AN4539 datasheet(28/33 Pages) STMICROELECTRONICS

Part #	AN4539

Description	HRTIM cookbook

PDF	33 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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28 / 33 page

Transition mode power factor controller

AN4539

28/33

DocID026506 Rev 1

Figure 15 and Figure 16 show the waveforms during the various operating mode, with the

following parameters defined:

•

Ton min: during this period, spurious over-currents are discarded (typically these are

freewheeling diode recovery currents). It is represented as OC blanking and

programmed with CMP3;

•

Ton max: practically, the converter set-point. It is defined with CMP1;

•

Toff min: limits the frequency when current limit is close to zero (demagnetization is very

fast). It is defined with CMP2 in auto-delayed mode;

•

Toff max: prevents the system to be stuck if no ZCD occurs. It is defined with CMP4 in

auto-delayed mode.

Figure 15. Transition mode PFC operation at Ton max and during over-current

AN4539 Datasheet(PDF) 28 Page - STMicroelectronics