JAJSMZ5B September 2021 – February 2022 DRV8311
PRODUCTION DATA
The SOx pin on the DRV8311 outputs an analog voltage proportional to current flowing in the low side FETs (IOUTx) multiplied by the gain setting (GCSA). The gain setting is adjustable between four different levels which can be set by the GAIN pin (hardware device variant) or the CSA_GAIN bits (SPI or tSPI device variant).
Figure 8-28 shows the internal architecture of the current sense amplifiers. The current sense is implemented with a sense FET on each low-side FET of the DRV8311 device. This current information is converted in to a voltage, which generates the CSA output voltage on the SOx pin, based on the voltage on the CSAREF pin (VREF) and the gain setting. The CSA output voltage can be calculated using Equation 15
Figure 8-29 and Figure 8-30 show the details of the amplifier operational range. In bi-directional operation, the amplifier output for 0-V input is set at VREF/2. Any change in the differential input results in a corresponding change in the output times the GCSA factor. The amplifier has a defined linear region in which it can maintain operation.