![background image](http://html1.mh-extra.com/html/viewsonic/vg700b-2/vg700b-2_service-manual_1021200015.webp)
f)
Panel Power Sequencing ( PPWR, PBIAS) ( Pin 40~41) : The gm2121 has two dedicated outputs PPWR
and PBIAS ( Pin113 and Pin114) to control LCD power sequencing once data and control signals are
stable.
g)
Parallel ROM Interface Port (Pin 1~6, Pin 139~160: The gm2121 has parallel ROM interface port,
Pin139~156 for address bus, pPin1~6, Pin159 and Pin160 for data bus.
h)
Panel interface (Pin 48~57, Pin64~73): The gm2121 driver interface is highly programmable. It supports
dual bus / dual port for SXGA drivers.
1.3 Power Regulator AIC1563 (U6), LT1117 (U7, U8):
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, comparator, controlled duty cycle.
Oscillator with an active current sense circuit. Desired output voltage is determined by the equation,
Volt = 1.25 (1 + R104 / R103), In this case, the output voltage is 5 Volts
The AIC1117 is a low dropout positive adjustable regulator with minimum of 1A output current capability,
so it is well suited for 3.3 V and 2.5 V Regulator.
U6 is a 2.5 V regulator, desired output voltage is determined by the equation.
Volt=1.25 x (1 + R93/R92) = 2.5,
U5 is a 3.3 V regulator, desired output voltage is determined by the equation
Volt=1.255 x (1+ R95/R94) = 3.3
1.4 Audio Amplifier TPA3003D2 (U1)
The TPA3003D2 is a class D, 2 channel audio power amplifier capable of delivering 3W of continuous average
power to 8 ohms with less than 1% (THD) from a 12 V power supply. TPA3003D2 can directly drive 8 ohms
speaker, and does not require output coupling capacitor, bootstrap capacitor, or LC filter. Audio line-in is fed into
pin 2, 6 of the TPA3003D2. The output gain is controlled by pin 11.
1.5 Inverter Board
This is a specific inverter for L7VB monitor backlight which converters 12 Vdc to drive four cold cathode
fluorescence tubes. Electrical specification described as below.
ViewSonic Corporation
11
Confidential
– Do Not Copy
VG700b-2