US6819179B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable gain low noise amplifier
Assignee: Agency for Science, Technology and Research
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Filing: 2003-04-16
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Granted: 2004-11-16
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Expires: 2023-04-16
Abstract
Abstract The load of the cascode amplifier is varied by connecting another (secondary) load in parallel with the original load. The secondary load is connected through a MOSFET switch. During the High Gain Mode the MOSFET switch is OFF and the secondary load is electrically isolated from the main load, whereas in the Low Gain Mode the switch is turned ON and the secondary load appears across the primary load, reducing the effective load impedance. The secondary load is AC coupled such that the DC bias current does not pass through the secondary load and hence the Noise Figure (NF) and linearity (IIP3) performance are better in the Low Gain Mode. A number of such switchable loads can be connected across the load to obtain programmability.
Inventors
- 👤 Muthusamy Kumarasamy Raja
- 👤 Nuntha Kumar Krishnasamy Maniam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:31
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/189; H03F3/19; H03F3/195; H03F1/00; H03F1/08; H03F1/22; H03F1/223; H03F1/26; H03F1/32; H03F3/72; H03G; H03G1/00; H03G1/0005; H03G1/0088; H03G3/00; H03G3/001; H03F2200/00; H03F2200/243; H03F2200/294; H03F2200/372; H03F2200/421; H03F2200/501
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
128 words
A low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a gain control circuit coupled to said output of said cascode amplifier stage, said gain control circuit providing said secondary load, where said secondary load is coupled via switching means to said output of said cascode amplifier stage, where said secondary load is varied by controlling the resistance of said switching means.
Claim 2
Dependent Claim
128 words
A low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a gain control circuit coupled to said output of said cascode amplifier stage, said gain control circuit providing said secondary load, where said secondary load is coupled via switching means to said output of said cascode amplifier stage, where said secondary load is varied by controlling the resistance of said switching means.
Claim 3
Dependent Claim
26 words
The low noise amplifier of claim 1 , wherein said cascode amplifier stage is in a high gain mode when said switching means is not conducting.
Claim 4
Dependent Claim
26 words
The low noise amplifier of claim 1 , wherein said secondary load is electrically isolated from said primary load when said switching means is not conducting.
Claim 5
Dependent Claim
25 words
The low noise amplifier of claim 1 , wherein said cascode amplifier stage is in a low gain mode when said switching means is conducting.
Claim 6
Dependent Claim
35 words
The low noise amplifier of claim 1 , wherein said secondary load is coupled across said primary load when said switching means is conducting, thereby reducing the effective load seen by said cascode amplifier stage.
Claim 7
Dependent Claim
19 words
The low noise amplifier of claim 1 , wherein said switching means acts as a voltage controlled resistive means.
Claim 8
Dependent Claim
30 words
The low noise amplifier of claim 6 , wherein said voltage controlled resistive means is varied as the control voltage is varied at the control gate of said switching means.
Claim 9
Dependent Claim
21 words
The low noise amplifier of claim 1 , wherein a plurality of said switching means is arranged in a series/parallel circuit.
Claim 10
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said switching means is a NMOS transistor.
Claim 11
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said switching means is a PMOS transistor.
Claim 12
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said switching means is a BJT transistor.
Claim 13
Dependent Claim
21 words
The low noise amplifier of claim 1 , wherein a plurality of said secondary loads is arranged in a series/parallel circuit.
Claim 14
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said secondary load is a resistive means.
Claim 15
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said secondary load is an inductive means.
Claim 16
Dependent Claim
16 words
The low noise amplifier of claim 1 , wherein said secondary load is a capacitive means.
Claim 17
Dependent Claim
165 words
A variable gain low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load, through a load switching means, in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a gain control circuit coupled between said output of said cascode amplifier stage and the negative terminal of a power supply with a positive and a negative terminal, said gain control circuit providing said secondary load, where said variable gain low noise amplifier is in a low gain mode when said secondary load is switched in through said load switching means, and where said variable gain low noise amplifier is in a high gain mode when said secondary load is switched out.
Claim 18
Dependent Claim
165 words
A variable gain low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load, through a load switching means, in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a gain control circuit coupled between said output of said cascode amplifier stage and the negative terminal of a power supply with a positive and a negative terminal, said gain control circuit providing said secondary load, where said variable gain low noise amplifier is in a low gain mode when said secondary load is switched in through said load switching means, and where said variable gain low noise amplifier is in a high gain mode when said secondary load is switched out.
Claim 19
Dependent Claim
147 words
The variable gain low noise amplifier of claim 16 , wherein said cascode amplifier stage further comprises: a first gain stage means coupled to a second gain stage means, where the control gate of said first gain stage means is coupled to biasing means, and via a first capacitive means in series with a first inductive means, to said input of said cascode amplifier stage; where the source of said first gain stage means is coupled via a second inductive means in series with a current source to the negative terminal of said power supply, where the drain of said second gain stage means is coupled via a third inductive means to the positive terminal of said power supply, and where the junction of said drain of said second gain stage means and said third inductive means is coupled to said output of said cascode amplifier stage.
Claim 20
Dependent Claim
72 words
The variable gain low noise amplifier of claim 16 , wherein said gain control circuit further comprises: a first capacitive means, said load switching means, and said secondary load all in series and coupled between said output of said cascode amplifier stage and the negative terminal of said power supply, where the control gate of said load switching means is coupled via resistive means to a control input providing a control voltage.
Claim 21
Dependent Claim
40 words
The variable gain low noise amplifier of claim 18 , wherein said load switching means acts as a voltage controlled resistive means which is varied as said control voltage is varied at the control gate of said load switching means.
Claim 22
Dependent Claim
34 words
The variable gain low noise amplifier of claim 16 , wherein the control gate of said load switching means is coupled via a second capacitive means to the negative terminal of said power supply.
Claim 23
Dependent Claim
29 words
The variable gain low noise amplifier of claim 16 , wherein said load switching means of said gain control circuit is conducting when said secondary load is switched in.
Claim 24
Dependent Claim
30 words
The variable gain low noise amplifier of claim 16 , wherein said load switching means of said gain control circuit is not conducting when said secondary load is switched out.
Claim 25
Dependent Claim
23 words
The variable gain low noise amplifier of claim 16 , wherein a plurality of said switching means is arranged in a series/parallel circuit.
Claim 26
Dependent Claim
19 words
The variable gain low noise amplifier of claim 16 , wherein said load switching means is a NMOS transistor.
Claim 27
Dependent Claim
19 words
The variable gain low noise amplifier of claim 16 , wherein said load switching means is a PMOS transistor.
Claim 28
Dependent Claim
19 words
The variable gain low noise amplifier of claim 16 , wherein said load switching means is a BJT transistor.
Claim 29
Dependent Claim
23 words
The variable gain low noise amplifier of claim 16 , wherein a plurality of said secondary loads is arranged in a series/parallel circuit.
Claim 30
Dependent Claim
18 words
The variable gain low noise amplifier of claim 16 , wherein said secondary load is a resistive means.
Claim 31
Dependent Claim
18 words
The variable gain low noise amplifier of claim 16 , wherein said secondary load is an inductive means.
Claim 32
Dependent Claim
18 words
The variable gain low noise amplifier of claim 16 , wherein said secondary load is a capacitive means.
Claim 33
Dependent Claim
137 words
A low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a programmable gain control coupled to said output of said cascode amplifier stage to provide said secondary load, said programmable gain control having decoding means to couple a plurality of load elements via load switching means to said output of said cascode amplifier stage by switching said load elements in and out, thereby varying the gain of said cascode amplifier stage.
Claim 34
Dependent Claim
137 words
A low noise amplifier comprising: a cascode amplifier stage with an input and an output, said amplifier stage delivering an amplified high frequency input signal to a primary load at said output, where the load of said cascode amplifier stage is varied by coupling a secondary load in parallel with said primary load, where said secondary load is AC coupled using capacitive means such that a DC bias current cannot pass through said secondary load; and a programmable gain control coupled to said output of said cascode amplifier stage to provide said secondary load, said programmable gain control having decoding means to couple a plurality of load elements via load switching means to said output of said cascode amplifier stage by switching said load elements in and out, thereby varying the gain of said cascode amplifier stage.
Claim 35
Dependent Claim
145 words
The low noise amplifier of claim 31 , wherein said cascode amplifier stage further comprises: a first gain stage means coupled to a second gain stage means, where the control gate of said first gain stage means is coupled to biasing means, and via a first capacitive means in series with a first inductive means, to said input of said cascode amplifier stage; where the source of said first gain stage means is coupled via a second inductive means in series with a current source to the negative terminal of said power supply, where the drain of said second gain stage means is coupled via a third inductive means to the positive terminal of said power supply, and where the junction of said drain of said second gain stage means and said third inductive means is coupled to said output of said cascode amplifier stage.
Claim 36
Dependent Claim
98 words
The low noise amplifier of claim 31 , wherein said programmable gain control further comprises: an analog-to-digital converter and decoder with a number of outputs equal to the plurality of said load elements, where each of said load elements comprises said load switching means in series with an impedance and coupled between said output of said cascode amplifier stage and the negative terminal of a power supply with a positive and a negative terminal, where the control gate of each of said load switching means is coupled to one of said outputs of said analog-to-digital converter and decoder.
Claim 37
Dependent Claim
29 words
The low noise amplifier of claim 31 , wherein said secondary load is varied as the control voltage is varied at the control gate of said load switching means.
Claim 38
Dependent Claim
21 words
The low noise amplifier of claim 31 , wherein a plurality of said switching means is arranged in a series/parallel circuit.
Claim 39
Dependent Claim
17 words
The low noise amplifier of claim 31 , wherein said load switching means is a NMOS transistor.
Claim 40
Dependent Claim
17 words
The low noise amplifier of claim 31 , wherein said load switching means is a PMOS transistor.
Claim 41
Dependent Claim
17 words
The low noise amplifier of claim 31 , wherein said load switching means is a BJT transistor.
Claim 42
Dependent Claim
21 words
The low noise amplifier of claim 31 , wherein a plurality of said secondary loads is arranged in a series/parallel circuit.
Claim 43
Dependent Claim
16 words
The low noise amplifier of claim 31 , wherein said secondary load is a resistive means.
Claim 44
Dependent Claim
16 words
The low noise amplifier of claim 31 , wherein said secondary load is an inductive means.
Claim 45
Dependent Claim
16 words
The low noise amplifier of claim 31 , wherein said secondary load is a capacitive means.
Claim 46
Dependent Claim
138 words
A gain control circuit comprising: a capacitive means, a load switching means, and a load, all in series, and coupled between the output of said gain control circuit and a reference potential, where the input of said gain control circuit is coupled to the control gate of said load switching means, where a control voltage, applied to said input, controls the impedance of said gain control circuit, such that when said load switching means is off, thus creating a high resistance between the terminals of said switching means, said gain control circuit offers a high impedance between said output and said reference potential, and when said load switching means is on, thus creating a low resistance between the terminals of said switching means, said gain control circuit offers a low impedance between said output and said reference potential.
Claim 47
Dependent Claim
138 words
A gain control circuit comprising: a capacitive means, a load switching means, and a load, all in series, and coupled between the output of said gain control circuit and a reference potential, where the input of said gain control circuit is coupled to the control gate of said load switching means, where a control voltage, applied to said input, controls the impedance of said gain control circuit, such that when said load switching means is off, thus creating a high resistance between the terminals of said switching means, said gain control circuit offers a high impedance between said output and said reference potential, and when said load switching means is on, thus creating a low resistance between the terminals of said switching means, said gain control circuit offers a low impedance between said output and said reference potential.
Claim 48
Dependent Claim
29 words
The gain control circuit of claim 43 , wherein a capacitive means is coupled between said output and said load switching means to provide AC coupling for said load.
Claim 49
Dependent Claim
31 words
The gain control circuit of claim 43 , wherein said control voltage when varied, varies the gain of a filter circuit when coupled to said output of said gain control circuit.
Claim 50
Dependent Claim
31 words
The gain control circuit of claim 43 , wherein said control voltage when varied, varies the gain of a mixer circuit when coupled to said output of said gain control circuit.
Claim 51
Dependent Claim
31 words
The gain control circuit of claim 43 , wherein said control voltage when varied, varies the gain of an amplifier circuit when coupled to said output of said gain control circuit.
Claim 52
Independent Claim
131 words
The method of varying the gain of a low noise amplifier, comprising the steps of: a) providing a cascode amplifier stage driving a primary load; b) AC coupling a secondary load across said primary load at the output of said cascode amplifier stage; c) coupling a switching means between said secondary load and the output of said cascode amplifier stage; d) applying a control voltage to said switching means to vary the impedance of said switching means; e) switching said switching means into the off state, thereby switching said low noise amplifier into a high gain mode; f) switching said switching means into the on state, thereby switching said low noise amplifier into a low gain mode, and g) AC coupling a plurality of said secondary loads across said primary load.
Claim 53
Independent Claim
131 words
The method of varying the gain of a low noise amplifier, comprising the steps of: a) providing a cascode amplifier stage driving a primary load; b) AC coupling a secondary load across said primary load at the output of said cascode amplifier stage; c) coupling a switching means between said secondary load and the output of said cascode amplifier stage; d) applying a control voltage to said switching means to vary the impedance of said switching means; e) switching said switching means into the off state, thereby switching said low noise amplifier into a high gain mode; f) switching said switching means into the on state, thereby switching said low noise amplifier into a low gain mode, and g) AC coupling a plurality of said secondary loads across said primary load.
Claim 54
Dependent Claim
23 words
The method of claim 48 , whereby the gain of said low noise amplifier can be varied continuously by varying said control voltage.
Claim 55
Dependent Claim
24 words
The method of claim 48 , where controlling said secondary loads through a decoder, provides programmability of the gain of said low noise amplifier.
References Cited (Backward Citations)
US6046640A
Cited
US6466095B1
Cited
EP0977352A2
Cited
US6184751B1
Cited
US6366166B1
Cited
US20030067359A1
Cited
US6438364B1
Cited
US6424222B1
Cited
US6392492B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-11-16 | 2008-05-17 | 2008-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-11-16 | 2012-05-17 | 2012-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-11-16 | 2016-05-17 | 2016-11-16 | $7700.00 | Window Closed / Lapsed |