| CLIENT | Startup Company |
| DATE | 18.10.2019 |
| TASK | Compact and efficient e-bike motor driver operated by a 24 V battery |
About the Company:
The Startup Company produces easy-to-install 250 to 500 W e-bike upgrade kits.
“Within minutes, you can turn your old dirt-bike into a brand new e-bike. Whether you are a casual cyclist who loves long trips across the countryside or you live in a busy city, and you need some light exercise while you navigate through the crowd with ease, the e-bike will allow you the freedom you always wanted”, says the CEO of the Startup Company
The Challenge:
While cities become overcrowded with cars, pollution levels steadily increase, year by year. In big cities, transportation becomes a real challenge. Therefore, electrically augmented bikes represent a perfect transportation solution: they are super-light, need a reasonably low amount of energy, and they are especially suitable for maneuvering through the city crowd. However, to allow as much range as possible with a 24 V battery, the hub motor driver has to be very efficient, and compact enough to fit inside a 24″ to 29″ bike wheel. In electronics, less voltage means more current, for the same power. More current also means thicker conductors, bulkier components, and more thermal losses. 24 V constraint became challenging for the designers.
The Solution:
By placing the driver circuitry inside the wheel, the length of wires, and thus their resistance, was reduced to a minimum. To overcome the second part of the problem (bulky switching components with a lot of heat dissipation), the designers used Nexperia’s MOSFET solution for motor driving. MOSFETs like the PSMNR70-40SSH feature low switching resistance (RDSON), low parasitic capacitance, and excellent thermal performance. By using clip bonding technology, these MOSFETs can achieve outstanding switching performances in a compact LFPAK88 package. Designers used these MOSFETs in the LFPAK88 package throughout the entire design, not only the motor driver (e.g., for battery management system), due to their outstanding performances.
| Type number | VDS max (V) | RDSON max @ 10 V (mΩ) | ID max @ 25 ˚C (A) | Rth(j-mb) Typ. (K/W) |
| PSMNR70-40SSH | 40 | 0.7 | 425 | 0.25 |
| PSMNR90-40SSH | 40 | 0.9 | 375 | 0.28 |
| PSMN1R0-40SSH | 40 | 1.0 | 325 | 0.32 |
About Nexperia
Nexperia is the expert in high-volume production of discrete and MOSFET components and analog & logic ICs that meet the stringent standards set by the automotive industry. We are the only company that focuses 100% of its efforts on making and supplying world-class discrete components, analog and logic ICs, and MOSFET devices. If you want to evaluate Nexperia’s industrial and automotive solutions for your own design, you can register for a free sample kit.
