BD9532EKN_08 Datasheet, PDF (9/21 Pages) Rohm – Switching Regulators for DDR-SDRAM Cores

●Explanation of Operation
The BD9532EKN is a synchronous buck 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
HG
LG
When VOUT falls to a threshold voltage (REF), the drop is
detected, activating the H³Reg^TM CONTROLLA system.
TON=
REF
VIN
×¹
f
[sec]・・・(1)
HG output is determined with the formula above.
LG outputs until the status of VOUT is lower than REF
after the status of HG is off.
(VOUT drops due to a rapid load change)
VOUT
REF
Io
TON+α
HG
LG
(SLLM )
VOUT
REF
HG
LG
0A
When VOUT drops due to a rapid load change, and
the voltage remains below REF after the
programmed TON time interval has elapsed, the
system quickly restores VOUT by extending the TON
time, improving the transient response.
In SLLM (SLLM=0V), SLLM function is operated when
LG pin is OFF and the coil current is lower than 0A
(the current goes from VOUT to SW). And it stops to
output next HG.
When VOUT goes lower than REF voltage again, the
status of HG is ON.
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