Lawrence Jacobs was born in Palo Alto, California, in 1963. He received the B.S. degree in electrical engineering from Stanford University and the M.S. degree in electrical engineering from Santa Clara University in 1985 and 1990, respectively. He joined LeCroy Corporation (now Teledyne LeCroy), a manufacturer of high-performance measurement equipment located in Chestnut Ridge, New York in 1999 where he is presently managing the probe development group. His interests include precision analog and high frequency electronics design and measurement. Mr. Jacobs holds fourteen patents.
While we get the scope’s bandwidth from the vendor, as soon as we add a cable, probe, or amplifier to the scope, we decrease the system bandwidth. The new system bandwidth is as important to know as the scope’s bandwidth, but it is generally difficult to measure except in a calibration lab. We offer a simple method of evaluating the transfer function and system bandwidth of any probing system using a wide band noise source. This method not only gives us information about the probes and interconnects, but it also tells us how the scope responds to the measurement system, information which cannot be measured by a VNA alone.
This paper, presented at EDI CON USA 2017, demonstrates the use of a special probe tip utilized to convert a differential measurement of inductor voltage to a measurement of inductor current. It shows the connection and calibration considerations in the measurement of inductor current, including the digital signal processing algorithms required to compensate for the components in the power supply and the probe tip. It also explains current sharing measurements made in the time and frequency domain using a transient current generator.