Ultraprecise Current Sense Amplifi er Dramatically Enhances Effi ciency and Dynamic Range:Accurate current measurement is indispensable in many
electronic systems. The current is usually measured by
amplifying the voltage it generates across a small value
resistance. For systems that require a large dynamic measurement
range, the sense resistance must be increased or
the precision of the amplifi er must be improved. Increasing
the value of the sense resistor has the detrimental effect
of increasing power dissipation. The better option is to
improve the precision of the sense amplifi er.
Amplifi er precision depends a great deal on the input
offset voltage of the amplifi er. Historically, current sense
amplifi ers on the market offered input offset voltage
performance on the order of hundreds or even thousands
of μV. With such parts, achieving a practical dynamic
range of 8 to 10 bits can cost more than a Watt of power
dissipation at full operating current. The LTC?6102 ultraprecise
current sense amplifi er reduces input error to a
miniscule 10μV. This dramatic performance enhancement
translates directly into a greater measurement dynamic
range—16 bits is possible even while lowering power
dissipation in the sense resistor—thus greatly expanding
the gamut of current sensing design options.