5 Applying the TPS1HC100 Power Distribution Board in a Reference Design

Combining the embedded system as described above and the power distribution board, it is possible to create a reference dashboard system to provide a real time example of the features and benefits of the TPS1HC100-Q1. The reference design uses a variety of loads to represent the different challenges faced as described in Section 2. The loads in this reference design are steering wheel heaters, haptics motors, buzzers and LEDs which represent a large proportion of resistive, capacitive and inductive loads. Furthermore, the power distribution board along with the microcontroller is packaged within a conventional steering wheel. While such a system can only be achieved by removing the driver airbag and airbag ignition system which is not realistic, this highlights another major benefit of using TI High Side switches namely, the low small PCB footprint and the high-power density. Figure 5-1 shows a block diagram of the reference design.

The distance sensors are not directly driven by the power distribution board. While it is possible to use TPS1HC100-Q1 to drive these devices, this reference design uses two independent circuits that communicate with one another through the iOS host. To this end, the distance sensors are mounted on an RC car which can be placed in various locations to trigger different responses on the loads driven by the power distribution board. They are mounted on the front left, front right, and center front of the RC car. The sensor data is sent to a secondary MCU which then sends this data to the iOS Host. The user also has the ability to manually turn on the steering wheel heater with the iOS host as this load is not triggered by any proximity warnings. The onboard gyroscope also provides rotation data which is sent to the iOS host and is represented with a steering wheel which updates its position in real time.

When the distance sensors are triggered on the RC car, the proximity data is sent to the iOS Host. Depending on how close and the location of the sense item, that is, left, right, or center, the iOS Host determines which set of loads needs to be enabled and the severity of the proximity warning. There are three levels of severity which have increasing PWM frequency higher the level of severity. The most severe warning results in a DC on signal sent to the loads. The LEDs, buzzers and haptics motors all respond simultaneously to this proximity trigger. Information is easily parsed by the user on the location of the item as well as its severity as the loads on the left side are triggered based on proximity on the front left sensor and loads on the right side are triggered based on proximity on the front right sensor. If both the left and right loads are enabled, the implication is that the proximity warning is generated from something straight ahead.