HA16107P Datasheet, PDF (29/40 Pages) Hitachi Semiconductor – PWM Switching Regulator for High-performance Voltage Mode Control

HA16107P/FP, HA16108P/FP
Operating waveform at the ON/OFF pin
When overcurrent is input at the point
where the duty cycle is 0%.
7
6
B
5
4
3
Test circuit
HA16108
V _IN = 18V
V_IN
R_T1 = R _T2 = 27 k½
C_T = 470 pF
f _OSC = 100kHz
ON/OFF
C_L
1000 pF
OUT
CL(+)
Clock
27 k½
470 pF ^RT1
C_T S_T
R _T2
27 k½
+
1 µF
C _ST
+^{1 µF}
2
A
1
0
Triangle
wave
CL(+) when
input at a
0.5 sec/div _{duty of 0%}
t _ON
t _OFF
t _ON
t _OFF
t _ON t _OFF
SW ON SW OFF
Output pulse shutdown region
CL(+) when
input at a
duty of 30%
t1
t2
When overcurrent is input at the point
where the duty cycle is 30%.
Du =
t1
t2
× 100 (%)
7
6
B
Enlargement of section A
ab ^c
5
V _TL
4
3
2
A
1
0
CTL discharged at 4 µA
CTL discharged at 12 µA
t
Enlargement of section B
V _TL
CTL discharged at 4 µA
t _ON
SW ON SW OFF
t _OFF
0.5 sec/div
t _ON
t _OFF
Output pulse shutdown region
t
a to b : PWM pulse output is High.
b
: The point where overcurrent
is detected.
b to c : PWM pulse output is Low.
Rev.4.00 Jun 15, 2005 page 29 of 39