Power Rising/Falling Edge Sequence Control Function - NEC LCD1550X Service Manual

1.6.3

Power rising/falling edge sequence control function

List of control signals
µ-COM Pin No.
I/O
53 O
59 O
47 ~ 51 I/O
57 O
58 O
56 O
55 O
54 O
60 O
52 O
Functions
• Inverter control:
The microcomputer pin 57 P_INVT is used to control the inverter lighting, and the microcom-
puter pin 59 PRO_DLY is used to control the validity of the inverter's protection circuit. The
ASIC PWM output DUTYCINV is used to control the royer oscillation of inverter. The micro-
computer can control panel dimming by controlling the ASIC PWM output frequency. The
inverter control signal timing specifications at the power's rising edge are shown below.
P_INVT
DUTYCINV
PRO_DLY
• Power board control
The microcomputer pin 53 P_SAVE is used to control the switching of the power board's PRC
mode and resonance mode. The sequence at the power's rising edge is shown below. During
power save, operation takes place at the PRC mode having good power efficiency. However,
as a high load current cannot be passed (maximum approx. 1A at 12V), the resonance mode
in which a load current can be applied is used normally.
Power ON
Microcomputer signal
(P_SAVE)
Inverter
Signal name
P_SAVE PRC mode of power borad : Lo / resonance mode : Hi switching
PRO_DLY Inverter protection circuit Invalid : Lo/Valid : Hi
MS*, RSTN
ASIC control (for DUTYCINV : PWM for inverter royer oscillation)
P_INVT Inverter lighting control Off : Lo / On : Hi
P_PANEL Panel 5V power
P_SUSP1 A2_5V power
P_SUSP2 D2_5V power
P_SUSP3 P2_5V power
P_ON A5V power
TM3_3V power
P_TMDS
100msec (Typ.)
PRC MODE
Stand-by
Function
OFF : Lo / ON : Hi
OFF : Lo / ON : Hi
OFF : Lo / ON : Hi
OFF : Lo / ON : Hi
OFF : Lo / ON : Hi
OFF : Lo / ON : Hi
1300msec (Typ.)
600msec (Typ.)
RESONANCE MODE
Full load
1 - 37
Remarks
PWB-POWER
PWB-POWER
ASIC
PWB-POWER
DTC114EUA
SI3025LSA
SI3025LSA
NJM2870F25
PQ1U501M2ZP
SI3033LSA
PRC MODE RESONANCE MODE
Stand-by
Full load