High-Power MOSFET IRFP4868PBF: Datasheet Analysis and Application Circuits

The IRFP4868PBF from Infineon Technologies is a quintessential component in the realm of high-power electronics. As an N-Channel HEXFET Power MOSFET, it is engineered to handle significant current and voltage levels, making it a cornerstone in the design of efficient and robust power conversion systems. This article provides a detailed analysis of its key parameters from the datasheet and explores practical application circuits.

Datasheet Analysis: Unpacking the Key Specifications

The performance of any power MOSFET is defined by its absolute maximum ratings and electrical characteristics. For the IRFP4868PBF, several parameters stand out.

Voltage and Current Ratings: The device boasts a drain-to-source voltage (V_DSS) of 200V, making it suitable for applications like offline SMPS (Switched-Mode Power Supplies) and motor drives operating from rectified mains voltages. Its continuous drain current (I_D) is a substantial 130A at a case temperature (T_C) of 25°C, highlighting its ability to handle very high power levels.

Low On-Resistance: A critical figure of merit for power MOSFETs is the static drain-to-source on-resistance (R_DS(on)). The IRFP4868PBF features an exceptionally low R_DS(on) of just 4.5 mΩ (max. at V_GS = 10 V, I_D = 65 A). This low resistance directly translates to reduced conduction losses, higher efficiency, and less heat generation.

Switching Performance: While designed for power, switching speed remains important. The device offers a typical turn-on delay time (t_d(on)) of 18 ns and a turn-off delay time (t_d(off)) of 65 ns. These fast switching characteristics are vital for high-frequency operation in switch-mode power supplies, minimizing switching losses.

Gate Charge: The total gate charge (Q_g) is 210 nC (typ.). This parameter is crucial for designing the gate drive circuit, as it determines the current required from the driver IC to switch the MOSFET quickly.

Application Circuits: Putting the MOSFET to Work

The combination of high voltage, high current, and low R_DS(on) makes the IRFP4868PBF ideal for several demanding applications.

1. High-Current DC Motor Drive / H-Bridge: In an H-bridge configuration, four IRFP4868PBF MOSFETs can be used to control the speed and direction of a large DC motor. Their low on-resistance ensures minimal voltage drop across the switches, delivering maximum power to the motor while maintaining high efficiency and thermal stability. A dedicated gate driver IC is mandatory to provide the high peak current needed to charge and discharge the large gate capacitance rapidly.

2. High-Power Switch-Mode Power Supplies (SMPS): This MOSFET is a perfect fit for the primary side of high-wattage AC-DC converters, particularly in full-bridge and half-bridge topologies. Its 200V V_DSS rating provides ample margin for operations from a rectified 100-120VAC line. The low switching losses and conduction losses are critical for achieving high efficiency targets in server power supplies and industrial power systems.

3. Solid-State Relays (SSRs) and Contactors: For switching heavy DC loads, a single IRFP4868PBF can act as the core switching element in a custom solid-state relay. An optocoupler can be used to isolate the low-voltage control signal from the high-power circuit. The MOSFET's extremely low R_DS(on) ensures that the voltage drop across the "relay" is minimal, even when conducting hundreds of amps.

Design Considerations:

When implementing this MOSFET, careful attention must be paid to:

Gate Driving: Use a powerful, low-output-impedance gate driver IC capable of delivering several amps of peak current to switch the MOSFET quickly and avoid excessive switching losses.

Heat Sinking: Due to the high power dissipation, a substantial heatsink is non-negotiable. Thermal calculations must be performed based on the expected power loss (I²R_DS(on) and switching losses) to ensure the junction temperature remains within safe limits.

Parasitic Inductance: Minimize stray inductance in the drain and source loops to prevent voltage spikes that could exceed the maximum V_DSS rating during switching transitions.

ICGOODFIND

The IRFP4868PBF is a benchmark in high-power MOSFET technology, offering an exceptional blend of high voltage tolerance, very high current capability, and remarkably low conduction losses. Its robust characteristics make it a top choice for engineers designing high-performance, high-efficiency systems in industrial, automotive, and renewable energy applications. Proper attention to driving and thermal management is key to unlocking its full potential.

Keywords:

1. Power MOSFET

2. Low On-Resistance

3. High-Current Switching

4. Motor Drive

5. Switch-Mode Power Supply (SMPS)