DRV8305_15 Datasheet, PDF (21/53 Pages) Texas Instruments – DRV8305 Three Phase Gate Driver With Current Shunt Amplifiers and Voltage Regulator

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DRV8305
SLVSCX2A – AUGUST 2015 – REVISED SEPTEMBER 2015
can be done at anytime, even when the FET is switching because 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_VREF
k
 G u SN_X
 SP_X 
where
•
•
•
•
VREF is the reference voltage.
G is the gain of the amplifier.
k = 2, or 4
SNx and SPx are the inputs of channel x. SPx should connect to resistor ground for the best common mode
rejection.
(1)
Figure 8 shows current amplifier simplified block diagram.
400
S4
DC _ CAL(SPI)
200 kO
S3
100 kO
S2
50 kO
S1
SN
5 kO
_
AVDD
100 O
S5
SO
5 kO
+
SP
DC _ CAL(SPI)
50 kO
S1
100 kO
S2
200 kO
S3
400 kO
S4
VREF
_
AVDD
VREF/k
k = 2, 4
+
Figure 8. Current Shunt Amplifier Simplified Block Diagram
7.3.8 Internal Regulators (DVDD and AVDD)
The DRV8305 has two internal regulators, DVDD and AVDD, that power internal circuits. These regulators
cannot be used to drive external loads and may not be supplied externally.
DVDD is the voltage regulator for the internal logic circuits and is maintained at a value of about 3.3 V through
the entire operating range of the device. DVDD is derived from the PVDD supply.
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