HA17384SPS Datasheet, PDF (13/29 Pages) Hitachi Semiconductor – High Speed Current Mode PWM Control IC for Switching Power Supply

HA17384SPS/SRP, HA17384HPS/HRP, HA17385HPS/HRP
1V
V_CS
CS terminal
2R
R
−
CS
+
V_COMP
2V_F
COMP terminal
(Error output)
CS
latch
R
S
Q
PWM pulse
Latch setting pulse
(Implemented in triagular
wave oscillator)
Latch setting
pulse
V_COMP
Error voltage
V_CS
Current sensing
level
×¹³
Figure 3 Operation Diagram of Current Sensing Part
Point: 1) At maximum rated load, the setting should be made to give
approximately 90% of area A below.
2) When the OVP latch is operated, the setting should be made
in area B or C.
1.0
B
Heavy load
0.8
0.6
0.4
0.2
0.0
0
Light load
1.4V
C
A : Stationary operation / PWM
A
(Current-mode operation)
B : Current limit operation / Max duty cycle
C : No sensitivity area / No PWM output
4.4V
7.5V
1
2
3
4
5
6
7
8
Error Amplifier Output Voltage Vcomp (V)
Figure 4 Current Sense Characteristics
Rev.3.00 Jun 15, 2005 page 13 of 28