Method of controlling parallel diverse conversion paths in DC-to-DC power converter

1. A DC-DC converter comprising:

a plurality of DC-DC converter channels having outputs thereof combined at an output (VOUT) to provide a composite DC power output to a load, and

wherein one of said channels comprises a fast transient response power path, said fast transient response power path having voltage feedback from VOUT to its input and a first current sensing circuit in its output current path for sensing output current provided by said fast transient response power path and

another of said channels comprises a high efficiency power path, said high efficiency power path having a difference amplifier coupled to its input,

wherein said high efficiency power path does not include any voltage feedback from said VOUT to its input; and

wherein an output of said first current sensing circuit is coupled to one input of said difference amplifier, the other input of said difference amplifier referenced to a reference level associated with a reference current.

2. The DC-DC converter according to claim 1 , wherein said first current sensing circuit of said fast transient response power path comprises a first current-to-voltage converter, and wherein said reference level associated with said reference current comprises a reference voltage.

3. The DC-DC converter according to claim 2 , wherein said high efficiency power path includes a second current-to-voltage converter coupled in an output current path therefrom to said load, and a current error amplifier which is operative to control the operation of said high efficiency power path in accordance with the outputs of said first and second current-to-voltage converters.

4. The DC-DC converter according to claim 1 , wherein said plurality of DC-DC converter channel comprises multi-phase DC-DC converter channels.

5. A method of supplying DC power to an output load comprising the steps of:

(a) providing a first DC-DC converter channel having a fast transient response power path;

(b) providing a second DC-DC converter channel having a high efficiency power path;

(c) combining current outputs of said fast and second DC-DC converter channels to provide a composite DC power output (VOUT) to a load,

(d) feeding back a signal associated with output current supplied by said fast transient response power path,

(e) controlling operation of said high efficiency power path using said signal associated with said output current supplied to said fast transient response power path; and

wherein said fast transient response power path includes voltage feedback from VOUT to its input, and said high efficiency power path does not include voltage feedback from said VOUT to its input.

6. The method according to claim 5 , further comprising the step of converting said output current supplied by said fast transient response power path using a first current-to-voltage converter, and wherein said high efficiency power path is operative to integrate the output of said current-to-voltage converter to produce an average current demanded by said load.

7. The method according to claim 6 , wherein said high efficiency power path includes a second current-to-voltage converter coupled in an output current path therefrom to said load, and a current error amplifier which is operative to control the operation of said high efficiency power path in accordance with the outputs of said first and second current-to-voltage converters.

8. The method according to claim 5 , wherein said plurality of DC-DC converter channels comprise multi-phase DC-DC converter channels.

9. A method of supplying DC power to an output load comprising the steps of:

(a) providing a plurality of DC-DC convener channels having outputs thereof combined at an output (VOUT) to provide a composite DC power output to a load, said plurality of channels comprising a first DC-DC converter channel having a fast response voltage regulation path and a feedback loop to monitor (VOUT) for rapidly supplying output current responsive to a change in said load to ensure voltage regulation and a second DC-DC converter channel having a high efficiency voltage regulation path, wherein said high efficiency voltage regulation path does not include voltage feedback from said VOUT to its input;

(b) feeding back a feedback signal representative of said rapidly supplied output current to an input of said a second DC-DC converter channel, and

(c) controlling said second DC-DC convener channel based on said feedback signal to supply an average current to said load.

10. The method according to claim 9 , wherein said fast transient response power path is operative to monitor current demand of said load.

11. The method according to claim 10 , wherein said fast transient response power path includes a first current-to-voltage convener coupled in an output current path to said load, and wherein high efficiency power path is operative to integrate the output of said current-to-voltage convener to produce said average current.

12. The method according to claim 11 , wherein said high efficiency power path includes a second current-to-voltage converter coupled in an output current path therefrom to said load, and a current error amplifier which is operative to control the operation of said high efficiency power path in accordance with the outputs of said first and second current-to-voltage converters.

13. The method according to claim 9 , wherein said plurality of DC-DC convener channels comprise multi-phase DC-DC converter channels.