ncp3127 ON Semiconductor, ncp3127 Datasheet - Page 16

• Manufacturer Part Number: ncp3127
• Description: Ncp3127 2 A Synchronous Pwm Switching Converter
• Manufacturer: ON Semiconductor

C
f
R
R
R
The cross over of the overall feedback occurs at F
C
F
F
R
R
R
V
V
used to calculate the transconductance output compensation
network as follows:
C
F
gm
R
R
cross
C
239 pF +
F
LC
PO
PO
F
1
2
F
F
1
2
F
C
1
2
16.86 kHz +
IN
ramp
PO
The cross over combined compensation network can be
F
+
57.5 nF +
+
C
2p
2p
C
+
2p
2
F
R
= Feed through capacitor
= Crossover frequency
= Top resistor divider
= Bottom resistor divider
= Feed through resistor
= Feed through capacitor
= Frequency of the output inductor and capacitor
= Pole frequency
= Top of resistor divider
= Bottom of resistor divider
= Feed through resistor
= Input voltage
= Peak−to−peak voltage of the ramp
= Compensation capacitor
= Pole frequency
= Transconductance of amplifier
= Top of resistor divider
= Bottom of resistor divider
PO
2p
1
16.86 kHz
1
C
) R
4p
31.6 kW
2
F
2
1
F
R
239 pF
) R
R
1
2
) R
R
R
2
2
1
10 kW ) 31.6 kW
20 kW ) 10 kW
R
F
) R
2
R
1
R
31.6 kW ) 20 kW
1
F
) R
10 kW
2
R
) R
gm ³
2
) R
F
2
31.6 kW ) 10 kW
1
R
1
R
31.6 kW ) 20 kW
F
20 kW ) 10 kW
4 ms
PO
f
cross
http://onsemi.com
20 kW ) 10 kW
:
R
F
) R
(eq. 42)
1
16
FLC
31.6 kW
V
ramp
20 kW
V
IN
³
30 kHz
20 kW ) 31.6 kW
(eq. 41)
(eq. 40)
2.119 kHz
1.1 V
12 V