Silicon Laboratories Si825x, Руководство пользователя

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S i 8 2 5 x M u l t i - P h a s e P O L - R D
Rev. 0.2 15
8.2. Compensation Editor
The Compensation Editor is a loop simulation and coefficient generator tool for frequency compensating the
system. To open the Compensation Editor window, open the Application Builder and select System
Configuration

Compensation Editor from the menu. The Compensation Editor for a buck regulator is shown in
Figure 12. As shown, this tool provides fields for the user to enter power stage parameters, such as the output filter
component and parasitic values; controller parameters, such as PWM frequency and pole/zero locations; and
Si825x-specific data, such as ADC sample frequency. The simulator comes pre-populated with default values for
the
Si8250 Half-Bridge Target Board . These model parameters can be changed as desired to accommodate
other buck topologies. To view the gain and phase plots with the default parameters, click on the View Graphs
button, and their plots will be generated a short time later. Moreover, clicking on the View Graphs button, the user
can view different responses of the buck regulator. Sample graphs are shown in Figure 12.
Table 1 shows two frequency responses for the multi-phase POL: one for steady-state operation and one for
operation during a transient. During transients, the Si8250 automatically extends loop bandwidth by writing faster
coefficients to the loop compensation filter (DSP filter engine). This nonlinear control response improves system
transient response, reducing both the magnitude and duration of the output transient.
Figure 12. Compensation Editor, Input/Output Windows
Table 1. Si8250 Multi-Phase POL Target Board’s Frequency Response
Steady-State Response Transient Response
Loop Gain Bandwidth 45 kHz 95 kHz
Phase Margin 54º 25º