Boost control signal generator

• US 10,454,424 B2
• Filed: 08/31/2018
• Issued: 10/22/2019
• Est. Priority Date: 10/31/2017
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: van Dommelen, Maarten, Chalet, Frederic, Krabbenborg, Benno
• Primary Examiner(s): Paul, Disler
• Application Number:
  US16/119,115
• Publication Number:
  US 20190131931A1
• Time in Patent Office: 417 Days
• Field of Search: 381120, 381 58- 59
• CPC Class Codes: H03F 1/0205 in transistor amplifiers
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 2200/03 the amplifier being designed for audio applications
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/321 Use of a microprocessor in an amplifier circuit or its control circuit
• CPC Class Codes: H03F 3/181 Low-frequency amplifiers, e.g. audio preamplifiers
• CPC Class Codes: H03F 3/183 with semiconductor devices only
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers
• CPC Class Codes: H03K 2005/00241 using shift registers
• CPC Class Codes: H03K 5/133 using a chain of active delay devices
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A method and operates for generating a boost control signal for a DC-DC-booster is described. An audio signal may be received comprising a plurality of audio sample values. The audio signal may be delayed for a delay time. A maximum-delayed-value of the audio sample values during the delay time may be determined. The boost control signal may be generated from the maximum of the non-delayed audio signal sample value and the maximum-delayed-value.

Claims

1. A boost control signal generator for controlling a DC-DC-booster, the boost control signal generator comprising:

a boost control input configured to receive an audio signal comprising a plurality of audio sample values;

a delay line having a delay line input coupled to the boost control input, at least one delay element coupled to the delay line input, a delay stage maximum value detector coupled to the at least one delay element, and a delay line output coupled to the delay stage maximum value detector, wherein the delay line is configured to output a maximum delayed value of the delayed audio sample values;

a maximum value detector having a first input coupled to the boost control input, a second input coupled to the delay line output, and an output coupled to a boost control output, wherein the maximum value detector is configured to output a boost control signal value from a maximum of a maximum value of the plurality of audio sample values and the maximum delayed value.

2. The boost control signal generator of claim 1, wherein the delay line further comprises:

a plurality of delay stages arranged between the delay line input and the delay line output, each of the plurality of delay-stages including;

a delay-stage-input,

a delay-stage-output, wherein the delay-stage-maximum-value-detector is coupled to the respective delay-stage-output, and, in operation, a sample rate of each subsequent delay stage is less than a sample rate of a preceding delay stage.

3. The boost control signal generator of claim 2, wherein each of the plurality of delay-stages comprises:

at least one delay element, and each delay-stage-maximum-value-detector has at least one input coupled to the at least one delay element output and an input coupled to the delay-stage-input.

4. The boost control signal generator of claim 2, wherein the plurality of delay-stages comprises:

a first delay-stage; and

a second delay-stage, wherein the first delay-stage-input is coupled to the delay line input, the first delay-stage-output is coupled to the second delay-stage-input, the second delay-stage-output is coupled to the delay line output, and the second delay stage is configured to down-sample the output of the first delay stage.

5. The boost control signal generator of claim 4, wherein the first delay-stage is configured to receive an audio signal which has been up-sampled by an up-sampling factor, U, and the second delay-stage is configured to operate at the original audio sample frequency.

6. The boost control signal generator of claim 5, wherein the first delay-stage comprises only one delay element, the delay stage maximum value detector is arranged to feedback the peak value to the first delay-stage input, and the delay element is reset every U cycles.

7. The boost control signal generator of claim 6, wherein the first delay-stage comprises:

a modulo-U counter coupled to a resettable delay element.

8. The boost control signal generator of claim 1, further comprising:

an up-sampler having an audio signal input configured to receive an audio signal sampled at a sample frequency and an audio signal output coupled to the delay line input.

9. The boost control signal generator of claim 8, further comprising:

an absolute value calculator having an input coupled to the up-sampler output and an output coupled tot the delay line input and the delay stage maximum value detector input.

10. A DC-DC-boost controller comprising the boost control signal generator of claim 1, wherein the DC-DC-boost controller is configured to vary the dc-supply to an audio amplifier in response to the generated boost control signal.

11. An audio amplifier comprising the DC-DC-boost controller of claim 9.

12. A method of generating a control signal for a DC-DC-boost controller, the method comprising:

receiving an audio signal;

delaying the audio signal for a delay time with a plurality of delay stages;

determining, in a delay stage maximum value detector, a maximum value of the audio signal in each of the plurality of delay stages;

providing the determined maximum value of the audio signal in each delay stage to succeeding delay stages of the plurality of delay stages;

wherein a final maximum-delayed-value is a determined maximum value of a final delay stage of the plurality of delay stages;

and

determining a boost control signal value from a maximum of the non-delayed audio signal and the final maximum-delayed-value.