AMC1305L25-Q1 Datasheet, PDF (29/38 Pages) Texas Instruments – High-Precision, Reinforced Isolated Delta-Sigma Modulators

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AMC1305L25-Q1, AMC1305M05-Q1, AMC1305M25-Q1
SBAS797 – FEBRUARY 2017
10 Power-Supply Recommendations
In a typical traction inverter application, the high-side power supply (AVDD) for the device is derived from the
floating power supply of the upper gate driver. For lowest cost, a Zener diode can be used to limit the voltage to
5 V ±10%. Alternatively a low-cost low-drop regulator (LDO), for example the LP2951-xx-Q1, can be used to
minimize noise on the power supply. A low-ESR decoupling capacitor of 0.1 µF is recommended for filtering this
power-supply path. Place this capacitor (C₂ in Figure 58) as close as possible to the AVDD pin of the AMC1305-
Q1 for best performance. If better filtering is required, an additional 10-µF capacitor can be used. The floating
ground reference (AGND) is derived from the end of the shunt resistor, which is connected to the negative input
(AINN) of the device. If a four-pin shunt is used, the device inputs are connected to the inner leads, while AGND
is connected to one of the outer leads of the shunt.
For decoupling of the digital power supply on controller side, TI recommends using a 0.1-µF capacitor assembled
as close to the DVDD pin of the AMC1305-Q1 as possible, followed by an additional capacitor in the range of
1 µF to 10 µF.
Floating
Power Supply
HV+
20 V
To Load
RSHUNT
Gate Driver
Z1
1N751A
R1
800
C1
10 F
5.1 V
C2
0.1 F
AMC1305-Q1
AVDD
DVDD
AGND
AINN
DGND
DOUT
C4
0.1 F
C5
2.2 F
3.3 V, or 5.0 V
TMS320F2837x
SD-Dx
Gate Driver
AINP
CLKIN
SD-Cx
PWMx
Copyright © 2016, Texas Instruments Incorporated
HV-
Figure 58. Zener-Diode-Based High-Side Power Supply
Copyright © 2017, Texas Instruments Incorporated
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