NCP1392B_09 ONSEMI [ON Semiconductor], NCP1392B_09 Datasheet - Page 13

• Manufacturer Part Number: NCP1392B_09
• Description: High-Voltage Half-Bridge Driver with Inbuiltc Oscillator
• Manufacturer: ONSEMI [ON Semiconductor]

This is valuable for applications that are supplied from
auxiliary winding and V
energy during PFC delay period.
it is necessary to adjust minimum operating frequency with
resistor value. This frequency is reached if there is no
optocoupler or current feedback action and soft start period
has been already finished. The maximum switching
frequency excursion is limited by the Rf
that the F
saturation voltage value. Resistor Rfstart together with
capacitor C
elapses. The Rt pin is grounded via an internal switch during
the PFC delay period to assure that the soft start capacitor
will be fully discharged via Rfstart resistor.
current control loop) to the Rt pin. The only one limitation
lies in the Rt pin reference voltage which is Vref
Used regulator has to be capable to work with voltage lower
than Vref
For the resonant applications and light ballast applications
The minimum switching frequency is given by the Rt
There is a possibility to connect other control loops (like
Rt
max
.
SS
prepares the soft start period after PFC timer
value is influenced by the optocoupler
CC
capacitor is supposed to provide
R
C
fstart
SS
NCP1392
max
R
t
Figure 29. Typical Rt Pin Connection
R
t
selection. Note
Rt
= 3.5 V.
http://onsemi.com
R
fmax
Voltage Feedback
13
(to secondary
voltage regulator)
high accuracy. The designer also needs to limit maximum
operating and startup frequency. All these parameters can be
adjusted using few external components connected to the Rt
pin as depicted in Figure 29.
figure 4 to prepare current feedback loop. Diode D1 is used
to enable regulator biasing via resistor Rbias. Total
saturation voltage of this solution is 1.25 + 0.6 = 1.85 V for
room temperature. Shottky diode will further decrease
saturation voltage. Rf
maximum frequency that can be pushed by this regulation
loop. This parameter is not temperature stable because of the
D1 temperature drift.
Brown−Out Protection
application from low DC input voltages. Below a given
level, the controller blocks the output pulses, above it, it
authorizes them. The internal circuitry, depicted by
Figure 30, offers a way to observe the high−voltage (HV)
rail.
The TLV431 shunt regulator is used in the example from
The Brown−Out circuitry (BO) offers a way to protect the
R
TLV431
D1
fmax
Current Feedback
R
−OCP
comp
max
− OCP resistor value, limits the
(to primary
current sensor)
V
C
CC
comp
R
bias