When people think of electric vehicles, they usually imagine a product that incorporates state-of-the-art technology. As such, the charging flap should also live up to these standards. After all, charging is unavoidable and occurs frequently in the everyday lives of electric vehicles. It should not only be safe, but also as convenient as possible.
The charging flap plays a decisive role here, as it initially gets in the way of the charging process. But it is also necessary to protect the charging port from environmental and other external influences and to extend its service life. In addition to the manually operated caps that dominate conventional vehicles, there are more and more electric charging flaps, especially in electric vehicles. Here, it makes sense to upgrade them with visual and functional details (Fig. 1).
Lighting improves charging in the dark
When charging at dusk or in the dark, a light source directly at the charging port makes it much easier to insert the charging plug. Energy-efficient LEDs are recommended for this task, as they offer much greater design freedom. For example, the color and shape of the LED display can also be used to show information about the charging process and the battery’s state of charge. To implement such functions, LEDs require dedicated IC drivers that control the colors and brightness of the LEDs.
One such driver for RGB and RGBW LEDs is the E521.39 from Elmos (Fig. 2). This one-chip solution combines an integrated microcontroller with flash memory as well as an LIN transceiver and four integrated power sources. The LED driver supports LIN auto-addressing. Each of the four drivers can drive external loads with a current of up to 60 mA. This means that the E521.39 currently offers the highest output current per channel on the market. A pulse width modulation (PWM) generator with a resolution of 16 bit is available for each channel. The PWM duty cycle can be set individually for each output via the LIN interface. Temperature and voltage compensation ensures that the set color of the RGB LEDs is maintained. Equipped in this way, the E521.39 enables stable output colors in all weather conditions as well as varying colors depending on the vehicle's state of charge.
When in sleep mode, drivers typically use 15–30 μA of power across the entire temperature range. For automotive use, the required temperature range of -40 °C to +125 °C is maintained (AEC-Q100 qualification).
Contactless control
Whether they have their hands full or just don’t want to get them dirty, contactless opening and closing of the charging flap can be another real USP for the end customer.
The E909.21 controller from Elmos Semiconductor even enables the recognition of various gestures. It is based on Elmos’ own proven Halios technology, which achieves reliable object detection by comparing the infrared light beam reflected by the object being detected with a reference light beam. The E909.21 is characterized by its high sensitivity and unbeatable immunity to ambient light of up to 200,000 lux, as well as the protection against rapid changes in ambient light. Moreover, it does not need to be calibrated over the vehicle’s entire service life. The Halios frequency is scalable to 1 MHz, thereby eliminating interference with other optical systems (Fig. 3).
The E909.21 can connect two receiver drivers and four LED drivers with 100 mA driver power each, which can also be connected in parallel for higher currents. The integrated 16-bit microcontroller has flash memory, SRAM, High-Speed-I2C, and SPI, and is programmable via two or four-wire JTAG.
With the E909 product family, which includes the E909.21, Elmos Semiconductor also offers scalable products for other HMI concepts. The E909.23, for example, is optimized for gesture control applications with touch displays in vehicles. It is also based on Halios technology, boasting the advantages of high sensitivity, automatic calibration, and immunity to ambient light and rapid changes in brightness.
Charging flap with actuator
Of course, an actuator is also required for contactless control of the charging flap. Typically, actuators consisting of a motor, a gear, and a corresponding IC driver are used. The IC drivers have the task of flexibly controlling the motor to open and close the flap smoothly. To always be able to determine optimal control of the motor, the position of the flap must also be monitored.
To do so, Elmos Semiconductor also has a cost-optimized chip in its portfolio, the fully integrated system-on-a-chip (SoC) controller E523.63 (Fig. 4). It enables high-precision motor control for drive currents up to 1 A. It is designed to drive a three-phase brushless motor (BLDC), a two-phase stepper motor, or up to two conventional DC motors. For this purpose, it combines a 32-bit Arm Cortex M23 microcontroller and an analog motor driver in a small TSSOP16-EP package. Its integrated measurement system provides all the input signals for sensorless closed control loop commutation as well as numerous monitoring and diagnostic functions.
For higher levels of power with drive currents above 1 A, Elmos offers the E533.06. The SoC controller is based on a 32-bit Arm Cortex M4 microcontroller and combines a 96 kB program memory, state-of-the-art co-processors, and the analog gate drivers in a QFN48 package. The integrated PWM and ADC accelerators improve performance for sensorless single-shunt motor control. This enables advanced control algorithms such as field-oriented control (FOC) with low CPU load. Both the E523.63 and the E533.06 are AEC-Q100 qualified and comply with the ISO 26262 standard (ASIL B). Their broad temperature range extends from -40 °C to +150 °C.
All the featured ICs can be flexibly adapted to new systems and innovations thanks to the implemented microcontrollers, making them well equipped for future requirements.
For more information and a direct ordering option, please visit our e-commerce platform at www.rutronik24.com.
Subscribe to our newsletter and stay updated.