MB3759-P Fujitsu Microelectronics, Inc., MB3759-P Datasheet - Page 15

• Manufacturer Part Number: MB3759-P
• Description: Pulse-width-modulation Control Circuit Push-pull/single-ended Output Mode
• Manufacturer: Fujitsu Microelectronics, Inc.

3. Soft Start
4. Output Current Limiting (Fallback system using a detection resistor inserted on the output side)
(1) Typical example
A soft start function can be incorporated by using the dead-time control element.
When the power is turned on, Cd is not yet charged and the DT input is pulled to the V
transistor to turn off. Next, the input voltage to the DT pin drops in accordance with the Cd, Rd constant causing
the output pulse width to increase steadily, providing stable control circuit operation.
If you wish to use both dead-time and softstart, combine these in an OR configuration.
V
R3
R4
IO
V
REF
Setting the dead-time
R1
R2
D
R1
R2
R
R5
S
V
DT
REF
I
O
V
GND
Cd
Rd
V
O
D
=
R1+R2
R2
R2
R1
V
R
V
DT
REF
Cd
Rd
V
Incorporating soft start
O1
0
V
0
O
V
DT
REF
I
L3
I
L2
REF
pin causing the output
I
MB3759
L1
I
O
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