DC-DC converter

1. A DC-DC converter comprising:

a power supply unit configured to supply an input voltage;

an inductor connected between an output terminal where an output voltage is outputted and the power supply unit;

an emulator connected to both ends of the inductor to generate a feedback voltage; and

a control circuit configured to control the power supply unit through a time domain control based on the output voltage and the feedback voltage.

2. The DC-DC converter of claim 1 , wherein the power supply unit supplies an input voltage and adjusts a pulse width of the input voltage according to a pulse width modulation signal, and the pulse width modulation signal is generated based on the output voltage and the feedback voltage by the control circuit.

3. The DC-DC converter of claim 2 , wherein the control circuit comprises an error correction circuit configured to amplify an error between the output voltage and a predetermined reference voltage; and a feed forward circuit configured to feed-forward-control the power supply unit based on the feedback voltage, the reference voltage, and the error amplified by the error correction circuit.

4. The DC-DC converter of claim 3 , wherein the error correction circuit comprises:

an output voltage controlled delay line configured to delay an inputted reference clock signal based on the output voltage;

a reference voltage controlled delay line configured to delay an inputted reference clock signal based on the reference voltage; and

a time zone amplifier configured to receive outputs of the output voltage controlled delay line and the reference voltage controlled delay line.

5. The DC-DC converter of claim 4 , wherein the feed forward circuit comprises a voltage controlled delay line configured to delay a signal amplified by the time zone amplifier based on the feedback voltage and the reference voltage.

6. The DC-DC converter of claim 5 , wherein the control circuit comprises a signal generation unit configured to generate the pulse width modulation signal based on an output of the feed forward circuit.

7. The DC-DC converter of claim 1 , wherein the feedback voltage has the same start time point and end time points as a current and a ripple flowing through the inductor, and the emulator further comprises a discontinuous current mode detection unit configured to detect a time point at which the current flowing through the inductor becomes zero based on the feedback voltage.

8. The DC-DC converter of claim 7 , wherein the discontinuous current mode detection unit comprises:

a discontinuous current mode detection node capacitively-coupled to a node where the feedback voltage is outputted; and

a transistor connected between the discontinuous current mode detection node and a ground node.

9. A DC-DC converter comprising:

a power supply unit configured to supply an input voltage and adjust a pulse width of the input voltage according to a pulse width modulation signal;

an inductor connected between an output terminal where an output voltage is outputted and the power supply unit;

an emulator connected in parallel to the inductor to generate a feedback voltage having the same start time point and end time point as a current and a ripple flowing through the inductor and a discontinuous current mode detection voltage; and

a control circuit configured to generate a control signal including the pulse width modulation signal through a time domain control based on the output voltage and the discontinuous current mode detection voltage,

wherein the emulator comprises a resistor and a first capacitor connected in series and a second capacitor connected to a feedback voltage node between the resistor; and

the first capacitor, and the feedback voltage is outputted from the feedback voltage node and the discontinuous current mode detection voltage is outputted from the feedback voltage node and a discontinuous current mode detection node capacitively-coupled to the second capacitor.

10. The DC-DC converter of claim 9 , wherein the emulator further comprises a first transistor connected between the discontinuous current mode detection node and a ground node; and

the first transistor discharges the discontinuous current mode detection node by a ground voltage in each predetermined period.

11. The DC-DC converter of claim 9 , wherein the control circuit comprises:

a first voltage controlled delay line configured to delay an inputted reference clock signal based on the output voltage;

a second voltage controlled delay line configured to delay the reference clock signal based on a predetermined reference voltage; and

a comparator configured to receive outputs of the first and second voltage controlled delay lines, perform a phase comparison by including a phase detector, and generate the control signal according to a comparison result.

12. The DC-DC converter of claim 11 , further comprising a second transistor connected in parallel to the inductor,

wherein the control circuit further comprises a discontinuous current mode control circuit, and as it is detected through the emulator that a current flowing through the inductor becomes zero, the discontinuous current mode control circuit generates a clock signal for controlling the second transistor to prevent a ringing of the current flowing through the inductor.