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BD9134MUV_0909 Datasheet, PDF (6/18 Pages) Rohm – Output 2A or More High-efficiency Step-down Switching Regulator with Built-in Power MOSFET | |||
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BD9134MUV
Technical Note
âInformation on advantages
Advantage 1ï¼Offers fast transient response with current mode control system.
Conventional product (Load response IO=1Aâ3A)
BD9134MUV (Load response IO=1Aâ3A)
VOUT
572mV
VOUT
328mV
IOUT
IOUT
Voltage drop due to sudden change in load was reduced by about 50%.
Fig.18 Comparison of transient response
Advantage 2ï¼ Offers high efficiency for all load range.
ã»For lighter load:
Utilizes the current mode control mode called SLLMTM for lighter load, which reduces various dissipation such as
switching dissipation (PSW), gate charge/discharge dissipation, ESR dissipation of output capacitor (PESR) and
on-resistance dissipation (PRON) that may otherwise cause degradation in efficiency for lighter load.
Achieves efficiency improvement for lighter load.
ã»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 : 82mâ¦(Typ.)
ON resistance of Lowside MOS FET : 70mâ¦(Typ.)
100
SLLMTM
â¡
Achieves efficiency improvement for heavier load.
Offers high efficiency for all load range with the improvements mentioned above.
50 â PWM
â inprovement by SLLMTM system
â¡improvement by synchronous rectifier
0
0.001 0.01
0.1
1
Output current Io[A]
Advantage 3ï¼ã»Supplied in smaller package due to small-sized power MOS FET incorporated.
Fig.19 Efficiency
ã»Output capacitor Co required for current mode control: 22μF ceramic capacitor
ã»Inductance L required for the operating frequency of 1 MHz: 2.2μH inductor
ã»Incorporates FET + Boot strap diode
Reduces a mounting area required.
EN
VREF
VCC
Gm Amp
+
Current
Comp
+ RQ
S
SLOPE
CLK
OSC
VCC
Soft
UVLO
Start
TSD
SCP
Current
Sense/
Protect
+
Driver
Logic
VCC
BST
PVCC
SW
PVCC
PGND
GND
3.3V
Input
Output
20mm
Cf
R2
CBST
Rf
L
15mm
R1
CIN
RITH
CITH
Co
VOUT
ITH
RITH CITH
Fig.20 Example application
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âc 2009 ROHM Co., Ltd. All rights reserved.
6/17
2009.09 - Rev.B
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