Datasheet

R
2
12W
R
3
12W
R
SHUNT
AMC1203
Gated
Drive
Circuit
ToLoad
Floating
PowerSupply
HV+
Isolation
Barrier
C
2
330pF
C
3
10pF
(optional)
V
DD1
V
IN+
V
IN-
GND1
V
DD2
MDAT
MCLK
GND2
C
4
10pF
(optional)
C
1
(1)
0.1 Fm
D
1
5.1V
R
1
Gated
Drive
Circuit
Power
Supply
HV-
NOTE:(1)PlaceC closetoAMC1203.
1
AMC1203
www.ti.com SBAS427C –FEBRUARY 2008– REVISED JUNE 2011
APPLICATION INFORMATION
A typical operation of the AMC1203 in a motor-control of 0.1μF is recommended for filtering this
application is shown in Figure 30. Measurement of power-supply path. This capacitor ©
1
in Figure 30)
the motor phase current is done via the shunt resistor should be placed as close as possible to the V
DD1
pin
®
SHUNT
; in this case, a 2-terminal shunt). For better for best performance. If better filtering is required, an
performance, the differential signal is filtered using additional 1μF to 10μF capacitor can be used. The
RC filters (components R
2
, R
3
and C
2
). Optionally, C
3
floating ground reference (GND1) is derived from the
and C
4
can be used to reduce charge dumping from end of the shunt resistor, which is connected to the
the inputs. In this case, care should be taken when negative input of the AMC1203 (V
IN–
). If a 4-terminal
choosing the quality of these capacitors—mismatch in shunt is used, the inputs of the AMC1203 are
values of these capacitors will lead to a connected to the inner leads, while GND1 is
common-mode error at the input of the modulator. connected to one of the outer leads of the shunt.
Both digital outputs, MCLK and MDAT, can be
The high-side power supply for the AMC1203 (V
DD1
)
directly connected to a digital filter (that is, the
is derived from the power supply of the upper gate
AMC1210); see Figure 23.
driver. For lowest cost, a Zener diode can be used to
limit the voltage to 5V ±10%. A decoupling capacitor
Figure 30. Typical Application Diagram
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