BD91361MUV_12 Datasheet, PDF (10/23 Pages) Rohm – 2.7V to 5.5V, 4A 1ch Synchronous Buck Converter Integrated FET

BD91361MUV
Datasheet
●Description of Operations
・Soft-start function
EN terminal shifted to “High” activates a soft-starter to gradually establish the output voltage with the current limited
during startup, by which it is possible to prevent an overshoot of output voltage and an inrush current.
・Shutdown function
With EN terminal shifted to “Low”, the device turns to Standby Mode, and all the function blocks including reference
voltage circuit, internal oscillator and drivers are turned to OFF. Circuit current during standby is 0µA (Typ.).
・UVLO function
Detects whether the input voltage sufficient to secure the output voltage of this IC is supplied. And the hysteresis width
of 50mV (Typ.) is provided to prevent output chattering.
Hysteresis 50mV
VCC
EN
VOUT
Standby mode
Tss
Soft start
Operating mode
Tss
Tss
Standby
mode
Operating mode
Standby
mode
Operating mode
Standby mode
UVLO
UVLO
EN
UVLO
Fig.24 Soft start, Shutdown, UVLO timing chart
・Short-current protection circuit with time delay function
Turns OFF the output to protect the IC from breakdown when the incorporated current limiter is activated continuously for
the fixed time(TLATCH) or more. The output thus held tuned OFF may be recovered by restarting EN or by re-unlocking
UVLO.
EN
1msec
VOUT
Limit
Output Current in non-control
1/2VOUT
Until output voltage goes up the half of
Vo or over, timer latch is not operated.
(No timer latch, only limit to the output current)
Output voltage OFF Latch
IL
Output Current in control by limit value
(With fall of the output voltage, limit value goes down)
Standby mode
EN
Operated mode
Standby mode
Operated mode
Timer Latch
EN
Fig.25 Short-current protection circuit with time delay timing chart
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