datasheetbank_Logo
Integrated circuits, Transistor, Semiconductors Search and Datasheet PDF Download Site

HA16114FP View Datasheet(PDF) - Hitachi -> Renesas Electronics

Part Name
Description
View to exact match
HA16114FP
Hitachi
Hitachi -> Renesas Electronics Hitachi
HA16114FP Datasheet PDF : 38 Pages
First Prev 11 12 13 14 15 16 17 18 19 20 Next Last
HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
3.2 Soft-Start Setting
Soft-start avoids overshoot at power-up by widening the PWM output pulses gradually, so that the
converted DC output rises slowly. Soft-start is programmed by connecting a capacitor between the DB pin
and ground. The soft-start time is determined by the time constant of this capacitor and the resistors that
set the voltage at the DB pin.
Note:
tsoft = C1 × R × ln (1
VX )
VDB
R=
R1 × R2
R1 + R2
VDB
=
Vref
×
R2
R1 + R2
VX is the voltage at the DB pin after time t (VX < VDB).
Undervoltage
lockout released Sawtooth wave
Sawtooth
To Vref wave
PWM
VTH 1.6 V
COMP VDB
R1
E/O
+
VX
DB
+
V TL
1.0 V
C1
R2
from
UVL
VX
UVL sink
transistor
t
Soft-start time
tsoft
Figure 3.2 Soft-Start Setting
3.3 Quick Shutdown
The quick shutdown function resets the voltages at all pins when the IC is turned off, to assure that PWM
pulse output stops quickly. Since the UVL pull-down resistor in the IC remains on even when the IC is
turned off, the sawtooth wave output, error amplifier output, and DB pin are all reset to low voltage.
This feature helps in particular to discharge capacitor C1 in figure 3.2, which has a comparatively large
capacitance. In intermittent mode (explained on a separate page), this feature enables the IC to soft-start in
each on-off cycle.
11
 

Share Link: 

datasheetbank.com [ Privacy Policy ] [ Request Datasheet ] [ Contact Us ]