DA6510.009

6 September, 2018

28 (32)

VDD LEVEL MONITORING MODE

The MAS6510 has VDD level monitoring feature to

measure supply voltage level which is useful

especially in battery operated systems. In systems in

which VDD can vary the VDD level monitoring could

be also used to compensate VDD dependency.

The VDD level monitoring measurement is started by

writing configuration data to the measurement

monitoring mode the regulator has to be disabled

(TEMPREGEN=0)

and

VDD

level

monitoring

selected

(SEL=01).

The

ratio

and

difference

converter bit (XRC) selection does not have any

influence on the result.

Typically the smallest over sampling ratio (OSR)

selection 256 offers sufficient resolution for the VDD

level monitoring.

VDD level monitoring model

The VDD level monitoring model for output code is following.











 −



=

VDD

b

a

CODEFS

CODE

Equation 23.

The output has inverse relationship to supply voltage VDD. The OSR selects full scale output code range value

CODEFS. See ELECTRICAL CHARACTERISTICS for CODEFS at different OSR values.

The typical VDD level monitoring model parameter values a and b are as follows.

a=1.6375

b=2.6942

Note that these parameter values are subject to about two percent variations.

The supply voltage VDD can be solved from the output result as follows.

CODEFS

CODE

a

b

VDD

−

=

Equation 24.

Figure 7 presents typical output code as function of supply voltage at OSR=256 (CODEFS=227328).

Figure 8 present supply voltage as function of output code at OSR=256 (CODEFS=227328).

Figure 7. CODE(VDD) at VDD level monitoring

Figure 8. VDD(CODE) at VDD level monitoring

30000

60000

90000

120000

150000

180000

210000

1.8

2

2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

VDD [V]

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

30000

60000

90000

120000 150000 180000 210000

CODE [LSB]