Circuit Operation (Handset) - Panasonic KX-TG4131MEB Service Manual

KX-TG4131MEB/KX-TG4132MEB/KX-TG4133MEB/KX-TGA410MEB
4.7.

Circuit Operation (Handset)

4.7.1. Outline
Handset consists of the following ICs as shown in Block Diagram (Handset) (P.18).
• 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 power 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.
GND
KEY LED
LCD BL
VBAT
VDDC (1.2 V)
Reset (RSTN)
(IC1_54 pin)
Startmonitor
(IC1 57pin)
(CKM/STM)
IC4
VBAT
BATTERY
2CELL
VDDC (1.2V)
BBIC
4.0V 3.0V
GHD GND
BBIC chip initialize
4.0V
3.0V 3.0V
3.0V 3.0V
DOUBLER OUT (Charge Pump)
For all peripherals
3.0V 3.0V
LCD
BELL LED
20
EEPROM