Soft start circuits and techniques

A switching regulator control circuit for controlling a switching regulator comprising a switch that conducts at a duty cycle to transfer energy from an input source to an output at which a regulated output having a regulation range is provided, the switching regulator control circuit comprising:

• a circuit configured to generate a control signal to control conduction of the switch at the duty cycle and having first input responsive to a soft start signal, a second input responsive to a feedback signal proportional to the regulated output, and an output at which the control signal is provided;
• and
• a soft start circuit generating the soft start signal, the soft start circuit comprising:
• a non-regulation detection circuit configured to detect a non-regulation condition in which regulated output cannot be maintained within the regulation range in response to the duty cycle being a maximum duty cycle;
• and
• a decreasing circuit configured to decrease the soft start signal in response to the detection by the non-regulation detection circuit of the non-regulation condition.

A regulator control circuit for controlling a regulator switch that conducts to transfer energy from an input source to an output at which a regulated output is provided, the regulator control circuit comprising:

• a circuit configured to generate a control signal to control conduction of the switch and having first input responsive to a soft start signal, a second input responsive to a feedback signal proportional to the regulated output, and an output at which the control signal is provided;
• and
• a soft start circuit generating the soft start signal, wherein the soft start circuit comprises:
• a comparator coupled to the feedback signal and to the soft start signal and configured to provide a soft start level indicator that transitions when the soft start signal is at a predetermined relationship with respect to the feedback signal;
• a first circuit configured to ramp the soft start signal in a first direction until the soft start level indicator transitions;
• and
• a second circuit configured to ramp the soft start signal in a second, opposing direction for a predetermined period of time after the soft start level indicator transitions.