Inhalt:
The basic idea of using a low resistance shunt to generate a small voltage proportional to current flow is older than the field of electronics itself. But although this simple application of Ohm’s law is easy to understand, there are several error sources which may need to be accounted for, especially at low ohmic values. Demands on energy efficiency are driving shunts to ever lower ohmic values, and sub-milliohm values are becoming increasingly common. This presentation focusses on SMT shunt components at the lowest available values and covers the following topics:
- Understanding the sources of resistive current sensing error
- Selecting the optimum component
- Laying out your PCB pads and tracks
- Measuring extremely low ohmic values
- Verifying the ohmic value of an unmounted part
- Minimising value shift due to soldering process
