DC-DC switching regulator with transconductance boosting

Patent metadata

Field	Value
Publication number	US-9397564-B2
Application number	US-201213628779-A
Country	US
Kind code	B2
Filing date	Sep 27, 2012
Priority date	Sep 27, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A switching regulator comprising a droop amplifier responsive to a reference voltage and a feedback voltage to generate a droop voltage. The droop amplifier includes a boost circuit configurable to increase a transconductance of the droop amplifier during an upward transition of the reference voltage. The switching regulator further includes a comparator responsive to the droop voltage and a current sense signal. The comparator is configured to initiate switching in the switching regulator.

First claim

What is claimed is:

1. The switching regulator comprising:
a droop amplifier, responsive to a reference voltage and a feedback voltage, to generate a droop voltage; the droop amplifier comprising a boost circuit configurable to increase a transconductance of the droop amplifier during an upward transition of the reference voltage; and
a comparator responsive to the droop voltage and a current sense signal, the comparator being configured to initiate switching in the switching regulator and wherein the boost circuit comprises an auxiliary resistor coupled to a switch, the switch being controlled to activate the boost circuit during the upward transition of the reference voltage, wherein the boost circuit is activated based on an output of an up/down counter wherein the up/down counter receives a target DAC code and compares the target DAC code against the current DAC code such that during the upward transition of the reference voltage the boost circuit is activated.

2. The switching regulator of claim 1 , wherein the droop amplifier comprises a main resistor and an auxiliary resistor, the auxiliary resistor being coupled in parallel to the main resistor in response to the upward transition of the reference voltage through a switch.

3. The switching regulator of claim 2 , wherein the transconductance of the droop amplifier is increased thereby increasing gain of the droop amplifier.

4. The switching regulator of claim 1 , wherein the reference voltage changes with time and wherein the reference voltage is generated from an output of a digital to analog converter.

5. The switching regulator of claim 1 further comprising an offset compensation circuit that compensates along with the boost circuit such that the feedback voltage follows the reference voltage.

6. The switching regulator of claim 1 , wherein an offset compensation circuit is in a feedback path of the switching regulator having a negative value.

7. The switching regulator of claim 6 , wherein the offset compensation circuit is configured to follow the slew rate of the upward transition of the reference voltage.

8. The switching regulator of claim 1 , wherein an offset compensation circuit is in a reference path of the switching regulator having a positive value.

9. The switching regulator of claim 1 further comprising:
a plurality of switches responsive to an output of the comparator to switch the switching regulator; and
an LC filter coupled to the switching regulator.

10. A switching regulator comprising:
a droop amplifier, responsive to a reference voltage and a feedback voltage, to generate a droop voltage; the droop amplifier comprising a boost circuit at an input thereof configurable to increase a transconductance of the droop amplifier during upward transition of the reference voltage, wherein the droop amplifier comprises a main resistor and an auxiliary resistor, the auxiliary resistor being coupled in parallel to the main resistor in response to the upward transition of the reference voltage through a switch, and wherein the boost circuit comprises the auxiliary resistor coupled to the switch, the switch being controlled to activate the boost circuit during the upward transition of the reference voltage; and
a comparator responsive to the droop voltage and a current sense signal, the comparator being configured to initiate switching in the switching regulator, wherein resistances of the main resistor and the auxiliary resistor are added in parallel upon activation of the boost circuit such that the transconductance of the droop amplifier is increased thereby increasing gain of the droop amplifier, wherein the boost circuit is activated based on an output of an up/down counter wherein the up/down counter receives a target DAC code and compares the target DAC code against the current DAC code such that during the upward transition of the reference voltage the boost circuit is activated.

11. The switching regulator of claim 10 further comprising an offset compensation circuit that compensates along with the boost circuit such that the feedback voltage follows the reference voltage.

12. The switching regulator of claim 11 , wherein the offset compensation circuit is in a feedback path of the switching regulator having a negative value.

13. The switching regulator of claim 11 , wherein the offset compensation circuit is in a reference path of the switching regulator having a positive value.

14. The switching regulator of claim 11 , wherein the offset compensation circuit is configured to follow the slew rate of the upward transition of the reference voltage.

Assignees

• Sahu Biranchinath
• Agrawal Jitendra K
• B S Dattatreya
• Texas Instruments Inc

Inventors

• Sahu Biranchinath
• Agrawal Jitendra K
• B S Dattatreya

Classifications

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M2003/1566

  Electricity · mapped topic

• H02M3/1566

  with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation · CPC title