DRV8305_16 Datasheet, PDF (15/59 Pages) Texas Instruments – Three Phase Gate Driver

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7 Detailed Description
DRV8305
SLVSCX2B – AUGUST 2015 – REVISED FEBRUARY 2016
7.1 Overview
The DRV8305 is a 4.4-V to 45-V gate driver IC for three-phase motor driver applications. This device reduces
external component count in the system by integrating three half-bridge drivers, charge pump, three current
shunt amplifiers, an uncommited 3.3-V or 5-V, 50-mA LDO, and a variety of protection circuits. The DRV8305
provides overcurrent, shoot-through, overtemperature, overvoltage, and undervoltage protection. Fault conditions
are indicated by the nFAULT pin and specific fault information can be read back from the SPI registers. The
protection circuits are highly configurable to allow adaptation to different applications and support limp home
operation.
The gate driver uses a tripler charge pump to generate the appropriate gate to source voltage bias for the
external, high-side N-channel power MOSFETs during low supply conditions. A regulated 10-V LDO derived from
the charge pump supplies the gate to source voltage bias for the low-side N-channel MOSFET. The high-side
and low-side peak gate drive currents are adjustable through the SPI registers to finely tune the switching of the
external MOSFETs without the need for external components. An internal handshaking scheme is used to
prevent shoot-through and minimize the dead time when transitioning between MOSFETs in each half-bridge.
Multiple input methods are provided to accommodate different control schemes including a 1-PWM mode which
integrates a six-step block commutation table for BLDC motor control.
V_DS sensing of the external power MOSFETs allows for the DRV8305 to detect overcurrent conditions and
respond appropriately. Integrated blanking and deglitch timers are provided to prevent false trips related to
switching or transient noise. Individual MOSFET overcurrent conditions are reported through the SPI status
registers and nFAULT pin. A dedicated VDRAIN pin is provided to accurately sense the drain voltage of the high-
side MOSFET.
The three internal current shunt amplifiers allow for the implementation of common motor control schemes that
require sensing of the half-bridge currents through a low-side current shunt resistor. The amplifier gain, reference
voltage, and blanking are adjustable through the SPI registers. A calibration method is providing to minimize
inaccuracy related to offset voltage.
Three versions of the DRV8305 are available with separate part numbers for the different devices options:
• DRV8305N: VREG pin has the internal LDO disabled and is only used as a voltage reference input for the
amplifiers and SDO pullup.
• DRV83053: VREG is a 3.3-V, 50-mA LDO output pin.
• DRV83055: VREG is a 5.0-V, 50-mA LDO output pin.
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