MB3785A_03 Datasheet, PDF (24/30 Pages) Fujitsu Component Limited. – Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)

MB3785A
It is also possible to set soft start simultaneously with the dead time by configuring the DTC terminals as shown
below.
For figure 15
Soft start time (time until output ON duty = 50%)
ts (s) = −
Cdt (F) × R1 (Ω) × R2 (Ω)
R1 (Ω) + R2 (Ω)
× ln (0.64 −
0.36R2 (Ω) ₎
R1 (Ω)
For figure 16
Soft start time (time until output ON duty = 50%)
ts (s) = −
Cdt (F) × R1 (Ω) × R2 (Ω)
R1 (Ω) + R2 (Ω)
× ln (1 −
1.6 (R1 (Ω) + R2 (Ω))
2.5R2 (Ω)
)
Figure 15. Setting Dead Time and Soft Start
for CH1 and CH2
Figure 16. Setting Dead Time and Soft Start
for CH3 and CH4
19 VREF
Cdt
R1
DTC1
(DTC2)
R2
19 VREF
R1
DTC3
(DTC4)
Cdt
R2
24