2 Gate Drivers in LEVs

There are multiple components that factor into the design of an LEV. Performance can depend on design choices in the DC-DC converter system, battery pack, or motor drive stage of the LEV. Each of these subsystems have power switches that gate drivers help drive. The switch is what is doing the actual switching, handling the majority of the power transfer and can be a MOSFET, IGBT, SiCFET or GaNFET. Finally, the gate driver is the in between of the controller and switch, the drive strength of the gate driver can determine how fast the switch turns on or off, reducing switching losses to make the system more efficient.

Low-side drivers are used when the power switch is referenced to ground. TI offers single or dual channel low-side drivers, referring to whether the gate driver can operate one or two ground referenced switches. Half-bridge drivers operate one switch referenced to ground, and another referenced to the switch node which has a floating voltage. Selecting the right gate driver is determined by the type and characteristics of the LEV battery voltage, system requirements, and other design elements.

TI’s gate drivers come in non-isolated and isolated varieties. Isolated drivers provide a barrier for use across high voltage differentials, protecting both components and people. Non-isolated gate drivers are used when there is no such differential or along with external isolators to optimize the system. Depending on the placement of the power switch in the system (connected to ground or referencing a floating voltage) different types of TI gate drivers service these FETs.

The battery voltage of an LEV determines which half-bridge bus voltage is required, as many manufacturers enjoy headroom on the voltage supply. For 12V or 48V batteries, many design engineers want a half-bridge driver rated for 107V or 120V VHB such as the LM2105 or UCC27301A-Q1; for 96V batteries, a half-bridge driver rated at 230V VHB such as the UCC27834-Q1 is required. Features such as UVLO and overcurrent protection help protect the switch from accidental damage, improve system efficiency, and make the system more reliable. Selecting the best gate driver for the system helps get the most out of each other component making sure high performance stays affordable.