DRV8305-Q1_16 Datasheet, PDF (23/54 Pages) Texas Instruments – Three-Phase Automotive Gate Driver

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DRV8305-Q1
SLVSD12A – MAY 2015 – REVISED MARCH 2016
change. If the gate voltage has not changed to the desired level after the t_DRIVE period (indicating a short circuit
or overcurrent condition on the MOSFET gate), the DRV8305-Q1 signals a gate drive fault and the gate drive is
disabled to help protect the external MOSFET and DRV8305-Q1. If the MOSFET does successfully enable or
disable, after the t_DRIVE period the DRV8305-Q1 will enable a lower hold current to ensure the MOSFET remains
enabled or disabled and improve efficiency of the gate drive.
Select a t_DRIVE time that is longer than the time needed to charge or discharge the gate capacitances of the
external MOSFETs. The TDRIVE SPI registers should be configured so that the MOSFET gates are charged
completely within t_DRIVE during normal operation. If t_DRIVE is too low for a given MOSFET, then the MOSFET may
not turn on completely. It is suggested to tune these values in-system with the required external MOSFETs to
determine the best possible setting for the application. A good starting value is a t_DRIVE period that is 2x the
expected rise or fall times of the external MOSFET gates. Note that TDRIVE will not increase the PWM time and
will simply terminate if a PWM command is received while it is active.
t_{DRIVE_HS}
t_{DRIVE_HS}
INHx
GHx Voltage
GHx Current
I_STRONG
I_DRIVE
I_HOLD
Gate Off
I_DRIVE
I_STRONG
INLx
GLx Voltage
GLx Current
Gate Off
I_HOLD
I_DRIVE
I_STRONG
I_DRIVE
t_{DRIVE_LS}
t_{DRIVE_LS}
Figure 11. TDRIVE Gate Drive State Machine
I_HOLD
7.3.5.3 CSAs: Current Shunt Amplifiers
The DRV8305-Q1 includes three high performance low-side current shunt amplifiers for accurate current
measurement utilizing low-side shunt resistors in the external half-bridges. They are commonly used to measure
the motor phase current to implement overcurrent protection, external torque control, or external commutation
control through the application MCU.
The current shunt amplifiers have the following features:
• Each of the three current sense amplifiers can be programmed and calibrated independently.
• Can provide output bias up to 2.5 V to support bidirectional current sensing.
• May be used for either individual or total current shunt sensing.
• Four programmable gain settings through SPI registers (10, 20, 40 and 80 V/V).
• Reference voltage for output bias provided from voltage regulator VREG for DRV83053Q and DRV83055Q
• Reference voltage for output bias provided from externally applied voltage on VREG pin for DRV8305NQ and
DRV8305NE
• Programmable output bias scaling. The scaling factor k can be programmed through SPI registers (1/2 or 1/4)
• Programmable blanking time (delay) of the amplifier outputs. The blanking time is implemented from any
rising or falling edge of gate drive outputs. The blanking time is applied to all three current sense amplifiers
equally. In case the current sense amplifiers are already being blanked when another gate driver rising or
falling edge is seen, the blanking interval will be restarted at the edge. Note that the blanking time options do
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