Current situation and solutions of the hottest mod

Current situation and solutions of modern automobile lighting system

in today's medium and high-end cars, the modern lighting concept is more and more incisively and vividly deduced. Both external lighting and internal lighting are fashionable and personalized. Emotion setting mode is used in different parts of the car to control the light color and brightness of "personal space", such as the backlight of the driver's foot space or console. This kind of automobile lighting adopts new light sources, which not only enriches the consumer experience, but also meets the requirements of environmental protection and energy conservation

in order to realize advanced automotive lighting applications, we must have the support of corresponding semiconductor technology. As a leading automotive lighting solution supplier, ansenmey semiconductor has been providing various general and special energy-efficient device solutions for automotive lighting applications, which meets the strict requirements of automotive applications and meets the rapid development market demand

modern automotive lighting system

in recent years, light emitting diodes (LEDs) have been widely used in automotive lighting applications. Compared with incandescent lamps, led based lighting systems have longer service life, lower power consumption and higher design flexibility. These characteristics make it very suitable for automotive interior lighting applications. In addition, with the continuous progress of technology, white LEDs with lower cost, improved conditioning speed and precision per watt and higher light output have emerged, making them more suitable for various lighting applications in the interior of cars

led has a wide range of applications in cars. For example, it can be set in the interior of the roof or the interior of the lower part of the door to focus the light on specific areas inside and outside the car. The LED can also be integrated near the door handle, key hole, pedal, cup holder, or as a steering flasher on the rearview mirror. The shape of the luminous indication can be very simple or exquisite to meet the precise lighting and provide convenience and beauty for people, as shown in Figure 1

Figure 1: various automotive lighting applications

advanced automotive lighting solutions of Anson semiconductor

Anson semiconductor has been providing standard products and customized devices for automotive lighting applications, including common bulb driver solutions, as well as stepping drivers, LED drivers and high intensity discharge lamp (HID, such as xenon lamp) drivers. In the HID drive application specific integrated circuit (ASIC) market, the headlamp level developed by ansenmey semiconductor can realize close contact adjustment with different markets and customers, and the rotary stepping driver has been widely used in the industry. In the automotive LED lighting market, ansenmey semiconductor has provided a rich product portfolio for in car and out of car applications. In the car lighting system block diagram shown in Figure 2, ansenmey semiconductor has various corresponding products. Several main solutions will be introduced below

Figure 2: vehicle lighting system block diagram

1 Headlamp stepper motor driver

most cars today are equipped with halogen lamps with high beam (HB) and low beam (LB) functions, which are the main functions of headlamps. The typical power consumption of high beam halogen lamp is 55 W, and the light output is about 1000 lumens. Hid technology has been available for more than ten years, with power consumption of about 35 W and optical output of about 3500 lumens, which has certain application advantages. Over time, HID lamps have integrated the high beam function into Bi xenon lamp solutions. However, because the high brightness and glare of HID will affect the line of sight of approaching vehicles, some countries require automatic adjustment of the height of low beam lamps

another important aspect of automotive headlights is the beam rotation of advanced headlighting system (AFS) to optimize the visibility curve, and the adaptive driving beam (ADB) function can adjust the beam according to the real-time situation. Stepper motor is the preferred controller for AFS and ADB

amis-30623 single chip bipolar stepper motor driver of ansenmey semiconductor is suitable for horizontal adjustment and rotation control of headlamp. The device is equipped with an integrated position controller and a local interconnection network (Lin) interface, which can realize the design of a special Mechatronics solution for remote connection with the Lin host, as shown in Figure 3. It uses configurable parameters such as current, speed, acceleration and deceleration to receive position commands through the bus and drive the motor coil to the required position. Amis-30623 can also detect motor stalling

Figure 3: headlamp level adjustment and rotation circuit using amis-0623

this device embeds a special finite state machine and Lin instruction set customized for the requirements of advanced headlamp system, and also integrates the sensorless step loss detection function, which can not only improve reliability, but also reduce the number of components and on-board space, and reduce product costs

2 LED headlamp system power ballast and dual LED driver

at present, most cars still use halogen headlamp scheme to provide high beam and low beam functions, but the future trend is to use xenon lamps and LED lamps. In particular, the application of LED lamps, which can significantly reduce the power consumption of headlamps, will rise rapidly. Within five years, 30% of cars will be equipped with a variety of LED headlamp functions. Le its experimental speed is generally smaller. D lighting provides a more fashionable choice, which can realize "instant" lighting, and allows brightness control from 0% to 100% power

Anson semiconductor's ncv78663 single chip intelligent headlamp LED driver is a new device to be launched in 2011. It supports single module control of high beam, low beam, daytime running lights, position lights, cornering lights and fog lights. With integrated digital dimming, programmable serial peripheral interface (SPI) settings and built-in diagnostic functions, ncv78663 provides an integrated and comprehensive energy-efficient solution for headlamp control

figure 4:ncv78663 single chip intelligent headlamp LED driver

ncv78663 adopts buck/boost topology, and only a few external components can realize LED current regulation, constant current sharing, efficient integrated buck switch (high side) and up to 2 a current; Its extended diagnostic functions include: detecting open circuit or failing driver, short circuit, overcurrent protection and single LED fault. In addition, the device also has the characteristics of thermal protection, system customization through SPI interface and/or OTP settings, multiple system configurations with one device, better EMC performance without additional filtering, low EMC of battery, low EMC of LED string, etc. Using ncv78663 can reduce the number of external components, and the total energy efficiency is higher than 90%. The evaluation board of the device has been launched, as shown in Figure 5

Figure 5: ncv78663 evaluation board

3 The advent of HID headlamp full function ASIC

hid lamp has improved the performance of headlamp system. Compared with traditional halogen lamps, hid improves color rendering, and has the characteristics of low power consumption, longer service life and higher light output. In order to support advanced functions, HID headlamps need efficient ballasts and complex control circuits

ansenmey semiconductor HID lamp control system is a hybrid analog/digital solution using 8-bit microcontroller or special state machine, as shown in Figure 6. The device integrates dc/dc controller, rich diagnostic functions (overvoltage, undervoltage, temperature sensor, life counter), various communication interfaces (Lin, SPI), and supports 35 W (d1/d2/d3/d4) and 25 W (D5) lights

Figure 6: hid headlamp full function ASIC

4 Vehicle LED combination tail lamp linear current stabilization and controller

at present, more and more vehicle combination tail lamps (RCL) adopt LED lamp body groups, which not only have beautiful appearance and high luminous efficiency, but also help the rear vehicle to clearly see the driving state of the front vehicle

ansenmey semiconductor ncv7680 is a linear current stabilizer and controller, which can supply power to the combined tail lamp with a single chip, providing better performance and higher energy efficiency, and the footprint is smaller than that of the solutions on the market. The device includes 8 linear programmable constant current sources, which are suitable for the current stabilization and control of automotive solid-state combined tail lamp (RCL), and support light-emitting diode (LED) driving current of up to 75 Ma per channel

ncv7680 integrates many functions and supports two brightness levels, one for parking and the other for tail lighting. If necessary, optional pulse width modulation (PWM) control can also be used. The system designer only needs to use an external resistor to set the output current (overall set point). In addition, for the design requiring high current, the optional external ballast field effect transistor (FET) can distribute power according to the high current required by the design. The delayed power limit reduces the drive current under overvoltage conditions. This is important for low current applications without external FETs

typical applications of this device include combined tail lamp, daytime running lamp (DRL), fog lamp, central high mounted stop lamp (CHMSL) array, turn signal lamp and other external modulation applications, liquid crystal display (LCD) backlight, lighting module, etc. Compared with the discrete scheme, the device can better match the LED output, open drain output function of open LED string diagnosis, and it is easy to find faults

Figure 7: application circuit using external FET transistor ballast

summary

Anson semiconductor has been using its advanced automotive technology to provide various standard products and customized devices for automotive lighting applications. In addition to some of the solutions introduced above, there are also industry-leading products and solutions such as LED drivers using linear and switching power supplies (SMPS), LED current regulators, and constant current regulators for central high mounted brake lights

like various automotive application products using advanced automotive technology, all these integrated circuits meet the specifications and environmental protection requirements such as automotive reliability and temperature, and can meet people's increasingly high requirements for interior lighting control, headlights, rear combination lamps, fog lamps, clearance lamps, especially new light sources, so that drivers can fully experience the comfort and fun brought by lighting. (end)