BD9528AMUV Datasheet, PDF (16/30 Pages) Rohm – High Performance Regulators for PCs Main Power Supply for Notebook PCs(With Built-in Linear Regulator)

BD9528AMUV
●Output Discharge
VIN,CTL
EN
VOUT
Technical Note
It will be available to use if connecting VOUT pin to DC/DC output.
(Total about 100Ω) . Discharge function operates when ①EN=’L’
②UVLO=ON(If input voltage is low) ③SCP Latch time ④TSD=ON.
The function at output discharge time is shown as left.
(1)during EN=’H’→‘L’
If EN pin voltage is below than EN threshold voltage, output
discharge function is operated, and discharge output capacitor
charge.
VIN, CTL
REG1
VOUT
The efficiency of
VIN voltage drop
Output Discharge
Output Hi-Z
UVLO ON
(2) during VIN=CTL=H→0V
① IC is in normal operation until REG1 voltage becomes lower than
UVLO voltage. However, because VIN voltage also becomes low,
output voltage will drop, too.
② If REG1 voltage reaches the UVLO voltage, output discharge
function is operated, and discharge output capacitor charge.
③ In addition, if REG1 voltage drops, inner IC logic cannot operate, so
that output discharge function does not work, and becomes output
Hi-z. (In case, FB has resistor against GND, discharge at the
resistor.）
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16/29
2011.11 - Rev.A