DRV8302 Datasheet, PDF (11/21 Pages) Texas Instruments – Three Phase Pre-Driver with Dual Current Shunt Amplifiers and Buck Regulator – Hardware Controlled

DRV8302
www.ti.com
FUNCTIONAL DESCRIPTION
SLES267 – AUGUST 2011
THREE-PHASE GATE DRIVER
The DRV8302 provides three half bridge drivers, each capable of driving two N-type MOSFETs, one for the
high-side and one for the low side.
Gate driver has following features:
• Internal hand shake between high side and low side FETs during switching transition to prevent current shoot
through.
• Support up to 200kHz switching frequency with Qg(TOT)=25nC or total 30mA gate drive average current
• Provide cycle-by-cycle current limiting and latch over-current (OC) shut down of external FETs. Current is
sensed through FET drain-to-source voltage and the over-current level is programmable through OC_ADJ pin
• High side gate drive will survive negative output from half bridge up to –10V for 10ns
• During EN_GATE pin low and fault conditions, gate driver will keep external FETs in high impedance mode.
• Programmable dead time through DTC pin. Dead time control range: 50ns to 500ns. Short DTC pin to ground
will provide minimum dead time (50ns). External dead time will override internal dead time as long as the time
is longer than the dead time setting (minimum hand shake time cannot be reduced in order to prevent shoot
through current).
• Bootstraps are used in high side FETs of three-phase pre-gate driver. Trickle charge circuitry is used to
replenish current leakage from bootstrap cap and support 100% duty cycle operation.
CURRENT SHUNT AMPLIFIERS
The DRV8302 includes two high performance current shunt amplifiers for accurate current measurement. The
current amplifiers provide output offset up to 3V to support bi-directional current sensing.
Current shunt amplifier has following features:
• Programmable gain: 2 gain settings through GAIN pin
• Programmable output offset through reference pin (half of the Vref)
• Minimize DC offset and drift over temperature with dc calibrating through DC_CAL pin. When DC calibration
is enabled, device will short input of current shunt amplifier and disconnect the load. DC calibrating can be
done at anytime even when FET is switching since the load is disconnected. For best result, perform the DC
calibrating during switching off period when no load is present to reduce the potential noise impact to the
amplifier.
The output of current shunt amplifier can be calculated as:
V_O
=
V_REF
2
- G ´ (SN_X
- SP_X )
(1)
Where Vref is the reference voltage, G is the gain of the amplifier; SNx and SPx are the inputs of channel x. SPx
should connect to resistor ground for the best common mode rejection.
Figure 2 shows current amplifier simplified block diagram.
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s): DRV8302
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