Multiplexed diagnostics

AN2859

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DocID15255 Rev 2

1.2

Failure mode detection of two AC switches

and R4 resitor values.Table 1 shows that we only need four different levels to define the

state of each AC switch.

VCC

VCC

R1

R2

R3

R4

V

STATE

V3

V2

V1

V0

VSTATE

V

AVF2

V

AVF1

AVF

AVF

V

AC

I

Load_1

V

AC

I

Load_2

AC

AC

VCC/COM

RAC

VCC/COM

ACS2

ACS1

Load1

Line

Load2

Line

I

Load_2

I

Load_1

RShunt

RAC

RShunt

IN2

IN1

G

G

ACS1 and ACS2 are not in conducting state

V2

V1

V0

I

Load_1

I

Load_2

VCC

VCC

R1

R2

R3

R4

V

STATE

V

AVF2

V

AVF1

AVF

AVF

AC

AC

VCC/COM

RAC

VCC/COM

ACS2

ACS1

Load1

Line

Load2

Line

I

Load_2

I

Load_1

RShunt

RAC

RShunt

V

AC

V

AC

VSTATE

STCC08

2

STCC08

1

V3

IN2

IN1

G

G

V

AC

V

AC

ACS1 and ACS2 are in conducting state