DIFFERENTIAL CURRENT SENSOR DEVICE AND METHOD
First Claim
1. A voltage converter device, comprising:
- a power switch;
a control module comprising an output to provide a control signal to control the conductivity of the power switch; and
a current sensor having an input configured to receive the control signal and an output configured to provide a feedback signal to the control module, the current sensor comprising;
a first resistor comprising a first terminal and a second terminal;
a first transistor comprising a first current electrode coupled to the second terminal of the first resistor, a second current electrode, and a control electrode configured to receive the control signal;
a second resistor comprising a first terminal coupled to the first terminal of the first resistor and a second terminal;
a second transistor comprising a first current electrode coupled to the second terminal of the second resistor, a second current electrode, and a control electrode configured to receive the control signal; and
a transconductor comprising a first input coupled to the second terminal of the first resistor, a second terminal coupled to the second terminal of the second resistor, and an output configured to provide the feedback signal.
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Accused Products
Abstract
A current sensor having a pair of sense transistors is disclosed. The sense transistors sense a current conducted by a power transistor of a voltage regulator. The ratio in size between the power transistor and the sense transistors corresponds to a scaling factor M. Each sense transistor has an associated series connected sense resistor. The two sense resistors are unbalanced and provide a differential voltage based on the sensed current at the sense transistor to a transconductor. The transconductor has heavy emitter degeneration to provide an output current substantially proportional to the current conducted by the primary power transistor, the proportion determined by the scaling factor M and a ratio of the emitter degeneration and sense resistors.
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Citations
20 Claims
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1. A voltage converter device, comprising:
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a power switch; a control module comprising an output to provide a control signal to control the conductivity of the power switch; and a current sensor having an input configured to receive the control signal and an output configured to provide a feedback signal to the control module, the current sensor comprising; a first resistor comprising a first terminal and a second terminal; a first transistor comprising a first current electrode coupled to the second terminal of the first resistor, a second current electrode, and a control electrode configured to receive the control signal; a second resistor comprising a first terminal coupled to the first terminal of the first resistor and a second terminal; a second transistor comprising a first current electrode coupled to the second terminal of the second resistor, a second current electrode, and a control electrode configured to receive the control signal; and a transconductor comprising a first input coupled to the second terminal of the first resistor, a second terminal coupled to the second terminal of the second resistor, and an output configured to provide the feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A current sensor device comprising:
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a first transistor comprising a first current electrode, and a control electrode configured to receive a control signal, the first transistor configured to draw a first current proportional to a sensed current; a first resistor comprising a first terminal and a second terminal coupled to the first current electrode of the first transistor, the second terminal configured to apply a first voltage based on the first current; a second transistor comprising a first current electrode, and a control electrode configured to receive a control signal, the second transistor configured to draw a second current proportional to a sensed current; a second resistor comprising a first terminal and a second terminal coupled to the first current electrode of the first transistor, the second terminal configured to apply a second voltage based on the first current; and a transconductor comprising a first input coupled to the second terminal of the first resistor, a second input coupled to the second terminal of the second resistor, and an output configured to provide an output current, the output current substantially proportional to the sensed current. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method comprising:
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sensing a first current at a power supply, wherein sensing comprises; receiving a first voltage and a second voltage, the first voltage and second voltage each based on the first current, a voltage difference between the first and second voltages based on a difference between a first resistance and a second resistance; and providing a second current based on the voltage difference; and regulating the first current based on the second current. - View Dependent Claims (18, 19, 20)
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Specification