6

Typical applications

6.1

Low-side current sensing

Power management mechanisms are found in most electronic systems. Current sensing is useful for protecting

applications. The low-side current sensing method consists of placing a sense resistor between the load and the

circuit ground. The resulting voltage drop is amplified using the TSV771 and TSV772 (see Figure 48. Low-side

current sensing schematic).

Figure 48. Low-side current sensing schematic

Vout can be expressed as follows:

VOut=Rsℎunt.I1− Rg2

Rg2+Rf2 . 1+Rf1Rg1 +Ip. Rg2.Rf2

Rg2+Rf2. 1+Rf1Rg1 −In.Rf1

−Vio. 1+Rf1Rg1

(4)

Assuming that Rf2 = Rf1 = Rf and Rg2 = Rg1 = Rg, this equation can be simplified as follows:

VOut=Rsℎunt.I.RfRg−Vio. 1+RfRg +Rf.Iio

(5)

The main advantage of using the TSV771 and TSV772 for a low-side current sensing relies on its low Vio,

compared to general purpose operational amplifiers. For the same current and targeted accuracy, the shunt

resistor can be chosen with a lower value, resulting in lower power dissipation, lower drop in the ground path, and

lower cost. Particular attention must be paid to the matching and precision of Rg1, Rg2, Rf1, and Rf2, to maximize

the accuracy of the measurement.

6.2

Photodiode transimpedance amplification

The TSV7722, with high bandwidth and slew rate, is well suited for photodiode signal conditioning in a

transimpedance amplifier circuit. This application is useful in high performance UV sensors, smoke detectors

or particle sensors.

TSV771, TSV772

Typical applications

DS13842 - Rev 3

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