Fast transient power supply with a separated high frequency and low frequency path signals

Patent metadata

Field	Value
Publication number	US-2016248328-A1
Application number	US-201615048591-A
Country	US
Kind code	A1
Filing date	Feb 19, 2016
Priority date	Feb 20, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

A power interface device includes a main switching converter, an auxiliary switching converter, and a feedback sense circuit. The main switching converter is coupled to an input terminal and an output terminal and configured to operate at a first switching frequency to source a low frequency current from the input terminal to the output terminal. The auxiliary switching converter is coupled to the input terminal and the output terminal in parallel with the main switching converter and configured to operate at a second and higher switching frequency than the first switching frequency to source a fast transient high frequency current from the input terminal to the output terminal.

First claim

What is claimed is:

1 . A power interface device comprising:
a main switching converter coupled to an input terminal and an output terminal and configured to operate at a first switching frequency to source a low frequency current from the input terminal to the output terminal; an auxiliary switching converter coupled to the input terminal and the output terminal in parallel with the main switching converter and configured to operate at a second and higher switching frequency than the first switching frequency to source a fast transient high frequency current from the input terminal to the output terminal; a feedback sense circuit configured to sense an output voltage at the output terminal; an error amplifier configured to receive the sensed output voltage and a reference voltage and output a transient signal based on the sensed output voltage and the reference voltage; a high pass filter configured to receive the transient signal and output a higher frequency component of the transient signal; and an auxiliary driver circuit configured to drive the auxiliary switching converter based on the higher frequency component of the transient signal.

2 . The power interface device of claim 1 , wherein the main switching converter and the auxiliary switching converter include current-mode switching regulators.

3 . The power interface device of claim 1 , wherein the main switching converter and the auxiliary switching converter include step-down, current mode, switching regulators configured to convert a higher input voltage of the input terminal to a lower voltage, the lower voltage being the output voltage.

4 . The power interface device of claim 1 , wherein the main switching converter includes a first main switch, a second main switch, and a main inductor, wherein the first main switch at one end is coupled to the input voltage terminal and at another end is coupled to a main node, the second main switch at one end is coupled to the main node and at another end is coupled to a ground terminal, and the main inductor at one end is coupled to the main node and at another end is coupled to the output terminal.

5 . The power interface device of claim 4 , wherein the auxiliary switching converter includes a first auxiliary switch, a second auxiliary switch, and an auxiliary inductor, wherein the first auxiliary switch at one end is coupled to the input terminal and at another end is coupled to an auxiliary node, the second auxiliary switch at one end is coupled to the auxiliary node and another end is coupled to the ground terminal, and the auxiliary inductor at one end is coupled to the auxiliary node and at another end is coupled to the output terminal.

6 . The power interface device of claim 5 , wherein:
the auxiliary switching regulator is configured to source the fast transient high frequency current only during a transient detected at a load device, and the transient includes a sudden increase or decrease in load current.

7 . The power interface device of claim 5 , wherein the first and second main switches and the first and second auxiliary switches include FET switches.

8 . The power interface device of claim 1 , wherein:
the feedback sense circuit includes a plurality of resistors and capacitors configured to sense the output voltage and generate a feedback voltage, and the error amplifier is configured to receive the feedback voltage and the reference voltage, and generate the transient signal when the feedback voltage and the reference voltage are not substantially equal to each other.

9 . The power interface device of claim 8 , further comprising:
a low pass filter configured to receive the transient signal and output a lower frequency component of the transient signal; and a main driver circuit configured to drive the main switching converter based on the lower frequency component of the transient signal.

10 . The power interface device of claim 9 , wherein:
the auxiliary driver circuit includes an auxiliary comparator configured to compare the higher frequency component of the transient signal with a sensed high frequency current sourced by the auxiliary switching converter and generate an auxiliary pulse-width signal for driving the auxiliary switching converter, and the auxiliary pulse-width signal enables the auxiliary switching converter to source high frequency current tracking the higher frequency component of the transient signal to the output terminal.

11 . The power interface device of claim 10 , wherein:
the main driver circuit includes a main comparator circuit configured to compare the lower frequency component of the transient signal with a sensed low frequency current sourced by the main switching converter and generate a main pulse-width signal for driving the main switching converter, and the main pulse-width signal enables the main switching converter to source the low frequency current tracking the lower frequency component of the transient signal to the output terminal.

12 . The power interface device of claim 10 , wherein in response to the first duty-cycle, the auxiliary switching converter is configured to source the fast transient high frequency current to the output terminal only during a transient sensed at a load device via the feedback sense circuit.

13 . The power interface device of claim 12 , wherein the auxiliary switching converter is configured to source substantially zero current during a steady-state operation of the load device.

14 . A power interface device comprising:
a main switching converter coupled to an input terminal and an output terminal and configured to operate at a first switching frequency to source a low frequency current from the input terminal to the output terminal; an auxiliary switching converter coupled to the input terminal and the output terminal in parallel with the main switching converter and configured to operate at a second and higher switching frequency than the first switching frequency to source a fast transient high frequency current from the input terminal to the output terminal; a main control loop configured to drive the main switching converter to source the low frequency current from the input terminal to the output terminal; and an auxiliary control loop being independent form the main control loop and configured to drive the auxiliary switching converter to source the fast transient high frequency current from the input terminal to the output terminal during a transient, wherein: the auxiliary control loop includes a high pass filter configured to output a higher frequency compensation component of an output voltage associated with the transient, and the auxiliary control loop is configured to drive the auxiliary switching converter based on the higher frequency compensation component of the output voltage.

15 . The power interface device 14 , wherein the main control loop includes:
a main feedback sense circuit having a plurality of resistors and capacitors configured to sense the output voltage and generate a feedback voltage, a main error operational amplifier configured to receive the feedback voltage and a reference voltage, and generate a transient signal when the feedback voltage and the reference voltage are not substantially equal to each other, and a main comparator circuit configured to compare the transient signal with a sensed low frequency current sourced by the main switching converter and generate a main pulse-width signal for driving the main switching converter, wherein the main pulse-width signal enables the main switching converter to source the low frequency curre

Assignees

• Linear Tech Corp

Inventors

• ZHANG Henry Jindong
• Li Jian

Classifications

• H02M3/158 Primary

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

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H02M3/1584 Primary

  with a plurality of power processing stages connected in parallel · CPC title

• H02M1/08 Primary

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M1/0038

  Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control · CPC title