BD9C301FJ-LB Datasheet, PDF (9/22 Pages) Rohm – 4.5V to 18V Input, 3.0A Integrated MOSFET Single Synchronous Buck DC/DC Converter

BD9C301FJ-LB
(b) Under Voltage Lockout Protection (UVLO)
The Under Voltage Lockout Protection circuit monitors the VIN pin voltage.
The operation enters standby when the VIN pin voltage is 3.8 V (Typ) or lower.
The operation starts when the VIN pin voltage is 4.0 V (Typ) or higher.
VIN
UVLO
Release
hys
UVLO detection
0
Vo
Soft Start
FB
HG
LG
Normal operation
UVLO
Normal operation
Figure 18. UVLO Timing Chart
HG : Hi side FET GATE signal
LG : Low side FET GATE signal
(c) Thermal Shutdown
When the chip temperature exceeds Tj = 175°C (Typ), the DC/DC converter output is stopped. The thermal
shutdown circuit is intended for shutting down the IC from thermal runaway in an abnormal state with the
temperature exceeding Tjmax = 150C. It is not meant to protect or guarantee the soundness of the application.
Do not use the function of this circuit for application protection design.
VIN
EN
Vout
Tj
HG
SCP delay time
Typ:1msec
SCP threshold
Soft Start
TSD release
LG
Normal operation
TSD Normal operation
TSD
SCP
(OFF Latch)
TSD release
Figure 19. TSD Timing chart
Normal operation
HG : Hi side FET GATE signal
LG : Low side FET GATE signal
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TSZ22111・15・001
9/19
TSZ02201-0J3J0AJ00540-1-2
21.Feb.2014 Rev.002