Smart High-Side Power Switch Two Channels: 2 x 60m Status Feedback# Technical Documentation: BTS728L2 High-Side Power Switch
Manufacturer : INFINEON
Document Version : 1.0
Date : October 26, 2023
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## 1. Application Scenarios
The BTS728L2 from Infineon is a dual-channel, high-side power switch based on proprietary Smart High-Side Power (PROFET™) technology. It is designed for robust, intelligent power distribution in demanding automotive and industrial environments.
### 1.1 Typical Use Cases
* Solenoid and Valve Control: Directly driving fuel injectors, transmission solenoids, exhaust gas recirculation (EGR) valves, and hydraulic control valves. Its high current capability (up to 40A per channel, pulsed) and integrated protection make it ideal for inductive loads.
* Lighting Loads: Powering high-current lighting modules such as LED headlights, fog lights, or auxiliary work lamps in vehicles and machinery. The diagnostic feedback is crucial for lamp outage detection.
* Heater and Motor Control: Managing PTC (Positive Temperature Coefficient) heaters for cabin/climate control or small DC motors for actuators (e.g., power windows, sunroofs, throttle control). The switch handles inrush currents effectively.
* General Purpose Power Distribution: Serving as a solid-state replacement for relays and fuses in centralized junction boxes or power distribution units, enabling smart load management and diagnostics.
### 1.2 Industry Applications
* Automotive: The primary target market. Applications include:
* Body Control Modules (BCM): For windows, wipers, seats, and locks.
* Engine Control Units (ECU): For injectors, ignition coils, and variable valve timing.
* Thermal Management: For cooling fans and heater systems.
* Advanced Driver-Assistance Systems (ADAS): For sensor cleaning pumps and actuator control.
* Industrial Automation: Controlling actuators, solenoids, and motors in PLC (Programmable Logic Controller) output stages and factory automation equipment.
* Heavy Machinery & Agriculture: In construction vehicles and tractors for implementing control, hydraulic systems, and high-power accessory control.
### 1.3 Practical Advantages and Limitations
Advantages:
* High Integration: Combines power MOSFETs, drive circuitry, protection, and diagnostics in one package, reducing board space and component count.
* Comprehensive Protection: Features integrated overload protection, short-circuit protection, over-temperature protection with shutdown and restart, and over-voltage clamp (e.g., load-dump protection) . This significantly enhances system reliability.
* Advanced Diagnostics: Provides precise current sense (IS) output proportional to the load current for real-time monitoring and open-load detection in ON and OFF states. A status flag (ST) pin indicates fault conditions.
* Low Power Consumption: Features very low quiescent current in standby mode, essential for automotive applications with strict quiescent current budgets.
* EMC Robustness: Designed to meet stringent automotive electromagnetic compatibility requirements.
Limitations:
* Power Dissipation: As a high-side switch, all load current passes through the IC, generating heat. Continuous high-current applications require careful thermal management (see Design Considerations).
* Voltage Range: While suitable for 12V/24V automotive systems (operating voltage up to ~40V), it is not suitable for higher voltage systems (e.g., 48V mild-hybrid or main traction voltages).
* Cost vs. Discrete Solutions: For very simple, non-critical switching without diagnostic needs, a discrete MOSFET solution may be lower cost. The BTS728L2's value is in its intelligence and robustness.
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