1. Active bypass diodes
1.1. The need for lossless diodes
The solar bike PV panels, in contrast to common PV panels, have a particular need for bypass diodes. That is because shade appears often and the PV panel efficiency during shadow must be optimized. Cool bypass switch "diodes" such as the LX2400 and the SPV1001T40 are the ultimate solutions here.
1.2. SM74611
Smart bypass diode from Texas Instruments. The average forward voltage drop is 30 mV at 5A, 85°C. Introduced in dec. 2012.
1.3. SPV1001
Cool bypass switch (CBS) from STMicroelectronics.
- Available in TO220, D2PAK and MLPD
- Very low profile with MLPD package, less than 1mm, to laminate device directly on the panel
- Available since October 2010
SPV1001T40 (TO-220).
| Vf [V] | Vf max | i [A] | Tj [°C] |
| 0.08 | 5 | 25 | |
| 0.11 | 8 | 25 | |
| 0.27 | 8 | 125 |
1.4. LX2400
The LX2400 IDEALSolarTM Bypass Diode with Microsemi’s patented CoolRUNTM technology provides a bypass diode with the industry’s lowest forward voltage drop resulting in negligible heat generation. The LX2400 temperature range is -65°C to +165°C. Load the datasheet here. The package is smaller compared to the TO-220. The LGA package dimensions are 7.5mm x 11.5mm.
| Vf [V] | Vf max | i [A] | Ta [°C] |
| 0.05 | 10 | 80 |
As we can see, the LX2400 has lower forward voltage drop than SPV1001.
2. Super barrier rectifier bypass diodes
A Super Barrier Rectifier (SBR) is effectively a MOSFET with its gate and source shorted together. They have a very low forward voltage drop.
2.1. SBR30U30CT
30A Super Barrier Rectifier from manufacturer Diodes.
- Connecting the two diodes parallel halves the current to 2.5A per pin.
- Price about $2
| Vf [V] | Vf max | i [A] | Tj [°C] |
| 0.19 | 2.5 | 125 | |
| 0.24 | 5 | 125 | |
| 0.41 | 0.45 | 15 | 25 |
| 0.34 | 0.37 | 15 | 125 |
2.2. SBR20U40CT
20A ultra low Vf Super Barrier Rectifier from manufacturer Diodes.
- Connecting the two diodes parallel halves the current to 2.5A per pin.
- Price about $1.15
| Vf [V] | Vf max | i [A] | Tj [°C] |
| ~0.27 | 2.5 | 125 | |
| ~0.32 | 5 | 125 | |
| 0.47 | 10 | 25 | |
| 0.41 | 0.44 | 10 | 125 |
2.3. PDS1040L-13 / PDS1045-13
10A low Vf schottky barrier rectifier from manufacturer Diodes.
| Vf [V] | Vf max | i [A] | Tj [°C] |
| 0.39 | 5 | 25 | |
| 0.28 | 5 | 125 | |
| 0.41 | 0.46 | 6 | 25 |
| 0.30 | 0.35 | 6 | 125 |
2.4. SBR10U45SP5
10A Super Barrier Rectifier for solar panels from manufacturer Diodes. Designed as Bypass Diodes for Solar Panels.
- Designed in accordance to Solar Industry Safety Standards (IEC61730-2, IEC61215-2)
- Large safe operating area (SOA) with maximum selectively rated 200°C junction temperature for higher reliability
- Low profile height of 1.1mm for possible integration into the solar panels
- Low leakage current <2mA @85ºC
| Vf [V] | Vf max | i [A] | Tj [°C] |
| 0.29 | 5 | 125 |
2.5. SBR10U45SD1
Same as SBR10U45SP5 but with case DO-201AD.
