Infineon BTS721L: High-Side Smart Power Switch for Automotive Applications

The increasing complexity of modern automotive electronic systems demands robust, intelligent, and highly reliable power management solutions. The Infineon BTS721L stands out as a premier high-side power switch engineered specifically to meet the stringent requirements of the automotive industry. This device integrates a multitude of control, protection, and diagnostic features into a single package, providing a compact and efficient solution for driving a wide range of resistive or inductive loads, such as lamps, motors, and heaters.

At its core, the BTS721L is built using Infineon's proven smart SIPMOS technology. It combines a vertical N-channel power MOSFET with a CMOS charge pump and extensive protection circuitry on a single monolithic chip. This integration allows it to be controlled directly by a microcontroller via a low-current logic-level input, simplifying system design and reducing the component count on the board.

A key strength of the BTS721L is its comprehensive suite of embedded protection and diagnostic functions, which are critical for ensuring system safety and longevity in the harsh automotive environment. These features include:

Overload and Short-Circuit Protection: The device actively limits the output current in case of a fault condition, safeguarding both the switch and the load from damage.

Overtemperature Shutdown: An integrated temperature sensor shuts down the output if the junction temperature exceeds a safe threshold, with automatic restart upon cooling.

Overvoltage Protection (including load-dump): It can withstand voltage transients typical in automotive systems, such as load-dump events.

Ground Loss and Supply Loss Protection: The switch remains in a safe state even if the ground connection or supply voltage is interrupted.

Advanced Diagnostic Capabilities: It provides precise feedback to the microcontroller through a status flag, indicating faults like overtemperature or open-load conditions in the off-state, which is vital for predictive maintenance and functional safety compliance.

Housed in a PG-DSO-20-47 package with exposed cooling clips, the BTS721L offers excellent thermal performance, enabling efficient dissipation of heat and allowing for a higher power density in the electronic control unit (ECU). Its high efficiency and low standby current make it an ideal choice for both conventional and electric vehicles, where energy conservation is paramount.

ICGOOODFIND: The Infineon BTS721L is a highly integrated and robust high-side switch that exemplifies the move towards smarter and safer automotive power distribution. Its blend of high reliability, comprehensive built-in protection, and detailed diagnostic feedback makes it an exceptional choice for designers tackling the challenges of next-generation automotive body and comfort control modules.

Keywords: High-Side Switch, Automotive Applications, Diagnostic Features, Overload Protection, Infineon BTS721L