Circuit Descriptions
EN 24 TCM3.2L LA7.
2009-Jun-19
7.3.3 IPL42L PSU
Block Diagram
Figure 7-4 Block diagram IPL42L PSU
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%
18520_214_090319.eps
090319
PFC IC
L6562A
(ST)
INVERTER
IC OZ9926A
(O2)
+HV
-
HV
PWM Power
Supply IC
FA5571
(FUJI)
S TB Power
Supply IC
F SQ510
(FAIRCHILD
3 .3 V
24V
DIM
BL-ON
P S -ON
AC
Inpu t
S witch control
Volta ge Detect
ENABLE
PFC outpu t
395V
Rela y
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