BD95500MUV Datasheet, PDF (9/21 Pages) Rohm – Switching Regulator with MOSFET for DDR-SDRAM Cores

BD95500MUV
Technical Note
●Explanation of Operation
The BD95500MUV is a switching regulator controller incorporating ROHM’s proprietary H³Reg^TM CONTROLLA control
system. When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the tON time interval.
Thus, it serves to improve the regulator’s transient response. Activating the Light Load Mode will also exercise Simple Light
Load Mode (SLLM) control when the load is light, to further increase efficiency.
H³Reg^TM control
(Normal operation)
VOUT
REF
When VOUT falls to a threshold voltage (REF), the drop is
detected, activating the H³Reg^TM CONTROLLA system.
HG
REF 1
TON=
× _{[sec]・・・(1)}
VIN
f
LG
HG output is determined by the formula above.
(VOUT drops due to a rapid load change)
VOUT
REF
Io
tON+α
HG
LG
When VOUT drops due to a rapid load change, and the
voltage remains below VREF after the programmed tON
time interval has elapsed, the system quickly restores
VOUT by extending the tON time, improving the transient
response.
REF
VOUT
VIN
H³Reg^TM
CONTROLLA
RQ
S
SLLM
SLLM
VIN
HG
Driver
Circuit
LG
SW
PGND
VOUT
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9/20
2010.05 - Rev.C