Detailed Hardware Description; Dc Bus And Phase Voltage Sense; Low-Side Current Shunt Sense; Voltage Sense - Texas Instruments BOOSTXL-DRV8305EVM User Manual

Detailed Hardware Description

5 Detailed Hardware Description
The BOOSTXL-DRV8305EVM BoosterPack is a complete drive stage for 3-phase motor applications. The
design consists of the DRV8305 motor gate driver, CSD18540Q5B N-Channel NexFET Power MOSFETs,
and LMR16006 buck regulator. See the respective data sheets for the DRV8305 (SLVSCX2),
CSD18540Q5B (SLPS488), and LMR16006 (SNVSA24) for more information concerning each device.
5.1

DC Bus and Phase Voltage Sense

The BoosterPack has been designed with voltage sense circuits on the DC bus (PVDD) and each half-
bridge outputs (phases A, B, and C). These circuits, shown
filtering capacitor to reduce high frequency noise on the ADC pins. These circuits have been scaled to
support 4.4 to 45 V. The high-side resistors for the phase outputs are located near the motor output
header (J4) while the low-side resistors and filtering capacitors are located near the ADC pins on the
BoosterPack to LaunchPad header (J1) for improved noise reduction purposes.
To achieve higher resolution voltage feedback, the scaling can be adjusted by replacing the high-side
resistors with a lower value.
Example: For a 12-V system, R8, R9, R10, and R14 could be replaced with 22-kΩ resistors to
approximately triple the voltage resolution. The new full scale voltage would be 17.85 V.
5.2

Low-Side Current Shunt Sense

The BoosterPack has low-side current shunt sense for each half-bridge (phases A, B, and C). The current
sense setup takes advantage of the DRV8305's triple shunt current amplifiers (phases A, B, and c). The
configuration for the low-side sense is shown in
a 0.007-Ω power sense resistor with differential connections. The differential voltage is then amplified by
10 V/V and centered at 1.65 V to allow for sensing both positive and negative currents. The sense resistor
has been scaled for 0- to 20-A peak currents.
8
BOOSTXL-DRV8305EVM User's Guide
PVDD
R14
C19
62.0k
µF 330µF
VSEN_PVDD
R16
4.99k
GND
GND
Figure 9. Voltage Sense
Figure
Figure 10. Current Sense
Copyright © 2015–2017, Texas Instruments Incorporated
Figure 9, consist of a voltage divider with a
C22
0.1µF
9. The differential amplifier senses voltage across
SLVUAI8A – August 2015 – Revised June 2017
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