TI Introduces Smart Bypass Diode to Replace Conventional Schottky Devices

Texas Instruments Incorporated (TI) today introduced a smart bypass diode in a standard surface-mount package with 15-A current handling capability and low power dissipation. In a typical application, each SM74611 can lower 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.

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 Jörg 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. Reduced leakage current in both forward and reverse operation increases energy harvesting yield in PV arrays compared to traditional arrays using Schottky diodes.

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 a drop-in replacement for conventional surface-mount Schottky diodes. It is priced at US$1.50 in 1,000-unit quantities.