AMC1305L25-Q1 Datasheet, PDF (25/38 Pages) Texas Instruments – High-Precision, Reinforced Isolated Delta-Sigma Modulators

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AMC1305L25-Q1, AMC1305M05-Q1, AMC1305M25-Q1
SBAS797 – FEBRUARY 2017
9.2 Typical Applications
9.2.1 Traction Inverter Application
Because to their high ac and dc performance, isolated ΔΣ modulators are being widely used in new generation
traction inverter designs. Traction inverters are critical parts of electrical and hybrid electrical vehicles. The input
structure of the AMC1305-Q1 is optimized for use with low-impedance shunt resistors and is therefore tailored for
isolated current sensing using shunts.
DC link
Gate Driver
Gate Driver
Gate Driver
RSHUNT
RSHUNT
RSHUNT
Gate Driver
5.0 V
AMC1305-Q1
AVDD DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
Gate Driver
5.0 V
AMC1305-Q1
AVDD DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
Gate Driver
5.0 V
AMC1305-Q1
AVDD DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
5.0 V
AMC1305-Q1
AVDD DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
TMS320F2837x
SD-D1
SD-C1
SD-D2
SD-C3
SD-D4
SD-C4
PWMx
SD-D5
SD-C5
Copyright © 2016, Texas Instruments Incorporated
Figure 54. The AMC1305-Q1 in a Traction Inverter Application
9.2.1.1 Design Requirements
A typical operation of the device in a traction inverter application is shown in Figure 54. When the inverter stage
is part of a motor drive system, measurement of the motor phase current is done via the shunt resistors (R_SHUNT).
Depending on the system design, either all three or only two phase currents are sensed.
In this example, an additional fourth AMC1305-Q1 is used to support isolated voltage sensing of the dc link. This
high voltage is reduced using a high-impedance resistive divider before being sensed by the device across a
smaller resistor. The value of this resistor can degrade the performance of the measurement, as described in the
Isolated Voltage Sensing section.
9.2.1.2 Detailed Design Procedure
The usually recommended RC filter in front of a ΔΣ modulator to improve signal-to-noise performance of the
signal path, is not required for the AMC1305-Q1. By design, the input bandwidth of the analog front-end of the
device is limited to 1 MHz.
For modulator output bit-stream filtering, a device from TI's TMS320F2837x family of dual-core MCUs is
recommended. This family supports up to eight channels of dedicated hardwired filter structures that significantly
simplify system level design by offering two filtering paths per channel: one providing high accuracy results for
the control loop and one fast response path for overcurrent detection.
Copyright © 2017, Texas Instruments Incorporated
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