Smart bypass diode claims industry's lowest power dissipation

Date
03/12/2013

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Active diode reduces photovoltaic junction box temperature by 50ï½C

Texas Instruments Iintroduced a smart bypass diode in a standard surface-mount package with 15-A current handling capability and the industry's lowest power dissipation. In a typical application, each SM74611 lowers power dissipation by 80 percent and reduces the operating temperature inside the junction box by 50 degrees C when compared with a similar box using three conventional Schottky diodes. TI will demonstrate the SM74611 in its booth #109 at the Applied Power Electronics Conference and Expo (APEC) in Long Beach, Calif., Mar. 18-20. Attend a seminar at APEC, "Smart Bypass Diodes Enable Electronics in the PV Junction Box," on Tuesday, Mar. 19, at 2:15 p.m. in meeting room 102B. When a photovoltaic (PV) solar panel is shaded, the SM74611 active diode provides an alternate low-resistance path for string current to prevent hot spots that can damage the panel. The SM74611 protects the panel and improves PV solar panel reliability by boosting efficiency, and the reduced thermal dissipation enables more compact junction boxes with smaller heat-sinks. "More stringent safety standards for junction boxes and increased currents from the newest generation of high-efficiency PV modules cannot be handled with conventional Schottky bypass diodes without significantly increasing the physical size of the junction box," said JÃrg Schmidt, director of sales for PV-Connecting Systems at Kostal Industrial Electronics. "TI's SM74611 smart bypass diode enables us to easily increase the current rating of our line of SAMKO junction boxes from 10 A to 13 A without changing the physical design." The SM74611 joins TI's family of solar products that include the UCD3138 digital power controller for solar micro-inverters, SM72441 maximum power point tracking controller and SM72295 full bridge driver. For more information about TI's solutions for solar power, visit . Key features and benefits of the SM74611 smart bypass diode 80-percent lower power dissipation than Schottky diodes reduces ambient temperature inside the junction box by 50 degrees C, improving the current rating of existing junction boxes, as well as enabling smaller boxes with improved current rating. Current handling up to 15 A with no avalanche effect. Reduced leakage current in both forward and reverse operation increases energy harvesting yield in PV arrays compared to traditional arrays using Schottky diodes. D2PAK package is a drop-in replacement for conventional surface-mount Schottky diodes. Availability, packaging and pricing The SM74611 smart bypass diode is available in volume now from TI and its authorized distributors. Offered in a two-terminal D2PAK package that measures 10.2 mm by 9 mm by 4.5 mm, the SM74611 is priced at US$1.50 in 1,000-unit quantities.

Texas Instruments

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