Power Meter (Single-phase)

Overview

Electronic power meters have been increasingly adopted world wide as a means to control the demand of energy use, to support AMR (Automatic Meter Reading), and to reduce fraudulent use of electricity. Recently, energy-saving and eco-friendly products are getting popular. The use of smart meters, which control household equipments, is expanding to realize smart grid which enables to improve energy efficiency of local districts. As power meters become a communication gateway to the home, they are becoming more advanced in both their performance and functionality.

A power meter must operate on its internal battery from when it leaves the factory to when it is installed at its final destination. Low-power consumption is essential when only the real-time clock (RTC) is running. Also needed is a UART (Universal Asynchronous Receiver Transmitter ) for AMR support, infrared communication for meter reading, and data transfer to and from prepaid cards.

Within the MCU lineup of Renesas, the 78K0R/Lx3 and the R8C/Lx Series implements three UART channels on-chip, enabling a variety of communication formats used by smart meters, and its integrated RTC operates on very little power. It is also equipped with large-capacity memory, making possible more sophisticated smart meter functions. Additional integrated functions include an on-chip oscillator (OCO), a watchdog timer (WDT), and an LCD drive control circuit. These reduce the number of external parts needed and helping to reduce the overall system cost.