IGBT/SiC Module Drivers Target Traction Inverters for EV, HEV, Fuel-Cell Vehicles
At PCIM Europe, Power Integrations announced the SCALE EV family of gate-driver boards for Infineon EconoDUAL modules. The SCALE EV family consists of automotive-qualified, dual-channel plug-and-play drivers for both silicon-carbide (SiC) MOSFETs and silicon IGBTs.
The boards are aimed at high-power automotive and traction inverters for electric, hybrid, and fuel-cell vehicles, including buses and trucks, as well as construction, mining, and agricultural equipment. They’re ASIL B certified, enabling implementation of ASIL C traction-inverter designs
“By offering a product where the development, testing, and qualification plus ASIL certification have already been done,” said Peter Vaughan, director of automotive business development at Power Integrations, “we are dramatically reducing development time and cost.”
SCALE EV Driver Details
SCALE EV board-level gate drivers incorporate two reinforced gate-drive channels, associated power supplies, and monitoring telemetry. The first SCALE EV family member to be released is the 2SP0215F2Q0C, designed for the EconoDUAL 17-mm, 900-A, 1200-V half-bridge module driving IGBT switches.
The 2SP0215F2Q0C uses two of the company’s gate-driver ASICs, one driving the top side switch and the other driving the bottom side switch. The plug-and-play gate driver receives commands from a microcontroller.
In its descriptive statement, Power Integrations asserts that with a high level of integration, this driver IC enables the entire driver board, including gate power, to fit onto the outline of the power module—yet it still provides the spacing necessary for reinforced isolation according to the IEC 60664 standard. Its package provides 11.4 mm of creepage and clearance, meeting the industry standards specifying spacing requirements. It also is specifically designed to meet the requirements for 800‑V vehicle system voltages.
Input and output lines to the system microcontroller are connected via two independent on-board connectors to meet functional-safety requirements. A single 5-V supply per channel is required, with other isolated voltages being generated on the board itself.
Integrated Active Miller Clamp
Supply voltages are closely monitored. In case of an undervoltage (UVLO) or overvoltage condition (OVLO), a failure signal or a warning signal is generated by the 2SP0215F2Q0C. The gate driver distinguishes between VCC and the two channels.
If the communication from the primary side to the secondary side is compromised for 10 µs (typical), the gate driver goes to logic low. If the interruption remains for longer than 20 µs (typical), then the output will be set to GND and the gate driver will turn off the gate-driver output stage of the related channel.
The gate driver provides automotive-related protection functionalities and diagnostics. A galvanically isolated IGBT module with integrated NTC read-out provides IGBT module temperature information.
One of the common problems faced when operating an IGBT is parasitic turn-on due to the Miller capacitor. When turning on the upper IGBT in a half-bridge, a voltage change dv/dt occurs across the lower IGBT.
In the 2SP0215F2Q0C, an integrated active Miller clamp protects power semiconductors with a low gate-emitter threshold voltage. To avoid parasitic turn-on in half-bridge topologies during switching events, the active Miller clamp provides a low-impedance connection between the gate of the power semiconductor and the negative supply voltage.
A potential that would be induced on the gate due to the switching dv/dt acting with the Miller capacitance is prevented by the low impedance to the negative gate voltage. This prevents the low high-frequency impedance of the Miller capacitance from charging the gate capacitance of the power semiconductor and driving the gate potential above the threshold voltage.
Protection Provisions
As a plug-and-play gate driver, the 2SP0215F2Q0C characteristics match the requirements of specific power modules. The command signals are transferred from the primary side (IN1 and IN2) to the secondary side via the FluxLink isolation technology. The 2SP02015F2Q0C constantly monitors the status of the internal communication channel (FluxLink) between the primary side and secondary side for both the top and bottom channels.
FluxLink communication technology enables feedback information to be delivered across an isolation barrier without the use of any magnetic materials. This proprietary technology is said to meet global noise-immunity standards. According to Power Integrations it complies not only with UL and TUV global isolation standards, but also the more stringent CQC 5,000-meter Chinese safety standard.
Primary-side supplies provide a positive gate voltage and drive the power-semiconductor gate during the turn-on process and while turned on. Similarly, the secondary-side supplies provide a negative gate voltage, discharge the gate during the turn-off process, and clamp the gate while turned off.
The design includes a wide range of protection provisions, including active short-circuit; active discharge of connected dc-link capacitor; overvoltage limitation via active gate control; diagnostic functions such as gate monitoring, signal transmission monitoring, and on-chip temperature monitoring; and short-circuit and overcurrent response of less than 1 µs for SiC MOSFETs and less than 3 µs for IGBTs.
Short-circuit protection as well as dynamic overvoltage limiting (AROC: Advanced Resistive Overvoltage Control) also are provided. In case of a short-circuit during a turn-on event, the 2SP0215F2Q0C initiates turn-off to protect the semiconductor device from damage due to the short circuit.
Power Supply
Two individual supply voltages (VCC2-GND and VCC1-GND) for the top channel and bottom channel, respectively, are necessary to operate the 2SP0215F2Q0C. The supply voltage must be within specification limits to avoid malfunction. The current consumption of the gate driver depends on the switching frequency.
The 2SP0215F2Q0C operates with an integrated dc-dc controller and power-stage MOSFETs for each channel. The dc-dc controller delivers, through the transformers, the secondary-side isolated supply voltages for the gate driver.
Power Integrations points out in documents developed for the 2SP0215F2Q0C that the gate driver doesn’t provide reverse-voltage protection.
Support materials for SCALE EV include the datasheet, pressFIT tool CAD design, the RDHP-2250Q adapter breakout board, and PC-based software. Power Integrations offers design services to tune switching performance for specific IGBT or SiC die, as well as to customize the layout for novel module form factors. Samples of the 2SP02152FQ are available now, with full production release in the fourth quarter of 2022. Pricing starts at $200 each for 100-piece quantities.