As industrial automation and robotics continue to advance, accurate and reliable distance measurement becomes increasingly important for numerous applications. Time-of-Flight (ToF) sensing technology has emerged as a leading solution, offering precise distance measurement capabilities in challenging industrial environments. Broadcom's family of ToF sensors represents a significant advancement in this field, combining sophisticated measurement techniques with robust performance characteristics. This article explores the fundamental principles of ToF technology, examines the architecture of modern ToF sensors, and demonstrates how these devices can be effectively implemented across various industrial applications.

Understanding ToF Fundamentals: Direct vs Indirect Methods

Time-of-Flight (ToF) technology represents a sophisticated approach to distance measurement, utilizing the known speed of light to determine the distance between a sensor and its target. This optical measurement technique has evolved into two distinct methodologies: Direct ToF (dToF) and Indirect ToF (iToF).

Direct ToF operates on a straightforward principle, emitting short light pulses (typically 5-10ns) and measuring the time until the reflected pulse returns to the sensor. This time measurement directly correlates to the distance travelled, making it conceptually simple but technically challenging to implement due to the need for extremely precise timing measurements.

In contrast, Indirect ToF, also known as Continuous Wave ToF (CW-ToF), employs a more sophisticated approach. Instead of discrete pulses, it utilizes continuously modulated light waves. The system measures the phase shift between the emitted and reflected signals to determine distance. This method offers several advantages in practical applications, particularly in terms of accuracy and ambient light rejection.

The choice between these technologies often depends on specific application requirements, with factors such as required accuracy, operating environment, and measurement range playing crucial roles in the selection process.

Broadcom’s AFBR-S50 Architecture

The architecture of Broadcom’s indirect ToF sensors represents a sophisticated integration of multiple technologies within a compact form factor. At the heart of these systems lies a multi-pixel avalanche photodiode (APD) array, typically comprising 32 pixels, which enables simultaneous measurement across multiple points within the sensor's field of view.

The sensor architecture incorporates several critical components: a regulated charge pump system operating between 20V to 80V, dual high-current laser drivers, and a factory-calibrated clock source working in conjunction with an all-digital phase-locked loop (PLL). This integration ensures precise timing control and accurate distance measurements.System health monitoring is achieved through built-in voltage and temperature sensors, while a dedicated reference pixel provides additional feedback for functional safety applications. The entire system operates from a single 5V supply, simplifying power management requirements. Data communication is handled through a Serial Peripheral Interface (SPI), enabling straightforward integration with host microcontrollers.

The sensor's sophisticated ambient light suppression capabilities, combined with its compact size and low power consumption, make it particularly suitable for industrial applications requiring reliable operation in challenging environmental conditions.

Full list of features:

Full range of Broadcom’s ToF Sensor Modules

The Unique Features of Broadcom’s AFBR-S50 Family

What sets these ToF sensors apart is their exceptional range capability of up to 50m (extending to 100m in specific conditions), combined with industry-leading ambient light suppression that exceeds 100klux - enabling reliable operation in full sunlight. The compact form factor and lightweight design (under 1g) make them ideal for space-constrained applications. With field of view options ranging from 0.4° x 0.4° to 13° x 6°, these sensors offer unprecedented flexibility in system design while maintaining laser Class 1 safety compliance.

• Long range → 50m and beyond (in special cases 100m)
• Strong in ambient light suppression → 100klux and beyond = full sunlight on target
• Very compact and lightweight
• FOV 0.4° x 0.4° up to 13° x 6°

Implementation Case Studies in Industrial Applications

Broadcom’s Time-of-Flight sensing technology finds diverse applications across industrial automation and robotics sectors, each leveraging different aspects of the sensor's capabilities. In Automated Guided Vehicle (AGV) and Autonomous Mobile Robot (AMR) applications, these sensors provide critical navigation and obstacle detection capabilities, utilizing their high frame rates and reliable performance even in variable lighting conditions.

Factory automation systems benefit from the sensors' ability to perform precise fill-level measurements in containers and tanks, where the multi-pixel array enables accurate volume calculations regardless of material surface properties. In predictive maintenance scenarios, the sensors' high precision and stability allow for early detection of mechanical wear or misalignment in production equipment.

The technology's robust performance in high-ambient light conditions makes it particularly valuable for UAV navigation and structural inspection tasks, where outdoor operation is essential. For traffic control and logistics applications, the sensors' ability to accurately measure against various surface types - including metallic, retroreflective, and dark materials - ensures reliable operation in dynamic environments.

Additionally, Broadcom’s ToF sensors play a crucial role in safety systems, such as light curtains and collision avoidance systems for industrial vehicles, where their Class 1 laser safety compliance and functional safety features are essential requirements.

EPS Global's engineering team, with 20+ years of experience, offers technical expertise for integrating Broadcom's Time-of-Flight sensor modules. We provide support from concept to manufacturing, including global logistics. Our FAEs help customers efficiently implement these sensors, speeding up development.