HA16120FP HITACHI [Hitachi Semiconductor], HA16120FP Datasheet - Page 10

• Manufacturer Part Number: HA16120FP
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: HITACHI [Hitachi Semiconductor]

HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
2.2 Error Amplifier Usage
Figure 2.3 shows an equivalent circuit of the error amplifier. The error amplifier in these ICs is a simple
NPN-transistor differential amplifier with a constant-current-driven output circuit.
The amplifier combines a wide bandwidth (f
stable feedback to be applied when the power supply is designed. Phase compensation is also easy.
3. Dead-Band Duty Cycle and Soft-Start Settings
3.1 Dead-Band Duty Cycle Setting
The dead-band duty cycle (the maximum duty cycle of the PWM pulse output) can be programmed by the
voltage V
external resistors. The dead-band duty cycle (DB) and V
Note: V
Vref is typically 2.5 V. Select R
10
V
DB
V
V
DB
TH
TL
DB
DB =
V
: 1.0 V (Typ)
: 1.6 V (Typ)
IC internal V
R
R
is the voltage at the DB pin.
To Vref
DB
at the DB pin. A convenient way to obtain V
1
2
= Vref
DB
V
V
TH
TH
IN( )
IN(+)
Sawtooth
wave
IN
V
V
R
E/O
DB
TL
1
R
+ R
Figure 2.3 Error Amplifier Equivalent Circuit
2
Figure 3.1 Dead-Band Duty Cycle Setting
2
100 (%)
+
+
1
and R
from
UVL
PWM
COMP
2
so that 1.0 V V
80 A
T
This applies when V
If V
= 4 MHz) with a low open-loop gain (50 dB Typ), allowing
DB
V
V
V
Note:
TH
DB
TL
< V
TL
V
Select constants by testing under implementation
conditions.
DB
TH
, there is no PWM output.
DB
can be calculated as follows.
and V
DB
1.6 V.
TL
is to divide the IC’s Vref output by two
DB
Sawtooth wave
40 A
vary depending on the oscillator.
> V
TL
Dead band
.
E/O
To internal PWM
comparator
Voltage at DB pin