NCP1397ADR2G ON Semiconductor, NCP1397ADR2G Datasheet - Page 20

• Manufacturer Part Number: NCP1397ADR2G
• Description: IC CTLR RESONANT HI PERF 16-SOIC
• Manufacturer: ON Semiconductor

Specifications of NCP1397ADR2G

• Pwm Type: Controller
• Number Of Outputs: 1
• Frequency - Max: 560kHz
• Duty Cycle: 52%
• Voltage - Supply: 10.3 V ~ 20 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width, 15 Leads)
• Frequency-max: 560kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

measurement as long as the NTC and the optocoupler are not
activated. As soon as the secondary optocoupler senses an
OVP condition, or the NTC reacts to a high ambient
temperature, Q1 base is brought to ground and the BO pin
goes up, permanently latching off the controller.
Protection Circuitry
input) to detect primary overcurrent conditions and protect
power stage from damage.
threshold the external timer capacitor starts charging by
I
switch is activated to shift operating frequency up to keep
primary current at acceptable level. In case the overload
disappears fast enough the Soft−Start discharge switch is
open, I
timer1
On Figure 42, Q1 is blocked and does not bother the BO
This resonant controller offers a dedicated input (Fault
Once the voltage on the Fault input exceeds 1.04 V
current. Simultaneously the Soft−Start discharge
timer1
Figure 42. Adding a Comparator on the BO Pin Offers a way to Latch−off the Controller
current turned−off and timer capacitor
Vout
NTC
V
CC
Q1
Vbulk
http://onsemi.com
Rupper
Rlower
BO
20
discharges via an external parallel resistor. In case the
overload lasts for more than timer duration (given by I
V
until the C
restarts via Soft−Start.
the primary current grows very fast and thus could reach
danger level prior the fault timer elapses. The NCP1397B
therefore features additional comparator (1.55 V) on the
Fault input to permanently latch the application and protect
against destruction. Figure 44 depicts the architecture of the
fault circuitry for NCP1397B controller.
but in this case it doesn’t latches off the IC but speeds up the
Fault timer capacitor charging by turning on additional
current source I
can thus be used in applications that have to recover
automatically from any fault conditions.
timer
In case of heavy overload, like transformer short circuit,
The NCP1397A features second fault comparator as well
+
VBO
, C
+
timer
V
+
−
latch
timer
IBO
+
−
and R
20 ms
RC
will discharge to 1 V. The application then
timer2
timer
– refer to Figure 43. The NCP1397A
) the IC stops the operation and waits
To permanent
latch
V
DD
BO
timer
,