Input overvoltage protection enables higher efficiency and lower cost power supplies in automotive applications


There are numerous power supplies in the modern day automobile.  The increasing number of electronic circuits require their own power supply, which creates a power draw and cost hurdle for designers.  Additional electronics are needed for new safety features, more infotainment options, extra driver assistance systems, and so on.  The cost of these new circuits adds up in the R&D effort and in the car price.  The power consumption of these new circuits shows up in your MPGs and in your gasoline bill.

The power supply design for each electronic system is critical.  For those electronics powered directly from the battery, the power supply must safely withstand a wide range of input voltage transients applied to it.  These voltage transients may occur when the car is started or when the air conditioning or another motor turns on or off.  This wide input voltage range increases the cost and power consumption of the power supply by requiring higher breakdown voltage transistors, which are already more costly and inefficient.

However, several of these electronics do not need to be powered all of the time.  Certain infotainment systems and the USB ports found throughout an automobile are not safety critical.  These systems can tolerate brief power outages, if it makes their design more efficient and lower cost.  If they could be protected from the brief input voltage transient, these electronics would not need to be rated for the very wide battery voltage and suffer the corresponding efficiency loss.

This is a job for the PMP9757 design: Step-Down Converter with Input Overvoltage Protection.  By using an overvoltage protection circuit to insulate the power supply from the battery, the power supply  can be designed to better optimize the cost and efficiency of the given electronic system. For example, the 17-V rated TPS62150A-Q1 could be used with PMP9757 to generate a 3.3-V rail from the 12-V nominal battery, instead of needing to use the 60-V rated TPS54160-Q1.  Using the TPS62150A-Q1 instead enables a 90% efficient power supply with a substantial IC cost and BOM count reduction.

Which of your automotive sub-systems could benefit from input overvoltage protection?