8

PS12

Programming ON and UV

The ON and OV inputs draw negligible current, allowing the

use of a high impedance divider. A divider current between

10µA and 100µA is more than adequate.

V

Start the design by programming the power-up voltage. The

power-down voltage VIN

up voltage. Next, program the overvoltage power down volt-

age V

VIN

A numerical example:

V

results in the following:

(1) R

(2) I

(3) [VIN

[10.32V, 8.60V, 15.98V, 13.32V].

Note the following:

Programming the Power-up Delay

The power-up delay (T

charge the C

A numerical example:

A 100nF capacitor results in a T

Programming the PS to PS Delay

The PS to PS delays are set by the six timing resistors. De-

lay time and resistance are related as follows:

A numerical example:

A resistance of 100kΩ results in a delay time of 10ms.

OVPD 1.20V

OVPU 1.10V

OV

ON

ONPU 1.20V

ONPD 1.10V

R 2

R 3

R 1

=

+

+

=

ON

Power-up:

V

ON

Power-down:

V

OV

Power-down:

V

OV

Power-up:

V

+

=

+

=

1

20

.

1

20

.

1

+

=

⎟⎟⎠

⎞

⎜⎜⎝

⎛

+

=

+

=

=

= 1.20V

= 12µA

Ω

=

•

=

ns

100