8.2 Typical Application

8.2.1 Solar Inverter Application

Isolated ΔΣ modulators are widely used for voltage measurements in high-voltage applications that must be

isolated from a low-voltage domain. Typical applications are AC line voltage measurements, either line-to-neutral

or line-to-line, and DC-link voltage measurements in frequency inverters. The AMC3336 integrates an isolated

power supply for the high-voltage side and therefore makes the device particularly easy to use in applications

that do not have a high-side supply readily available or where a high-side supply is referenced to a different

ground potential than the signal to be measured.

Figure 8-1 shows a simplified schematic of the AMC3336 in a solar inverter where the AC phase voltage is

measured on the grid-side. At that location in the system there is no supply readily available for powering the

isolated amplifier. The integrated isolated power-supply, together with its bipolar input voltage range, makes

the AMC3336 ideally suited for AC line-voltage sensing. In this example, phase current is sensed by the

AMC3306M05 across a shunt resistor on the grid-side of an LCL filter where there is also no suitable supply

available for powering the isolated amplifier. The integrated power-supply of the AMC3306M05 eliminates this

problem and enables current sensing at locations that are optimal for the system.

1 µF

100 nF

1 nF

1 nF

100 nF

10

10

10 nF

DCDC_OUT

DCDC_HGND

HLDO_IN

HLDO_OUT

HGND

INP

INN

NC

AMC3306M05

1 µF

1 nF

100 nF

47 k

DCDC_IN

LDO_OUT

VDD

CLKIN

DOUT

GND

DIAG

DCDC_GND

3.3 V / 5 V supply

to uC (optional)

GND

1 µF

100 nF

1 nF

1 nF

100 nF

1 nF

DCDC_OUT

DCDC_HGND

HLDO_IN

HLDO_OUT

HGND

INP

INN

NC

AMC3336

1 µF

1 nF

100 nF

47 k

DCDC_IN

LDO_OUT

VDD

CLKIN

DOUT

GND

DIAG

DCDC_GND

3.3 V / 5 V supply

to uC (optional)

GND

to grid (L1)

PGND

SW

SW

PGND

N

N

to uC

from uC

to uC

from uC

DC+

DC-

Figure 8-1. The AMC3336 in a Typical Application

AMC3336

SBASA70 – APRIL 2021

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