High-power LF starter boosts car trunk for keyless entry

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When you are close to your car, do you think it is extremely painful to vacate the car key to open the trunk? Why can't the car automatically open the trunk? Today, Shiqiang can provide such a solution.

The advantage of this solution is that it can effectively improve the recognition kicking action ability, make full use of the high power LF starter MLX74190 , which has the technical advantages of independently programmable low frequency driver and built-in anti-theft lock, which perfectly helps the car keyless entry system function. It is also known in China as a trunk-inductive opening system.

Figure 1: The role of the MLX74190 in the trunk

The working principle of the MLX74190 is that when the sensor key is carried around, the sensor cover is automatically opened only by using the sensor about 10 cm below the bottom edge of the guard bar. This makes it easy to open the trunk to place items when both hands are occupied.

In the trunk kick controller solution, the main function of the MLX74190 is to use the high-power LF signal to wake up the car's key, after which the key is sent to the car with an encrypted identification number via a UHF signal to complete the owner's key. Certification process. The latest and most comprehensive product information can be downloaded through the Shiqiang Component E-commerce APP.

Figure 2: Typical circuit diagram of MLX94190 by Shiqiang Agent

As can be seen from the block diagram below, the solution mainly includes the vehicle owner key authentication technology and the kick scan recognition technology, and the technology brought by Shiqiang's MLX74190 product to the engineer precisely meets these two points. For example, the MLX74190 is used to implement the owner's key authentication, and the MLX90621 based on the thermal imaging principle can recognize the kicking action, which is an advantage that other brand solutions cannot replace. The car kick controller can communicate with the ECU via the LIN transceiver MLX80051, and it is recommended to use the motor driver of the MLX81150 to control the trunk motor.

Figure 3: Car trunk kick function block diagram

Let's take a look at some of the main features of the MLX74190, which is the main component of the trunk kick controller solution:

1) Internally integrated two low frequency drivers can generate a 1A sine wave current from 109kHz to 140kHz or a square wave current of 2.5A with an output amplitude from 0.25V to 32V (PP).

2) The MLX74190 allows multiple encoding modes to be supported.

3) When the key is exhausted and the transmission signal cannot be generated, the MLX74190 can support amplitude shift keying and frequency shift keying modulation to ensure passive RFID communication.

4) The diagnostic capabilities of the MLX74190 enable it to detect misconnections with various forms of the LF antenna.

5) The MLX74190 is available in a compact 48-pin TQFP package.

6) Operating temperature range is -40 ° C to 105 ° C.

In addition, the MLX74190 is fully scalable to a wide range of demanding wireless communications applications in a variety of industries including industrial, security and building automation. For example, motorcycles, all-terrain vehicles (ATVs), snowmobiles and motor boats can be detected when the key holder approaches the engine, and the engine can be started using the "Start" button to complete the keyless start function. It can also be integrated into the building's entry system, the starter in the tire pressure monitoring system (TPMS) and the pet identification controller.