HA16120 RENESAS [Renesas Technology Corp], HA16120 Datasheet - Page 10

• Manufacturer Part Number: HA16120
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: RENESAS [Renesas Technology Corp]

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
resistors. The dead-band duty cycle (DB) and V
Note: V
Vref is typically 2.5 V. Select R
Rev.2.0, Sep.18.2003, page 10 of 37
V
DB
V
V
DB =
V
DB
DB
TH
TL
DB
: 1.0 V (Typ)
: 1.6 V (Typ)
IC internal V
R
R
at the DB pin. A convenient way to obtain V
is the voltage at the DB pin.
To Vref
1
2
= Vref
V
V
TH
TH
DB
IN( )
IN(+)
V
V
R
Sawtooth
wave
DB
IN
TL
1
E/O
R
+ R
2
Figure 2.3 Error Amplifier Equivalent Circuit
2
100 (%)
Figure 3.1 Dead-Band Duty Cycle Setting
+
+
1
and R
from
UVL
PWM
COMP
2
so that 1.0 V ≤ V
This applies when V
If V
80 A
T
DB
= 4 MHz) with a low open-loop gain (50 dB Typ), allowing
DB
< V
V
V
V
Note:
can be calculated as follows.
TH
DB
TL
TL
, there is no PWM output.
V
Select constants by testing under implementation
conditions.
TH
DB
DB
is to divide the IC’s Vref output by two external
and V
≤ 1.6 V.
DB
TL
> V
Sawtooth wave
vary depending on the oscillator.
40 A
TL
.
Dead band
E/O
To internal PWM
comparator
Voltage at DB pin