The need for Gate Driver ICs for motion control
Article By : M. Di Paolo Emilio
The increase in the adoption of engine control, smart grid and smart home technology and the increased need for high voltage devices have fostered the growth of the global gate driver market.
A complete engine control system includes a power supply, a host microcontroller, a gate driver and MOSFETs in a half-bridge topology. The microcontroller sets the PWM duty cycle and takes care of feedback or open-loop control. In low voltage projects, the gate driver and MOSFET are usually integrated into a unit. However, for high power units, the two units are separated to facilitate thermal management and minimize electromagnetic interference.
The gate driver in an engine control system is primarily designed to improve the performance of external power MOSFETs to feed the current to an electric motor. The gate driver acts as an intermediate stage between the logic level control inputs and the power MOSFETs.
Given the variety of external MOSFETs that a typical circuit can include, the gate driver must be robust and flexible, and must be able to offer an intelligent solution to drive the power semiconductor correctly. Modular motor control solutions offer an alternative, and there is a wide range of integrated gate drivers on the market, providing a high gate drive voltage to ensure that the MOSFET has minimal internal resistance.
Texas Instruments
Smart Instrument Drive from Texas Instrument offers a smart solution aimed at driving and protecting the power MOSFET. This feature allows designers to optimize EMI switching and performance, but it also allows them to reduce bill of materials counting and provide additional protection for MOSFETs. Texas Instruments Smart Gate drivers incorporate a current layout to control the speed of MOSFET variation easily. The current parameter of the adjustable gate drive is called IDRIVE (figure 1).
The DRV8323x family is available in three independent gate drivers, which are capable of driving a high-side and low-side MOSFET pair. Gate drivers include a charge pump to generate an elevated gate voltage (with duty cycle support up to 100%) for high-side transistors and a linear regulator to supply low-side transistors (figure 2).
ST Microelectronics
The ST gate driver family is designed to operate in harsh industrial environments with high voltages up to 600 V, maintaining good noise immunity and low switching losses. The high-voltage half-bridge drivers L6491, L6494 and L6498 are particularly suitable for medium and high capacity power switches due to their current capacity up to 4 A.
L6385E is a compact and straightforward high voltage gate driver, made with the BCD™ technology and capable of driving a power MOSFET or IGBT devices. The high-side section can operate with voltage rails up to 600 V. The L6385E device provides two input pins and two output pins and ensures that the outputs alternate in phase with the inputs. L6385E is equipped with UVLO protection on both guide sections, ensuring more excellent protection against voltage drops on the power lines (Figure 3).
Infineon
The EiceDRIVER™ gate drivers offer a wide range of typical output current options, from 0.1 A to 10 A. The robust gate drive protection features such as fast short-circuit protection (DESAT), make these driver ICs suitable for both silicon and broadband power supplies, including CoolGaN ™ and CoolSiC ™. The single-channel galvanically isolated gate driver IC 1EDF5673K is fitted for enhancement mode (e-mode) gallium nitride (GaN) HEMTs with non-isolated gate (diode input characteristic) and low threshold voltage. 2ED020I06-FI is a high voltage, high-speed power MOSFET, and IGBT driver with a high pulse current buffer stage designed for minimal conduction. All logic inputs are compatible with 3.3 V and 5 V TTL. Propagation delays are combined to simplify use in high-frequency applications (figure 4).
Power Integrations
Power Integrations offers a variety of gate driver solutions for the motor drive market up to 6500 V. SID11x2K Scale iDriver is a single-channel IGBT and MOSFET driver in an eSOP package. An innovative FluxLink technology provides reinforced galvanic insulation. An isolated unipolar voltage source provides positive and negative voltages for gate control. Additional features include short circuit protection (DESAT) with Advanced Soft Shut Down (ASSD) and minimum voltage block (UVLO). The controller signals (PWM and fault) are compatible with the CMOS 5 V logic, which can also be adjusted to 15 V levels by using an external resistance divider (figure 5).
ON Semiconductor
ON Semiconductor's NCP510x devices are high-voltage gate drivers with two outputs for direct driving of 2 N-channel or IGBT power MOSFETs arranged in a half-bridge configuration (version B) or any other high-side configuration plus low- side (version A). A bootstrap technique is used to ensure proper driving of the high-side power switch. The pilot circuit works with two independent inputs.
ROHM Semiconductor
BM63764S-VC is a 600 V / 15 A intelligent IGBT (IPM) power supply module for high-speed switching units in a 25-pin HSDIP package. It consists of gate drivers, bootstrap diodes, IGBTs, flywheel diodes. Small loss-making IGBTs are used, and they are optimized for high-speed switching operation such as a washing machine or fan motor. Typical applications include a high-speed AC100 to 240 Vrms frequency converter (DC voltage less than 400 V), high-speed motor frequency converter.
Pre-Switch
The PDEC1215A Pre-Drive is an EconoDUAL™ 1200V IGBT 200A half-bridge gate driver that incorporates integrated ZVS circuits. This module is a plug-and-play compatible driver with other major hard-switch gate drivers. The system is designed so that engineers can measure the system-level advantages of Pre-Switching in a three-phase industrial system before product development. Pre-Drive offers lower switching losses and a complete working current of 150A to Fsw 1-5Khz (figures 6).
Analog Devices
ADuM4135 is the single-channel high voltage isolated gate driver optimized for insulated gate bipolar transistors (IGBTs). Based on the Analog Devices iCoupler® technology, ADuM4135 provides isolation from the input signal towards the output gate unit.
The ADuM4135 gate driver offers robust IGBT deactivation with a single power rail when the gate voltage drops below 2 V. An integrated desaturation detection circuit protects against IGBT operation from high voltage short circuit (Figure 7).
Conclusion
A MOSFET/IGBT is a voltage-controlled device that is used as a switching element in the motor drive circuits. The gate is the electrically isolated control terminal for each device. Dedicated drivers are used to apply a voltage and provide drive current to the gate of the power supply device.
The increase in the adoption of engine control, smart grid and smart home technology and the increased need for high voltage devices have fostered the growth of the global gate driver market. The increase in power transistors for different renewable energy systems and the rapid electrification of cars should soon create profitable opportunities.
