AMC1304L05-Q1 Datasheet, PDF (26/39 Pages) Texas Instruments – High-Precision, Reinforced Isolated Delta-Sigma Modulators with LDO

AMC1304L05-Q1, AMC1304L25-Q1, AMC1304M05-Q1, AMC1304M25-Q1
SBAS799 – FEBRUARY 2017
www.ti.com
9.2 Typical Applications
9.2.1 Traction Inverter Application
Isolated ΔΣ modulators are being widely used in new-generation traction inverter designs because of their high
ac and dc performance. Traction inverters are critical parts of electrical and hybrid electrical vehicles. The input
structure of the AMC1304-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
L1
RSHUNT
RSHUNT
L3
L2
Gate Driver
15 V
AMC1304-Q1
LDOIN DVDD
AINP DOUT
AINN
AGND
CLKIN
DGND
3.3 V
Gate Driver
15 V
AMC1304-Q1
LDOIN DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
Gate Driver
15 V
AMC1304-Q1
LDOIN DVDD
AINP DOUT
AINN CLKIN
AGND DGND
3.3 V
15 V
AMC1304-Q1
LDOIN DVDD
AINP DOUT
AINN
AGND
CLKIN
DGND
3.3 V
TMS320F28x7x
SD-D1
SD-C1
SD-D2
SD-C2
SD-D3
SD-C3
PWMx
SD-D4
SD-C4
Copyright © 2016, Texas Instruments Incorporated
Figure 54. The AMC1304-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 AMC1304-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 typically recommended RC filter in front of a ΔΣ modulator to improve signal-to-noise performance of the
signal path is not required for the AMC1304-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 TMS320F2807x family of low-cost microcontrollers
(MCUs) or TMS320F2837x family of dual-core MCUs is recommended. These families support 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.
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