Current sensing circuit design guidelines

AN4076

4/14

Doc ID 022923 Rev 1

1

Current sensing circuit design guidelines

Figure 2 shows, in more detail, the block diagram of the power stage where two (or three)

shunt resistors are placed on the bottom of two (or three) inverter legs.

Figure 2.

Power stage block diagram (three-shunt-resistor case)

Figure 3 is the electrical circuit actually used for the proper conditioning of the signals on

each of the two (or three) shunt resistors (generically referred to as 'Current sensing' in

Figure 2). The voltage across the shunt resistor is filtered, shifted and finally amplified. Each

of these tasks requires attention and are discussed separately.