NCP1399AA, NCP1399BA, NCP1399AC
Figure 3. Typical Application Example with PFC Stage (Active ON off−mode)
PIN FUNCTION DESCRIPTION
Pin No.
Pin Name
Function
Pin Description
1
HV
High*voltage startup
current source input
Connects to rectified AC line or to bulk capacitor to perform functions of
Start*up Current Source and Dynamic Self*Supply
2
3
NC
Not connected
Increases the creepage distance
VBULK /
PFC FB
Bulk voltage monitoring input Receives divided bulk voltage to perform Brown−out protection.
4
SKIP/REM
Skip threshold adjust /
Off−mode control input
Sets the skip in threshold via a resistor connected to ground – version
NCP1399Ay. Activates off−mode (or Standby) when pulled−up by external
auxiliary voltage source / deactivates off−mode when pull down by external
off−mode control optocoupler – version NCP1399By.
5
6
7
LLC FB
LLC CS
LLC feedback input
Defines operating frequency based on given load conditions. Activates skip
mode operation under light load conditions. Activates off−mode operation for
NCP1399Ay version.
LLC current sense input
Senses divided resonant capacitor voltage to perform on−time modulation, out
of resonant switching protection, over−current protection and secondary side
short circuit protection.
OTP / OVP
Over−temperature and
over−voltage protection input
Implements over−temperature and over−voltage protection on single pin.
8
9
P ON/OFF
PFC turn−off FB level adjust Adjusts the FB pin to a level below which the PFC stage operation is disabled.
PFC MODE
PFC and external HV
switch control output
Provides supply voltage for PFC front stage controller and/or enables Vbulk
sensing network HV switch.
10
11
VCC
GND
Supplies the controller
Analog ground
The controller accepts up to 20 V on VCC pin
Common ground connection for adjust components, sensing networks and
DRV outputs.
12
13
14
15
16
MLOWER
NC
Low side driver output
Not connected
Drives the lower side MOSFET
Increases the creepage distance
Drives the higher side MOSFET
MUPPER
HB
High side driver output
Half*bridge connection
Bootstrap pin
Connects to the half*bridge output.
The floating VCC supply for the upper stage
VBOOT
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