Ultra-small power supplies help designers deliver energy-efficient LED alternatives

Unlike incandescent light sources, which can be powered directly from the mains supply, each LED lightbulb requires a power supply to be incorporated within the Edison (E27) or Bayonet (GU10) sockets.
According to Don Ashley, product marketing manager for AC-DC products at Power Integrations: “Producing a power circuit that fits within such a small space is not a trivial task, especially if you effectively attenuate EMI to the current standards. To address the size constraints posed by this application, Power Integrations has released its LinkSwitch-TN family of non-isolated offline switcher ICs in tiny SO-8 packaging. Our RDK-131 incorporates this device in a tested, working power supply board and offers a blank PCB, extra samples of the LinkSwitch-TN ICs and guidelines on how to design LED lighting supplies around our ICs. This kit significantly simplifies the task of designing LED lights, reducing their time to market.”

Because electricity generation accounts for around 40 percent of greenhouse gas emissions, regulatory bodies and authorities worldwide are looking at ways to reduce energy wastage. For example, in a recent address (Reuters/Yahoo: Wednesday, January 31, 2007), California Assemblyman Lloyd Levine commented: “Incandescent lightbulbs were first developed almost 125 years ago, and remain incredibly inefficient, converting only about five percent of the energy they receive into light.” If his proposed bill, the ‘How Many Legislators Does it Take to Change a Lightbulb Act,’ is passed, incandescent bulbs would be banned for use in California by 2012. By contrast, LED lightbulbs consume about one-third as much power as incandescents, and have a much longer life.