Active voltage positioning implementation for microprocessor power supplies or the like

• US 7,098,637 B2
• Filed: 05/10/2004
• Issued: 08/29/2006
• Est. Priority Date: 05/12/2003
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Jauregui, David, Zhang, Jason
• Primary Examiner(s): CERNOCH, STEVEN MICHAEL
• Application Number:
  US10/843,165
• Publication Number:
  US 20040240238A1
• Time in Patent Office: 841 Days
• Field of Search: 323/268, 323/270, 323/273, 323/275, 323/279, 323/280, 363/50
• US Class Current: 323/268
• CPC Class Codes: G11C 5/147 Voltage reference generators, voltage or current regulators; Internally lowered supply levels; Compensation for voltage drops G11C5/141 takes precedence
• CPC Class Codes: H02M 1/088 for the simultaneous control of series or parallel connected semiconductor devices
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

An improved active voltage positioning (AVP) implementation for a power supply for a microprocessor or the like includes an AVP circuit which is separated from the power supply error amplifier by a buffer amplifier having a parallel RC feedback circuit to controllably adjust the transient response. An AVP signal derived from an output load current sensing element provides an input to the buffer amplifier. A second input is provided by power supply reference voltage. A output of the buffer amplifier is connected as an input to the error amplifier to provide the AVP window. This permits separate adjustment of the transient behavior of the error loop and the AVP loop.

Claims

1. A power supply controller comprising:

an error correction circuit including an error amplifier, an input circuit for the error amplifier, and a feedback compensation network; and

an active voltage positioning (AVP) circuit which cooperates with the error correction circuit to maintain the voltage output of the power supply within a predetermined voltage range V_max to V_min independent of rapid changes in power supply load current,

the AVP circuit including;

a buffer circuit having an output connected to the input circuit for the error amplifier;

an AVP signal source coupled to provide an input to the buffer circuit which varies according to the power supply output current; and

a compensation circuit operative to control the transient behavior of the buffer circuit in response to changes in the buffer circuit input provided by the AVP signal source.

2. A power supply controller according to claim 1, wherein the AVP circuit and the error amplifier are in separate integrated circuits.

3. A power supply controller according to claim 1, wherein the AVP circuit and the error amplifier are in a single integrated circuit.

4. A power supply controller according to claim 1, wherein the AVP signal signal source is provided by a power supply load current sensing element coupled to an input amplifier having a predetermined gain.

5. A power supply controller according to claim 4, wherein:

the buffer circuit includes a buffer amplifier having direct and inverting inputs;

the input signal source is connected to one of the buffer amplifier inputs; and

a reference voltage signal is connected to the other of the buffer amplifier inputs.

6. A power supply controller according to claim 5, wherein:

the buffer circuit includes a buffer circuit having an output connected to the error circuit and an input connected to the AVP circuit, and

the compensation network for the buffer amplifier comprises a feedback circuit connected between the output of the buffer amplifier and the input connected to the AVP signal source.

7. A power supply controller according to claim 6, wherein the compensation network for the buffer circuit comprises a parallel RC circuit connected between the input and output of the buffer amplifier.

8. A power supply controller according to claim 1, wherein:

the buffer circuit includes a buffer circuit having an output connected to the error circuit and an input connected to the AVP circuit, and

the compensation network for the buffer amplifier comprises a feedback circuit connected between the output of the buffer amplifier and the input connected to the AVP signal source.

9. A power supply controller according to claim 1, wherein the compensation network for the buffer circuit comprises a parallel RC circuit connected between the input and output of the buffer amplifier.

10. A power supply controller according to claim 1 wherein:

the error circuit includes an error amplifier having direct and inverting inputs;

one of the inputs is provided by a feedback signal derived from the power supply load current; and

the second input is provided by an output of the buffer circuit.

11. A power supply controller according to claim 5, wherein the AVP circuit is operative to provide an offset to the reference voltage signal which causes the power supply output voltage to approach V_max when the load current is low and to approach V_min when the load current is high, whereby increases in output voltage resulting from a rapid drop in load current are not sufficient to cause the output voltage to exceed V_max and decreases in the output voltage resulting from a rapid increase in load current are not sufficient to cause the output voltage to fall below V_min.

12. A power supply controller comprising:

an error correction circuit including an error amplifier, an input circuit for the error amplifier and a feedback compensation network; and

an active voltage positioning (AVP) circuit which cooperates with the error correction circuit to maintain the voltage output of the power supply within a predetermined voltage range V_max to V_min independent of rapid changes in the power supply current,

the AVP circuit including;

a buffer circuit having an output connected to an input of the error correction circuit;

an AVP signal source coupled to a first input of the buffer circuit;

a voltage reference signal connected to a second input of the buffer circuit; and

a compensation circuit operative to control the transient behavior of the buffer circuit in response to changes in the buffer input provided by the AVP signal source,

the AVP circuit being operative to adjust the output of the buffer circuit relative to the reference voltage to cause the power supply output voltage to approach V_max when the power supply load current is low, and to approach V_min when the power supply load current is high, whereby increases in the output voltage resulting from a rapid drop in load current are not sufficient to cause the output voltage to exceed V_max and decreases in the output voltage resulting from a rapid increase in load current are not sufficient to cause the output voltage to fall below V_min.