7 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

7.1 Application Information

Isolated modulators are widely used in application where a high-voltage domain is galvanically isolated from a

low-voltage domain for safety or functional reasons. A typical application is the sensing of the DC link voltage in

a frequency inverter.

7.2 Typical Application

Figure 7-1 shows a simplified schematic of a full-bridge motor drive that uses an AMC0136 to sense the 48V

DC link voltage. The DC link voltage is divided down to a 1V level by the resitive divider consisting of R1 and

R2. The AMC0136 digitizes the analog input signal on the high-side and transfers the data across the isolation

barrier to the low-side. The device then outputs the digital bitstream on the DOUT pin that is synchronized to the

clock applied to the CLKIN pin. The digital bitstream is processed by a low-pass digital filter in a micro control

unit (MCU) or FPGA.

The motor current in this application is sensed by an AMC0106M05 isolated modulator.

49.9

RSHUNT

1 nF

AVDD

AGND

INP

INN

AMC0106M05

DVDD

CLKIN

DOUT

DGND

4.7 uF

1 uF

100 nF

Low-side supply

(3.3 V or 5 V)

2

M

Gate

Driver

GND

1 nF

Signal Domain

Power Domain

+50 mV

0 V

–50 mV

D1

10 nF

100 nF

Gate

Driver

AVDD

AGND

IN

AGND

AMC0136

DVDD

CLKIN

DOUT

DGND

100 pF

+

–

48V

R1

R2

ICROSS

49.9

1 uF

100 nF

MCU

100 nF

1uF

DC/DC

GND

6V

5V

Figure 7-1. Using the AMC0136 for Voltage Sensing in a Full-Bridge, 48V Motor Driver Design

The AMC0136 requires a 3.3V or 5V supply to power the high-side (AVDD) of the isolated modulator. In this

example, AVDD is derived from the 48V rail by a DC/DC converter and a shunt regulator. The low-side supply

(DVDD) is shared with circuitry in the signal domain. Use the optional 49.9Ω resistor on the DOUT pin for

line-termination to improve signal integrity on the receiving end.

The galvanic isolation barrier and high common-mode transient immunity (CMTI) of the AMC0136 provide

reliable and accurate operation even in high-noise environments.

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AMC0136

SBASAZ0 – AUGUST 2024

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