US 10,056,874 B1Granted

Power amplifier self-heating compensation circuit

AssigneepSemi Corporation

InventorsTero Tapio Ranta, Keith Bargroff, Christopher Murphy, Robert Mark Englekirk

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Abstract

Temperature compensation circuits and methods for adjusting one or more circuit parameters of a power amplifier (PA) to maintain approximately constant Gain versus time during pulsed operation sufficient to substantially offset self-heating of the PA. Some embodiments compensate for PA Gain “droop” due to self-heating using a Sample and Hold (S&H) circuit. The S&H circuit samples and holds an initial temperature of the PA at commencement of a pulse. Thereafter, the S&H circuit generates a continuous measurement that corresponds to the temperature of the PA during the remainder of the pulse. A Gain Control signal is generated that is a function of the difference between the initial temperature and the operating temperature of the PA as the PA self-heats for the duration of the pulse. The Gain Control signal is applied to one or more adjustable or tunable circuits within a PA to offset the Gain droop of the PA.

Claims16

Dependent claims

A compensation circuit configured to monitor a target circuit having one or more performance parameters affected by self-heating during operation of the target circuit, wherein the compensation circuit is configured to be coupled to and adjust one or more circuit parameters of the target circuit sufficient to substantially offset the effect of self-heating during operation of the target circuit on the one or more performance parameters, the compensation circuit including:

(a) at least one sensor located with respect to the target circuit so as to measure the temperature T of the target circuit and generate an output signal representing such temperature T;
(b) at least one tracking circuit, each coupled to at least one sensor, configured to capture a temperature T(t=t0) at a time t0 after the commencement of operation of the target circuit, and to sample a temperature T(t>t0) at times after time t0 and during operation of the target circuit, the at least one tracking circuit including:
(1) a differential amplifier having a first input coupled to the output signal of a corresponding sensor, a second input, and an output representing the difference between signals applied to the first input and the second input;
and
(2) a storage capacitor coupled to the second input of the differential amplifier and selectively coupled to the differential amplifier output;
wherein:
(A) in a first phase, the output of the differential amplifier is coupled to the storage capacitor and to the second input of the differential amplifier at least at time t0, such that a charge on the capacitor represents an initial temperature T(t=t0);
and
(B) in a second phase, the output of the differential amplifier is uncoupled from the storage capacitor and represents the difference AT between (i) the output signal of the corresponding sensor coupled to the first input and representing the temperature T(t>t0), and (ii) the storage capacitor charge coupled to the second input and representing the temperature T(t=t0);
and
(c) a correction circuit, coupled to at least one tracking circuit, for generating a correction signal as a function of AT from the coupled at least one tracking circuit, the correction signal being configured to be coupled to and adjust the one or more circuit parameters of the target circuit sufficient to substantially offset the effect of self-heating during operation of the target circuit on the one or more performance parameters.

8 more elements

An integrated circuit including (1) an amplifier having a Gain that droops during operation and (2) a compensation circuit, the compensation circuit including:

(a) at least one sensor located with respect to the amplifier so as to measure the temperature T of the amplifier and generate an output signal representing such temperature T;
(b) at least one tracking circuit, each coupled to at least one sensor, configured to capture a temperature T(t=t0) at a time t0 after the commencement of operation of the amplifier, and to sample a temperature T(t>t0) at times after time t0 and during operation of the amplifier, the at least one tracking circuit including:
(1) a differential amplifier having a first input coupled to the output signal of a corresponding sensor, a second input, and an output representing the difference between signals applied to the first input and the second input;
and
(2) a storage capacitor coupled to the second input of the differential amplifier and selectively coupled to the differential amplifier output;
wherein:
(A) in a first phase, the output of the differential amplifier is coupled to the storage capacitor and to the second input of the differential amplifier at least at time t0, such that a charge on the capacitor represents an initial temperature T(t=t0);
and
(B) in a second phase, the output of the differential amplifier is uncoupled from the storage capacitor and represents the difference AT between (i) the output signal of the corresponding sensor coupled to the first input and representing the temperature T(t>t0), and (ii) the storage capacitor charge coupled to the second input and representing the temperature T(t=t0);
and
(c) a correction circuit, coupled to at least one tracking circuit, for generating a correction signal as a function of AT from the coupled at least one tracking circuit, the correction signal being coupled to one or more circuits on the integrated circuit to adjust one or more circuit parameters of the one or more circuits sufficient to substantially offset the effect of self-heating during operation of the amplifier on the Gain of the amplifier.

8 more elements

A method for compensating a target circuit having one or more performance parameters affected by self-heating during operation of the target circuit, including:

(a) providing at least one sensor located with respect to the target circuit so as to measure the temperature T of the target circuit and generate an output signal representing such temperature T;
(b) providing at least one tracking circuit, each coupled to at least one sensor, configured to capture a temperature T(t=t0) at a time t0 after the commencement of operation of the target circuit, and to sample a temperature T(t>t0) at times after time t0 and during operation of the target circuit, the at least one tracking circuit including:
(1) a differential amplifier having a first input coupled to the output signal of a corresponding sensor, a second input, and an output representing the difference between signals applied to the first input and the second input;
(2) a storage capacitor coupled to the second input of the differential amplifier and selectively coupled to the differential amplifier output;
(c) in a first phase, coupling the output of the differential amplifier to the storage capacitor and to the second input of the differential amplifier at least at time t0, thereby charging the capacitor to a charge that represents an initial temperature T(t=t0);
(d) in a second phase, uncoupling the output of the differential amplifier from the storage capacitor, such that the output of the differential amplifier represents the difference AT between (i) the output signal of the corresponding sensor coupled to the first input and representing the temperature T(t>t0), and (ii) the storage capacitor charge coupled to the second input and representing the temperature T(t=t0);
and
(e) generating a correction signal as a function of AT from the at least one tracking circuit, the correction signal being configured to be coupled to and adjust the one or more circuit parameters of the target circuit sufficient to substantially offset the effect of self-heating during operation of the target circuit on the one or more performance parameters.

5 more elements

A method for compensating an integrated circuit including (1) an amplifier having a Gain that droops during operation and (2) a compensation circuit, the method including:

(a) providing at least one sensor located with respect to the amplifier so as to measure the temperature T of the amplifier and generate an output signal representing such temperature T;
(b) providing at least one tracking circuit, each coupled to at least one sensor, configured to capture a temperature T(t=t0) at a time t0 after the commencement of operation of the amplifier, and to sample a temperature T(t>t0) at times after time t0 and during the operation of the amplifier, the at least one tracking circuit including:
(1) a differential amplifier having a first input coupled to the output signal of a corresponding sensor, a second input, and an output representing the difference between signals applied to the first input and the second input;
and
(2) a storage capacitor coupled to the second input of the differential amplifier and selectively coupled to the differential amplifier output;
(c) in a first phase, coupling the output of the differential amplifier to the storage capacitor and to the second input of the differential amplifier at least at time t0, thereby charging the capacitor to a charge that represents an initial temperature T(t=t0);
(d) in a second phase, uncoupling the output of the differential amplifier from the storage capacitor, such that the output of the differential amplifier represents the difference AT between (i) the output signal of the corresponding sensor coupled to the first input and representing the temperature T(t>t0), and (ii) the storage capacitor charge coupled to the second input and representing the temperature T(t=t0);
(e) providing a comparison and correction circuit, coupled to at least one sample and hold circuit, for determining ΔT=T(t>t0)−T(t=t0);
(f) generating a correction signal as a function of AT;
and
(g) coupling the correction signal to one or more circuits on the integrated circuit to adjust one or more circuit parameters of the one or more circuits sufficient to substantially offset the effect of self-heating during operation of the amplifier on the Gain of the amplifier.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/445,811Filed 28 Feb 2017
Granted: 21 Aug 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

H03G 3/3042
In high-frequency amplifiers or in frequency-changers: in modulators, frequency-changers, transmitters or power amplifiers
H03F 1/30
Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements: modifications of…
H03F 1/303
Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters: using a switching device
H03F 1/304
Using a switching device: and using digital means