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BD9102FVM BD9104FVM

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© 2012 ROHM Co., Ltd. All rights reserved.

TSZ22111･14･001

TSZ02201-0J3J0AJ00340-1-2

24.Oct.2013 Rev.003

2.

Description of Functions

(1) Soft-Start Function

During start-up, the soft-start circuit gradually establishes the output voltage to limit the input current. This prevents the

overshoot in the output voltage and inrush current.

(2) Shutdown Function

When the EN terminal is “low”, the device operates in Standby Mode and all functional blocks, such as reference

voltage circuit, internal oscillator and drivers, are turned OFF. Circuit current during standby is 0μA (Typ).

(3) UVLO Function

The UVLO circuit detects whether the supplied input voltage is sufficient to obtain the output voltage of this IC. The

UVLO threshold, which has a hysteresis of 50mV to 300mV (Typ), prevents output bouncing.

(4) BD9102FVM BD9104FVM

Figure 33. Soft Start, Shutdown, UVLO Timing Chart

(5) Short-Circuit Protection with Time Delay Function

To protect the IC from breakdown, the short-circuit protection turns the output OFF when the internal current limiter is

activated continuously for at least 1 ms. The output that is kept off may be turned ON again by restarting EN or by

resetting UVLO.

Figure 34. Short-Circuit Protection with Time Delay Timing Diagram

Hysteresis 100mV

Soft start

Standby mode

Operating mode

Standby

mode

Operating mode

Standby

mode

Operating mode

Standby mode

UVLO

EN

UVLO

UVLO

EN

1msec

Output OFF

latch

EN

Limit

Standby

mode

Operating mode

Standby

mode

Operating mode

EN

Timer latch

EN