Switch mode power supply with feed-forward pulse limit control

A switch mode power supply, comprising:

• a source of an AC, mains supply voltage;
• an inductance;
• a first rectifier coupled to said mains source for rectifying said mains supply voltage to apply to said inductance a rectified, first supply voltage;
• switching means responsive to a switching signal for generating in said inductance pulse-width modulated current pulses from said first supply voltage at a frequency that is substantially higher than a frequency of said mains supply voltage, said current pulses being coupled from said inductance to a load circuit to energize said load circuit;
• a pulse-width modulator responsive to a feedback signal for generating said switching signal in accordance with said feedback signal;
• and
• means coupled to said pulse-width modulator and responsive to said mains supply voltage for limiting a pulse-width of said switching signal such that a limit associated with said pulse-width varies during a period of said mains supply voltage in accordance with a waveform of said mains supply voltage and such that when said pulse-width reaches said limit, a further change in said feedback signal is prevented from further changing said pulse-width in a direction that tends to exceed said limit.