BD9E303EFJ-LB Datasheet, PDF (4/31 Pages) Rohm – Over-Current Protection

BD9E303EFJ-LB
Datasheet
Description of Block
 VREG3
Block creating internal reference voltage 3V (Typ).
 VREG
Block creating internal reference voltage 5V (Typ).
 BOOTREG
Block creating gate drive voltage.
 TSD
This is the thermal shutdown block. Thermal shutdown circuit shuts down the whole system if temperature exceeds 175°C
(Typ). When the temperature decreases, it returns to normal operation with hysteresis of 25°C (Typ).
 UVLO
This is the under voltage lock-out block. IC shuts down when VIN is under 5V (Typ). The threshold voltage has a
hysteresis of 1.4V (Typ).
 ERR
This circuit compares the feedback voltage at the output to the reference voltage. The output of this circuit is the COMP
terminal voltage and this determines the switching duty. Also, because of soft start during start-up, COMP terminal voltage
is controlled by internal slope voltage.
 OSC
Block generating oscillation frequency.
 SLOPE
This circuit creates a triangular wave from generated clock in OSC. The voltage converted from current sense signal of
high side MOSFET and the triangular wave is sent to PWM comparator.
 PWM
This block determines the switching duty by comparing the output COMP terminal voltage of error amplifier and output of
SLOPE block.
 DRIVER LOGIC
This is the DC/DC driver block. Input to this block is signal from PWM and output drives the MOSFETs.
 SOFT START
This circuit prevents the overshoot of output voltage and In-rush current by forcing the output voltage to rise slowly, thus,
avoiding surges in current during start-up.
 OCP
This block limits the current flowing in high side MOSFET for each cycle of switching frequency during over-current.
 RCP
This block limits the current flowing in low side MOSFET for each cycle of switching frequency during over-current.
 SCP
The short circuit protection block compares the FB terminal voltage with the internal standard voltage VREF. When the FB
terminal voltage has fallen below 0.7V (Typ) and remained in that state for 1.0msec (Typ), SCP activates and stops the
operation for 14msec (Typ) and subsequently initiates a restart.
 OVP
Over voltage protection function (OVP) compares FB terminal voltage with the internal standard voltage VREF. When the
FB terminal voltage exceeds 1.30V (Typ) it turns MOSFET of output part MOSFET off. After output voltage drop it returns
with hysteresis.
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TSZ22111•15•001
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TSZ02201-0J3J0AJ00650-1-2
13.Feb.2015 Rev.002