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17. Switch Mode Power Supply (SMPS) R764349
17.2 Technical Description
General
The following functions are performed by this unit :
•
Generation of the standby voltages for the controller and the interfacing.
•
Generation of the "operational voltages" to the rest of the circuits (PMP, Formatter, etc...)
•
Supply voltages and regulation of the speed of the fans and the TEC's (Thermo Electric Cooler).
•
Processing of a number of controls (like temperature sensors) and driving on and off the appropriated circuits by the use of a
microprocessor.
Standby power supply
This is a separate Flyback Converter built around the I100 TOP249 and the transformer T100, running at approximately 132KHz.
The +380VM, arriving at J609 from the LPS board, is further smoothed by L100/ D100 / C102 .
The ++5V , from the Flyback Converter, is used in the controller, LPS interface and to generate the 3V3 for the controller on board.
The ++30V ,from the Flyback Converter, is used in the interfacing circuits, motor control and Fan 1-2-3.
The status of this SMPS is shown with the green LED diode D107. By using the +5V as feedback, there is no further need to stabilise
this ++5V on the CPU.
The drain in the TOP249 is protected by the snubber network D101/D102/C104/R107.
This Standby SMPS is active as soon the mains switch is turned on. The maximum power of this converter is 120W.
Power supply for the electronic circuits
This SMPS, built around the I150 TOP249 and the transformer T150, delivers one unique voltage +15V with a maximum power of
100W. This voltage is then further down converted by DC / DC converters to various other voltages.
The Flyback Converter is switched On and Off via the opto-coupler I151, on its turn driven by the SHDN_SMPS (SHut DowN) line
from the microprocessor I2 (port P1.7, pin 4).
This +15V power supply is utilised by the operational modules in the projector.
Following down converted voltages are obtained by DC/DC converters:
The+3.3V- PMP and Formatter board (driver of the DMD units, between PMP and DMD).
The IC I200 (LT1339) drives the two parallel power FETs Q202/Q203 in the bottom (BG output) and Q204 is driven by the TG (Top
Gate) output of the IC. The total required current by the PMP and formatter is approximately 24A.
The current sensing resistors R211/R212/R213 limit the output current in the event of a short or very heavy load.
The Voltage feedback happens through R214, R215/R216 and R217 to pin 9 I200.
The power voltage+30V and the power voltage +5V
If the +15V is existing, the ++30V is switched through by Q230 and acts further as the +30V power voltage. The maximum output
current totals 0.5A.
The same voltage switches also the ++5V via Q233/Q232 and acts further as the +5V power voltage. The maximum output current
totals 7A.
The +12V- Formatter, Motor drive PMP.
The +15V is also applied to the stabilizer IC I230, supplying a stable +12V power voltage. The maximum output current totals 1A.
Voltage monitoring
The mains voltage is constantly monitored in order to have an immediate reaction and to put the mirrors in their parking position as
soon the mains voltage would disappear.
The V_SIN (half wave rectified mains input voltage) , taken from the mains input, is coupled by an opto-coupler I190 to the voltage
comparator I240. As long the pulses can switch on the opto-coupler, the voltage at pin 10 remains below the threshold installed by
the zener Z240.
The output "PWR_GOOD line (active low= Error)" can equally be pulled low by the output of two other voltage comparators (+3V3
and +5V). These two level detectors are constantly checking whether these voltages still are present or at least not too low.
The status of the PWR_GOOD line is shown by the YELLOW LED D240 This LED is on when all voltages are OK.
The local uProcessor with flash memory and I²C interface on board performed the following functions:
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R5976820 SLM R12+ PERFORMER 08/03/2005
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