US6492845B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low voltage current sense amplifier circuit
Assignee: Shenzhen STS Microelectronics Co Ltd
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Filing: 2001-12-27
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Granted: 2002-12-10
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Expires: 2021-12-27
Abstract
Abstract A current sense amplifier including a transconductance amplifier to measure a current passing through a sense resistor and generate a reference current indicative of the measured current. A current mirror circuit is connected to the transconductance amplifier and receives the reference current for amplification to generate an amplified output current. A cascode circuit is connected serially to the current mirror circuit to boost an output impedance for the amplifier at the output of the generated amplified output current. The current mirror circuit and cascode circuit of the current sense amplifier are each formed from a pair of transistors sharing a common control node, with the transistors realized using with bipolar or MOS technology.
Inventors
- 👤 Weiguo Ge
- 👤 Congqing Xiong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:12
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/08; H03F1/22; H03F1/223
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
65 words
A current sense amplifier, comprising: a transconductance amplifier measuring a current passing through a sense resistor to generate a reference current indicative of the measured current; a current mirror circuit connected to the transconductance amplifier to amplify the reference current and generate an amplified output current; and a cascode circuit connected between the current mirror circuit and an output of the generated amplified output current.
Claim 2
Dependent Claim
65 words
A current sense amplifier, comprising: a transconductance amplifier measuring a current passing through a sense resistor to generate a reference current indicative of the measured current; a current mirror circuit connected to the transconductance amplifier to amplify the reference current and generate an amplified output current; and a cascode circuit connected between the current mirror circuit and an output of the generated amplified output current.
Claim 3
Dependent Claim
33 words
The amplifier as in claim 1 wherein the connection of the cascode circuit to the current mirror circuit boosts an output impedance for the amplifier with respect to the generated amplified output current.
Claim 4
Dependent Claim
37 words
The amplifier as in claim 1 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in the measured current passing through the sense resistor.
Claim 5
Dependent Claim
42 words
The amplifier as in claim 1 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in amplifier operating voltage over a range extending from about 2V to about 5V.
Claim 6
Dependent Claim
68 words
The amplifier as in claim 1 wherein the current mirror circuit comprises a first pair of transistors sharing a first common control node, and wherein the cascode circuit comprises a second pair of transistors sharing a second common control node, and wherein the first and second pairs of transistors are connected serially with each other to effectuate the connection of the cascode circuit and the current mirror circuit.
Claim 7
Dependent Claim
66 words
The amplifier as in claim 5 wherein the serial connection is accomplished by connecting a node of a first transistor in the first pair of transistors to a node of a first transistor in the second pair of transistors, and connecting a node of a second transistor in the first pair of transistors to a node of the second transistor in the second pair of transistors.
Claim 8
Dependent Claim
30 words
The amplifier as in claim 6 wherein the transconductance amplifier comprises: an operational amplifier having an output; and a transistor having a control node connected to the operational amplifier output.
Claim 9
Dependent Claim
28 words
The amplifier as in claim 7 wherein the transistor of the transconductance amplifier is the first transistor in the first pair of transistors comprising the current mirror circuit.
Claim 10
Dependent Claim
33 words
The amplifier as in claim 7 wherein a node of the first transistor in the second pair of transistors is connected to an input of the operational amplifier to receive the reference current.
Claim 11
Dependent Claim
24 words
The amplifier as in claim 7 wherein the first pair of transistors are matched transistors and the second pair of transistors are matched transistors.
Claim 12
Dependent Claim
22 words
The amplifier as in claim 1 wherein the recited components of the current sense amplifier are implemented on an integrated circuit chip.
Claim 13
Dependent Claim
116 words
A current sense amplifier, comprising: an operational amplifier having an output and a pair of inputs connected across a sense resistor to measure a current passing therethrough and generate at one of the inputs a reference current indicative of the measured current; a first pair of transistors having a first common control node connected to the output of the operational amplifier; a second pair of transistors having second common control node, a first transistor of the second pair connected to receive the reference current and a second transistor of the second pair connected to an output of the current sense amplifier, wherein the first pair of transistors and the second pair of transistors are connected serially.
Claim 14
Dependent Claim
116 words
A current sense amplifier, comprising: an operational amplifier having an output and a pair of inputs connected across a sense resistor to measure a current passing therethrough and generate at one of the inputs a reference current indicative of the measured current; a first pair of transistors having a first common control node connected to the output of the operational amplifier; a second pair of transistors having second common control node, a first transistor of the second pair connected to receive the reference current and a second transistor of the second pair connected to an output of the current sense amplifier, wherein the first pair of transistors and the second pair of transistors are connected serially.
Claim 15
Dependent Claim
26 words
The current sense amplifier as in claim 12 wherein the operational amplifier and a first transistor of the first pair of transistors form a transconductance amplifier.
Claim 16
Dependent Claim
18 words
The current sense amplifier as in claim 12 wherein the first pair of transistors form a current mirror.
Claim 17
Dependent Claim
18 words
The current sense amplifier as in claim 12 wherein the second pair of transistors form a cascode circuit.
Claim 18
Dependent Claim
24 words
The current sense amplifier as in claim 12 wherein the recited components of the current sense amplifier are implemented on an integrated circuit chip.
Claim 19
Dependent Claim
68 words
The current sense amplifier as in claim 12 wherein the serial connection comprises: connecting a node of a first transistor in the first pair of transistors to a first node of the first transistor in the second pair of transistors; and connecting a node of a second transistor in the first pair of transistors to a first node of the second transistor in the second pair of transistors.
Claim 20
Dependent Claim
56 words
The current sense amplifier as in claim 17 wherein a second node of the first transistor in the second pair is connected to the input of the operational amplifier to receiver the reference current and a second node of the second transistor in the second pair is connected to the output of the current sense amplifier.
Claim 21
Dependent Claim
27 words
The current sense amplifier as in claim 12 wherein the serial connection boosts an output impedance for the amplifier with respect to the generated amplified output current.
Claim 22
Dependent Claim
39 words
The current sense amplifier as in claim 12 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in the measured current passing through the sense resistor.
Claim 23
Dependent Claim
44 words
The current sense amplifier as in claim 12 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in amplifier operating voltage over a range extending from about 2V to about 5V.
Claim 24
Dependent Claim
149 words
A current sense amplifier, comprising: a differential amplifier having an output and a pair of inputs connected across a sense resistor to measure a current passing therethrough and generate at one of the inputs a reference current indicative of the measured current; a first transistor pair having a first common control node connected to a bias voltage, a first one of the transistors connected to the differential amplifier input to conduct the reference current and a second one of the transistors conducting an output current; a second transistor pair having a second common control node connected to the output of the operational amplifier, the second transistor pair connected serially to the first transistor pair such that a first one of the transistors for the second transistor pair also conducts the reference current and a second one of the transistors for the second transistor pair also conducts the output current.
Claim 25
Dependent Claim
149 words
A current sense amplifier, comprising: a differential amplifier having an output and a pair of inputs connected across a sense resistor to measure a current passing therethrough and generate at one of the inputs a reference current indicative of the measured current; a first transistor pair having a first common control node connected to a bias voltage, a first one of the transistors connected to the differential amplifier input to conduct the reference current and a second one of the transistors conducting an output current; a second transistor pair having a second common control node connected to the output of the operational amplifier, the second transistor pair connected serially to the first transistor pair such that a first one of the transistors for the second transistor pair also conducts the reference current and a second one of the transistors for the second transistor pair also conducts the output current.
Claim 26
Dependent Claim
24 words
The amplifier as in claim 22 wherein the second transistor pair effectuates a 1:n gain enhancement of the reference current to the output current.
Claim 27
Dependent Claim
15 words
The amplifier as in claim 23 wherein the second transistor pair forms a current mirror.
Claim 28
Dependent Claim
25 words
The amplifier as in claim 22 wherein the first transistor pair boosts an output impedance for the amplifier with respect to the generated output current.
Claim 29
Dependent Claim
15 words
The amplifier as in claim 25 wherein the first transistor pair forms a cascode circuit.
Claim 30
Dependent Claim
37 words
The amplifier as in claim 22 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in the measured current passing through the sense resistor.
Claim 31
Dependent Claim
42 words
The amplifier as in claim 22 wherein a value calculated from a ratio of the output current to the reference current is substantially stable with respect to changes in amplifier operating voltage over a range extending from about 2V to about 5V.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-12-09 | 2006-06-10 | 2006-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-12-09 | 2010-06-10 | 2010-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-12-09 | 2014-06-10 | 2014-12-10 | $7700.00 | Window Closed / Lapsed |