TSX920, TSX921, TSX922, TSX923

Application information

DocID024310 Rev 4

21/32

5.7

High-side current sensing

TSX92x rail to rail input devices can be used to measure a small differential voltage on a

high side shunt resistor and translate it into a ground referenced output voltage. The gain is

fixed by external resistance.

Figure 41: High-side current sensing configuration

Equation 8

Equation 9

With the TSX92x operational amplifiers, the high side current measurement must be made

the application requires a higher common voltage please refer to the TSC high side current

sensing family.

V

ou t

R

shun t

I 1

R

g2

R

g2

R

f2

+

1

R

f1

R

g1

–

×

I

p

R

g2

R

f2

R

g2

R

f2

1

R

f1

R

g1

l

n

R

f1

V

R

f1

R

g1

+

–

–

+

=

+

+

×

×

+

×

V

out

R

shunt

I

R

f

R

g

×

V

R

f

R

g

–

R

f

I

io

×

+

=

+