Circuit Descriptions
7.
7.3.3
IPL42L P
S
U
Block Diagram
Figure 7-4 Block diagram IPL42L P
S
U
Key Components
The key component ICs are:
•
Stand-by power supply IC: FSQ510 (Fairchild).
•
PFC control IC: L6562 (ST).
•
24V PWM control IC: FA5571N (FUJI).
•
Inverter high voltage control IC: OZ9926 (O2).
Control Signals
Table 7-4 Control signals
Output Characteristics
Table 7-5 Output characteristics
Fault Finding
Normal PSU working order:
•
Connect the AC power plug.
•
The 3.3V Stand-by power supply (Stand-by uP U801) will
start. This is a “single-ended flyback regulator”. For a good
functioning of this part, check the availability of 1.25V on
U803 (TL431).
•
On connector P802, signal line “PS_ON” will go “high”
(3V3) and relay K801 will be activated.
•
Also capacitors C811/C812 will be charged, supplying
IC806 with electricity. This will start the PFC circuit and
generate the +24 V control.
•
Now, IC805 will start, and will generated the 24V output.
•
On connector P802, signal “DIM” sets the PWM dimming
status.
•
On connector P802, when signal “BL-ON” goes “high”, the
high voltage Inverter (IC901, OZ9926A) will start.
Control signal
Comments
Output
PS-ON
5.0V >= ON >= 2.0V
AC power output ON
1.0V >= OFF >= 0V
AC power output OFF
BL_ON
5.0V >= ON >= 2.0V
The inverter is working
1.0V >= OFF >= 0V
The inverter is switched OFF
Burst dimming freq. / duty
100 - 200 Hz / 10 - 100%
PWM Dimming
High level: 2V ~ 5.0V
Low level: 0V ~ 0.7V
Output Voltage Tolerance Min. current Max. current
Load regulation
+3V3
+/- 5%
5 mA
300 mA
+/- 5%
24V
+/- 5%
0.5 A
2.5 A
+/- 5%
1
8
520_214_090
3
19.ep
s
090
3
19
P F C IC
L6562A
(
S
T)
IN V E R T E R
IC OZ9926A
(O2)
+ H V
-
H V
P W M P ow er
S u
pply IC
FA 5571
(F U JI)
S
T B P ow er
S u
pply IC
F
S
Q 510
(FA IR C H ILD
3
.
3
V
2 4 V
D IM
B L-O N
P
S
-O N
A C
In p
u
t
S
w itc h c o n tro l
Vo lt
a
g e D e te c t
E N A B LE
P F C o
u
tp
u
t
3
9 5 V
R e l
a
y
