R1212D002A RICOH [RICOH electronics devices division], R1212D002A Datasheet - Page 15

• Manufacturer Part Number: R1212D002A
• Description: STEP-UP DC/DC CONTOLLER
• Manufacturer: RICOH [RICOH electronics devices division]

<Latch Protection Operation>
maximum duty cycle, charge to an external capacitor, C2 of D
and the voltage of DELAY pin reaches delay voltage detector threshold, V
the external power MOSFET.
and make it rise up to the normal input voltage.
charging the capacitor stops immediately, and the DELAY pin voltage is fixed at GND level with I
the next formula.
The operation of Latch protection circuit is as follows: When AMPOUT becomes "H" and the IC detects
Once after becoming the maximum duty cycle, if the duty cycle decreases before latch operation works, the
The delay time of latch protection can be calculated with C2, V
t=C2 × V
To release the latch protection operation, make the supply voltage down to UVLO detector threshold or lower,
DLY
/I
DLY1
Normal
Output Short
V
I
DLY1
DLY
DELAY
C
Maxduty Operation
2
ELAY
DLY
pin starts. The maximum duty cycle continues
, and the delay pin charge current, I
DLY
, outputs "L" to EXT pin and turns off
Latched
V
DLY
DTC
D
A
EXT
DLY2
MPOUT
ELAY
.
R1212D
DLY1
, as in
15