SLVSG24C November 2021 – November 2022 DRV8244-Q1
PRODMIX
The device integrates a current sensing feature with a proportional analog current output on the IPROPI pin that can be used for load current regulation. This eliminates the need of an external sense resistor or sense circuitry reducing system size, cost, and complexity.
The device senses the load current by using a shunt-less high-side current mirror topology. This way the device can only sense an uni-directional high-side current from VM → OUTx → Load through the high-side FET when it is fully turned ON (linear mode). The IPROPI pin outputs an analog current proportional to this sensed current scaled by AIPROPI as follows:
IIPROPI = (IHS1 + IHS2) / AIPROPI
The IPROPI pin must be connected to an external resistor (RIPROPI) to ground in order to generate a proportional voltage VIPROPI. This allows for the load current to be measured as a voltage-drop across the RIPROPI resistor with an analog to digital converter (ADC). The RIPROPI resistor can be sized based on the expected load current in the application so that the full range of the controller ADC is utilized.
The current expressed on IPROPI is the sum of the currents flowing out of the OUTx pins from VM. This implies that: