Page 36

EETE JAN 2015

ANALOG DESIGN LTPoE++ plug-and-play solution LTPoE++ provides a safe and robust plug-n-play solution that dramatically reduces engineering complexity in power sourcing equipment (PSEs) and powered devices (PDs). The benefit of LTPoE++ over other power-extending topologies is that only a single PSE and PD is required to deliver up to 90W over a single CAT-5e cable, resulting in significant space, cost and development time advantages. The LTPoE++ solution significantly lowers the cost of ownership not only by reducing the bill of materials and associated component cost, but also by providing the most power efficient end-to-end solution available today, maximizing the power delivered to the application while minimizing heat dissipation and costly heat sink design. One important distinction for LTPoE++ is that it does not require the use of the Link Layer Discovery Protocol (LLDP) that was mandated in the IEEE PoE+ specification for software-level power negotiation. LLDP requires extensions to standard Ethernet stacks and can represent a significant software development effort. LTPoE++ PSEs and PDs autonomously negotiate power level requirements and capabilities at the hardware level while remaining fully compatible with LLDP-based solutions. This gives LTPoE++ system designers the choice of whether or not to implement LLDP. Proprietary end-to-end systems may choose to forgo LLDP support. This creates time-to-market advantages while further reducing BOM costs, board size and complexity. Advanced fourth generation features Linear’s Power over Ethernet PSE controller family incorporates a wealth of PoE experience and expertise backed by well over 200 million shipped ports. New fourth generation features include field-upgradable firmware for future-proofing designs. Also new is optional 1-second current averaging, which simplifies host power management. Advanced power management includes prioritized fast shutdown, 12-bit per-port voltage and current read back, 8-bit programmable current limits and 7-bit programmable overload current thresholds. A 1MHz I2C interface allows a host controller to digitally configure the IC or query port readings. “C” libraries are available to reduce engineering costs and improve time to market. Automotive-grade buck regulator delivers 3A This 3.0A device features low inputvoltage dropout and enhanced idle/stop/ start recovery operation; the A8590 buck regulator joins Allegro MicroSystems’ range of automotive-grade AEC-Q100 qualified regulator ICs. The device has been designed to provide the powersupply requirements of next-generation car audio and infotainment systems, and provides all the control and protection circuitry for a 3A regulator which will withstand the rigours of a wide automotive battery input voltage range. The A8590 can also be used in cluster and centre stack applications and in advanced driving assistance systems. The device employs pulse frequency modulation to draw less than 50 μA from a 12V input while supplying a 3.3V/40 μA output. After startup, the A8590 operates down to an input voltage (falling) of at least 3.6V, and maintains ±1% output voltage accuracy. Other features of the A8590 include PWM/PFM mode control and the ability to synchronise PWM frequency to an external clock. Allegro MicroSystems www.allegromicro.com Chipset measures 3-phase AC power parameters Analog Devices has posted details of a chipset specifically designed for measuring 3-phase electrical energy, using shunts as current sensors. The chipset comprises the ADE7978, the ADE7933/ADE7932, and ADE7923. The ADE7933/ADE7932 are isolated, 3-channel sigma-delta analogue-todigital converters (Σ-Δ ADCs) for polyphase energy metering applications that use shunt current sensors. The ADE7923 is a nonisolated, 3-channel Σ-Δ ADC for the neutral line that uses a shunt current sensor. The ADE7932 features two 24-bit ADCs, and the ADE7933 and ADE7923 feature three 24-bit ADCs. One channel is dedicated to measuring the voltage across the shunt when a shunt is used for current sensing. This channel provides a signal-to-noise ratio (SNR) of 67 dB over a 3.3 kHz signal bandwidth. Up to two additional channels are dedicated to measuring voltages, which are usually sensed using resistor dividers. Analog Devices www.adi.com Thermocouple interface IC for automotive powertrains Increasing environmental concerns and ever more stringent legislation are driving the demand for more energy efficient vehicles. Increasing the operational effectiveness and decreasing the environmental impact of the powertrain necessitates higher working temperatures which must be strictly controlled and monitored at all times. Melexis now announces the MLX90327, a high performance sensor interface IC which enables accurate and reliable monitoring of high operating temperatures, thus addressing this key requirement for next generation powertrains. The device can cope with operating temperatures of from -40˚C to 155˚C without any compromise in accuracy being witnessed. The MLX90327 comes with a digital SENT interface for advanced powertrain electronic control units (ECUs). In addition a PWM output is available for general-purpose automotive and non-automotive applications. Melexis www.melexis.com 36 Electronic Engineering Times Europe January 2015 www.electronics-eetimes.com


EETE JAN 2015
To see the actual publication please follow the link above