Switching converter mode transition control

A circuit comprising:

• a first transistor having a first terminal, a second terminal, and a control terminal;
• a second transistor having a first terminal coupled to the first terminal of the first transistor, a second terminal, and a control terminal coupled to the control terminal of the first transistor;
• a third transistor having a first terminal coupled to the second terminal of the second transistor, a second terminal, and a control terminal;
• a fourth transistor having first terminal coupled to the second terminal of the first transistor, a second terminal, and a control terminal coupled to the control terminal of the third transistor;
• a first amplifier having a first input coupled to a reference voltage terminal, a second input coupled to the second terminal of the first transistor, and an output;
• a voltage-to-current converter having a first input coupled to the second terminal of the third transistor, a second input coupled to the second terminal of the fourth transistor, a third input coupled to the output of the first amplifier, a fourth input, and a fifth input;
• and
• a first current source having an input coupled to a power terminal, and an output coupled to the fourth input of the voltage-to-current converter;
• and
• a second current source including:
• a fifth transistor having a first terminal coupled to a power terminal, a second terminal, and a control terminal coupled to a reference terminal;
• a sixth transistor having a first terminal coupled to the power terminal, a second terminal, and a control terminal coupled to the reference terminal;
• a third current source having an input coupled to the second terminal of the fifth transistor, and an output coupled to the reference terminal;
• a second amplifier having a first input coupled to the second terminal of the fifth transistor, a second input coupled to the second terminal of the sixth transistor, and an output;
• a seventh transistor having a first terminal coupled to the second terminal of the sixth transistor, a second terminal coupled to the reference terminal, and a control terminal coupled to the output of the second amplifier;
• and
• an eighth transistor having a first terminal coupled to the fifth input of the voltage-to-current converter, a second terminal coupled to the reference terminal, and a control terminal coupled to the control terminal of the seventh transistor.

A system, comprising:

• a switching converter, comprising:
• a low-side transistor having a first terminal coupled to a voltage terminal, a second terminal coupled to a reference terminal, and a control terminal;
• a high-side transistor having a first terminal coupled to the voltage terminal, a second terminal, and a control terminal;
• a sense transistor having a first terminal coupled to the first terminal of the high-side transistor, a second terminal, and a control terminal coupled to the control terminal of the high-side transistor, the sense transistor configured to conduct a sense current representative of a current flowing through the high-side transistor;
• a voltage-to-current converter having first, second, third, fourth, and fifth inputs;
• a first transistor coupled between the second terminal of the sense transistor and the first input of the voltage-to-current converter, the first transistor configured to conduct the sense current;
• a second transistor coupled between the second terminal of the high-side transistor and the second input of the voltage-to-current converter;
• a comparator having a first input coupled to the second terminal of the first transistor, a second input coupled to the second terminal of the second transistor, and an output;
• an error amplifier having a first input coupled to the second terminal of the high-side transistor, a second input coupled to a reference voltage terminal, and an output coupled to the third input of the voltage-to-current converter;
• a controller having a first output coupled to the control terminal of the low-side transistor, a second output coupled to the control terminal of the high-side transistor, and an input coupled to the output of the comparator, the controller configured to drive the high-side transistor in a first mode and a second mode;
• and
• a current source coupled between the second terminal of the second transistor and the reference terminal, the current source configured to draw a current from the second transistor in the first mode and the second mode.