ViewSonic vx912-1 Service Manual page 27

e) Panel Power Sequencing ( VDDCTRL1, 2) ( Pin 32, 3) : The MTV312 has two dedicated outputs
VDDCTRL1 and 2 ( Pin32 and Pin3) to control LCD power sequencing once data and control signals
are stable.
f) Panel interface (Pin 1~25, Pin75~128) : The MTV312 driver interface is highly programmable. It supports
dual bus / dual port for SXGA drivers.
6.1.2 Power Regulator MC34063A (U6),AIC1739 (Q4) : The MC34063A is a monolithic control IC
containing the primary functions required for DC to DC converters. The device consists of an
internal temperature compensated reference, comparator, controlled duty cycle.
Oscillator with an active current sense circuit. Desired output voltage are determined by the equation,
Volt = 1.25 ( 1 + R67 / R66), In this case, the output voltage are 3.3 Volts
The AIC1739 is a low dropout positive adjustable regulator with minimum of 300mA output current
capability. So it is well suited for 3.3 V and 2.5 V Regulator
6.1.3 Power Regulator MC34063A (U7) : The MC34063A is a monolithic control IC containing the
primary functions required for DC to DC converters. The device consists of an internal temperature
compensated reference, comparator, controlled duty cycle.
Oscillator with an active current sense circuit. Desired output voltage are determined by the equation,
Volt = 1.25 ( 1 + R85 / R86), In this case, the output voltage are 5.0 Volts for panel power.
6.2 Power(Inverter) Board
This is a specific power(inverter) power board for VE912 monitor 40W 12V 3.5A output power and backlight
which converters 12 Vdc to drive four cold cathode fluorescence tubes.
6.2.1 Inverter Electrical specification described as below.
Input
Output
6.2.2 power
This is a general purpose AC / DC adapter which converter 90~240 Vac to a stabilized DC voltage 12 V with
rated output current of 4.16A . Electrical specification described as below.
ViewSonic Corporation
3 P5.0
36 P4.0
Rated Input Voltage
Input Voltage Range
Input Current
On / Off control Voltage
Rated Output Strike-on Voltage
Rated Output Voltage
Rate Output Frequency
Rated Ourput Current
Rated Input Voltage
Operation Input Voltage
Input Current
Inrush Current
Standby Input Voltage
Output Voltage Regulation
Output Ripple & Noise
Rate Output Current
Turn-on delay
LCD panel power2 on / off control
Backlight on / off control
.
12Vdc
11.4 ~ 12.6 Vdc
<2A
2~3.3 for on , 0~1 for off
1500Vrms
912Vrms at 7mA
40~50KHz
7~8 mA
90~240 Vac , 50 / 60Hz
90~260 Vac , 47 ~ 63Hz
<1.5A
<100A@120Vac
12Vdc
+/-5%
120mVp-p
<3.5A
<3secs
Confidential - Do Not Copy
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VX912