Infineon AUIRS2113STR High- and Low-Side Driver IC: Features and Application Design Considerations
The Infineon AUIRS2113STR is a high-voltage, high-speed power MOSFET and IGBT driver capable of driving both the high-side and low-side switches in a half-bridge configuration. This driver IC is engineered to meet the rigorous demands of power conversion applications, including motor drives, switched-mode power supplies (SMPS), and inverters. Its robust design integrates critical functionalities to enhance system reliability, simplify design, and optimize performance.
A primary feature of the AUIRS2113STR is its floating channel designed for bootstrap operation, which allows the high-side driver section to operate with supply voltages up to 600V. This capability is essential for driving the high-side switch in a bridge topology where the source terminal voltage swings rapidly. The device incorporates a sophisticated level-shift circuit that ensures accurate and robust signal transmission from the low-voltage logic inputs to the high-side gate driver, effectively isolating the high-voltage domain from the control circuitry.
To safeguard the power switches and the driver itself, the IC includes a comprehensive suite of protection features. Undervoltage lockout (UVLO) is provided for both the high-side and low-side driver sections. This feature ensures the power MOSFET or IGBT is only turned on when the gate drive voltage is sufficient, preventing operation in the high-resistance linear region, which minimizes switching losses and prevents thermal runaway. The matched propagation delays between the two channels, typically 120ns, are crucial for preventing shoot-through currents—a catastrophic condition where both high-side and low-side switches conduct simultaneously, causing a short circuit across the DC bus. The inclusion of a shutdown pin offers designers a direct means to quickly disable the driver outputs for system-level protection.
When designing an application circuit with the AUIRS2113STR, several key considerations are paramount for stable and efficient operation.
Bootstrap Circuit Design: The bootstrap circuitry is fundamental to powering the high-side driver. It consists of a diode and a capacitor. The bootstrap capacitor (`C_BOOT`) must be carefully sized to hold sufficient charge to keep the high-side driver powered during the on-time of the high-side switch without drooping below the UVLO threshold. The bootstrap diode must be a fast-recovery type to block the high voltage when the low-side switch turns on and to efficiently charge the capacitor.
Gate Drive Strength: The value of the gate resistor (`R_G`) is a critical design choice. It controls the switching speed of the power device by limiting the charge and discharge current from the driver's output. A lower value resistor enables faster switching, reducing switching losses but increasing voltage overshoot and electromagnetic interference (EMI). A higher value reduces EMI and overshoot but increases switching losses. This trade-off must be optimized based on the specific application requirements.
PCB Layout: A proper printed circuit board (PCB) layout is non-negotiable for high-speed, high-current switching circuits. Minimizing parasitic inductance in the high-current loop (from the DC bus capacitors to the half-bridge and back) is vital to suppress voltage spikes and ringing. The bootstrap capacitor and diode must be placed as close as possible to the IC pins. A low-ESR/ESL decoupling capacitor should be placed very near the `VCC` and `COM` pins to provide a clean, stable low-voltage supply.
Thermal Management: Although the AUIRS2113STR can deliver high peak currents, its average power dissipation must be managed. Power loss in the driver comes from the gate drive current and the quiescent currents. Designers should ensure the IC is mounted on a sufficient copper area to dissipate heat, especially in high-frequency switching applications.
ICGOODFIND: The Infineon AUIRS2113STR is a highly integrated and robust solution for driving half-bridge stages. Its high-voltage capability, matched propagation delays, and integrated protection features make it an excellent choice for designers seeking to build efficient and reliable motor control and power conversion systems. Success hinges on meticulous attention to the bootstrap design, gate resistance selection, and PCB layout to fully leverage the IC's performance.
Keywords:
1. Bootstrap Operation
2. Undervoltage Lockout (UVLO)
3. Shoot-Through Protection
4. Gate Driver IC
5. Half-Bridge Configuration
