Noncontact Power Module Current Measurement Based on Bonding Wire Current Sensing Using Hybrid Sensor

Abstract

In applications with high current and high power, designers tend to prefer the use of semiconductor power modules over discrete devices. The wire-bonding power module is the most widely used type. The wire-bonding power module integrates multiple power semiconductor chips internally. The device exhibits complex multiphysics coupling, where uneven distribution of heat and mechanical stress can result in uneven current distribution. Therefore, real-time current monitoring of power modules is an effective approach to enhance their reliability. However, traditional methods of measuring current involve monitoring the external current of the power module, which cannot provide real-time detection of the current flowing through each power semiconductor chip and is hard to integrate within the module. This article introduces contactless current sensing of bonding wires utilizing a magnetoresistance-Rogowski coil type hybrid sensor. The sensor is designed in a multilayer printed circuit board. The magnetic field around bonding wires is studied, and a simple signal processing circuit is designed. The design approach of the current system’s parameters is proposed. The sensor has dimensions of 10.0 × 10.0 mm. According to lumped model, it has a measurement bandwidth from dc to 100 MHz. The hybrid sensor accurately measures periodic, turn-on, and turn-off currents for single-chip power module current measurement and detects current imbalances between chips in multichip current measurement.