BD9E302EFJ Datasheet, PDF (17/44 Pages) Rohm – Integrated MOSFET Single Synchronous Buck DC/DC Converter

BD9E302EFJ
3-2) Under Voltage Lockout Protection (UVLO)
The under voltage lockout protection circuit monitors the VIN terminal voltage.
The operation enters standby when the VIN terminal voltage is 6.4 V (Typ) or lower.
The operation starts when the VIN terminal voltage is 6.6 V (Typ) or higher.
VIN
UVLO
ON
UVLO
OFF
hys
0V
Datasheet
VOUT
FB
Soft start
VOUT×0.85
High-side
MOSFET gate
Low-side
MOSFET gate
Normal operation
UVLO
Figure 37. UVLO Timing Chart
Normal operation
3-3) Thermal Shutdown Function (TSD)
This is thermal shutdown block. Usually IC operating in the allowable power dissipation, but when the IC power
dissipation more than rating value, Tj will increase, when the chip temperature exceeds 175C(Typ), The thermal
shutdown circuit is intended to shut down internal power devices. Then the Tj will decreased and IC restart. 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.
3-4) Over Current Protection Function (OCP)
The overcurrent protection function is realized by using the current mode control to limit the current that flows through
the high-side MOSFET at each cycle of the switching frequency.
3-5) Over Voltage Protection Function (OVP)
Over voltage protection function (OVP) compares FB terminal voltage with internal standard voltage VREF and when FB
terminal voltage exceeds1.04V (Typ) it turns MOSFET of output part MOSFET OFF. After output voltage drop it returns
with hysteresis.
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TSZ02201-0J3J0AJ00890-1-2
27.Apr.2016 Rev.002