Infineon BTS133TC Smart High-Side Power Switch: Features and Application Circuit Design
The Infineon BTS133TC is a versatile smart high-side power switch designed for a broad range of automotive and industrial applications, offering robust performance and integrated protection features in a compact package. As part of Infineon’s PROFET™ (Protected MOSFET) family of devices, it is engineered to drive resistive, capacitive, and inductive loads with high reliability and diagnostic capability.
Key Features of the BTS133TC
The BTS133TC integrates a vertical power MOSFET with a CMOS control circuit on a single chip. Key features include:
- Overcurrent Protection: The device features an adjustable current limitation mechanism that protects the switch from short circuits and overloads.
- Overtemperature Protection: An integrated thermal shutdown function disables the output when the junction temperature exceeds a safe threshold, restarting automatically upon cooling.
- Overvoltage Protection: The built-in clamp protects the switch against voltage transients, such as those encountered in automotive environments (e.g., load dump).
- Ground Loss and Supply Loss Protection: The device remains safe and controllable even in cases of temporary ground or supply disconnection.
- Diagnostic Feedback: An open-drain status output (ST) provides fault signaling for conditions such as overtemperature, short circuit, or open load.
- Low Quiescent Current: Ideal for always-on or battery-sensitive applications.
Application Circuit Design
A typical application circuit for the BTS133TC is straightforward yet highly effective. The device is controlled via a microcontroller (MCU) and can drive loads such as lamps, solenoids, or motors.
Basic Connection Scheme:
1. The input pin (IN) is connected to a GPIO pin of an MCU, with a series resistor (e.g., 1kΩ) for current limiting.
2. The output pin (OUT) is connected directly to the load.
3. The status pin (ST) is pulled up to the MCU’s supply voltage (typically 5V) with a resistor (e.g., 10kΩ) and read by another GPIO pin for diagnostic purposes.
4. A bypass capacitor (e.g., 100nF) should be placed between the supply voltage (Vbb) and ground (GND) near the device to suppress noise and stabilize operation.
For inductive loads, such as relays or motors, it is recommended to add a freewheeling diode in parallel with the load to suppress voltage spikes during turn-off. Although the BTS133TC includes internal protection, an external diode enhances reliability in harsh environments.
Design Considerations:
- Load Current: Ensure the maximum load current does not exceed the device’s current rating, considering derating for temperature.
- Thermal Management: The BTS133TC is available in a DPAK (TO-252) package with low thermal resistance. For high-current applications, proper PCB copper area under the tab is essential for heat dissipation.
- Diagnostics Utilization: The status pin allows the system to implement predictive maintenance or fault alerts, improving system safety and availability.
Conclusion
The Infineon BTS133TC provides a compact, efficient, and protected solution for high-side switching. Its combination of integrated protections, diagnostic feedback, and ease of use makes it suitable for demanding applications in automotive body electronics, industrial automation, and power management systems.
The Infineon BTS133TC stands out as a highly integrated and protected high-side switch, offering excellent reliability and diagnostic features for robust electronic designs.
Keywords:
High-Side Switch, Overcurrent Protection, Diagnostic Feedback, Automotive Applications, Thermal Shutdown
