BD9137MUV Datasheet, PDF (4/17 Pages) Rohm – High Efficiency Step-down Switching Regulator

●Information on advantages
Advantage 1：Offers fast transient response with current mode control system.
Conventional product (Load response IO=1A→3A)
BD9137MUV (Load response IO=1A→3A)
VOUT
145mV
VOUT
72mV
IOUT
IOUT
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 Highside MOS FET : 82mΩ(Typ.)
ON resistance of Lowside MOS FET : 70mΩ(Typ.)
Achieves efficiency improvement for heavier load.
Offers high efficiency for all load range with the improvements mentioned above.
100
SLLM
②
50 _{① PWM}
①inprovement by SLLM system
②improvement by synchronous rectifier
0
0.001 0.01
0.1
1
Output current Io[A]
Fig.19 Efficiency
Advantage 3：・Supplied in smaller package due to small-sized power MOS FET incorporated.
・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
Reduces a mounting area required.
EN
VREF
VCC
Gm Amp
+
Soft
Start
ADJ
R1 ^R2
Current
Comp
+ ^RQ
S
SLOPE
CLK
OSC
VCC
UVLO
TSD
Current
Sense/
Protect
+
Driver
Logic
SCP
ITH
SLLM
select
PWM
RITH CITH
VCC
BST
PVCC
SW
PVCC
PGND
GND
3.3V
Input
Output
15mm
Fig.20 Example application
R2
R1
RITH
CITH
20mm
Cf
CBST
Rf
L
CIN
Co
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