NR111D Datasheet, PDF (6/14 Pages) Sanken electric – Light Load High Efficiency

Light Load High Efficiency,31V, Current Mode Step-Down 4A Switcing Regulator IC
NR111D
Oct./17/2013
Functional Block Diagram
2 _５ IN
VIN
C1 C2
R1
7
３
EN
6
７
ISET
ON/
OFF
ISET
OSC
P.REG
Σ
Current
Sense
Amp
OCP
OCP_REF
Drive
REG
VREF
0.8V
OCP_REF
PWM
LOGIC
D2
（ Option)
1
６
BS
R3
C10
3
L1
VO
４
SW
R5
D1
C4
C5
FB OVP
UVLO
R4
Compensation
FB
5
８
0.8V
FB
Err Amp
R6
TSD
１
GND 4
SS
１
SS 8
C9
Pin Assignment & Functions
Pin Assign & Functions
Pin Assign
Pin
No.
Symbol
Description
1
BS
High-side Boost input. BS supplies the drive for High-side Nch-MOSFET switch.
Connect a capacitor and a resistor between SW to BS.
2
IN ^{Power input. IN supplies the power to the IC as well as the regulator switches}
Power switching output.SW supplies power to the output.
3
SW Connect the LC filter from SW to the output.
Note that a capacitor is required from SW to BS to supply the power the High-side switch
4
GND ^{Ground.Connect the exposed pad to Pin No.4}
Feedback input Pin to compare Reference Voltage. The feedback threshold is 0.8V.
5
FB
To set the output voltage, FB Pin is required to connect between resistive voltage divider R4
and R6.
6
Iset
Adjust Pin of OCP starting current.OCP starting current can be adjusted by connecting a resistor to
ISET Pin.In the case of using at Maximum Io, ISET Pin is required to connect to GND.
7
EN ^{Enable input. Drive EN Pin high to turn on the regulator, low to turn it off.}
8
SS ^{Soft-Start control input. To set the soft-start period, connect to a capacitor between GND.}
Rev.1.1
SANKEN ELECTRIC CO., LTD.
6
http://www.sanken-ele.co.jp