Anaheim, Calif. ON Semiconductor unveiled its latest GreenPoint reference design for 40-W power supplies used to power desktop printers. Providing active-mode energy efficiency above 83% when delivering an output power between 5 and 40 W, the reference design achieves a no-load power consumption of 150 mW. The frequency foldback technique implemented in the design keeps the efficiency of the power supply very high under light load conditions. The combination of these characteristics makes the GreenPoint reference design compliant with the most requirements from Energy Star to the Group for Energy Efficient Appliances (GEEA) via the US Executive Order "1-Watt Standby" and the Japanese Eco Mark program. The reference design enables a peak power of 80 W to be delivered. An over-power protection below 100 W has been implemented for the entire input voltage range of 88 to 265 Vac to comply with the limited power source (LPS) test.
The enabling device is the NCP1351, a current-mode controller targeting low-power, off-line flyback switched-mode power supplies (SMPS). Based on a fixed peak current technique (quasi fixed TON), the controller decreases its switching frequency as the load becomes lighter. When the frequency decreases, the peak current is gradually reduced down to approximately 30 percent of the maximum peak current to prevent transformer mechanical resonance. The risk of acoustic noise is diminished while keeping standby power performance.
Pricing: $0.32 in 2,500-piece quantities
Data Sheet: Click here
ON Semiconductor, 602-244-6600, www.onsemi.com