Linear power amplifier

• US 6,788,150 B2
• Filed: 07/16/2002
• Issued: 09/07/2004
• Est. Priority Date: 07/16/2001
• Status: Expired due to Term

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Hug, John, Keenan, Richard, Joly, Christophe
• Primary Examiner(s): NGUYEN, LONG T
• Application Number:
  US10/196,110
• Publication Number:
  US 20030020545A1
• Time in Patent Office: 784 Days
• Field of Search: 330/284, 330/285, 330/289, 330/295, 330/296, 330/305, 330/292, 330/293
• US Class Current: 330/296
• CPC Class Codes: H03F 1/26 Modifications of amplifiers to reduce influence of noise generated by amplifying elements
• CPC Class Codes: H03F 1/302 in bipolar transistor amplifiers H03F1/303, H03F1/305, H03F1/307 take precedence

Abstract

A bias circuit for a radio frequency linear power amplifier includes an input for selecting an operating mode varying in quiescent current of an output transistor. A sensor senses a current through the output transistor and a circuit biases the output transistor for maintaining linear performance in each of mode over a range of temperatures. A filter attenuates noise generated within the linear power amplifier. A tank circuit at the collector of a power radio frequency transistor, having an inductor capable of handling the collector current, resonating with a capacitor at the design frequency, permits a reduction in the required inductance and therefore higher levels of integration.

Claims

1. A method for biasing a radio frequency linear power amplifier having an output frequency band having an output transistor, comprising:

(a) selecting one of a plurality of operating modes of a bias circuit, said operating modes differing in at least a quiescent current of the output transistor;

(b) sensing current flowing through said output transistor;

(c) biasing the output transistor based on the selected operating mode and the sensed current, in order to maintain linear performance in each of said operating modes over a range of temperatures; and

(d) attenuating frequency components outside the output frequency band.

2. The method according to claim 1, further comprising connecting a transistor device to an input of the output transistor to maintain said linear performance.

3. The method according to claim 1, further comprising the step of providing breakdown voltage protection for the output transistor with a bipolar breakdown device.