TSOP32438SS1F Vishay, TSOP32438SS1F Datasheet - Page 9

• Manufacturer Part Number: TSOP32438SS1F
• Manufacturer: Vishay

Specifications of TSOP32438SS1F

• Lead Free Status / RoHS Status: Supplier Unconfirmed

DETAILED OPERATION
Start-Up
When V
begins to charge up the V
external V
internal DMOS device. When Vcc exceeds the UVLO voltage
of 8.8 V a soft-start cycle of the switch mode supply is
initiated. The V
pre-regulator until V
between V
in V
operation. This situation is avoided by the hysteresis
between V
Document Number: 71815
S-80038-Rev. J, 14-Jan-08
C
L_CONT
V
CS2
CS1
INDET
R
V
REF
OSC
CC
EP
SS
INEXT
falling below V
CC
UVLO
Oscillator
REG
Feedforward
60 kΩ
8 V
Voltage
Current
Control
capacitor is limited to typically 40 mA by the
rises above 0 V, the internal pre-regulator
100 mV
CC
Reference
and V
and V
Bandgap
V
3.3 V
132 kΩ
CC
supply continues to be charged by the
CC
-
+
+
-
OSC
REG
UVLO
Gain
V
20 µA
REF
equals V
UVLO
Clock
, excessive load current will result
/2
Frequency
C
Foldback
Control
CC
Loop
and correct sizing of the V
L_CONT
and stopping switch mode
Blanking
Soft-Start
capacitor. Current into the
REG
. During this period,
−
+
PWM
Generator
V
+
-
+
-
550 mV
REF
Figure 4. Detailed Functional Block
SS Enable
V
V
UV
SD
GND
Clock
CC
V
SD
capacitor, bootstrap capacitor and the soft-start capacitor.
The value of the V
to be capable of maintaining switch mode operation until the
V
transformer winding and zener regulator). Feedback from the
output of the switch mode supply charges V
and fully disconnects the pre-regulator, isolating V
V
switch mode operation. In the event of an over voltage
condition on V
14.5 V to shunt excessive current to GND.
V
V
CC
IN
CC
UV
Logic
Logic
Timer
BBM
. V
V
can be supplied from the external circuit (e.g via a power
9.1 V
V
REG
UVLO
CC
160 °C Temp
Protection
V
IN
is then maintained above V
OTP
V
CC
UVLO
, an internal voltage clamp turns on at
CC
Pre-Regulator
capacitor should therefore be chosen
High V oltage
+
+
Interface
-
-
Si9122
8.8 V
Vishay Siliconix
V
V
V
REG
CC
CC
CC
9.1 V
for the duration of
High-Side
Synchronous
Synchronous
Primary
Driver
CC
www.vishay.com
Low-Side
Driver
(High)
Driver
(Low)
Driver
Si9122
above V
CC
BST
D
L
D
PGND
SR
SR
X
H
L
H
L
from
REG
9