PS10/PS11

11

A051204

RTB

16.5k

9.76k

487k

RTD

RTC

TB

OV

UV

V

TC

PWRGD-C

PWRGD-D

TD

PWRGD-A

PWRGD-B

PS11

-48V

GND

Note:

1. Other power good outputs will have the same configuration as

PWGRGD-A for Active Low Enabled Converters.

2. Over voltage shut down set to 63.6V

10nF

Ramp

COM

+3.3V

V-

V+

DC/DC

Converter

/EN

Ruvhys

499k

10k

V

IN

EE

Ruvhys can be calculated based on higher UV On voltage (say

42V):

Ruvhys = (Vuvon - Vdiode - Vce/((Vin-Vuvon)/487k -

Vuvon/16.5k)

= (1.22-0.65-0.1)/((42-1.22)/487k - 1.22/16.5k)

= 47.97k

Power Down Sequencing

In some applications, a power down sequence may be required. To accomplish this, a capacitor is connected to the power

good pins that need to be sequenced down. The power good turn off delays can be approximated by

where:

-Time delay from PWRGD-A going High to PWRGD-B going high.

-Time delay from PWRGD-A going High to PWRGD-C going high.

-Time delay from PWRGD-A going High to PWRGD-D going high.

Note: Adding C1, C2, C3 will have a negligible affect on the power good fall time.

RTB

9.76K

6.81K

487K

RTD

RTC

10nF

C1

C3

C2

-48V

GND

PWRGD-C

DC/DC

Converter

/EN

PWRGD-B

V-

V+

PS11

PWRGD-A

Notes:

1. Under Voltage Shutdown (UV) set to 37V.

2. Over Voltage Shutdown (OV) to 57.8V.

3. Only PWRGD-A to DC/DC converter connection is shown

for simplicity.

PWRGD-D

TD

TC

TB

+3.3V

COM

Ramp

/EN3

/EN2

OV

UV

/EN4

V

EE

IN

V