Processors are the heart of the smartphone. For different types of processing,(ex image processing, graphics processing  )we use different processors. All these processors are embedded in a chip called S.o.C (systems on chip).

Systems on chip contain many processing units -

  • Central processing unit(CPU).
  • Graphics processing unit(GPU). 
  • Neural Processing Unit (NPU).
  • Digital signal processing unit(DSP )
  • Image processing unit(ISP)
  • Multimedia unit.
  • Navigation unit.
  • Display unit
  • Modem


Some of these units are placed outside of the SoC for more flexibility (units like Modem, Navigation. Connectivity).S.o.c are manufactured by different giants like

  • Qualcomm(snapdragon chips ex SD-865) .
  • Samsung(Exynos chip ex-Exynos 990) .
  • Mediatek(helio chip ex-HelioG90T).
  • Huawei(kirin chip ex-Kirin 990).

                                   Each S.o.c differ in performance due to the technology used to manufacture S.o.c and technology used within the S.o.c.You may have seen 7nm, 8nm,10nm, and 12nm mentioned with the processor's name. This is basically the size of the transistor used in these chips. Chips made of 7nm technology contain more transistors than 12nm in a given size. So the transistor density will be high which means more compute units, more efficient and powerful. Companies like Qualcomm, Samsung, Apple, and Huawei do not design architecture('building design of the chip') for these chips. ARM is a company that licenses these architectures.





ARM HOLDINGS

                                 ARM holdings is a semiconductor and software design company that designs architecture and licenses them to Samsung, Qualcomm, Mediatek and Huawei. Cortex is its CPU architecture. the latest architecture from ARM is cortex A77 and cortex A78 is yet to come. Cortex A77 is the third generation premium CPU based on DynamIQ technology. Other CPUs from 
ARM include-
  • Cortex-A77       -  Third generation premium CPU based on DynamIQ technology.
  • Cortex-A76      - Second-Generation, High-Performance CPU Based on DynamIQ
  • Cortex-A76AE - First High-Performance Split-Lock DynamIQ CPU
  • Cortex-A75       -First DynamIQ-based high-performance CPU

                                Companies like Qualcomm takes this architecture, make few changes and rebrand it and releases as Kryo (ex-Cortex A77 to Kryo 585)

                                 ARM also design GPU(Graphics Processing Unit). Mali GPU is one of them. Mali G77 is powerful among them. Latest Samsung Exynos 990 uses this GPU.Other GPUs from ARM include-
  • Mali G77 -  Based on the Valhall architecture First-generation premium GPU.
  • Mali-G76 -  Third premium Bifrost architecture GPU
  • Mali-G57 -  First-generation Valhall-based GPU
  • Mali-G52 -  Second mainstream Bifrost architecture GPU
  • Mali-G31 -  Based on the innovative Bifrost architecture

CENTRAL PROCESSING UNIT

                                 It is the brain. It is responsible execution of operating systems and applications. There are CPUs which have dual-core,quad-core, hexa-core and octa-core. More core means more tasks that the CPU can do at a time. More core doesn't mean more power. Speed also matter(frequency), higher the speed means faster CPU


GRAPHICS PROCESSING UNIT
    
                                GPU is designed to process graphical items such as 3D/2D content, app interface, etc. like CPU, GPU also has cores and speed also matters.


NEURAL  PROCESSING UNIT  

                                 This processing unit is used to enhance the AI features of the smartphone. More powerful the NPU, more intelligent your smartphone


DIGITAL PROCESSING UNIT  

                                  DSP is responsible for processing the sensor data, sensors like accelerometer, gyroscope, light sensor, etc. DSP creates a digital signal based on the data from these sensors, thus we can display these data or use for other compute processes.


IMAGE PROCESSING UNIT

                                  IPU is responsible for processing the data from the camera unit. , Parameters like Mega Pixel, Resolution and frame per second(FPS) id depends on IPU.


MULTIMEDIA UNIT

                                    It handles multimedia functions like video playback, audio files, etc


DISPLAY UNIT

                                    Smartphones panel type, refresh rate, and resolution depends on the display unit. More powerful the unit it can support high resolution, high refresh rate, etc.


NAVIGATION UNIT

                                    It determines which global navigation system it support.There are four navigation system GPS(USA),GLONASS(Russia),Galileo(EU)BeiDou(China) and NaVic(India)
Now we can see SoCs that support Navic system.


MODEM

                                    It responsible for which type of cellular network your phone  support(2G,3G,4G,5G), Wifi generation, Bluetooth version, Hotspot, etc.X55 is 5G modem from snapdragon

                                    These systems on chips are very efficient.In near future they may overtake the perfomance of desktop CPUs