An IC card prepaid electricity meter comprises several structural sections and components, including an energy metering unit, an IC card interface unit, a data processing unit, and a communication interface unit. The energy metering unit typically consists of an energy metering chip, current transformers, voltage transformers, and filtering circuits. The IC card interface unit generally comprises an IC card slot, an IC card read-write circuit, and a data processing unit.
The data processing unit typically consists of a microprocessor, memory, and a display. Acting as the "brain" of the smart meter, the microprocessor is responsible for processing sampled data, managing the display, and facilitating the exchange of external data streams. Mainstream MCU solutions include Freescale's S08MZ, S08GW, MCF51EM, and Kinetis K30 series; STMicroelectronics' low-power STM8L and STM32 series; and Texas Instruments' MSP430 series. Smart meters commonly integrate an ESAM security module to ensure data security.
The communication interface unit typically consists of a communication module and associated interface circuitry. Communication solutions encompass wired methods-such as RS-485 or Power Line Communication (PLC)-as well as wireless methods, such as 4G cellular communication and NB-IoT (Narrowband Internet of Things). For carrier modulation schemes such as OFDM and S-FSK, various manufacturers offer dedicated chips-examples include Freescale's MC13260 and STMicroelectronics' ST7590. Wireless solutions are predominantly based on ZigBee technology, exemplified by Freescale's MC13202 and MC1322x series.