Undershoot reduction

Patent metadata

Field	Value
Publication number	US-2016299520-A1
Application number	US-201514685590-A
Country	US
Kind code	A1
Filing date	Apr 13, 2015
Priority date	Apr 13, 2015
Publication date	Oct 13, 2016
Grant date	—

Abstract

Undershoot reduction circuitry includes, for example, a first comparator, a second comparator, and a controller. The first comparator is operable for comparing an indication of a power supply voltage output against a first threshold. The second comparator is operable for comparing an indication of the power supply voltage output against a second threshold. The controller is operable for generating a first power control signal to raise the power supply voltage output when the indication of the power supply voltage output has a first slope and crosses the first threshold and to lower the power supply voltage output when the indication of the power supply voltage output has an opposite slope and crosses the second threshold.

First claim

What is claimed is:

1 . A circuit for voltage undershoot control, comprising:
a first comparator operable for comparing an indication of a power supply voltage output against a first threshold; a second comparator operable for comparing an indication of the power supply voltage output against a second threshold; and a controller operable for generating a first power control signal to raise the power supply voltage output when the indication of the power supply voltage output crosses the first threshold when the power supply voltage output has a first slope and to lower the power supply voltage output when the indication of the power supply voltage output crosses the second threshold when the power supply voltage output has a second slope opposite in direction to the first slope.

2 . The circuit of claim 1 , wherein the first threshold is higher than the second threshold.

3 . The circuit of claim 2 , wherein the controller is operable for generating a second power control signal to raise the power supply voltage when the indication of the power supply voltage output crosses the second threshold when the power supply voltage output has the first slope and when no signal to raise to raise the power supply voltage has been asserted.

4 . The circuit of claim 3 , wherein the first power control signal and the second power control signal are the same power control signal.

5 . The circuit of claim 1 , wherein the first slope is a negative slope and the second slope is a positive slope.

6 . The circuit of claim 1 , wherein the second threshold is lower than the first threshold.

7 . The circuit of claim 6 , wherein the first power control signal is generated to raise the power supply voltage output for at least a selected period of time.

8 . The circuit of claim 1 , wherein the first power control signal is responsive to a first comparator latch for latching an output of the first comparator and is responsive to a second comparator latch for latching an output of the second comparator.

9 . The circuit of claim 8 , wherein the controller includes a state machine responsive to signals of the first and second comparator latches.

10 . The circuit of claim 1 , wherein the first threshold is higher than the second threshold, wherein the first threshold is equal to a first voltage reference signal, and wherein the second threshold is equal to the sum of a second voltage reference signal and a hysteresis voltage of the second comparator.

11 . A voltage regulation system, comprising:
a power supply operable for generating a power supply voltage output; a first comparator operable for comparing an indication of the power supply voltage output against a first threshold; a second comparator operable for comparing an indication of the power supply voltage output against a second threshold; and a controller operable for signaling the power supply to raise the power supply voltage output when the indication of the power supply voltage output crosses the first threshold when the power supply voltage output has a first slope and to lower the power supply voltage output when the indication of the power supply voltage output crosses the second threshold when the power supply voltage output has a second slope opposite in direction to the first slope.

12 . The system of claim 11 , wherein the power supply includes a multiphase buck converter.

13 . The system of claim 11 , wherein the power supply is operable for raising the power supply voltage output by coupling power to an inductor and for lowering the power supply voltage output by decoupling power from the inductor.

14 . The system of claim 13 , wherein power is coupled to the inductors by closing a respective FET (field-effect transistor) transistor and power is decoupled from the inductor by opening the respective FET transistor.

15 . The system of claim wherein the first threshold is a undershoot reference voltage and wherein the second threshold is equal to the first threshold voltage minus a voltage offset plus a hysteresis value of the second comparator.

16 . A method, comprising:
comparing an indication of a power supply voltage output against a first threshold; comparing an indication of the power supply voltage output against a second threshold; and generating a power control signal to raise the power supply voltage output when the indication of the power supply voltage output crosses the first threshold when the power supply voltage output has a first slope and to lower the power supply voltage output when the indication of the power supply voltage output crosses the second threshold when the power supply voltage output has a second slope opposite in direction to the first slope.

17 . The circuit of claim 16 , wherein the first threshold is higher than the second threshold.

18 . The circuit of claim 17 , wherein the power control signal is generated to raise the power supply voltage when the indication of the power supply voltage output rises above the second threshold and when no signal to raise to raise the power supply voltage has been asserted.

19 . The circuit of claim 16 , wherein the first slope is a negative slope and the second slope is a positive slope.

20 . The circuit of claim 16 , wherein the first slope is a positive slope and the second slope is a negative slope.

Assignees

• Texas Instruments Inc

Inventors

• Mangina Prasadu
• Sahu Biranchinath
• Pydah Pradeep
• Raimar Nandakishore

Classifications

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• G05F1/575 Primary

  characterised by the feedback circuit · CPC title