6
KX-TD7685
4.2.
Circuit Operation (Handset)
4.2.1.
Outline
Handset consists of the following ICs as shown in
.
•BBIC (Base Band IC): IC201
-All data signals (forming/analyzing ACK or CMD signal)
-All interfaces (ex: Key, Detector Circuit, Charge, LCD)
Include EEPROM and Flash memory
EEPROM stores the temporary operating parameters (for RF, etc.)
•AMPLIFIER IC: IC401
-Single OP_AMP for SPEAKER
•MIDI: IC301
-16-Tone 32-Poly PCM Sound Generator
-Port (LED direct driver with PWM)
•RF Module: IC601
-PLL Oscillator
-Detector
-Compress/Expander
-Amplifier for reception
-Amplifier for transmission
-Power control
4.2.2.
Power Supply Circuit/Reset Circuit
When power on the Handset, the voltage is as follows;
BATTERY(3.5 V to 4.2V: )
→
Q104 (1.8V)
→
Q105 (2.7V)
The Reset signal generates pin 78 of IC201 and 1.8V.
3.1V for IC601 is generated with IC602.
5.0V for Key back-light and LCD back-light is generated with IC302.
Battery(3.5V to 4.2V) is used for RF Module (IC601), Amplifier IC (IC401), Vibrator, DC/DC Converter (IC302).
1.8V is used only for BBIC (IC201).
2.7V is used for BBIC (IC201), LCD, MIDI (IC301), INVERTER (LOGIC IC (IC303)), Red LED, Green LED.
Summary of Contents for KX-TD7685 - Wireless Digital Phone
Page 5: ...5 KX TD7685 4 Technical Descriptions 4 1 Block Diagram Handset ...
Page 11: ...11 KX TD7685 5 Location of Controls and Components 5 1 Handset ...
Page 12: ...12 KX TD7685 ...
Page 57: ...57 KX TD7685 MEMO ...
Page 69: ...69 KX TD7685 16 2 Cabinet and Electrical Parts Location 16 2 1 Handset ...
Page 70: ...70 KX TD7685 16 2 2 Charger ...
Page 71: ...71 KX TD7685 16 3 Accessories and Packing Materials ...