ZHCSJU7 May 2019 DRV8340-Q1
PRODUCTION DATA.
The IDRIVE component implements adjustable gate drive current to control the MOSFET VDS slew rates. The MOSFET VDS slew rates are a critical factor for optimizing radiated emissions, energy, and duration of diode recovery spikes, dV/dt gate turnon resulting in shoot-through, and switching voltage transients related to parasitics in the external half-bridge. The IDRIVE component operates on the principal that the MOSFET VDS slew rates are predominately determined by the rate of gate charge (or gate current) delivered during the MOSFET QGD or Miller charging region. By letting the gate driver adjust the gate current, the gate driver can effectively control the slew rate of the external power MOSFETs.
The IDRIVE component lets the DRV8340-Q1 device dynamically switch between gate drive currents either through a register setting on SPI devices or the IDRIVE pin on hardware interface devices. The SPI devices provide 16 IDRIVE settings ranging from 1.5-mA to 1-A source and 3-mA to 2-A sink. Hardware interface devices provide 7 IDRIVE settings within the same ranges. The setting of the gate drive current is delivered to the gate during the turnon and turnoff of the external power MOSFET for the tDRIVE duration. After the MOSFET turnon or turnoff, the gate driver switches to a smaller hold current (IHOLD) to improve the gate driver efficiency. In the event of an overcurrent condition, the IDRIVE component is automatically decreased to help prevent device damage. For additional details on the IDRIVE settings, see the Register Maps section for the SPI devices and the Pin Diagrams section for the hardware interface devices.