R

2

12W

R

3

12W

R

SHUNT

AMC1204

Gated

Drive

Circuit

ToLoad

Floating

PowerSupply

HV+

Isolation

Barrier

C

2

330pF

C

3

10pF

(optional)

AVDD

VINP

VINN

AGND

DVDD

DATA

CLKIN

DGND

C

4

10pF

(optional)

C

1

(1)

0.1 F

m

D

1

5.1V

R

1

Gated

Drive

Circuit

Power

Supply

HV-

AMC1204

www.ti.com

SBAS512B

– APRIL 2011 – REVISED AUGUST 2011

APPLICATION INFORMATION

A typical operation of the AMC1204 in a motor control application is shown in Figure 50. Measurement of the

can be used to reduce charge dumping from the inputs. In this case, care should be taken when choosing the

quality of these capacitors

—mismatch in values of these capacitors leads to a common-mode error at the input of

the modulator.

The high-side power supply for the AMC1204 (AVDD) is derived from the power supply of the upper gate driver.

For lowest cost, a zener diode can be used to limit the voltage to 5V

±10%. A decoupling capacitor of 0.1µF is

possible to the AVDD pin for best performance. If better filtering is required, an additional 1

µF to 10µF 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 of the AMC1204 (VINN). If a four-terminal shunt is used, the inputs of AMC1204

are connected to the inner leads, while AGND is connected to one of the outer leads of the shunt. Both digital

signals, CLKIN and DATA, can be directly connected to a digital filter (for example, the AMC1210); see

Figure 51.

Figure 50. Typical Application Diagram

Copyright

© 2011, Texas Instruments Incorporated

21