HA16116 Hitachi Semiconductor, HA16116 Datasheet - Page 8

• Manufacturer Part Number: HA16116
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: Hitachi Semiconductor

operation.
Note that I
HA16116FP/FPJ, HA16121FP/FPJ
The triangle wave is a voltage waveform used as a reference in creating a PWM pulse. This block operates
according to the following principles. A constant current I
is made to flow continuously to external timing capacitor C
comparator threshold voltage V
from C
causes the switch to operate, stopping the I
should be set to 5 k (I
With this IC series, V
internal resistors R
Note that the value of f
in the comparator circuit. Also, at high frequencies this comparator delay can cause triangle wave
overshoot or undershoot, skewing the dead band threshold. Confirm the actual value in implementation
and adjust the constants accordingly.
8
T
. Next, when the C
O
Here,
Accordingly,
V
= 1.1 V/R
H
f
t
t
t
t
f
OSC
1
2
1
3
OSC
=
=
= t
V
0.8 s (comparator delay time in the oscillator)
L
=
2
(2
C
A
= 0.6 V
, R
=
T
C
t
2t
1.1 V/R
1
T
T
H
B
1
+ t
1)
0.6
1.1
(V
OSC
. Since the I
1
, and R
+ t
and V
(V
1
O
H
2
may differ slightly from the above calculation depending on the amount of delay
3
+ t
H
1.1 V/R
C
T
T
220 A).
T
V
3
pin voltage drops below threshold voltage V
L
L
R
V
C
H
)
1.1 C
. The oscillator frequency can be calculated as follows.
L
T
of the triangle wave are fixed internally at about 1.6 V and 1.0 V by the
, the comparator output causes a switch to operate, discharging a current I
)
=
T
O
T
C
current mirror circuit has a very limited current producing ability, R
=
T
R
1
T
R
C
T
+ 0.8 s
T
1.1 V
R
O
(V
T
discharge. The triangle wave is generated by this repeated
1.1 V
H
(V
H
V
[Hz]
L
)
V
L
)
O
= t
, determined by an external timing resistor R
1
T
. When the C
L
, the comparator output again
T
pin voltage exceeds the
T
T
O
,