BD9141MUV Datasheet, PDF (6/19 Pages) Rohm – Output 2A or More High-efficiency Step-down Switching Regulator with Built-in Power MOSFET

BD9141MUV
Technical Note
●Information on advantages
Advantage 1：Offers fast transient response with current mode control system.
Conventional product (Load response IO=0.5A→1A)
BD9141MUV (Load response IO=0.5A→1A)
VOUT
IOUT
110mV
VOUT
IOUT
50mV
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 : 150mΩ(Typ.)
ON resistance of N-channel MOS FET : 80mΩ(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}
①improvement 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 1MHz: 2.2μH inductor
Reduces a mounting area required.
VCC
(BD9141MUV:Co=22μF, L=4.7μH)
RITH
CITH
DC/DC
Convertor
Controller
Cin
L
VOUT
Co
15mm
CIN
RITH
L
10mm
CITH
CO
Fig.20 Example application
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6/18
2009.06 - Rev.A