Datasheet

Technical Note
BD9111NV
5/13
www.rohm.com
2010.04 - Rev.B
© 2010 ROHM Co., Ltd. All rights reserved.
●Information on advantages
Advantage 1：Offers fast transient response with current mode control system.
Voltage drop due to sudden change in load was reduced by about 50%.
Fig.18 Comparison of transient response
Advantage 2
： Offers high efficiency for all load range.
・For lighter load:
Utilizes the current mode control mode called SLLM for lighter load, which reduces various dissipation such as switching
dissipation (P
SW
), gate charge/discharge dissipation, ESR dissipation of output capacitor (P
ESR
) and on-resistance
dissipation (P
RON
) that may otherwise cause degradation in efficiency for lighter load.
Achieves efficiency improvement for lighter load.
・For heavier load:
Utilizes the synchronous rectifying mode and the low on-resistance
MOS FETs incorporated as power transistor.
ON resistance of P-channel MOS FET : 200mΩ(Typ.)
ON resistance of N-channel MOS FET : 160mΩ(Typ.)
Achieves efficiency improvement for heavier load.
Offers high efficiency for all load range with the improvements mentioned above.
Advantage 3
：・Supplied in smaller package due to small-sized power MOS FET incorporated.
Reduces a mounting area required.
Fig.20 Example application
Fig.19 Efficiency
Conventional product (Load response IO=0.1A→0.6A)
BD9111NV
(Load response IO=1A→2A)
・Output capacitor Co required for current mode control: 22μF ceramic capacitor
・Inductance L required for the operating frequency of 1 MHz: 2.2μH inductor
(BD9111NV:Co=22μF, L=2.2μH)
0.001 0.01 0.1 1
0
50
100
①
②
PWM
SLLM
①inprovement by SLLM system
②improvement by synchronous rectifier
Efficiency η[%]
Output current Io[A]
VOUT
IOUT
VOUT
I
OUT
160mV
100mV
RITH
L
Co
V
OUT
CITH
V
CC
Cin
10mm
15mm
R
ITH
C
ITH
C
IN
C
O
L
DC/DC
Convertor
Controller