PS10 SUTEX [Supertex, Inc], PS10 Datasheet - Page 11

• Manufacturer Part Number: PS10
• Description: Quad Power Sequencing Controller
• Manufacturer: SUTEX [Supertex, Inc]

Increasing the Under and Over Voltage Hysteresis,
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
T
T
T
where:
T
T
T
V
I
Note: Adding C1, C2, C3 will have a negligible affect on the power good fall time.
PULLUP
PWRGD-B(off)
PWRGD-C(off)
PWRGD-D(off)
PWRGD-B(off)
PWRGD-c(off)
PWRGD-D(off)
ENOFF
-48V
GND
-48V
GND
- DC/DC minimum off voltage (2.7V typ)
- DC/DC /EN pin pull-up current (1mA typ)
9.76K
487K
6.81K
= C1 x V
= C2 x V
= C3 x V
Ruvhys can be calculated based on higher UV On voltage (say
42V):
Ruvhys = (Vuvon - Vdiode - Vce/((Vin-Vuvon)/487k -
Vuvon/16.5k)
16.5k
487k
= (1.22-0.65-0.1)/((42-1.22)/487k - 1.22/16.5k)
= 47.97k
-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.
V
UV
OV
EE
RTB
ENOFF
ENOFF
ENOFF
TB
V
IN
499k
9.76k
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.
RTC
Ruvhys
PS11
TC
/ I
/ I
/ I
RTD
PULLUP
PULLUP
PULLUP
TD
Ramp
,
,
,
PWRGD-D
PWRGD-B
PWRGD-C
PWRGD-A
10nF
OV
V
UV
EE
RTB
V
TB
IN
PS11
RTC
C3
TC
RTD
/EN4
C2
TD
/EN3
C1
/EN2
Ramp
PWRGD-D
PWRGD-C
PWRGD-B
PWRGD-A
10nF
V+
/EN
V-
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
11
DC/DC
Converter
+3.3V
COM
10k
V+
/EN
V-
DC/DC
Converter
continued
+3.3V
COM
A051204