SLOS719F August 2011 – January 2016 DRV8301
Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.
The DRV8301 is a gate driver designed to drive a 3-phase BLDC motor in combination with external power MOSFETs. The device provides a high level of integration with three half-bridge gate drivers, two current shunt amplifiers, and overcurrent protection.
The DRV8301 gate drivers may not correctly power up if a voltage greater than 8.5 V is present on any SH_X pin when EN_GATE is brought logic high (device enabled) after PVDD1 power is applied (PVDD1 > PVDD_UV). This sequence should be avoided by ensuring the voltage levels on the SH_X pins are less than 8.5 V when the DRV8301 is enabled through EN_GATE.
The following design is a common application of the DRV8301.
Table 14 shows the design parameters for this application.
|Supply voltage||PVDD||24 V|
|Motor winding resistance||MR||0.5 Ω|
|Motor winding inductance||ML||0.28 mH|
|Motor poles||MP||16 poles|
|Motor rated RPM||MRPM||4000 RPM|
|Target full-scale current||IMAX||14 A|
|Sense resistor||RSENSE||0.01 Ω|
|MOSFET Qg||Qg||29 nC|
|MOSFET RDS(on)||RDS(on)||4.7 mΩ|
|VDS trip level||OC_ADJ_SET||0.123 V|
|Switching frequency||ƒSW||45 kHz|
|Series gate resistance||RGATE||10 Ω|
|Amplifier reference||VREF||3.3 V|
|Amplifier gain||Gain||10 V/V|
The gate drive supply (GVDD) of the DRV8301 can deliver up to 30 mA (RMS) of current to the external power MOSFETs. Use Equation 3 to determine the approximate RMS load on the gate drive supply:
This is a rough approximation only.
The DRV8301 provides overcurrent protection for the external power MOSFETs through the use of VDS monitors for both the high side and low side MOSFETs. These are intended for protecting the MOSFET in overcurrent conditions and not for precise current regulation.
The overcurrent protection works by monitoring the VDS voltage of the external MOSFET and comparing it against the OC_ADJ_SET register value. If the VDS exceeds the OC_ADJ_SET value the DRV8301 takes action according to the OC_MODE register.
MOSFET RDS(on) changes with temperature and this will affect the overcurrent trip level.
The DRV8301 provides two bidirectional low-side current shunt amplifiers. These can be used to sense a sum of the three half-bridges, two of the half-bridges individually, or in conjunction with an additional shunt amplifier to sense all three half-bridges individually.