Operation; Block Diagram; Led Display Circuit - Toshiba e-STUDIO163 Service Manual

5.4

Operation

5.4.1

Block diagram

The control panel is controlled by the serial data input/output to the SoC on the MAIN board.
The input status of each button is output to the SoC as serial data (OPKYSI) by the parallel-serial con-
version IC and detected. Each LED is controlled to be lit by the LED driver based on the information of
the serial data (OPLDSO) output from the SoC.
MAIN board
SoC
ASIC
5.4.2

LED display circuit

<Example> Lighting circuit method of "Cover open lamp"
FET (Q2) is turned ON when the FET control signal (C0) becomes "L" level.
Then when the control signal (LEDM12) of the LED driver changes to "L" level, the current flows to the
cover open lamp (LED22) to turn ON the LED.
Conditions to turn ON the LED
The LED is turned ON only when the two conditions below are met.
1) The FET connected to the LED anode is ON.
2) The cathode side of the LED is "L" level.
December 2005 © TOSHIBA TEC
Control panel
+5V, +5VB
Serial data
(OPKYSI)
Serial data
(OPLDSO)
Buzzer ON signal
(BZON)
Fig. 5-1
Low
C0
Cover open lamp
(LED22)
Low
LEDM12
Fig. 5-2
5 - 5
Decoder
Parallel-serial
conversion IC
Hard-key matrix
LED
driver
LED
Buzzer
+5V
Q2
Current
R
e-STUDIO163/203 CONTROL PANEL
5