Circuit Operation (Handset); Outline; Power Supply Circuit/Reset Circuit - Panasonic KX-TGE240B Service Manual

4.9.

Circuit Operation (Handset)

4.9.1.

Outline

Handset consists of the following ICs as shown in Block Diagram (Handset) (P.21).
• DECT BBIC (Base Band 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)
4.9.2.

Power Supply Circuit/Reset Circuit

Circuit Operation:
When powering on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: BATT+)  F1  BBC1 (IC1) 10 pin
The Reset signal generates IC1 (54 pin) and 1.8 V.
VBAT
External Charge Pump
VBAT
VDDC (1.2 V)
Reset (RSTN)
(IC1_54 pin)
Start monitor
(IC1 57pin)
(CKM/STM)
VBAT
BATTERY
2CELL
GND
VDDC (1.2V)
4.0V
Circuit or IC
4.0 output
LCD BACKLIT LED
KX-TGE240/242/243/244/245/260/262/263/264/270/272/273/274/275/TG454/TG465/TGEA20/TGA20
BBIC chip initialize
3.0V 3.0V
DOUBLER OUT (Charge Pump)
For all peripherals
3.0V 3.0V
BBIC
3.0V
KEY LED
GND
23
3.0V 3.0V
EEPROM
LCD