Keithley Instruments, Inc.

Mary Anne Tupta

Alexander N Pronin

Andrew Alan Shetler

A test and measurement instrument, includes a user interface, one or more probes configured to connect to a device under test comprising a MOSFET, and one or more processors configured to execute code that causes the one or more processors to: set a target voltage to be measured across the MOSFET, apply a force voltage to the MOSFET, measure a drain current and a drain voltage of the MOSFET with the one or more probes, determine if a difference between the measured drain voltage and the target voltage meets a threshold, when the difference does not meet the threshold, use the measured drain voltage, the measured drain current, and a load resistance to determine a new force voltage value to compensate for the load resistance, set the force voltage to the new force voltage value, and repeat the apply, measure and determine steps as needed.

Correcting for load resistance when making I-V measurements with constant drain voltage on power MOSFETS

A testing environment includes a first measuring unit connected to a gate of a MOSFET device and a second measuring unit connected to a drain of the MOSFET device. The testing environment is particularly useful for testing gate charge for MOSFET devices. In a first phase, the gate of the device is driven with electrical current while the drain is driven with a constant voltage. As the MOSFET device turns on, the second measuring unit switches from providing the constant voltage to providing a constant current to the drain of the MOSFET, while measuring the drain voltage. The switching of modes is automatic and occurs without user intervention. After the MOSFET device has been driven to VgsMax by the gate current, all of the relevant data is stored, which may be analyzed and presented to a user in a User Interface or presented in other manner.

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Twinsburg, OH, United States of America

Mary Anne Tupta