Tri p ath Techn o l o g y, I n c. - T echn i cal I n fo rmation

16

TCA2002 – KLi/0.95/04.06

R

VPP2

VNN

19

17

R

VNN1

R

VPP1

V5

R

VNN2

VPPSENSE

VNNSENSE

VPP

V5

TCA2002

Figure 6: Over / Under voltage sense circuit

VPPSENSE

VPP1

I

VPP

R

=

Set

VPP1

VPP2

R

R

=

.

VNNSENSE

VNN1

I

VNN

R

=

Set

VNN1

VNN2

R

3

R

×

=

.

for VPPSENSE and VNNSENSE, respectively.

can be used for the direct calculation of the actual VPP and VNN trip voltages without considering the

Using the resistor values from above, the actual minimum over voltage turn off points will be:

RN_OFF)

(MIN_OV_TU

VPPSENSE

VPP1

N_OFF

MIN_OV_TUR

I

R

VPP

×

=

)

I

R

(

VNN

RN_OFF)

(MIN_OV_TU

VNNSENSE

VNN1

N_OFF

MIN_OV_TUR

×

−

=

The other three trip points can be calculated using the same formula but inserting the appropriate

between the minimum overvoltage turn off and maximum under voltage turn-off for both the VPP and

VNN supplies.

N_OFF

MAX_UV_TUR

N_OFF

MIN_OV_TUR

RANGE

VPP

-

VPP

VPP

=

N_OFF

MAX_UV_TUR

N_OFF

MIN_OV_TUR

RANGE

VNN

-

VNN

VNN

=