FSB117H Fairchild Semiconductor, FSB117H Datasheet - Page 4

• Manufacturer Part Number: FSB117H
• Manufacturer: Fairchild Semiconductor

© 2011 Fairchild Semiconductor Corporation
FSB117H / FSB127H / FSB147H • Rev. 1.0.4
Pin Configuration
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
Name
Drain
GND
VDD
IPK
HV
FB
Ground. This pin internally connects to the SenseFET source and signal ground of the PWM
controller.
Supply voltage of the IC. Typically the holdup capacitor connects from this pin to ground.
Rectifier diode in series with the transformer auxiliary winding connects to this pin to supply bias
during normal operation.
Feedback. The signal from the external compensation circuit connects to this pin. The PWM duty
cycle is determined by comparing the signal on this pin and the internal current-sense signal.
Adjust peak current. Typically a resistor connects from this pin to the GND pin to program the
current-limit level. The internal current source (50µA) introduces voltage drop across the resistor,
which determines the current limit level of pulse-by-pulse current limit.
Startup. Typically, resistors in series with diodes from the AC line connect to this pin to supply
internal bias and to charge the external capacitor connected between the VDD pin and the GND
pin during startup. This pin is also used to sense the line voltage for brownout protection and AC
line disconnection detection.
SenseFET drain. This pin is designed to directly drive the transformer.
Figure 3.
Pin Configuration
Description
4
F
Z
X
Y
TT
T
P
M
– Fairchild Logo
– Plant Code
– Package Type (N: DIP)
– 1-Digit Year Code
– 1-Digit Week Code
– Y: Green Package
– Manufacture Flow Code
– 2-Digit Die Run Code
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