Limits in boost power factor corrector operating in border-line mode

The single-phase boost power factor correctors may operate in the so called border-line mode, which is distinguished by variable switching frequency. If some constraints are imposed on variability of this frequency some limits to output voltage and power of the circuit appear at once. The paper shows the origin of them and presents formulas and graphs helpful in a proper choice of circuit parameters in order to keep the switching frequency within a predefined range, also under the changes of input line voltage and of the load resistance.