Patent ID: 7262587

Claim:
A control circuit for controlling output of a DC-DC converter with a plurality of control signals, the control circuit comprising: a plurality of error amplification circuits, each generating a control signal based on a difference between a reference voltage and voltage derived from an output that is to be controlled; a soft start circuit for generating a soft start signal, the soft start signal having voltage lower than voltage of each of the control signals and being used to control the output of the DC-DC converter when the DC-DC converter is activated; and a clamp circuit, connected to the error amplification circuits, for receiving the control signals from the error amplification circuits and clamping the voltage of each of the control signals to substantially the same voltage as the soft start signal in at least the period from when the DC-DC converter is activated to when the controlling of the output of the DC-DC converter is switched from the soft start signal to one of the plurality of control signals.