Automotive LIDAR: Integrated MEMS Mirror Control & Sensing

LIDAR is the backbone of modern ADAS and autonomous driving architectures, relying on precise environmental scanning. For Innoluce BV (acquired by Infineon Technologies AG), the core technology was a patented resonant 1D Micro-Electro-Mechanical System (MEMS) mirror. The engineering challenge was not simply driving the mirror, but accurately detecting its position in real-time to synchronize laser pulses without increasing the module's footprint or cost.

The Challenge: Precision Feedback in Miniature Footprints

In resonant MEMS mirror systems, the mirror oscillates at a specific frequency to scan laser light across the field of view. To construct an accurate 3D point cloud, the system must know the mirror's instantaneous angle with extreme precision.

Traditional solutions often separate the actuation electrodes (driving the movement) from the sensing electrodes (measuring the position). While this simplifies the circuit design, it increases the size of the MEMS mirror die and the complexity of the optical package—luxuries that are not affordable in cost-sensitive, space-constrained automotive applications.

Solution: Shared Capacitive Actuation and Sensing

Bruco IC designed a custom Mixed-Signal ASIC that integrates both the high-voltage driver and the precision readout circuitry.

The critical innovation in this design was the "shared capacity" architecture. Instead of using separate structures, the ASIC uses the exact same capacitive electrodes for both:

Actuation: Driving the mirror into resonance.
Sensing: Measuring the capacitance change to determine position.

This required a sophisticated control loop capable of decoupling the driving signal from the sensing signal, likely using time-division or frequency-division techniques, to ensure that the high-voltage drive noise did not corrupt the sensitive position measurement.

Results and Acquisition

By combining these functions into a single control IC, the client achieved a significant reduction in the MEMS mirror size and a lower overall Bill of Materials (BOM).

The success of this miniature laser scanning module was a key factor in Innoluce BV's technology portfolio, leading to their full acquisition by Infineon Technologies AG in October 2016. This technology now serves as a platform for robust, solid-state-like LIDAR components in the automotive supply chain.