer (120) having a secondary winding (S1) having a number N of turns, and a primary winding. The primary winding has four separate primary winding sections (P1, P2, P3, P4) each coupled in series with a different one of the four power devices of the dual totem power stage. Different ones of the four primary winding sections have different numbers of turns such that different turns ratios result between the primary winding (P1, P2, P3, P4) and the secondary winding for different current paths, thus generating a modulated signal on the secondary winding. The modulated signal is demodulated for accurate representation or reproduction of the current flowing through the load.