Service manual

c) SST 39VF040 Micro Controller: The SST 39VF040 micro controller (MCU) serves as the system micro
controller. It programs the Gm1601 and manages other devices in the system such as the keypad
Pin number
Pin Number Usage
AE24 Key / Power on ,off
P3 NV_RAM (U4) SDA
P4 NV_RAM (U4) SCL
AF24 Key_down
AF26 Key_right
AF25 Key_up
AE25 Key_left
AD24 Key_select
D25 LED_red
D26 LED_green
AC2 LCD panel power1 on / off control
C25 Backlight on / off control
d) Panel interface (Pin B1,B2,C1,C2,D1,D2,A6,B6,A8,B8,A9,B9,A10,B10,) : The Gm1601 driver interface is
highly programmable.
6.1.2 Power Regulator AIC1577 (U23), AP1084 (U16,U20),LT1117(U18): The AIC1577 is a current switching
regulator control IC containing the primary functions required for DC to DC converters and external NMOS
STEP-DOWN PWM controller ,operating input voltaqge from 4.5V to 24V The desired output voltage is
determined by the equation, Volt = 0.8[ ( R218+R219) / R218]. In this case, the output voltage is 5 Volts. The
AIC1577 is a low dropout operation
6.1.3 Power Regulator AP1084 (U16,U20): The AP1084 is a low dropout positive adjustable or fixed mode
regulator with minimum of 5A output current capability. Specifically designed to provide supply for low voltage
IC and low current 3.3V logic supply. AP1084 is guaranteed to have lower than 1.4V dropout at full load
current ,provide well-regulated output of 1.25 to 3.3 with 4.7 to 12V input supply.
6.1.4 Power Regulator LT1117(U18): The LT1117 is a low drop voltage regulator ,provide up to 800 mA of output
current. Concerning fixed version, are offered the output voltage:1.2V,1.8V,2.5V,2.85V,3.0V,3.3V,the regulator to
reach a very tight output voltage tolerance, within ± 1% at 25?C. The adjustable LD1117 is pin to pin compatible
with the other LD1117.
6.3 Power (Inverter) Board
This is a specific power (inverter) board for VP2030B monitor with output of 56W /12V / 2.4A and 20V/1.8A. It
provides 20 VDC to drive the four cold cathode fluorescence tubes in the backlight.
6.3.1 The inverter's electrical specification is described below.
Viewsonic Corporation 32 VP2130b-1 Confidential - Do Not Copy