Consider the simplified LIDAR system block diagram shown in Figure 3-2, with the MCU or processor, the time-of-flight sensor, and the laser array. Each of these components requires redundant and diverse temperature monitoring to meet safety requirements. As a result, at least two temperature sensing elements are needed for each component, and each of those temperature sensing elements must be diverse.

In this design, the MCU or processor temperature is monitored by two TMP451-Q1 remote temperature sensors, satisfying the redundancy requirements for monitoring the temperature of that component. The remote channels (shown in red) of those two sensors are connected to two different integrated thermal transistors inside the time-of-flight sensor, meeting the redundancy and diversity requirements for that device. As a result, no additional external components are needed to monitor the temperature of the time-of-flight sensor. Lastly, two TMP451-Q1 sensors monitor the temperature of the laser modules. The remote channels of each sensor are connected to discrete thermal transistors (PNP or NPN) on the opposite laser module, achieving redundancy and diversity in monitoring the temperature of the laser modules. Although the same temperature sensor is used throughout this design, using two different packages of the TMP451-Q1 can contribute to the diversity requirement. Also note that, in this example, it is assumed the time-of-flight sensor has an integrated thermal transistor. Depending on the design, other components, such as the MCU or processor, may also have integrated thermal transistors that can be read using channels of remote temperature sensors.

The remote temperature sensors connect to I2C buses on the MCU or processor, where temperature measurements are processed and compared. Depending on the architecture of the system, the temperature sensors may connect to the same I2C bus or separate I2C buses.

If more diversity is desired, another option is to use two different remote temperature sensors, such as one TMP451-Q1 and one TMP421-Q1, as shown in Figure 3-3.