Managing Pulse Top Decay Improves Accuracy Of Current Sensing Circuits

Focus:

When a current transformer senses current in switched-mode power supplies and other applications, the current transformer and the associated burden resistor can alter the shape of the switching waveform as seen by the current sensing circuit. This change in the shape of the switching pulse can be described as pulse top decay and it degrades the accuracy of the current sense signal. This article quantifies the effect of the current sensing circuit on the pulse decay, providing guidance on how to properly determine the value of the burden resistor. This article also aims to show that the secondary side of a current transformer should provide the inductance energy discharge through a controllable voltage limiter, which ensures the zero volt-second integral of the current transformer.

What you’ll learn:

• How to improve accuracy of current-sensing circuits using current transformers
• How to understand the effect of the current transformer and burden resistor on the sensed switching waveform in current-sensing circuits

View the Source

Author & Publication:

Gregory Mirsky, Continental Automotive Systems, Deer Park, Ill., How2Power Today, Nov 15 2018

This article summary appears
in the HOW2POWER Design Guide.

The Design Guide offers
organized access to
hundreds of articles
on dozens of power conversion
and power management topics.

The Design Guide search results
include exclusive summaries
and accurate "how to" analysis
to help you make faster,
more informed decisions.

Search
for more articles