Quiescent current determination using in-package voltage measurements

• US 8,816,775 B2
• Filed: 09/13/2012
• Issued: 08/26/2014
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Hart, Paul R, Staudinger, Joseph, Annes, Justin N, Bokatius, Mario M
• Primary Examiner(s): Choe, Henry
• Application Number:
  US13/614,850
• Publication Number:
  US 20140070881A1
• Time in Patent Office: 712 Days
• Field of Search: 330/296, 330/285, 330/302, 330/279
• US Class Current: 330/296
• CPC Class Codes: H03F 1/0288 using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers
• CPC Class Codes: H03F 1/301 in MOSFET amplifiers H03F1/303, H03F1/305, H03F1/308 take precedence
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence

Abstract

Apparatus, systems, and fabrication methods are provided for biasing amplifier arrangements inside device packages to a target quiescent current. In one embodiment, an amplifier device has an output interface and includes an amplifier arrangement having an amplifier output and impedance matching circuitry coupled between the amplifier output and the output interface. A method for biasing the amplifier arrangement involves measuring or otherwise obtaining a voltage between the amplifier output and the output interface, determining an estimated quiescent current through the amplifier arrangement based on that voltage, and adjusting a bias voltage provided to the input of the amplifier arrangement based on a difference between the estimated quiescent current. In exemplary embodiments, the bias voltage is adjusted until the estimated quiescent current is substantially equal to a target quiescent current.

Claims

1. An amplifier system comprising:

an amplifier device comprising an output interface, an amplifier arrangement having an amplifier input and an amplifier output, and impedance matching circuitry coupled between the amplifier output and the output interface; and

a control system coupled to the amplifier output and the output interface to determine an estimated current through the amplifier arrangement based on a voltage between the amplifier output and the output interface and adjust a bias voltage at the amplifier input based on the estimated current.

2. The amplifier system of claim 1, further comprising an input interface to receive an indication of a target current, wherein the control system adjusts the bias voltage at the amplifier input based on a difference between the estimated current and the target current.

3. The amplifier system of claim 1, wherein:

the amplifier device comprises a second amplifier arrangement having a second amplifier input; and

the control system adjusts a second bias voltage at the second amplifier input in response to adjusting the bias voltage at the amplifier input to maintain a desired operating relationship between the second amplifier arrangement and the amplifier arrangement.

4. The amplifier system of claim 1, wherein the control system includes a first high impedance input node coupled to the amplifier output and a second high impedance input node coupled to the output interface.

5. An amplifier system comprising:

an amplifier device comprising an output interface, an amplifier arrangement having an amplifier output, and impedance matching circuitry coupled between the amplifier output and the output interface; and

a control system coupled to the amplifier output and the output interface to determine an estimated current through the amplifier arrangement based on a voltage between the amplifier output and the output interface, the control system including a first high impedance input node coupled to the amplifier output and a second high impedance input node coupled to the output interface, wherein an input impedance between the first high impedance input node and the second high impedance input node is greater than an impedance of the impedance matching circuitry.

6. The amplifier system of claim 5, further comprising:

a first conductive element coupled between the first high impedance input node and the amplifier output; and

a second conductive element coupled between the second high impedance input node and the output interface.

7. An amplifier system comprising:

an amplifier device comprising an output interface, an amplifier arrangement having an amplifier output, and impedance matching circuitry coupled between the amplifier output and the output interface; and

a control system coupled to the amplifier output and the output interface to determine an estimated current through the amplifier arrangement based on a voltage between the amplifier output and the output interface, the control system including a first high impedance input node coupled to the amplifier output and a second high impedance input node coupled to the output interface, wherein the control system includes a voltage measuring arrangement coupled to the first high impedance input node and the second high impedance input node to obtain a measured voltage between the amplifier output and the output interface.

8. The amplifier system of claim 7, the amplifier arrangement having an amplifier input, wherein the control system includes:

a biasing arrangement coupled to the amplifier input to provide a bias voltage to the amplifier input; and

control circuitry coupled to the voltage measuring arrangement and the biasing arrangement to determine the estimated current based on the measured voltage and operate the biasing arrangement to adjust the bias voltage based on the estimated current.

9. The amplifier system of claim 8, further comprising an input interface to receive indication of a target current through the amplifier arrangement, wherein the control circuitry is coupled to the input interface to identify the target current and operate the biasing arrangement to adjust the bias voltage at the amplifier input based on a difference between the estimated current and the target current.

10. An amplifier system comprising:

an amplifier device comprising an output interface, an amplifier arrangement having an amplifier output, and impedance matching circuitry coupled between the amplifier output and the output interface; and

a control system coupled to the amplifier output and the output interface to determine an estimated current as a function of a voltage between the amplifier output and the output interface based on a relationship between a voltage across the impedance matching circuitry and a corresponding current through the impedance matching circuitry.

11. An amplifier system comprising:

an amplifier device comprising an output interface, an amplifier arrangement having an amplifier output, and impedance matching circuitry coupled between the amplifier output and the output interface, wherein the impedance matching circuitry comprises a shunt inductance impedance matching circuit or a shunt capacitance impedance matching circuit; and

a control system coupled to the amplifier output and the output interface to determine an estimated current through the amplifier arrangement based on a voltage between the amplifier output and the output interface.

12. An amplifier device package comprising:

an amplifier arrangement having an output terminal;

an output interface electrically connected to the output terminal;

a first conductive element connected between the output terminal and a first node;

a second conductive element connected between the output interface and a second node, wherein an input impedance between the first node and the second node is greater than an impedance between the output terminal and the output interface; and

a voltage measuring arrangement coupled to the first node and the second node to obtain a measured voltage between the output terminal and the output interface.

13. The amplifier device package of claim 12, further comprising:

a third conductive element coupled to an input terminal of the amplifier arrangement;

a biasing arrangement coupled to the third conductive element to provide a bias voltage to the input terminal of the amplifier arrangement; and

control circuitry coupled to the voltage measuring arrangement and the biasing arrangement to determine an estimated quiescent current through the amplifier arrangement based on the measured voltage and adjust the bias voltage based on a difference between the estimated quiescent current and a target quiescent current.

14. The amplifier device package of claim 12, further comprising package substrate, wherein the amplifier arrangement is provided on a first die mounted to the package substrate and the voltage measuring arrangement is provided on a second die mounted to the package substrate.

15. A method for biasing an amplifier system, the amplifier system comprising a plurality of bondwires coupled between the output of the amplifier arrangement and the output interface, the method comprising:

obtaining a voltage difference between an output of an amplifier arrangement and an output interface of the amplifier system, wherein obtaining the voltage difference between the output of the amplifier arrangement and the output interface comprises;

obtaining a first voltage at a first node via a first individual bondwire connected to the first node;

obtaining a second voltage at a second node via a second individual bondwire connected to the second node; and

measuring a difference between the first voltage and the second voltage to obtain the voltage between the output of the amplifier arrangement and the output interface;

determining an estimated quiescent current through the amplifier arrangement based on the voltage difference; and

adjusting a bias voltage provided to an input of the amplifier arrangement based on the estimated quiescent current.

16. A method for biasing an amplifier system, the method comprising:

obtaining a voltage difference between an output of an amplifier arrangement and an output interface of the amplifier system;

determining an estimated quiescent current through the amplifier arrangement based on the voltage difference; and

adjusting a bias voltage provided to an input of the amplifier arrangement based on a difference between the estimated quiescent current and a target quiescent current until the difference is less than a threshold value.

17. A method for biasing an amplifier system, the method comprising:

obtaining a voltage difference between an output of an amplifier arrangement and an output interface of the amplifier system;

determining an estimated quiescent current through the amplifier arrangement based on the voltage difference;

adjusting a bias voltage provided to an input of the amplifier arrangement based on the estimated quiescent current; and

adjusting a second bias voltage provided to a second input of a second amplifier arrangement of the amplifier system based on the estimated quiescent current to maintain a desired operation of the second amplifier arrangement with respect to the amplifier arrangement.