Audio power source with improved efficiency

• US 10,404,218 B2
• Filed: 10/17/2018
• Issued: 09/03/2019
• Est. Priority Date: 01/09/2018
• Status: Active Grant

• Current Assignee: Biamp Systems, LLC
• Original Assignee: Biamp Systems, LLC
• Inventors: Baretich, David F., Broadley, Simon J.
• Primary Examiner(s): Nguyen, Patricia T
• Application Number:
  US16/163,208
• Publication Number:
  US 20190214947A1
• Time in Patent Office: 321 Days
• CPC Class Codes: H02M 1/0022 the disturbance parameters being input voltage fluctuations
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/1566 with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
• CPC Class Codes: H02M 3/33561 having more than one ouput with independent control
• 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 2200/165 A filter circuit coupled to the input of an amplifier
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/462 the current being sensed
• CPC Class Codes: H03F 2200/471 the voltage being sensed
• CPC Class Codes: H03F 2200/481 A resistor being used as sensor
• CPC Class Codes: H03F 3/183 with semiconductor devices only
• CPC Class Codes: H03F 3/45071 with semiconductor devices only
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit

Abstract

One example includes a differential amplifier, a voltage weighting element, coupled to a voltage source which provides an input voltage, to provide a reference voltage with a constant power limit when the input voltage varies, an error amplifier configured to receive and compare the reference voltage provided from the voltage weighting element and a feedback sensed voltage provided from the differential amplifier to identify whether the sensed voltage exceeds the reference voltage, and a pulse width modulation (PWM) controller, coupled to a power transformer and the error amplifier, that reduces a transformer input current provided to the power transformer based on the comparison of the reference voltage from the voltage weighting element and the feedback sensed voltage from the differential amplifier.

Claims

1. A device comprising:

a differential amplifier;

a voltage weighting element, coupled to a voltage source which provides an input voltage, to provide a reference voltage with a constant power limit when the input voltage varies;

an error amplifier configured to receive and compare the reference voltage provided from the voltage weighting element and a feedback sensed voltage provided from the differential amplifier to identify whether the sensed voltage exceeds the reference voltage; and

a pulse width modulation (PWM) controller, coupled to a power transformer and the error amplifier, that reduces a transformer input current provided to the power transformer based on the comparison of the reference voltage from the voltage weighting element and the feedback sensed voltage from the differential amplifier.

2. The device of claim 1, wherein the voltage weighting element provides the reference voltage based on a voltage decrease to a current limit set point as the input voltage increases.

3. The device of claim 1, wherein the differential amplifier comprises a low pass filter.

4. The device of claim 1, wherein the feedback sensed voltage from the differential amplifier is provided from a current sense resistor coupled to the power transformer and the differential amplifier.

5. The device of claim 1, wherein the power transformer input current is detected by a metal-oxide semiconductor field-effect transistor (MOSFET) transistor switch.

6. The device of claim 1, wherein when the pulse width modulation (PWM) controller reduces a transformer current provided to the power transformer when the feedback sensed voltage from the differential amplifier exceeds the reference voltage from the voltage weighting element.