Copyright © 2016, Texas Instruments Incorporated

VIN

R1

10 k

Reset

2N2945

R5

C1

10 k

R3

D1

R2

10 k

V+

1N914A

LMV71x

(A2)

LMV71x

(A1)

R4

10 k

V+

VO

+

-

+

-

1

2

3

4

5

1

2

3

4

5

ILOAD (A)

VOUT (V)

C003

20

LMV712-N, LMV712-N-Q1

SNOS534J – FEBRUARY 2001 – REVISED NOVEMBER 2016

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Product Folder Links: LMV712-N LMV712-N-Q1

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Copyright © 2001–2016, Texas Instruments Incorporated

Typical Applications (continued)

IG, a current proportional to ICHARGE, flows according to Equation 1.

IG = VRSENSE / R1 = ( RSENSE × ICHARGE ) / R1

(1)

IG also flows through the gain resistor R3 developing a voltage drop equal to Equation 2.

V3 = IG × R3 = ( VRSENSE / R1 ) × R3 = ( ( RSENSE × ICHARGE ) / R2 ) × R3

(2)

VOUT = (RSENSE × ICHARGE ) × G

where

•

G = R3 / R1

(3)

The other channel of the LMV712-N may be used to buffer the voltage across R3 to drive the following stages.

8.2.1.3 Application Curve

Figure 35. High-Side Current-Sensing Results

8.2.2 Peak Detector

Figure 36. Peak Detector Schematic

8.2.2.1 Design Requirements

A peak detector outputs a DC voltage equal to the peak value of the applied AC signal. Peak detectors are used

in many applications, such as test equipment, measurement instrumentation, ultrasonic alarm systems, and so

forth. Figure 36 shows the schematic diagram of a peak detector using LMV712-N. This peak detector basically

consists of a clipper, a parallel RC network, and a voltage follower.