Infineon BPD948: A Comprehensive Technical Overview and Application Note

The Infineon BPD948 represents a state-of-the-art integration of a high-voltage half-bridge driver with two N-channel power MOSFETs in a single, compact package. Designed to drive inductive loads such as solenoids, valves, and small DC motors, this device is engineered for robustness and efficiency in a wide range of automotive and industrial applications. By combining the driver IC and power switches, it significantly reduces the external component count, minimizes PCB space, and enhances overall system reliability.

Technical Deep Dive: Architecture and Key Features

At its core, the BPD948 incorporates a smart driver circuit capable of operating from a supply voltage (V_CC) ranging from 5.5 V to 52 V, making it exceptionally suited for the demanding environments of 12 V and 24 V automotive systems. The integrated MOSFETs feature a very low typical on-state resistance (R_DS(on)) of just 160 mΩ each. This low resistance is critical for minimizing conduction losses and improving thermal performance, allowing the device to handle high continuous and peak currents efficiently.

A standout feature of the BPD948 is its comprehensive suite of built-in protection functions. These include:

Undervoltage Lockout (UVLO): Prevents operation when the supply voltage is too low, ensuring predictable behavior and preventing malfunction.

Overcurrent Protection (OCP): Safely limits the output current during a short-circuit or overload condition, protecting the MOSFETs from damage.

Overtemperature Shutdown (TSD): Monitors the junction temperature and disables the output if a critical threshold is exceeded, with automatic restart upon cooling.

The device is controlled via two TTL/CMOS compatible input pins (IN1 and IN2), which offer a simple interface to a microcontroller. The driver stage is optimized for fast switching characteristics to reduce switching losses, while internal circuitry prevents cross-conduction (shoot-through) within the half-bridge.

Application Insights and Circuit Implementation

A primary application for the BPD948 is driving DC motors in bidirectional control setups. The half-bridge configuration allows for forward, reverse, and brake operations. The typical application circuit is remarkably simple. The microcontroller’s GPIO pins are directly connected to the IN1 and IN2 pins. The load (e.g., a motor) is connected between the two outputs (OUT1 and OUT2), and the power supply is decoupled with capacitors close to the V_CC and GND pins of the BPD948.

For optimal performance and reliability, PCB layout is paramount. It is crucial to:

Use a solid ground plane to minimize noise and provide stable reference.

Place the decoupling capacitors (e.g., 100 nF and 100 µF) as close as possible to the V_CC pin to suppress voltage spikes and provide local charge.

Ensure that the high-current paths (from V_CC to the load and back to GND) are kept short and wide to reduce parasitic inductance and resistance.

The device's ability to handle high inrush currents, common when starting motors or activating solenoids, makes it an ideal choice for replacing mechanical relays and discrete solutions, offering a longer lifetime and silent, wear-free operation.

ICGOODFIND

The Infineon BPD948 is a highly integrated, robust, and efficient solution for driving inductive loads in harsh electrical environments. Its combination of a high-voltage driver, low-R_DS(on) MOSFETs, and extensive protective features makes it an exceptional choice for designers seeking to simplify their architecture while enhancing performance and reliability in automotive and industrial systems.

Keywords:

Half-Bridge Driver

Power MOSFETs

Automotive Applications

Overcurrent Protection

Low R_DS(on)