R

2

12W

R

3

12W

R

SHUNT

AMC1200

Gated

Drive

Circuit

ToLoad

Floating

PowerSupply

HV+

Isolation

Barrier

C

2

(1)

330pF

C

3

10pF

(optional)

VDD1

VINP

VINN

GND1

VDD2

VOUTP

VOUTN

GND2

C

4

10pF

(optional)

C

1

(1)

0.1 F

m

D

1

5.1V

R

1

Gated

Drive

Circuit

Power

Supply

HV-

C

5

(1)

0.1 F

m

ADC

TMC320

C/F28xxx

AMC1200

SBAS542A

– APRIL 2011 – REVISED AUGUST 2011

www.ti.com

APPLICATION INFORMATION

MOTOR CONTROL

A typical operation of the AMC1200 in a motor-control application is shown in Figure 32. 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.

(1)

Place these capacitors as close as possible to the AMC1200.

Figure 32. Typical Application Diagram for the AMC1200

The high-side power supply for the AMC1200 (VDD1) 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 5 V

±10%. A decoupling capacitor of 0.1 µF is

possible to the VDD1 pin for best performance. If better filtering is required, an additional 1-

µF to 10-µF capacitor

can be used. The floating ground reference (GND1) is derived from the end of the shunt resistor, which is

connected to the negative input of the AMC1200 (VINN). If a four-terminal shunt is used, the inputs of AMC1200

are connected to the inner leads, while GND1 is connected to one of the outer leads of the shunt.

The high transient immunity of the AMC1200 ensures reliable and accurate operation even in high-noise

environments such as the power stages of the motor drives.

The differential output of the AMC1200 can either directly drive an analog-to-digital converter (ADC) input or can

be further filtered before being processed by the ADC.

As shown in Figure 33, it is recommended to place the bypass and filter capacitors as close as possible to the

AMC1200 to ensure best performance.

12

Copyright

© 2011, Texas Instruments Incorporated