Methods and apparatuses for combined frequency compensation and soft start processes

A soft start circuit for a switching power converter, comprising:

• an amplifier configured to operate from a common bias node and amplify a difference between a non-inverting input signal and an inverting input signal to generate an amplifier output;
• a soft start bias circuit operably coupled to the common bias node and configured to supply a soft start bias current during a soft start process for the switching power converter;
• and
• an operational bias circuit operably coupled to the common bias node and configured to supply an operational bias current after the soft start process;
• wherein the soft start bias current is at least an order of magnitude smaller than the operational bias current and substantially limits a current that the amplifier can produce on the amplifier output during the soft start process.

A method of operating a switching power converter, comprising:

• producing a soft start bias current for a common bias node during a soft start process;
• producing an operational bias current for the common bias node after the soft start process;
• combining the soft start bias current and the operational bias current on the common bias node;
• supplying a combined bias current from the common bias node to an amplifier to amplify a difference between a non-inverting input signal and an inverting input signal on an amplifier output;
• charging a capacitor with the amplifier output during the soft start process;
• and
• providing frequency compensation for the switching power converter with the capacitor after the soft start process.

A method of operating a switching power converter, comprising:

• producing a soft start bias current for a common bias node during a soft start process;
• producing an operational bias current for the common bias node after the soft start process;
• combining the soft start bias current and the operational bias current on the common bias node;
• and
• supplying a combined bias current from the common bias node to an amplifier to amplify a difference between a non-inverting input signal and an inverting input signal on an amplifier output;
• wherein the soft start bias current is at least an order of magnitude smaller than the operational bias current and substantially limits a current that the amplifier can produce on the amplifier output during the soft start process.