OAR1R01JP Datasheet, PDF (7/58 Pages) Token Electronics Industry Co., Ltd. – Chip Current Sense / Open-Air Current Shunts / Axial Current Sense Resistors

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Terminology & Glossary
Terminology Glossary
of Current Sensing
Resistors
What is a Current Sensing Resistor
Current sensing products are the newest and fastest growing resistive products in the industry today.
As with most passive products, the majority of new designs are surface mount. These resistors are
used to monitor the current in a circuit and translate the amount of current in that circuit into a voltage
that can be easily measured and monitored.
Current Detecting Resistors
Due to the increase in sales of notebook PCs, the demand for the DC/DC converter has shown rapid
growth because of its high-energy conversion efficiency, and its precise current-limiting capability.
However, to ensure the performance of the multiple output DC/DC converter, the current limiting
voltage must be detected precisely to protect an expensive notebook PC from an overload, which is
generally due to shorts within the capacitors used in these devices.
For high-energy conversion efficiency various control ICs have been developed that utilize resistive
components. To achieve the perfect cutoff mode of the DC load current at the programmed
current-limiting voltage of the control IC, a very stable and accurate sense resistor with the
following characteristics is required for precise voltage comparison.
● Very Low Ohmic Value should be below 25mΩ for minimizing power consumption at the current
sensing resistor.
● Tight Tolerance must be ±1% or tighter for maximizing the current supply within the limit of
accept able current.
● Low TCR is required for current sensing across the ambient temperature range of 0°C to 60°C.
● Low Thermal EMF for an accurate comparison between the programmed current-limiting voltage
of the control IC and the detected voltage.
Furthermore, the self-inductance should be for high frequency applications. Recommended types are
general purpose current sensing products or a flame retardant type.
What is a Current Sensing Resistor
Current sensing products are the newest and fastest growing resistive products in the industry today.
As with most passive products, the majority of new designs are surface mount. These resistors are
used to monitor the current in a circuit and translate the amount of current in that circuit into a voltage
that can be easily measured and monitored.
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