SPV1001 STMicroelectronics, SPV1001 Datasheet - Page 4

• Manufacturer Part Number: SPV1001
• Description: Cool bypass switch for photovoltaic applications
• Manufacturer: STMicroelectronics

3
4/12
Device description
A photovoltaic panel consists of a series of PV cells. In optimal conditions, all the cells are
equally irradiated and function at the same current level. However, during normal operation
some cells may become partially shaded or obscured. These shaded cells limit the current
generated by the fully irradiated cells and, in the extreme cases where these cells are totally
obscured, the current flow is blocked.
In this case the shaded cells behave like a load, and the current generated from the fully
irradiated cells produces overvoltages which can reach the breakdown threshold. This
phenomenon, known as a “hot spot”, can cause overheating of the shaded cells and, in
some cases, even permanent damage resulting in current leakage. To prevent hot spots,
therefore, bypass diodes are connected in parallel to the cell strings.
The device described here has the same functionality as a Schottky diode, but with
improved performance. It features very low forward voltage drop and reverse leakage
current. It consists of a power MOSFET transistor which charges a capacitor during the OFF
time, and drives its gate during the ON time using the charge previously stored in the
capacitor. The ON and OFF times are set to reduce the average voltage drop across the
drain and source terminals, resulting in reduced power dissipation.
Doc ID 18076 Rev 3