Digitally controlled voltage regulator

• US 7,023,672 B2
• Filed: 02/03/2003
• Issued: 04/04/2006
• Est. Priority Date: 02/03/2003
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Primarion Incorporated (Infineon Technologies AG)
• Inventors: Carroll, Robert T., Trivedi, Malay, Mori, Kevin, Goodfellow, John Ryan, McShane, Erik
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): Nguyen, Danny
• Application Number:
  US10/358,066
• Publication Number:
  US 20040150928A1
• Time in Patent Office: 1,156 Days
• Field of Search: 361/18, 361 911- 913, 361/90, 361/92, 361/110, 361/111, 361/93.1, 323/272, 323/282, 323/283, 323/284
• US Class Current: 361/18
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Disclosed is a digitally controlled multi-phase voltage regulator system providing regulated power to electronic components that have variable power requirements. Power is supplied by one or more power integrated circuits (IC) each having a high side power switch controlled by pulse width modulated signals and a low side power switch. The power IC senses voltage at the load and has an on-chip current mirror for generating a current that is a ratio of current delivered to the load. The power IC also has current limiting and on-chip temperature sensing components. The voltage and current information is digitized and provided to a control integrated circuit (IC). The control IC receives this digitized information as well as user provided parameters and, in the regulation mode of operation, provides digitized pulse width modulated control signals to the power IC. In an active transient response mode of operation, the control IC provides signals to turn either the high side switches or low side switches ON. Fault detection circuitry identifies over voltage, under voltage, and excessive temperatures. All communications between the control IC and the power IC are digital providing high bandwidth, optimal control frequency response, noise immunity and efficient active transient response.

Claims

1. A digitally controlled voltage regulator comprising:

a plurality of power integrated circuits adapted for coupling to a load having variable power requirements and for providing regulated power to said load, at least one of said plurality of power integrated circuits also sensing voltages at said load;

wherein at least one of said power integrated circuits comprises a window comparator sensing voltage variations at said load and providing an output that initiates an active transient response to voltage variations sensed at said load, said window comparator comprising a first digital to analog converter providing a signal to a first comparator enabling it to provide a high active transient response signal and a second digital to analog converter providing a signal to a second comparator enabling it to provide a low active transient response signal;

a control integrated circuit coupled to said plurality of power integrated circuits for providing digital control signals to said plurality of power integrated circuits and for receiving digital signals from said power integrated circuits;

said control integrated circuit adjusting the digital control signals in response to the signals received from said power integrated circuits.

2. A digitally controlled voltage regulator as in claim 1, wherein said load having variable power requirements is a microprocessor.

3. A digitally controlled voltage regulator as in claim 1 wherein said control integrated circuit further comprises:

a programmable storage device providing stored instructions, said control integrated circuit adjusting the digital control signals in response to the signals received from both said programmable storage device and said power integrated circuits.

4. A digitally controlled voltage regulator as in claim 3 wherein said programmable storage device comprises an electrically erasable programmable memory (EEPROM).

5. A digitally controlled voltage regulator as in claim 1, wherein said digital control signals are digital pulses of variable width providing pulse width modulated (PWM) digital control signals to control a high side power switch.

6. A digitally controlled voltage regulator as in claim 5, wherein said digital control signals also provide signals to control a low side power switch.

7. A digitally controlled voltage regulator as in claim 1, wherein said window comparator comprises a circuit for sensing over voltage and under voltage conditions.

8. A digitally controlled voltage regulator as in claim 1, wherein at least one of said power integrated circuits comprises a temperature sensing device.

9. A digitally controlled voltage regulator as in claim 8, wherein said temperature sensing device is formed on the same semiconductor substrate as the power integrated circuit.

10. A digitally controlled voltage regulator as in claim 1, wherein at least one of said plurality of power integrated circuits comprises:

a voltage analog to digital converter circuit for sensing the voltages at said load;

said voltage analog to digital converter circuit providing a digital error signal to said control integrated circuit in response to the voltages sensed at said load and a reference voltage.

11. A digitally controlled voltage regulator as in claim 10, wherein said digital error signal is the difference between a programmable reference voltage and a regulated output voltage.

12. A digitally controlled voltage regulator as in claim 1, wherein at least one of said power integrated senses the voltage directly at the load by means of a Kelvin connection to the load.

13. A digitally controlled voltage regulator as in claim 1, wherein all of said power integrated circuits comprise:

a high side power switch; and

a driver circuit responsive to digital control signals from said control integrated circuit to selectively turn said power switch on and off.

14. A digitally controlled voltage regulator as in claim 13, further comprising:

a low side power switch; and

a driver circuit responsive to digital control signals from said control integrated circuit to selectively turn said power switch on and off.

15. A digitally controlled voltage regulator as in claim 13, wherein each of said plurality of power integrated circuits provides a different phase of power to said load.

16. A digitally controlled voltage regulator as in claim 13, further comprising:

a current mirror circuit for generating a current that is a ratio of the current delivered to the load; and

a current analog to digital converter for providing the digital value of the fractional peak current to said control integrated circuit.

17. A digitally controlled voltage regulator as in claim 16, wherein said current mirror circuit is formed on the same semiconductor substrate and by the same process as said high side switch assuring accurate scaling with automatic process and temperature variation compensation.

18. A digitally controlled voltage regulator as in claim 16, said current analog to digital converter comprises:

a capacitor for storing the peak current provided by the current mirror; and

a comparator for comparing the peak current with a reference and providing as its output a serial digital output IDIG.

19. A digitally controlled voltage regulator as in claim 1, wherein one of said power converters comprises:

a voltage analog to digital converter for sensing voltages at said load, comparing said voltages with a reference voltage and providing a digitized error signal to said control integrated circuit.

20. A digitally controlled voltage regulator as in claim 19, wherein said voltage analog to digital converter comprises:

a capacitor for storing the sensed load voltage; and

a comparator for comparing the sensed load voltage to a reference voltage and providing as its output a serial digital output error signal.

21. A digital control integrated circuit comprising:

a digital current interface for receiving digital information representing current measurements;

a voltage error interface for receiving a voltage error signal;

a programmable storage device for storing desired parameters;

a compensation network responsive to digital signals from each of said digital interfaces and said voltage error interface and instruction storage device, said compensation network comprising a circuit for current averaging and balancing responsive to signals from said digital current interface, an active voltage positioning circuit responsive to the output of said circuit for current averaging and balancing and a proportional integrated derivative feedback control circuit (PID) for receiving inputs from the active voltage positioning circuit and the instruction storage device, for providing signals to said pulse width modulator; and

said pulse width modulator responsive to signals from said compensation network for providing signals of varying pulse width to thereby control the power to a load device.

22. A digital control integrated circuit as in claim 21, further comprising:

an active transient response interface for providing signals to said pulse width modulator, said signals from said transient response interface overriding signals from said compensation network for controlling the width of pulses controlling the power to a load device.

23. A digital control integrated circuit as in claim 22, further comprising:

a state control for receiving parameters from said storage device and enabling said pulse width modulator to start producing pulse width modulated gate signals,

said state control monitoring fault signals and disabling the pulse width modulator if a fault is detected.