High-Voltage Half-Bridge Driver IC: Infineon AUIRS21271STR Datasheet and Application Guide

In the realm of power electronics, efficiently and reliably controlling high-voltage switching elements like MOSFETs and IGBTs is a fundamental challenge. The Infineon AUIRS21271STR stands out as a robust and highly integrated high-voltage half-bridge driver IC engineered to meet this demand. This article delves into the key specifications from its datasheet and explores its primary application circuits.

The AUIRS21271STR is designed to drive both high-side and low-side N-channel power switches in a half-bridge configuration, operating from a high-voltage rail of up to 600V. This makes it an ideal choice for applications such as motor drives, switch-mode power supplies (SMPS), and solar inverters. Its monolithic 600V IC technology eliminates the need for cumbersome high-voltage level-shifting circuits, simplifying board design and enhancing overall system reliability.

A core feature of this driver is its floating channel architecture for the high-side drive. This allows the high-side output voltage to swing with the switch node (VS), which can be hundreds of volts above ground. The driver incorporates advanced level-shift technology to accurately translate the logic-level input signals from the low-voltage microcontroller domain to the high-side gate drive, ensuring precise switching control.

The device is equipped with robust protection features that are critical for system longevity. It includes a dead time generator to prevent shoot-through currents, a condition where both high-side and low-side switches conduct simultaneously, which can be catastrophic. Furthermore, it offers undervoltage lockout (UVLO) protection for both the high-side and low-side driver sections. UVLO ensures that the power switches are only turned on when the gate drive voltage is sufficient, preventing operation in a high-resistance linear region that leads to excessive heating and potential failure.

The logic inputs are compatible with standard CMOS and TTL levels, down to 3.3V, facilitating easy interfacing with modern microcontrollers and DSPs. The output drivers feature a high pulse current capability, typically 290 mA source and 600 mA sink, enabling fast switching transitions essential for minimizing switching losses in high-frequency applications.

Application Guide:

A typical application circuit involves connecting the VCC pin to a low-side supply (e.g., 15V), bootstrapping the high-side supply via a diode and capacitor from VCC to VB, and connecting the two power switches in a half-bridge arrangement. The bootstrap circuit is a simple and cost-effective method for generating the required floating supply for the high-side driver. The HO and LO outputs connect directly to the gates of the respective power switches, with series resistors often used to fine-tune switching speed and control EMI.

ICGOODFIND Summary:

The Infineon AUIRS21271STR is a highly reliable, high-voltage half-bridge driver that simplifies the control of power switches. Its integrated 600V level-shifter, robust protection features like UVLO and matched propagation delays, and high output current capability make it an exceptional choice for designers seeking to build efficient and durable high-power systems.

Keywords:

Half-Bridge Driver, High-Voltage IC, Bootstrap Circuit, Undervoltage Lockout (UVLO), Level-Shift Technology