AN8016 Panasonic Semiconductor, AN8016 Datasheet - Page 14

• Manufacturer Part Number: AN8016
• Description: Single-channel 1.8-volt step-up DC-DC converter control IC
• Manufacturer: Panasonic Semiconductor

AN8016NSH
15
[6] Setting the soft start time
capacitor is connected to the SS pin. This can prevent rush currents and overshoot when the power supply is turned
on.
k , and is charged from 230 mV to 1.22 V by a constant current of about 5 A.
Application Notes (continued)
A soft start function, which gradually increases the width of the output pulses at power on, will be applied if a
The capacitor C
The following formulas express the soft start time for the duty of up to 50%.
1) 0.06
2) 0.23
V
t
0.52 V = 0.23 V
t
PE1
PE2
SCP
t
SS
[s]
[s]
[s]
V
V
(0.23
SCP
SCP
0.017
0.058
t
SS
SS1
[V]
[V]
1.22
0.75
0.52
0.23
0.06
(V)
is charged from 60 mV to about 230 mV with a time constant determined by a resistor of 6
0.06)
t
C
C
SS2
0.23
1.26
I
t
S
S
SS1
CHG
[mF]
[ F]
OSC
{1
FB
0.075
t
C
SS2
exp(
S
Figure 5. Soft start operating waveforms
Soft start time
C
S
t
SS2
6k · C
[ F]
t
SS1
S
)} [V]
DC-DC converter output voltage
Duty: 50%
SS
Voltage Regulators
t (s)