Integrated current-time characteristic measurement system for multichannel positive temperature coefficient thermistors

摘要

The current-time characteristic plays a crucial role in assessing the actual working performance of a positive temperature coefficient (PTC) thermistor. However, the existing measurement instruments have serious limitations and hardly adapt to the actual production. This paper presents a state-of-the-art measurement system for the current-time characteristic of the PTC thermistor. Multiple updated measurement methods, including pulsed dry circuit testing, RMS digital computation, oversampling and decimation, are proposed to design this system. Several advanced techniques, specifically CAN bus, mixed signal SoC and VI, are introduced to implement this system. As a result, high accuracy class 0.1 is achieved. The current dynamic range is extended to 10~(4). The efficiency is increased by more than 12 times. In short, this highly integrated and cost-effective system reaches commercial grade for actual production. The practical application demonstrates that this system is quite suitable for batch production.