Introduction to Digital Power Conversion
XMC4000/1000 Family
Control Loops
Application Guide
78
V1.0, 2015-01
Comparator and Slope Generation unit (CSG)
A CSG combines all the essential interaction factors for a system adaptive inductor current control, in
any modulation mode, with a CMP-DAC-pair unit. The flexible input selectors map the external signals
into internal functions. The set/clear protocols for PWM control include for eample, blanking, filtering
or clamping.
7.2
Using embedded ACMP and external Slope Compensation Ramp
This concept is applicable in any Mid to Low-end DC/DC converter using current mode control
modulation, even in combined peak-valley detection with two ACMP channels. In the following
example a PCC is used. External slope generation and blanking or clamping control is performed
interactively with the CCU.
Slope Compensation Operation Point when Using External Slope Compensation Ramp
Slope compensation in peak current mode control can be performed by adding a ramp (V
SC
) onto the
inductor current measurement signal (I
L
*[R
i
]), instead of ramping down the peak reference level. This
approach offers a favorable operating point, referred to ground, for the Analog Comparator (ACMP).
Figure 63
Peak Current Mode Control w/ Embedded ACMP
– External SC & Blanking Control
