PFS757HG POWERINT [Power Integrations, Inc.], PFS757HG Datasheet - Page 5

• Manufacturer Part Number: PFS757HG
• Description: Combined Two-Switch Forward and Flyback Power Supply Controllers with Integrated High Voltage MOSFETs
• Manufacturer: POWERINT [Power Integrations, Inc.]

Pin Functional Description
MAIN DRAIN (D) Pin
Drain of the low-side MOSFET transistor forward converter.
STANDBY DRAIN (DSB) Pin
Drain of the MOSFET of standby power supply.
GROUND (G) Pin
This pin gives a signal current path to the substrate of the
low-side controller. This pin is provided to allow a separate
Kelvin connection to the substrate of the low-side controller to
eliminate inductive voltages that might be developed by high
switching currents in the SOURCE pin. The GROUND pin is
not intended to carrier high currents, instead it is intended as a
voltage-reference connection only.
SOURCE (S) Pin
SOURCE pin that is common to both the standby and main
supplies.
RESET (R) Pin
This pin provides information to limit the maximum duty cycle as a
function of the current fed into the RESET pin during the off-time
of the main converter MOSFET. This pin can also be pulled up to
bypass to signal remote ON/OFF of the main converter only.
ENABLE (EN) Pin
This is the ENABLE pin for the standby controller. Prior to the
start-up a resistor connected from ENABLE to BYPASS, can be
detected to select one of several internal current limits.
LINE-SENSE (L) Pin
This pin provides input bulk voltage line-sense function. This
information is used by the undervoltage and overvoltage
detection circuits for both main and standby. The pin can also
be pulled up to BYPASS or be pulled down to SOURCE to
implement a remote ON/OFF of both standby and main
supplies simultaneously. The LINE-SENSE pin works in
conjunction with the RESET pin to implement a duty-cycle limit
function. Also the LINE-SENSE pin compensates the value of
standby current limit so as to flatten the output overload
response as a function of input voltage.
FEEDBACK (FB) Pin
This pin provides feedback for the main two transistor forward
converter. An increase in current sink from FEEDBACK pin to
ground, will lead to a reduction in operating duty cycle. This pin
also selects the main device current limit at start-up (in a similar
manner to ENABLE pin).
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BYPASS (BP) Pin
This is the decoupled operating voltage pin for the low-side
controller. At start-up the bypass capacitor is charged from an
internal device current source. During normal operation the
capacitor voltage is maintained by drawing current from the
low-side bias winding on the standby power supply. This pin is
also used to implement remote ON/OFF for the main controller.
This is done by driving extra current into the BYPASS pin when
we want to turn-on the Main controller. The BYPASS pin also
implements a latch-off function to disable standby and main
when the BP pin current exceeds latching threshold. Latch is
reset when LINE-SENSE pin falls below UV (off) standby
threshold.
HIGH-SIDE OPERATING VOLTAGE (VDDH) Pin
This is the high-side bias (VDD) of approximately 11.5 V. This
voltage is maintained with current from a high-side bias winding
on the main transformer and/or from a bootstrap diode from the
low-side standby bias supply.
HIGH-SIDE SOURCE (HS) Pin
SOURCE pin of the high-side MOSFET.
HIGH-SIDE DRAIN (HD) Pin
DRAIN pin of the high-side MOSFET. This MOSFET is floating
with respect to low-side source and ground.
Figure 2.
Exposed Metal
(On Edge)
Internally
Connected
Pin Configuration.
1
H Package (eSIP-16/12)
3
5 6 7 8
TFS757-764HG
9
10 11
13
Exposed Pad
(Backside) Internally
Connected to SOURCE
Pin (see eSIP-16B
Package Drawing)
14
16
PI-5290-110510
Rev. C 02/11
5