Data Sheet

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3
FSL106HR — Green Mode Power Switch
Pin Configuration
GND
V
CC
I
PK
V
STR
8-DIP
V
FB
Drain
Drain
Drain
Figure 3. Pin Configuration
Pin Definitions
Pin #
Name
Description
1
GND
Ground. SenseFET source terminal on the primary side and internal control ground.
2
V
CC
Positive Supply Voltage Input. Although connected to an auxiliary transformer w inding,
current is supplied from pin 5 (V
STR
) via an internal sw itch during startup (see Figure 2 ). Once
V
CC
reaches the UVLO upper threshold (12V), the internal startup sw itch opens and device
pow er is supplied via the auxiliary transformer w inding.
3
V
FB
Feedback Voltage. The non-inverting input to the PWM comparator, it has a 0.4mA current
source connected internally, w hile a capacitor and opto-coupler are typically connected
externally. There is a delay w hile charging external capacitor C
FB
from 2.4V to 6V using an
internal 5µA current source. This delay prevents false triggering under transient conditions, but
still allow s the protection mechanism to operate under true overload conditions.
4
I
PK
Peak Current Limit. Adjusts the peak current limit of the SenseFET. The feedback 0.4mA
current source is diverted to the parallel combination of an internal 6kΩ resistor and any
external resistor to GND on this pin to determine the peak current limit.
5
V
STR
Startup. Connected to the rectified AC line voltage source. At startup, the internal sw itch
supplies internal bias and charges an external storage capacitor placed betw een the V
CC
pin
and ground. Once V
CC
reaches 12V, the internal sw itch is opened.
6, 7, 8
Drain
Drain. Designed to connect directly to the primary lead of the transformer and capable of
sw itching a maximum of 650V. Minimizing the length of the trace connecting these pins to the
transformer decreases leakage inductance.