3.3.10 Controlling a Peak Current Mode Controlled Buck Module
Peak current control techniques offer a number of benefits like automatic over current limiting, fast correction
for input voltage variations, and reducing magnetic saturation.
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 10-bit DAC
can be used to provide a reference peak current at the negative terminal of the comparator. Alternatively, an
external reference could be connected at this input. The comparator output is an input to the digital compare
submodule. 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.
shows
the waveforms generated by the configuration.
Figure 3-68. Peak Current Mode Control of a Buck Converter
ePWM1A
ePWM1
Time base
TBPRD
=300
TBCTR = 0
TO 300
Increased Reference
DAC Out
Isense
DCAEVT 2.force
DAC OUT/
COMP1-
Figure 3-69. Peak Current Mode Control Waveforms for
Enhanced Pulse Width Modulator (ePWM) Module
324
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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