NCP1910B65DWR2G ON Semiconductor, NCP1910B65DWR2G Datasheet - Page 31

• Manufacturer Part Number: NCP1910B65DWR2G
• Description: AC/DC Switching Converters GREENM COMBO 2GND N/SKIP
• Manufacturer: ON Semiconductor
• Type: Combo Controllerr

Specifications of NCP1910B65DWR2G

• Input / Supply Voltage (max): 20 V
• Switching Frequency: 500 KHz
• Operating Temperature Range: - 60 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: SO-24
• Maximum Operating Temperature: + 150 C
• Minimum Operating Temperature: - 60 C
• Number Of Outputs: 2
• Output Current: 5 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

•
•
•
Where:
LLC Power Good Signal and Brown−out (PG
and BO
Brown−Out circuitry (BO) that offer a way to protect the
resonant converter from operating at too low V
mean time, NCP1910 provides a Power Good signal (PG
to inform the isolated secondary side that the NCP1910 is in
order of match.
its regulated voltage, an internal “PFC_OK” signal is
asserted. 20 ms later (t
PG
•
•
As shown in Figure 22, the NCP1910 provides the
Once the PFC has started and raises V
The PG
The minimum switching frequency is given by the R
resistor value. This frequency is reached if there is no
feedback action and soft start period has already
elapsed.
The maximum switching frequency excursion is limited
by the R
frequency is influenced by the opto−coupler saturation
voltage value.
Resistor R
soft start period for the resonant converter.
V
voltage imposed on PG
above the LLC turn−off voltage, programmed by BO
pin. Therefore, in a normal turn−off sequence, PG first
drops and informs the secondary side that it must be
prepared for shutdown.
The second event that can drop the PG signal is when
the PFC experiences a fault: broken feedback path
(PFC UVP), PFC abnormal, or input line brown−out. In
either case, the internal PFCok signal will drop and
then assert the PG
(t
can be safely halted.
♦
♦
♦
♦
out
DEL2
bulk
V
F
F
F
pin open, in two cases:
min
max
SS
Rt
adj
decreases to the level, programmed by a reference
). Once this timer is elapsed, the LLC converter
= 3.5 V
is the maximal soft start switching frequency
out
max
is the minimal frequency
is the maximal frequency
Pin)
SS
signal can now disappear, which will release
R
selection. Note that the maximum
together with capacitor C
min
R
R
max
SS
+
out
DEL1
+
490
+
signal high, and starts a 5 ms timer
490
adj
490
F
F
), the PG
F
SS
max
pin. This level is usually
min
10
* F
* F
10
6
10
V
6
Rt
min
6
V
out
min
V
Rt
Rt
pin is brought low.
bulk
SS
prepares the
above 95% of
adj
bulk
, PG
(eq. 22)
(eq. 23)
(eq. 24)
. In the
http://onsemi.com
out
min
out
adj
)
31
timers (t
management section”.
brown−out comparator:
•
•
pin, which minimizes the losses of the high voltage sensing
circuit. As depicted in Figure 22, 3 resistors (R
among V
levels of PG
formulas:
Where:
between R
value R
R
V
303 W. Choose 300 W as it is the closet standard resistor.
Then we can get the R
V
V
1
bulk,BO
The definition of start−up, shut−off and these 2 delay
There are the other 2 delay timers are built−in after the
NCP1910 gets the information of V
Divide Equation 25 by 26, we can get the relationship
Hence, by given V
For example, V
t
BO level.
t
the BO level.
♦
♦
♦
♦
♦
♦
♦
BOK
BONOTOK
PG
BO
by Equation 26.
feedback OTA (2.5 V typically)
released open.
function of LLC activates.
V
V
V
V
V
V
V
+
+
+ V
+ V
3
PG
BO
REF
PREF
bulk,PG
bulk,BO
bulk,nom
is the delay timer after V
DEL1
as the 1
is 330 V. Choose 10 kW resistor as R
REF
R
R
2
is the voltage on PG
1
1
is the voltage on BO
bulk,PG
bulk,BO
is the reference voltage (5 V typically).
out
and R
R
) R
) R
, PG
is the internal reference voltage for PFC
is the delay timer after V
2
and t
is the bulk voltage when PG
is the bulk voltage when brown−out
R
signal and LLC brown−out as the following
) R
is the normal bulk voltage, e.g. 390 V.
st
2
3
2
adj
@
@
step, we can get the R
3
bulk,nom
) R
) R
DEL2
R
R
in Equation 27:
, BO
3
R
R
FBU
FBU
bulk,PG
2
3
1
3
3
+
R
R
is 13.3 kW.
) will be depicted later in “combo
@ V
@ V
adj
) R
) R
FBL
FBL
V
V
is 390 V, V
REF
REF
bulk,PG
bulk,BO
pin, and ground determine the
and V
FBL
FBL
adj
adj
bulk
+ V
+ V
pin
* 1
pin
bulk,BO
is rising above the
bulk
bulk,PG
bulk,BO
bulk,PG
2
bulk
by Equation 27 and
from the PFC FB
, and choose the
is falling down
out
@
@
1
is 340 V, and
3
pin is
, R
V
V
. Then R2 is
V
V
bulk,nom
bulk,nom
2
PREF
PREF
, and R
(eq. 25)
(eq. 26)
(eq. 27)
3
)