Dual-phase dc-dc converter with wide input voltage range and control method thereof

A control circuit for a DC-DC converter with a first-leg portion, a second-leg portion and a third-leg portion, comprising:

• a first error amplifying circuit configured to receive an output feedback signal representative of an output voltage of the DC-DC converter and to provide a first error amplifying signal based upon the output feedback signal and an output reference signal;
• a second error amplifying circuit configured to receive the first error amplifying signal and a current sense signal to provide a second error amplifying signal, wherein the current sense signal is representative of a sum of a first current flowing through a first inductor of the DC-DC converter and a second current flowing through a second inductor of the DC-DC converter;
• a control voltage generator configured to provide a control voltage based upon the second error amplifying signal and a reference voltage;
• and
• a pulse width modulation circuit configured to control the first-leg portion, the second-leg portion, and the third-leg portion, respectively, based upon an input voltage, the output voltage and the control voltage.

A control method used in a DC-DC converter, comprising:

• providing a first error amplifying signal based upon an output feedback signal representative of an output voltage of the DC-DC converter and an output reference signal;
• providing a current sense signal representative of a sum of a first current flowing through a first inductor of the DC-DC converter and a second current flowing through a second inductor of the DC-DC converter;
• providing a second error amplifying signal based upon the first error amplifying signal and the current sense signal;
• providing a control voltage based upon the second error amplifying signal and a reference voltage;
• and
• controlling a first-leg portion, a second-leg portion and a third-leg portion of the DC-DC converter, respectively, based upon an input voltage, the output voltage and the control voltage.