Switching regulator having improved switching control arrangement

Claim 1

A switching regulator, comprising: a transformer, said transformer having a primary winding and a secondary winding, said primary winding being coupled to receive an unregulated dc voltage; an electrical switching means, said electrical switching means being coupled to said primary winding for intermittently operating said transformer; a first controller, said first controller being coupled to control said electrical switching means by varying a duty cycle thereof; a rectifier, coupled to said secondary winding, for producing a dc output to be derived as an output of said switching regulator; an error amplifier, coupled to receive the dc output of said rectifier and a first reference signal, for generating an error signal indicating an amplitude difference therebetween; an A-D converter, coupled to receive said error signal, for generating a digital error signal corresponding to said error signal; an optical coupler, said optical coupler being coupled to receive said digital error signal; a D-A converter, coupled to receive the output of said optical coupler, for generating an analog error signal corresponding to the digital error signal; and a second controller, said second controller being coupled to control said electrical switching means via said first controller in accordance with said analog error signal.