NCP1237 ONSEMI [ON Semiconductor], NCP1237 Datasheet - Page 19

• Manufacturer Part Number: NCP1237
• Description: Fixed Frequency Current Mode Controller for Flyback Converters
• Manufacturer: ONSEMI [ON Semiconductor]

Feedback with Slope Compensation
is typically 5. This means that the FB voltage corresponding
duty cycle above 50%, a fixed slope compensation is
internally applied to the current−mode control. The slope
appearing on the internal voltage setpoint for the PWM
The ratio from the FB voltage to the current sense setpoint
In order to allow the NCP1237 to operate in CCM with a
Figure 15. Overpower Compensation Current Relation to Feedback Voltage and Input Voltage
I
OPC
CS
FB
V
FB(fold)
20 kW
blanking
t LEB
VDD
Figure 16. FB Circuitry
K FB
http://onsemi.com
V
FB(OPC)
+
−
19
to V
(typical) from FB pin to the internal reference V
comparator is −32.5 mV/ms typical for the 65 kHz version
(and respectively −50 mV/ms and −67 mV/ms for the
100 kHz and 133 kHz versions).
comp.
slope
ILIM
PWM
is 3.5 V. There is a pullup resistor of 20 kW
V
Oscillator
HV
V
FB
FB(ref)
.