Technical Note

6/16

BD9150MUV

www.rohm.com

2010.04 - Rev.C

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c

2010 ROHM Co., Ltd. All rights reserved.

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Information on advantages

Advantage 1：Offers fast transient response with current mode control system.

Fig.24Transient 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

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 Highside MOS FET : 170mΩ(Typ.)

ON resistance of Lowside MOS FET : 130mΩ(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.26 Example application

Fig.25 Efficiency

・

Output capacitor Co required for current mode control: 22μF ceramic capacitor

・

Inductance L required for the operating frequency of 1 MHz: 2.2μH inductor

・

Incorporates FET + Boot strap diode

0.001

0.01

0.1

1

0

50

100

①

②

PWM

SLLM

①

inprovement by SLLM system

②

improvement by synchronous rectifier

Output current Io[A]

L1

VOUT1

ITH1

FB1

EN1

SW1 SW1

AGND

PGND1

PVcc

COUT1

CIN1

PGND1

RITH1

L2

FB2

EN2 SW2 SW2

N.C

.

AVcc

ITH2

PVcc

PVcc

PGND2

VOUT2

R2

R1

CIN2

COUT2

PGND2

RITH2

CITH2

CITH

1

15mm

20mm

CITH1

L1

R1

RITH1

CIN1

CIN2

COUT1

COUT2

L2

R2

CITH2

RITH2