DRV8320_17 Datasheet, PDF (68/89 Pages) Texas Instruments – 6 to 60-V Three-Phase Smart Gate Driver

DRV8320, DRV8320R
DRV8323, DRV8323R
SLVSDJ3A – FEBRUARY 2017 – REVISED APRIL 2017
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10 Power Supply Recommendations
The DRV832x family of devices is designed to operate from an input voltage supply (VM) range between 6 V and
60 V. A 0.1-µF ceramic capacitor rated for VM must be placed as close to the device as possible. In addition, a
bulk capacitor must be included on the VM pin but can be shared with the bulk bypass capacitance for the
external power MOSFETs. Additional bulk capacitance is required to bypass the external half-bridge MOSFETs
and should be sized according to the application requirements.
10.1 Bulk Capacitance Sizing
Having appropriate local bulk capacitance is an important factor in motor drive system design. It is generally
beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size. The
amount of local capacitance depends on a variety of factors including:
• The highest current required by the motor system
• The power supply's type, capacitance, and ability to source current
• The amount of parasitic inductance between the power supply and motor system
• The acceptable supply voltage ripple
• Type of motor (brushed DC, brushless DC, stepper)
• The motor startup and braking methods
The inductance between the power supply and motor drive system will limit the rate current can change from the
power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or
dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage
remains stable and high current can be quickly supplied.
The data sheet provides a recommended minimum value, but system level testing is required to determine the
appropriate sized bulk capacitor.
Power Supply
Parasitic Wire
Inductance
Motor Drive System
VM
+
+
Motor Driver
±
GND
Local
Bulk Capacitor
IC Bypass
Capacitor
Figure 63. Motor Drive Supply Parasitics Example
68
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