POWER SUPPLY CIRCUIT AND HYSTERESIS BUCK CONVERTER

• US 20140084888A1
• Filed: 09/17/2013
• Published: 03/27/2014
• Est. Priority Date: 09/27/2012
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Kwangho, Heo, DongHun
• Application Number:
  US14/029,048
• Publication Number:
  US 20140084888A1
• Time in Patent Office: Days
• US Class Current: 323/283
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence
• CPC Class Codes: H02M 3/157 with digital control

Abstract

A power supply unit converting a DC power supply using an inductor includes a feedback circuit dividing an output voltage being output from a first end of the inductor to convert the output voltage into a first feedback voltage; a differentiator differentiating the first feedback voltage to convert the first feedback voltage into a second feedback voltage; a hysteresis comparator comparing a level of the second feedback voltage with a reference voltage band to output a comparison signal; and a switch pulling an input voltage up or pulling the input voltage down to the second end of the inductor with reference to the comparison signal.

Claims

1. A power supply unit converting a DC power supply using an inductor comprising:

a feedback circuit dividing an output voltage being output from a first end of the inductor to convert the output voltage into a first feedback voltage;

a differentiator differentiating the first feedback voltage to convert the first feedback voltage into a second feedback voltage;

a hysteresis comparator comparing a level of the second feedback voltage with a reference voltage band to output a comparison signal; and

a switch performing at least one of pulling up a second end of the inductor with an input voltage or pulling down the second end of the inductor in response to the comparison signal.

2. The power supply unit of claim 1, wherein the differentiator controls a delay such that a phase of the second feedback voltage is synchronized with a phase of a current flowing through the inductor.

3. The power supply unit of claim 2, wherein a waveform of the second feedback voltage is configured to restore a waveform of the current flowing through the inductor.

4. The power supply unit of claim 1, wherein the differentiator comprises:

an operational amplifier receiving the first feedback voltage through a non-inverting terminal;

a capacitor connected between an inverting terminal of the operational amplifier and a ground; and

a resistor connected between an output terminal of the operational amplifier and the inverting terminal of the operational amplifier.

5. The power supply unit of claim 4, wherein at least one of the capacitor and the resistor is variable.

6. The power supply unit of claim 5, wherein a period of pull-up or pull-down of the switch is controlled by controlling the at least one of the capacitor and the resistor.

7. The power supply unit of claim 1, wherein the feedback circuit comprises a first feedback resistor and a second feedback resistor for dividing the output voltage and wherein the first feedback resistor is variable.

8. The power supply unit of claim 1, wherein the reference voltage band corresponds to a linear section of the second feedback voltage.

9. The power supply unit of claim 8, wherein the reference voltage band corresponds to the gap between the minimum value and the maximum value of the second feedback voltage.

10. A hysteresis buck converter comprising:

a feedback circuit dividing an output voltage being output from a first end of an inductor to convert the output voltage into a feedback voltage;

a hysteresis comparator comparing a level of the feedback voltage with a reference voltage band to output a comparison signal;

a switch pulling an input voltage up or pulling the input voltage down to a second end of the inductor with reference to the comparison signal; and

an adaptive hysteresis window controller adaptively controlling a hysteresis window such that the reference voltage band is proportional to the input voltage and is reverse proportional to the output voltage.

11. The hysteresis buck converter of claim 10, wherein the hysteresis window controller comprises:

a hysteresis current generator generating a hysteresis current that is proportional to the input voltage and is reverse proportional to the output voltage; and

a hysteresis voltage generator setting the reference voltage band with reference to the hysteresis current.

12. The hysteresis buck converter of claim 11, wherein the hysteresis current generator comprises a variable resistor having a resistance value corresponding to feedback resistors included in the feedback circuit and wherein the variable resistor is proportional to the level of the output voltage.

13. The hysteresis buck converter of claim 12, wherein the hysteresis current generator generates the hysteresis current having a level that is reverse proportional to the variable resistor and is proportional to the input voltage.

14. The hysteresis buck converter of claim 11, wherein the hysteresis voltage generator generates a first reference voltage and a second reference voltage according to the hysteresis current.

15. A hysteresis buck converter comprising:

an inductor having a first end and a second end;

a feedback circuit converting an output voltage from the first end of the inductor into a first feedback voltage;

a differentiator converting the first feedback voltage into a second feedback voltage; and

a hysteresis comparator comparing a level of the second feedback voltage with a reference voltage band and outputting a comparison signal,

wherein the differentiator controls a delay such that a phase of the second feedback voltage is synchronized with a phase of a current flowing through the inductor.

16. The hysteresis buck converter of claim 15 further comprising a switch, wherein the switch comprises a pull-up switch and a pull-down switch controlling an input voltage of the second end of the inductor in response to the comparison signal.

17. The hysteresis buck converter of claim 16, wherein, when the pull-up switch is activated, a power supply voltage is applied to the second end of the inductor and, when the pull-down switch is activated, the second end of the inductor is grounded.

18. The hysteresis buck converter of claim 15, wherein the differentiator comprises:

an operational amplifier receiving the first feedback voltage through a non-inverting terminal;

a capacitor connected between an inverting terminal of the operational amplifier and a ground; and

a resistor connected between an output terminal of the operational amplifier and the inverting terminal of the operational amplifier.

19. The hysteresis buck converter of claim 18, wherein at least one of the capacitor and the resistor is variable.

20. The hysteresis buck converter of claim 15, wherein the feedback circuit comprises a first feedback resistor and a second feedback resistor for dividing the output voltage and wherein the first feedback resistor is variable.