ATM90E26 extends smart energy roadmap

Atmel has introduced the ATM90E26, a low-cost metering Analog Front End (AFE) IC. According to an Atmel engineering rep, the ATM90E26 is specifically designed for smart grid communications, electricity metering systems and energy measurement applications.

“The Atmel Smart Energy platform includes several System-on-Chip (SoC) devices built around a unique dual-core ARM Cortex M4-based architecture. The platform includes the SAM4C with advanced security, in addition to metrology-enabled versions for single- and poly-phase metering (SAM4CMx) and Power-Line Communications (PLC) enabled solution (SAM4CPx),” the Atmel engineering rep told Bits & Pieces.

“The new ATM90E26 is pin-to-pin compatible with the IDT 90E22/23/24/25 devices, featuring UART support and improved power measurement resolution. By providing the discrete metrology AFE ATM90E26 as well as various MCU/MPU and PLC/wireless solutions, our Smart Energy Platform offers designers multiple options and various levels of integration to address their smart metering designs. For example, the ATM90E26 can be bundled with the SAM4CPx for a complete smart metering architecture.”

Key ATM90E26 features include:

• Dynamic range of 5000:1 with 0.1% kWh accuracy and 0.2% kvarh accuracy.
• Temperature co-efficient of reference voltage 15ppm/ºC (typ.).
• Single-point calibration for active energy.
• Up to 24x PGA to support shunt sensing in L line current channel.
• Programmable startup and no-load power threshold.
• Measures Vrms, Irms, P(Q/S), frequency, power factor and phase angle. Enhanced resolution for RMS and mean power.
• Measurement accuracy better than 0.5%.
• Configurable high-pass filter (HPF) in each ADC channel.
• On-chip parameter diagnosis function and programmable interrupt output to reduce complexity and increase robustness of the meter.
• Standard four-wire, simplified three-wire SPI interface, or a UART interface.
• Dedicated voltage zero-crossing output pin (ZX); voltage sag detection.
• Software reset available.
• 3.3V single power supply; 5V compatible for digital input.

It should also be noted that Atmel’s ATM90E2x single-phase energy metering demo board can be used to evaluate and test ATM90E2x chips. More specifically, the board is capable of sampling single-phase voltage/current, meter active/reactive energy, output active/reactive energy pulses, as well as measure parameters such as voltage, current and power.

Interested in learning more about Atmel’s smart energy platform? You can check out our detailed deep dive here.

Defining the LF Driver’s Main Parameters in Automotive PEPS Systems

By Dr. Jedidi Kamouaa

Passive entry passive start (PEPS) systems, already well established in the high-end car market, are the latest trend in mid-price vehicles. Strategy Analytics anticipates annual demand for PEPS systems to reach almost 19 million units by 2016. This trend is fueled by cost savings from a reduction in the number of coils per vehicle, the greatest contributor to system cost.

PEPS system design presents a number of challenges:

• Generation of high drive current and, thus, the low-frequency (LF) magnetic field required to detect the key fob inside the vehicle or in the near vicinity
• Drive-current regulation to allow reliable receive signal strength indicator (RSSI) measurement
• Protection under thermal stress conditions and electrical diagnostics
• Reduction in electromagnetic radiation
• PEPS system speed

 A key part of PEPS systems is the LF driver. The Atmel ATA5279C multichannel LF antenna driver IC includes technical features to meet PEPS system requirements. It operates alongside the Atmel ATA5791 single-chip key fob controller, integrating the RF transmitter.

When developing an LF antenna driver system, you’ll need to consider:

• Capability to generate sufficient magnetic field to detect the key fob inside the vehicle or in the vicinity of the vehicle
• Use of a regulation loop of the drive current for reliable field strength and thus RSSI measurement
• Protection under thermal stress conditions and electrical diagnostics
• Electromagnetic radiation
• The interface with the host microcontroller
• Thermal factors

With the need for cost savings, car makers also expect the LF driver to perform the immobilizer backup function, which requires the merging of the immobilizer and LF driver functions, multiplexing one of the antennas and thus eliminating one coil (a major cost contributor). This merger allows the immobilizer base station coil in the steering lock cylinder to be removed, and the resulting change in car architecture will enable significant cost savings that should further increase PEPS system adoption.

For diagrams and detailed information about how to define the LF driver, see the article “How to Define the LF Driver’s Key Parameters in Automotive PEPS Systems.”