TIDUF64A December 2023 – August 2024
A big challenge of multi-phase converters is even balancing of the currents between the active phases to avoid thermally stressing any one phase and provide optimal ripple cancellation. Hence it is important to have symmetrical design and layout, similar switching loops, synchronized current sensing for current loop feedback that needs to be fed back to the controller to accurately monitor the phase currents.
The current measurement is done at the respective switching nodes, as seen in Figure 3-7, for each phase with an isolated current amplifier the AMC1302 which is a precision current sensing reinforced isolated amplifier without integrated DC/DC. This IC has ±50mV input voltage range optimized for current measurement with low input impedance. The DC current is passed through a 1mΩ shunt, thus leading to a linear range of the measurement ±50A. The power to the device is supplied by the internally generated 5V from the LDO of the LMG3522R030 device.
For the voltage measurement of the boost stages, the OPA2388 is used which is a dual channel operational amplifier.