Circuit Operation (Handset); Outline; Power Supply Circuit/Reset Circuit - Panasonic KX-TG6841B Service Manual

4.7.

Circuit Operation (Handset)

4.7.1.

Outline

Handset consists of the following ICs as shown in Block Diagram (Handset) (P.19).
• 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)
4.7.2.

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-TG6841B/KX-TG6842B/KX-TG6843B/KX-TG6844B/KX-TG6845B/KX-TG6873B/KX-TGA680B
BBIC chip initialize
3.0V 3.0V
DOUBLER OUT (Charge Pump)
For all peripherals
3.0V 3.0V
BBIC
3.0V
KEY LED
GND
21
3.0V 3.0V
EEPROM
LCD