Sections and Parts Inside a Mobile Cell Phone

1. Keyboard or Keypad Section: The keyboard section of any mobile cell phone is directly connected with the CPU. This means that rows and columns of keys are directly connected with the CPU. Protector IC or Interface IC or Verector diode is connected in the row or column line for the protection of key section. In modern mobile cell phones which have qwerty keys, a separate control IC is connected with the CPU for extra protection to the keys.
2. Display Section: The display section is directly connected with the CPU to receive following signals – LCD Data Signal, LCD Reset Signal, LCD WR Signal, LCD RD Signal, LCD FLM Signal, LCD HSYN Signal etc. These signals are given to the LCD Module through the CPU. 2.8V power supply or 1.8V power supply is given to the LCD for functioning. LCD signal interface filter are connected in many mobile cell phones for interfacing these signals of LCD Module.
3. SIM Card Section: The SIM Card Interface section is directly connected with the CPU in most mobile cell phones. If there is no power supply in a mobile phone then the SIM section is connected with the CPU through the Power IC. Mainly V-SIM (3.0V), SIM-RST (2.85V), SIM CLK, SIM-Data (2.5V), and SIM GND are made in the SIM Section. These four pins (Beside (SIM GND) are directly connected with the SIM interface / control section and V-SIM volt are given to the SIM data pin from V-SIM pin through the 10-18 Kilo Ohms Resistance.
4. Memory Card Section: Now mostly Micro SC Card is connected in most mobile cell phones which is connected with micro card section through a 8 pin socket. Memory card section is made inside the CPU. Description of these 8 pins are as follows:
   1. MMC-Data-2
   2. MMC Data
   3. MMC CMD (Command)
   4. VMMC / VSD (Positive Supply Pin)
   5. MMC-CLK
   6. GND
   7. MMC-Dta0
   8. MMC Data-1
   2.8 Volt Power is supplied to Pin Number 4 from Power Supply for functioning of the MMC Card and connection the 50 tp 100 Kilo Ohms resistance in this power supply. This power supply is given to Pin Numbers – 1,2,3,7,8 of MMC Socket. One MMC detector switch or pin is made in MMC socket at which, if there is no MMC Card then 1.8 V power is continuously received and after the MMC is connected, it becomes zero.
5. MIC Interface Section: MIC interface section is directly connected with the CPU inmost mobile phones. Working voltage (MIC Bios) (1.8 to 2.8 V) is supplied from the CPU or the Power Supply Section for functioning of the MIC and MIC Positive and Negative Volt are input through two capacitors.
6. Ear Speaker Section: In most modern mobile cell phones, in which there is a separate ear speaker, it is directly to the CPU. It receives sound via signals directly from the CPU of from the audio section inbuilt within the CPU. In some mobile phones, these sound signals are received via coil / resistance. Some mobile phones have audio IC in the audio section. Some mobile phones have audio amplifier.
7. Speaker / Ringer Section: Ringer, Buzzer or Speaker in most mobile phones are connected with the audio amplifier IC to obtain loud sound. The amplifier IC amplifies the sound or audio signal received from the CPU of the audio section.
8. Key Backlight Section: LED Lights are connected according to the parallel circuit in the key backlight section. Anode ends of all the LEDS are connected to each other and all the cathode ends are to each other. 3 to 3.3 V is supplied for the functioning of these Key LED Lights. This power supply is given to the cathode ends of LEDs from the ground ends. Power supply to the anode ends of LED Lights is controlled bu using LED-Driver or PNR IC.
9. LCD Backlight Section: LCD Backlight in mobile cell phones is made according to the series circuit. A Boost Voltage Generator Section is built for the supply of high voltage (10 to 18V) for the functioning of the LCD LED. Boost coil, Boost Volt Driver IC, Rectifier Diode etc are present in this section.
10. Vibrator Motor Section: Positive power supply is given to this section directly from the positive end of the battery. Negative power supply is given through a NPN transistor or from the ground of any circuit.
11. Network Section: Antenna, External Antenna Socket, RX-Band Pass Filter, RF Crystal, FEM, PFO, TX-Band Pass Filter, RF IC, CPU are connected in the Network Section. Signal received at the antenna during the RX is given to the antenna switch or FEM through the antenna socket where the next processing is completed by selecting a frequency of proper band and is passed on to the RF IC through RX-Band Pass Filter. RF Signal out from the RF IC during TX is given to the FEM or PFO to amplify the signal. After the Band Selection Process the signal is passed through the antenna.
12. Battery Charging Section: Charger and system interface connector is made together in most modern mobile cell phones. Regulator section is made separately for the battery charging section. In some mobile phones, the battery charging section is made inside the Power IC.
13. FM Radio Section: FM Radio Driver IC, FM Antenna, Signal and Supply Components are made in the FM Radio Section.
14. Bluetooth Section: Bluetooth Antenna, Bluetooth RF Signal Filter, Bluetooth Driver IC, Supply and Signal Components are made in this section. The Bluetooth sections functions like the Network Section. RF-CLK signal is given to the Bluetooth driver IC during signal processing.
15. Set Power ON: Power IC, CPU (UCP), Flash IC, RF-CLK, Crystal, RF-IF, PWR Ket etc components are present this section. Battery positive supply is given to the power IC and connecting the battery (3.7V) from 2.87 to 3.0 Power ON Volts are received at one tip of the Power Key. Supply is given to the CPU, Flash IC, RF-CLK, Generator Section (RF Crystal, RF IC) by which the mobile phone gets switched ON.
16. Handsfree (Earphone Section): Mainly hands free jack, hands free MIC, speaker signal component and hands free audio amplifier are present in this section. Hands free symbol is displayed after connection the Handsfree jack.