Improvements in power efficiency bring both economic and ecological savings and the intelligent use of energy has become one of the driving forces in product development across the manufacturing industry. The leading supplier of semiconductors for power management*, STMicroelectronics has designed and assembled a large portfolio of solutions to optimize energy consumption in end equipment. ST designers use innovative IC architectures and advanced transistor technologies, such as Power MOSFET and IGBT (Insulated-Gate Bipolar Transistor), to address all power applications in our homes, from lighting, heating and air-conditioning to white-goods appliances and entertainment electronics.

An ST internal analysis has shown that using end products built around ST’s energy-saving technologies and products can cut the residential energy consumption by a third. For example, a 4-person household with an annual power consumption of 3.36 MWh can save about 1 MWh a year - the equivalent of almost two barrels of oil – reducing both the electricity bill and environmental impact of power generation.

Lighting
Experts have calculated that replacing traditional incandescent bulb lamps with compact fluorescent lamps (CFL) cut energy use by a factor of five. The market leader in ICs for electronic lighting*, ST supports the shift to energy-efficient lamps with an electronic ballast, a device that limit the amount of current needed to drive the fluorescent tube.

ST’s microcontroller-based lamp ballast reduces the energy consumption by as much as 80% by using high-performing switching components to minimize the power losses. The microcontroller inside the ballast also extends the lamp’s life and makes its light intensity almost constant throughout the life cycle. The increase in lighting efficiency between a bulb lamp and a CFL is eightfold, from 10 to 80 lumens per watt.

Considerable savings can be achieved with traditional bulb lamps, too. Intelligent dimming solutions save power, extend the bulb life, and enhance the consumer experience. Product analyses have shown that ST’s phase-control dimmer reduces power consumption in a bulb lamp by 25%. One 300W bulb that is on for two hours a day, dimmed to a 75% dim level saves 54 kWh off the full-light annual consumption of 219 kWh. ST’s dimmers provide smooth up-and-down light adjustments and memory presets. They can be combined with ST’s innovative peripherals for remote control, including RF and infrared, and networking capability.

White goods
Most domestic appliances, from heating and air-conditioning systems to “white goods,” contain an electric motor. Using advanced motor-control technologies ensures energy efficiency, higher reliability, smaller physical dimensions and silent operation in a variety of end-user devices around the home. Due to the variable-speed capability, new motor-control systems can optimize the motor speed to the load needs, thus reducing the energy used.

The most integrated system in its category, ST’s patented sensorless motor controller with inverter driving allows a microcontroller to control the frequency and voltage of the power supplied to the motor. In white-goods appliances and air-conditioning systems, this approach delivers real-world savings of 30% compared to existing solutions.

Efficient motor driving, together with temperature control, can reduce energy consumption in refrigerators and washing machines by as much as 40%. New electronic solutions also extend the lifetime of an appliance and increase its reliability and user convenience.

ST’s dedicated solution for refrigerators integrates full digital temperature regulation that helps maintain the internal temperature more accurately for better food preservation while saving power. The electronic thermostat also optimizes defrosting cycles based on the current temperature in the cabinet.

Typical annual power consumption of a fridge or a washing machine can be reduced almost 60%, from 600 kWh to 250 kWh. If all refrigerators in Europe were using ST’s technology for power management and thermal control, the continent would save 1500 MW (an equivalent of two nuclear power units) and would reduce its production of CO2 by about 1.2 million tons a year.

Nowadays, the majority of domestic appliances can be operated by remote control. The devices operate in stand-by mode for 24 hours a day, waiting for signals from the remote. ST’s power-supply units for stand-by systems use innovative technologies such as BCD (Bipolar-CMOS-DMOS) to reduce power consumption below 1W. In a model household with two TV sets, one set-top box, one video recorder, one radio and one PC, low-power stand-by systems can reduce energy consumption by 77%, from 203 kWh to 45 kWh a year.

Emerging trends
At the vanguard of technology research and development, ST is constantly looking for new ways to further improve energy efficiency in the end applications. These emerging technologies include LED-based lighting and ZigBee.

Experts believe that Light Emitting Diodes (LEDs) are set to become a new standard source of illumination for the 21st century. Among other benefits, LEDs consume far less energy than standard light bulbs, last up to 100 000 hours, and offer a wide color spectrum. These advantages are closely related to the performance of the LED’s driving electronics. ST offers a large portfolio of compact and efficient LED drivers, including the recently introduced high-brightness LED drivers with auto-power-saving features.

ZigBee is a standards-based wireless technology optimized for remote monitoring and control applications. Power-miserly themselves, ST’s ZigBee devices can function as sensors that are connected to a centralized control system and help optimize the use of energy around the house. For example, if the sensor detects there is nobody in the room, it can prompt the central unit to switch off the air-conditioning system or dim the lights.
*iSuppli 2005

April 2007