
20
KX-TG3721BX/KX-TG3722BX/KX-TGA371BX
4.8.
Circuit Operation (Handset)
4.8.1.
Outline
Handset consists of the following ICs as shown in
Block Diagram (Handset)
(P.18).
• DECT BBIC (
B
ase
B
and IC): IC1
- All data signals (forming/analyzing ACK or CMD signal)
- All interfaces (ex: Key, Detector Circuit, Charge, EEPROM, LCD)
• EEPROM: IC3
- Setting data is stored. (e.g. ID, user setting)
4.8.2.
Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: BATT+)
→
F1
→
BBIC (IC1) 41 pin
The Reset signal generates IC1 (62 pin) and 1.8 V.
1.8 V
VBAT
Reset (RSTN)
(IC1_62 pin)
GND
BATTERY
2CELL
BBIC
3.0V
3.0V
DOUBLER OUT (Charge Pump)
For all peripherals
2.8V
EEPROM
BELL, LED
VBAT
GND
KEY BACKLIGHT
LCD BACKLIGHT
LED
3.0V
VBAT
1.8V
2.8V
LCD
2.8V