DRV8320 Datasheet, PDF (40/80 Pages) Texas Instruments – 6 to 60-V Three-Phase Smart Gate Driver

DRV8320, DRV8320R
DRV8323, DRV8323R
SLVSDJ3 – FEBRUARY 2017
www.ti.com
8.3.4.2 Unidirectional Current Sense Operation (SPI only)
On the DRV8323 and DRV8323R SPI devices, use the VREF_DIV bit to remove the VREF divider. In this case
the shunt amplifier operates unidirectionally and SOx outputs an analog voltage equal to the voltage across the
SPx and SNx pins multiplied by the gain setting (G_CSA). Use Equation 4 to calculate the current through the shunt
resistor.
I ^{VVREF VSOx}
G_CSA u R_SENSE
(4)
R2
R3
R4
SOx
V_CC
V_REF
0.1 …F
R6
+
±
R5
R1
±
R1
+
R2
R3
R4
I
SPx
SNx
R_SENSE
R5
Figure 38. Unidirectional Current-Sense Configuration
To minimize DC offset and drift overtemperature, a DC calibration mode is provided and enabled through the SPI
registers (CSA_CAL_X) or through the CAL pin. When the calibration setting is enabled, the inputs to the
amplifier are shorted and the load is disconnected. DC calibration can occur at any time, even when the half-
bridges are switching. For the best results, perform DC calibration during the switching off period to reduce the
potential noise impact to the amplifier.
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