Method for controlling a switching regulator and related switching regulator

Circuit means for generating a signal representative of a current delivered by a primary-sensing flyback switching regulator, having a primary side generating a primary voltage magnetically coupled to a secondary side that generates a regulated output voltage on output terminals of the regulator, the primary side including a feedback control circuit that generates a feedback voltage representative of said output voltage and a logic flag for flagging demagnetization phases of said switching regulator, the circuit means comprising:

• a first monostable flip-flop input with said logic flag, that generates a first pulse signal in correspondence of trailing or leading edges of said logic flag;
• a second monostable flip-flop input with said logic flag, that generates a second pulse signal in correspondence of leading or trailing edges of said logic flag;
• a circuit block connected in cascade to said first monostable flip-flop, that generates a third pulse signal as a delayed replica of said first pulse signal;
• a linear voltage ramp generator, reset at each assertion of said third pulse signal;
• a first sample-and-hold circuit that samples the voltage generated by said ramp generator at each assertion of said first pulse signal;
• a second sample-and-hold circuit that samples the voltage generated by said ramp generator at each assertion of said second pulse signal;
• a divider that generates said representative signal as the ratio between the sampled voltages of said second sample-and-hold circuit and of said first sample-and-hold circuit.

A power-supply controller, comprising:

• a switching-control circuit operable to control a switch coupled to a primary winding of a transformer;
• an error amplifier having a first input node operable to receive a first feedback signal from an auxiliary winding of the transformer, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit;
• and
• a comparison-signal generator operable to generate the comparison signal in response to a first compensation signal that is isolated from a secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

A power-supply controller, comprising:

• a switching-control circuit operable to control a switch coupled to a primary winding of a transformer;
• an error amplifier having a first input node operable to receive a first feedback signal, a second input node operable to receive a reference signal, and an output node operable to provide a control signal to the switching-control circuit;
• and
• a feedback-signal generator operable to generate the first feedback signal in response to a first compensation signal that is isolated from a secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

A power supply, comprising:

• a transformer having primary, secondary, and auxiliary windings;
• a switch serially coupled to the primary winding;
• and
• a power-supply controller, comprising
• a switching-control circuit operable to control the switch,
• an error amplifier having a first input node operable to receive a first feedback signal from the auxiliary winding, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit, and
• a comparison-signal generator operable to generate the comparison signal in response to a first compensation signal that is isolated from the secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

A power supply, comprising:

• a transformer having primary, secondary, and auxiliary windings;
• a switch serially coupled to the primary winding;
• and
• a power-supply controller, comprising
• a switching-control circuit operable to control the switch,
• an error amplifier having a first input node operable to receive a first feedback signal, a second input node operable to receive a reference signal, and an output node operable to provide a control signal to the switching-control circuit, and
• a feedback-signal generator operable to generate the first feedback signal in response to a first compensation signal that is isolated from a secondary winding and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

A system, comprising:

• a load;
• a conductor having a first node coupled to the load and having a second node;
• and
• a power supply comprising
• a transformer having a primary winding, a secondary winding coupled to the second node of the conductor, and an auxiliary winding,
• a switch serially coupled to the primary winding, and
• a power-supply controller, comprising
• a switching-control circuit operable to control the switch,
• an error amplifier having a first input node operable to receive a first feedback signal from the auxiliary winding, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit, and
• a comparison-signal generator operable to generate the comparison signal in response to a first compensation signal that is isolated from the secondary winding of the transformer and that is proportional to a current through the conductor.

A system, comprising:

• a load;
• a conductor having a first node coupled to the load and having a second node;
• and
• a power supply, comprising
• a transformer having primary, secondary, and auxiliary windings,
• a switch serially coupled to the primary winding, and
• a power-supply controller, comprising
• a switching-control circuit operable to control the switch,
• an error amplifier having a first input node operable to receive a first feedback signal, a second input node operable to receive a reference signal, and an output node operable to provide a control signal to the switching-control circuit, and
• a feedback-signal generator operable to generate the first feedback signal in response to a first compensation signal that is isolated from a secondary winding and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

A method, comprising:

• generating a regulated output voltage with a secondary winding of a transformer;
• generating a comparison signal in response to a first compensation signal that is isolated from, and that is proportional to a current through, the secondary winding;
• generating a control signal in response to the comparison signal and in response to a first feedback signal from an auxiliary winding of the transformer;
• and
• switching a current through a primary winding of the transformer in response to the control signal.

A method, comprising:

• generating a regulated output voltage with a secondary winding of a transformer;
• generating a feedback signal in response to a first compensation signal that is isolated from, and that is proportional to a current through, the secondary winding;
• generating a control signal in response to a reference signal and in response to the feedback signal;
• and
• switching a current through a primary winding of the transformer in response to the control signal.