NCP1588 ON Semiconductor, NCP1588 Datasheet - Page 8

• Manufacturer Part Number: NCP1588
• Description: Low Voltage Synchronous Buck Controller
• Manufacturer: ON Semiconductor

UG
PG
LG
Feedback and Compensation
from 0.8 V to 5.0 V via an external resistor divider network.
The controller will try to maintain 0.8 V at feedback pin.
Thus, if a resistor divider circuit was placed across the
feedback pin to V
voltage proportional to the resistor divider network in order
to maintain 0.8 V at the FB pin. The same formula applies
to the VOS pin and the controller will maintain 0.8 V at the
VOS pin.
above and the output voltage is shown in the following
equation:
The same formula can be applied to the feedback resistors
at VOS.
The NCP1588 allows the output voltage to be adjusted
The relationship between the resistor divider network
V
OS
R 4 + R 1
R 9 + R 10
0.88V
OUT
, the controller will regulate the output
Figure 9.
R1
R4
V
V OUT * V REF
OUT
V OUT * V REF
V REF
V REF
Overvoltage
FB
Figure 8. Typical Power Good Function
0.88V
0.8V
1.0V
http://onsemi.com
0.72V
NCP1588
0.4V
8
Design Example:
Voltage Mode Control Loop with TYPE III
Compensation
Converter Parameters:
Input Voltage: V
Output Voltage: V
Switching Frequency: 300 kHz
Total Output Capacitance: C
Total ESR: ESR = 6 mW
Output Inductance: L
Ramp Amplitude: V
a.. Set a target for the close loop bandwidth at 1/6
V
the switching frequency.
OUT
F
cross_over
R3
R1
:+ 50 kHz
IN
OUT
R4
= 5 V
RAMP
OUT
C3
= 1.65 V
Figure 10.
: 1 mH
= 1 V
OUT
V
REF
= 3600 mF
0.8V
-
+
E/A
R2
Undervoltage
0.6V
C1
C2
V
COMP
th
of