Nokia 2180 Manual Do Serviço
PAMS
Technical Documentation
NHD–4
Uif Module
Page 6–6
Original 11/97
The display module contains an oscillator to generate a negative voltage
required for operation. The oscillator frequency is fixed on the UIF module
by the resistance from pins 2 to 3 of X1, with the values of R6 and R16
shown, the frequency is within 180 kHz to 370 kHz. The negative going
pulses appear at pin 9 of X1 where they are smoothed by C1 to give a
voltage which is nominally equal but opposite to VL1.
required for operation. The oscillator frequency is fixed on the UIF module
by the resistance from pins 2 to 3 of X1, with the values of R6 and R16
shown, the frequency is within 180 kHz to 370 kHz. The negative going
pulses appear at pin 9 of X1 where they are smoothed by C1 to give a
voltage which is nominally equal but opposite to VL1.
For correct operation of the display, DC voltages between –VL1 and VL1
need to be generated and fed back to the driver chip, at pins 4 to 8
inclusive (of X1). The exact voltages depend on the relative values of the
resistors R21, R37, R38, R39, R40 and R33.
need to be generated and fed back to the driver chip, at pins 4 to 8
inclusive (of X1). The exact voltages depend on the relative values of the
resistors R21, R37, R38, R39, R40 and R33.