BD9140MUV-E2 Rohm Semiconductor, BD9140MUV-E2 Datasheet - Page 6

• Manufacturer Part Number: BD9140MUV-E2
• Description: IC SWITCH REG 2A W/FET VQFN020
• Manufacturer: Rohm Semiconductor
• Series: -r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of BD9140MUV-E2

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 2.5 V ~ 6 V
• Current - Output: 2A
• Frequency - Switching: 500kHz
• Voltage - Input: 4.5 V ~ 13.2 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

●Operation
© 2009 ROHM Co., Ltd. All rights reserved.
BD9141MUV
Current
RESET
www.rohm.com
Comp
V
SET
BD9141MUV is a synchronous rectifying step-down switching regulator that achieves faster transient response by employing
current mode PWM control system. It utilizes switching operation in PWM (Pulse Width Modulation) mode for heavier load,
while it utilizes SLLM (Simple Light Load Mode) operation for lighter load to improve efficiency.
○Synchronous rectifier
It does not require the power to be dissipated by a rectifier externally connected to a conventional DC/DC converter IC, and
its P.N junction shoot-through protection circuit limits the shoot-through current during operation, by which the power
dissipation of the set is reduced.
○Current mode PWM control
Synthesizes a PWM control signal with a inductor current feedback loop added to the voltage feedback.
・PWM (Pulse Width Modulation) control
・SLLM (Simple Light Load Mode) control
SW
OUT
The oscillation frequency for PWM is 500kHz. SET signal form OSC turns ON a P-channel MOS FET (while a N-channel
MOS FET is turned OFF), and an inductor current I
signals, a current feedback control signal (SENSE: Voltage converted from I
and issues a RESET signal if both input signals are identical to each other, and turns OFF the P-channel MOS FET (while a
N-channel MOS FET is turned ON) for the rest of the fixed period. The PWM control repeat this operation.
When the control mode is shifted from PWM for heavier load to the one for lighter load or vise versa, the switching pulse is
designed to turn OFF with the device held operated in normal PWM control loop, which allows linear operation without
voltage drop or deterioration in transient response during the mode switching from light load to heavy load or vise versa.
I
Although the PWM control loop continues to operate with a SET signal from OSC and a RESET signal from Current Comp,
it is so designed that the RESET signal is held issued if shifted to the light load mode, with which the switching is tuned
OFF and the switching pulses are thinned out under control. Activating the switching intermittently reduces the switching
dissipation and improves the efficiency.
L
Fig.22 PWM switching timing chart
V
OUT
Gm Amp.
Level
Shift
Fig.21 Diagram of current mode PWM control
ITH
FB
SENSE
Current
Comp
PVCC
GND
GND
GND
I
V
RESET
L
(AVE)
OUT
OSC
SET
L
(AVE)
increases. The current comparator (Current Comp) receives two
FB
SENSE
R Q
S
6/15
Current
RESET
Comp
Driver
Logic
V
SET
SW
OUT
I
L
Fig.23 SLLM
L
) and a voltage feedback control signal (FB),
SW
I
L
TM
Not switching
switching timing chart
Load
V
OUT
Technical Note
2009.09 - Rev.B
FB
PVCC
SENSE
GND
GND
GND
0A
V
OUT
(AVE)