Method and apparatus for optimizing power dissipation in a low noise amplifier

• US 7,459,970 B2
• Filed: 01/11/2007
• Issued: 12/02/2008
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Yang, Neng-Tze
• Primary Examiner(s): CHOE, HENRY
• Application Number:
  US11/622,424
• Publication Number:
  US 20080211579A1
• Time in Patent Office: 691 Days
• Field of Search: 330/51, 330/98, 330/150, 330/310
• US Class Current: 330/51
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 2200/105 A non-specified detector of the power of a signal being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/507 A switch being used for switching on or off a supply or supplying circuit in an IC-block amplifier circuit
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/45197 Pl types H03F3/45224, H03F3/45251 take precedence
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence

Abstract

A method and a low noise amplifier are provided such that the low noise amplifier has a power dissipation that is adaptive to the noise interference levels. The low noise amplifer includes (i) first, second and third differential amplifiers connected in series each having a terminal for receiving a power supply current; and (ii) first and second switches responsive to a control signal, the first and second switches configured such that, (a) when the control signal is in a first state, the first switch and the second switch enable independent currents to flow in the terminals for receiving a power supply current; and (b) otherwise, the first switch and the second switch enable the terminal for receiving a power supply current of the second differential amplifier to reuse a current provided to the terminal for receiving a power supply current of the third differential amplifier. The control signal is provided by a radio frequency noise power detector, which senses an output signal of the low noise amplifier.

Claims

1. A low noise amplifier, comprising:

first, second and third differential amplifiers connected in series each having a terminal for receiving a power supply current; and

first and second switches responsive to a control signal, the first and second switches configured such that, (a) when the control signal is in a first state, the first switch and the second switch enable independent currents to flow in the terminals for receiving a power supply current; and

(b) otherwise, the first switch and the second switch enable the terminal for receiving a power supply current of the second differential amplifier to reuse a current provided to the terminal for receiving a power supply current of the third differential amplifier.

2. A low noise amplifier as in claim 1, wherein the control signal is provided by a radio frequency noise power detector, which senses an output signal of the low noise amplifier.

3. A low noise amplifier as in claim 2, further comprising a mixer that filters the output signal.

4. A low noise amplifier as in claim 2, further comprising a baseband filter that filters the output signal.

5. A method for providing a low noise amplifier adaptive to interference, comprising:

Connecting first, second and third differential amplifiers in series, each differential amplifier having a terminal for receiving a power supply current; and

Controlling first and second switches by a control signal, the first and second switches configured such that, (a) when the control signal is in a first state, the first switch and the second switch enable independent currents to flow in the terminals for receiving a power supply current; and

(b) otherwise, the first switch and the second switch enable the terminal for receiving a power supply current of the second differential amplifier to reuse a current provided to the terminal for receiving a power supply current of the third differential amplifier.

6. A method as in claim 5, wherein the control signal is provided by a radio frequency noise power detector, which senses an output signal of the low noise amplifier.

7. A method as in claim 6, further comprising filtering the output signal in a mixer.

8. A method as in claim 6, further comprising filtering the output signal in a baseband filter.