SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
Peak current control techniques offer a number of benefits like automatic over current limiting, fast correction for input voltage variations and reducing magnetic saturation. Figure 30-104 shows the use of ePWM1A along with the on-chip analog comparator for buck converter topology. The output current is sensed through a current sense resistor and fed to the positive terminal of the on-chip comparator. The internal programmable 12-bit DAC can be used to provide a reference peak current at the negative terminal of the comparator. Alternatively, an external reference can be connected at this input. The comparator output is an input to the Digital compare sub-module. The ePWM module is configured in such a way so as to trip the ePWM1A output as soon as the sensed current reaches the peak reference value. A cycle-by-cycle trip mechanism is used. Figure 30-105 shows the waveforms generated by the configuration.
Figure 30-104 Peak Current Mode Control
of Buck Converter
Figure 30-105 Peak Current Mode Control
Waveforms for Control of Buck Converter