Systems and methods for providing intelligent constant on-time control

1. A system that provides intelligent constant on-time control, comprising:

a first switch coupled to a power input;

a second switch coupled to the first switch;

a switching node between the first switch and the second switch, the switching node configured to be connected to an inductor and a power output;

feedback paths coupled to (1) a synthesized node and (2) the power output, the feedback paths enabling feedback of signals from (1) the synthesized node, and (2) the power output; and

a controller coupled to the feedback paths, the controller configured to control a voltage at the power output based on a combination of the signals carried by the feedback paths;

wherein the controller is further configured to control an on-time of the first switch based on the combination of the signals carried by the feedback paths;

wherein the on-time is controlled by digitally changing a capacitance value, a current mirror ratio or a threshold voltage of the system via a phase-locked loop; and

wherein the phase-locked loop includes a sequential phase detector, a state machine, and an n-bit bi-direction counter.

2. The system of claim 1 , wherein the combination of the signals carried by the feedback paths includes a DC signal from the power output and an AC signal from the synthesized node, the combination excluding a DC signal from the synthesized node.

3. The system of claim 1 , wherein the signals from the synthesized node are provided by an inductor current emulator.

4. The system of claim 3 , wherein the inductor current emulator comprises:

a first current source configured to provide a first current; and

a second current source configured to provide a second current;

wherein the synthesized node is coupled between the first current source and the second current source.

5. The system of claim 4 , wherein:

the first current is proportional to a voltage at the power input node, and

the second current is proportional to a voltage at the power output node.

6. The system of claim 5 , wherein:

the first current is proportional to a product of a constant and the voltage at the power input node, and

the second current is proportional to a product of the constant and the voltage at the power output node.

7. The system of claim 4 , further comprising:

a capacitor coupled in parallel with the second current source.

8. The system of claim 4 , further comprising:

a capacitor coupled between the synthesized node and the controller.

9. The system of claim 8 , wherein the controller is further configured to control the first switch and the second switch based on a voltage that includes an AC component of the voltage at the synthesized node, and excludes a DC component of the voltage at the synthesized node.

10. The system of claim 1 , further comprising:

a first resistor coupled between the power output node and the synthesized node; and

a second resistor coupled to the synthesized node.

11. The system of claim 10 , wherein the controller is further configured to control the first switch and the second switch based on a voltage that includes a DC component of a voltage at the power output node, and excludes an AC component of the voltage at the power output node.

12. The system of claim 1 , further comprising:

a capacitor coupled between the synthesized node and the controller;

a first resistor coupled between the power output node and the synthesized node; and

a second resistor coupled to the synthesized node.

13. The system of claim 12 , wherein the controller is further configured to control the first switch and the second switch based on a voltage that:

includes an AC component of the voltage at the synthesized node;

excludes a DC component of the voltage at the synthesized node;

includes a DC component of a voltage at the power output node; and

excludes an AC component of the voltage at the power output node.

14. The system of claim 1 , wherein:

the controller is further configured to provide a first control signal and a second control signal;

the first switch operates according to the first control signal; and

the second switch operates according to the second control signal.

15. The system of claim 4 , further comprising:

a third switch coupled between the first current source and the synthesized node, wherein the third switch operates according to the first control signal.