BD9106FVM Rohm, BD9106FVM Datasheet - Page 9

• Manufacturer Part Number: BD9106FVM
• Description: (BD9102FVM / BD9104FVM / BD9106FVM) Output 1.5A or Less High Efficiency Step-down Switching Regulators
• Manufacturer: Rohm

●Operation
© 2009 ROHM Co., Ltd. All rights reserved.
BD9102FVM, BD9104FVM, BD9106FVM
Current
RESET
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Comp
V
SET
SW
OUT
BD9102FVM, BD9104FVM, BD9106FVM are the 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
efficiency.
○Synchronous rectifier
○Current mode PWM control
I
L
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.
Synthesizes a PWM control signal with a inductor current feedback loop added to the voltage feedback.
・PWM (Pulse Width Modulation) control
・SLLM
The oscillation frequency for PWM is 1 MHz. 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
receives two signals, a current feedback control signal (SENSE: Voltage converted from I
control signal (FB), 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.
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.
TM
V
OUT
(Simple Light Load Mode) control
Fig.45 PWM switching timing chart
Gm Amp.
Level
Shift
Fig.44 Diagram of current mode PWM control
ITH
FB
SENSE
Current
Comp
PVCC
GND
GND
GND
I
V
L
RESET
(AVE)
OUT
OSC
SET
(AVE)
FB
SENSE
R Q
S
TM
9/17
(Simple Light Load Mode) operation for lighter load to improve
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Current
RESET
Comp
Driver
Logic
V
SET
SW
OUT
L
I
increases. The current comparator (Current Comp)
L
Fig.46 SLLM
SW
I
L
Not switching
TM
switching timing chart
Load
L
) and a voltage feedback
V
OUT
Technical Note
2009.05 - Rev.A
FB
PVCC
SENSE
GND
GND
GND
0A
V
OUT
(AVE)
Datasheet pdf - http://www.DataSheet4U.net/