Current Detection Circuit - Renesas RX200 Series User Manual

Renesas RX Family
5.1.2

Current detection circuit

The inverter board has the current detection circuit to measure the current at the U, V and W phase. The
current detection circuit uses shunt resistor at each phase. Voltage drop caused by the current flowing through
the shunt resistor is amplified by the current detection amplifier to output. The default gain of the current
detection amplifier is set to 20x, but the gain can be changed to 10x by setting JP5, JP7, JP9, JP10, JP14,
and JP15 to open. The relationship between the current Iin flowing through the shunt resistor and the voltage
Vout output from the current detection circuit is shown in equations (1) and (2). In addition, by switching JP8
and JP11 to 2-3 pin short circuit, one shunt current detection can be supported.
Amplifier gain 10x : Vout[V] = Iin[A] × Rs[Ω] × 10 + AVCC/2
Amplifier gain 20x : Vout[V] = Iin[A] × Rs[Ω] × 20 + AVCC/2
R12UZ0111EJ0100 Rev 1.00
November 15, 2022
Figure 5-2 Current detection circuit
MCK-RX26T User's Manual
(1)
(2)
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