HA16108FP HITACHI [Hitachi Semiconductor], HA16108FP Datasheet - Page 7

• Manufacturer Part Number: HA16108FP
• Description: PWM Switching Regulator for High-performance Voltage Mode Control
• Manufacturer: HITACHI [Hitachi Semiconductor]

1. Timing in Normal Operation
2. Triangle Oscillator, Waveform and Frequency
Timing in these ICs is based on a triangular voltage waveform. The rising edge (leading edge) defines
the deadband time t
output is on in the area within t
The following pin outputs are related to PWM control:
C
E/O (pin 15): error output voltage
R
OUT (pin 2): PWM pulse output (for driving the gate of a power MOS FET)
The triangle oscillator in these ICs generates a triangular waveform by charging and discharging timing
capacitor C
The discharge current is:
In these equations Vref (reference voltage) is typically 6.45 V, and V
internal transistors) is about 0.7 V.
The deadband time is:
The ON-duty time is:
The 0.8 s in these equations is a correction term for internal circuit delays.
The maximum ON-duty is
The oscillating frequency is:
When R
This approximation is fairly close, but it should be checked in-circuit.
T
T2
(pin 7): triangle-wave voltage output
(pin 8): ON-duty pulse output voltage
t
I(C
t
Du max =
f
f
T1
DB
I(C
ON
OSC
OSC
= R
Tchg
T
Tdischg
=
= t
=
=
with a constant current, as shown in the equivalent circuit. The C
0.4
C
V
DB
T2
) = I
T
0.8 C
1
REF
, the maximum ON-duty is 50%, and:
0.8
) = 2I
2R
1
2R
R
C
R
Du max
2R
DB
t
=
T1
T
DB
T
T2
T1
T1
C
. The falling edge (trailing edge) defines the ON-duty control band t
2V
R
T1
V
2
R
T
R
T1
1
REF
BE
1
T2
2V
T1
R
I
+ 0.8 s
1
R
R
T2
R
1
, where I
+ 0.8 s
+ 0.8 s
T1
T2
+ 0.8 s
T1
2V
2
ON
+ 0.8 s
BE
that is bounded above by the triangle wave V
(Hz)
2
=
V
(Hz)
REF
R
T2
2V
BE
HA16107P/FP, HA16108P/FP
BE
(base-emitter voltage of
T
CT
charge current is:
and error output V
ON
. PWM
E/O
.
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