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4.1.3 Power Regulator AIC1563 (U12),LT1117 (U5, U6)
The AIC1563 is a monolithic control IC containing the primary functions required for DC to DC converters.
The device consists of an internal temperature compensated reference, conparator, controlled duty cycle
oscillator with an active current sense circuit. Desired output voltage are determined by the equation
Vout = 1.25 ( 1 + R104 / R103), In this case, the output voltage are 5 Volts.
The AIC1117 is a low dropout positive adjustable regulator with minumum of 1A output current capability.
So it is well suited for 3.3 V and 2.5 V Rregulator.
U6 as a 2.5 V regulator , Desired output voltage are determined by the equation
Vout=5 x ( R53 / R53+R56)= 2.5
U5 as a 3.3 V regulator , Desired output voltage are determined by the equation
Vout=5 x ( R30 / R30+R36)= 3.3
4.2 Audio Board AN7522 (U1)
The AN7522 is a 2 channel audio power amplifier capable of delivering 2W of continuous average power
to an 8 ohms with less than 0.5% (THD) from a 12 V power supply.
An7522 can directly drive 8 ohms speaker , does not require output coupling capacitor, bootstrap capacitor
,or snubber network. Audio line-in are feed into pin 6,8 of the AN7522. The output power is controlled by
the DC voltage of pin 8 from gm2120 GPIO port.
4.3 Inverter Board
This is a specific inverter for L7E monitor backlight which converters 12 Vdc to drive four cold cathod
fluorescence tubes. Electrical specification describled as below.
INPUT
Rated Input Voltage
Maximum Input Voltage
Input Current
Off state Input Power
On / Off Voltage
OUTPUT
Rated Output Strike-on Voltage
Rated Output Voltage
Rated Output Frequency
Rate Output Current per tube
12Vdc
11.4~12.6 Vdc
< 2A
< 0.1 W
2~3.3 for On, 0~1 for Off
1310 Vrms
710 Vrms at 6 mA
45~60KHz
6 mA
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