New 48 V Reference Design Aims to Propel E-Bike and E-Scooter Development

August 27, 2020 by Jake Hertz

Looking to expedite the design of e-bikes and the like, Renesas recently released a new 48 V mobility solution.

The demand for e-bikes, e-scooters, and similar products are undoubtedly on the rise. In fact, in an article on how e-bikes are designed, AAC contributor Steve Arar notes that e-bike company Lime recently announced that they have reached 150 million rides in just 3 years. 


E-bike sales over the past couple of years

E-bike sales over the past couple of years. Image used courtesy Cycle Volta

To help improve and develop such technologies, Renesas recently released a new 48 V mobility solution. Dubbing their solution a “winning combination,” Renesas expressed hope that the reference design will help customers accelerate their designs and push them more quickly to market.


Why 48 Volts?

48 V may seem like an arbitrary number, but it actually serves a specific purpose

Historically, 12 V has been a standard voltage level for power distribution in many applications. Yet as devices from power tools to server racks grow and require more power, I2R losses have become significant. So, to combat this challenge, engineers have started to adopt 48 V as a standard for industrial-type power supplies.

Delivering the same amount of power to a load at 48 V as opposed to 12 V offers 16 times less I2R losses—nothing to scoff at. And since e-bike systems often require high power outputs to the motor in order to produce large amounts of torque, 48 V has become a standard in many designs.


Renesas' Reference Design for 48 V 

With this standard in mind, Renesas has now released a new mobility solution for e-bikes designed at 48 V


Applications of the new Renesas solution

Applications of the new Renesas solution. Image used courtesy of Renesas


This reference design employs a modular approach to assist in the design of both core and optional functional blocks that can be adopted for many 24 V–48 V. The design itself consists of 15 different Renesas ICs, highlighted by the ISL94216 16-cell battery front end (BFE), the HIP2211 100 V MOSFET drivers, and the RX23T 32-bit microcontroller for motor control. 

The solution is designed to be powered from a 25 AHr Li-ion battery that drives a 1,600 W inverter, good for reaching speeds up to 5,000 rpm.


The Main Blocks

The system consists of two core functional blocks and two optional ones. The core functional blocks include the battery front end (BFE) and the motor control board while the optional blocks are a Bluetooth low-energy control board and a wireless charging receiver board. 

The BFE boasts over 200 mA external cell balancing, which Renesas claims to enable fast recharging and high utilization in large battery packs.


System block diagram

System block diagram. Image used courtesy of Renesas


The motor control board supports a 48 V battery pack and can reach up to 5,000 RPM using a 1,600-W inverter powertrain with motor control sensors. 


Purpose-Built for Mobility Solutions

With this release, Renesas hopes to help its customers develop e-bikes and many other mobility solutions. According to the company, the solution is designed for applications like lawnmowers, electric carts, robot cleaners, power tools, power banks, and more. 

DK Singh, director of the systems and solutions team at Renesas, says, “Our new 48 V mobility winning combination solution combines Renesas’ advanced BFE, industry-leading MCUs, along with analog and power devices, and innovative motor control technology to help customers speed up the development of their high power and torque e-scooters and e-bikes.”