DC-to-DC converter with improved transient response

• US 6,678,178 B2
• Filed: 10/01/2002
• Issued: 01/13/2004
• Est. Priority Date: 10/26/2000
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro Incorporated
• Inventors: Lipcsei, Laszio
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US10/262,537
• Publication Number:
  US 20030086283A1
• Time in Patent Office: 469 Days
• Field of Search: 363/98, 363/97, 363/72, 363/16, 363/17, 363/131, 363/132, 323/282, 323/283, 323/284, 323/285, 323/288
• US Class Current: 363/98
• CPC Class Codes: H02M 1/15 using active elements
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1586 switched with a phase shift, i.e. interleaved

Abstract

A DC to DC converter includes a comparator, a driver, and a pair of switches. The comparator compares the output voltage with a reference voltage signal and generates a PWM signal. The driver drives the switches so as to force the output voltage to follow the reference signal. In a multiphase architecture, two or more such converter circuits are incorporated to minimize the output voltage ripple and further reduce the recovery time. In a two-phase architecture, two reference signals are phase-shifted by 180 degrees. In an N-phase architecture, the reference signals are phase-shifted by 360/N degrees.

Claims

1. A DC—

DC converter comprising;

a comparator configured to compare a signal representative of an output voltage with a periodic reference signal having a DC offset determined by a DC reference voltage, and said comparator further configured to provide a control signal to a driver that drives an output voltage of said DC—

DC converter towards a pre-established value.

2. The DC—

DC converter of claim 1, wherein said control signal comprises a pulse width modulated signal.

3. The DC—

DC converter of claim 2, wherein a pulse width of said pulse with modulated signal changes when said output voltage is different than said pre-established value.

4. The DC—

DC converter of claim 1, wherein said DC—

DC further comprises a pair of switches and wherein said driver drives said pair of switches, one high, one low which alternatively control said output voltage.

5. The DC—

DC converter of claim 4, further comprising a low pass filter electrically coupled to an output of said pair of switches.

6. The DC—

DC converter of claim 4, wherein each of said switches comprises a metal oxide semiconductor field effect transistor.

7. A multiphase DC to DC converter comprising N conversion circuits which are electrically coupled in said DC to DC converter, wherein each said conversion circuit comprises a comparator configured to compare a signal representative of an output voltage with a periodic reference signal having a DC offset determined by a DC reference voltage, and to provide a control signal to a driver that drives an output voltage of said DC—

DC converter towards a pre-established value, and wherein each said periodic reference signal to each said converter circuit is phase shifted by 360/N degrees from each other.

8. The multiphase DC to DC converter of claim 7, wherein at least one said control signal for at least one of said N conversion circuits comprises a pulse width modulated signal.

9. The multiphase DC to DC converter of claim 8, wherein a pulse width of said pulse with modulated signal changes when said output voltage is different than said pre-established value.

10. The multiphase DC to DC converter of claim 7, wherein at least one of said N conversion circuits comprises a pair of switches and wherein said driver of an associated conversion circuit drives said pair of switches, one high, one low which alternatively control said output voltage.

11. The multiphase DC to DC converter of claim 10, wherein said associated conversion circuit further comprise a low pass filter electrically coupled to an output of each said pair of switches.

12. The multiphase DC to DC converter of claim 10, wherein said pair of switches comprises a metal oxide semiconductor field effect transistor.

13. The multiphase DC to DC converter of claim 7, further comprising:

a current balancing device configured to maintain currents delivered by all said N conversion circuits at a substantially similar level.

14. The multiphase DC to DC converter of claim 13, wherein said current balancing device modifies said signal representative of an output voltage for a second conversion circuit to said N conversion circuit to balance output currents from said second conversion circuit to said N conversion circuit with an output current from a first conversion circuit.

15. The multiphase DC to DC converter of claim 13, wherein said current balancing device modifies said periodic reference signal for a second conversion circuit to said N conversion circuit to balance output currents from said second conversion circuit to said N conversion circuit with an output current from a first conversion circuit.

16. A two-phase DC to DC converter comprising a first conversion circuit and a second conversion circuit, wherein said first conversion circuit comprises:

a first comparator configured to compare a first signal representative of an output voltage with a first periodic reference signal having a DC offset determined by a DC reference voltage, said first comparator further configured to provide a first control signal to a first driver that drives an output voltage of said DC—

DC converter to a pre-established value;

wherein said second conversion circuit comprises;

a second comparator configured to compare a second signal representive of an output voltage with a second periodic reference signal having a DC offset determined by a DC reference voltage, said second comparator further configured to provide a second control signal to a second driver that drives an output voltage of said DC—

DC converter to a pre-established value; and

wherein said first periodic reference signal and said second periodic reference signal are phase shifted by 180 degrees from each other.