Shunt Current Amplification Circuit - Renesas RAA3064002GFP User Manual

RAA3064002GFP/RAA3064003GFP
2.3.3

Shunt Current Amplification Circuit

The shunt current amplification circuit consists of two differential amplifiers. The differential amplifiers amplify the
differential voltage between the InINP and InINN pins and outputs the results through InOUT (n = 1 or 2). The bias
voltage and gain of the differential amplifiers are specifiable.
Figure 2.6 shows an example of usage of the shunt current amplifiers connected to motor drivers and shunt resistors.
VDD
Connecting the shunt resistors for use in current detection may lead to the generation of noise by the surge voltage of
the MOSFET motor driver. The external components that configure low-pass filters are required to eliminate this noise.
Note that, when resistors for the filter circuits (RA, RB, RC, and RD) are connected in series to the InINN and InINP pins
(n = 1 or 2), the value should be no greater than 100 Ω.
Relatively larger resistances may increase the input impedance, with the result of failure to attain a value for current gain
that is in the specified range.
R03UZ0002EJ0120 Rev.1.20
Apr 05, 2021
R
A
C
A
R
M
B
C
B
R
C
C
C
R
D
C
D
Figure 2.6
Shunt Current Amplification Circuit
Shunt current amplification circuit
Reference Differential
I1INP
voltage Note amplifier 1
I1INN
Reference Differential
I2INP
voltage Note amplifier 2
I2INN
Note: Gains of 10 or 25
2. Circuit Configuration
I1OUT
I2OUT
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