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US 2009/0212872 A1Published application
Wideband Active Balun Using Darlington Pair
AssigneeNational Central University
InventorsHong-Yeh CHANG, Shou-Hsien Weng
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Abstract
An active balun with Darlington pairs obtains a wideband operation. With differential output signals, a size of the active balun is minimized. The present invention can be applied to a transceiver. With a wideband amplitude match and 180° out of phase, the performance of the transceiver is improved by the present invention for a few wide applications.
Claims4
A wideband active balun using Darlington pairs, comprising:
- two Darlington pair modules, said Darlington pair modules comprising a first Darlington pair module and a second Darlington pair module,
- said first Darlington pair module having an input matching circuit, said input matching circuit comprising a first capacitor,
- said first Darlington pair module and said second Darlington pair module separately controlling base biases of first transistors and base biases of second transistors through first resistors and bias resistors respectively,
- said first Darlington pair module and said second Darlington pair module being stabilized through negative feedback resistors separately,
- said first Darlington pair module and said second Darlington pair module separately having output matching circuits said output matching circuit comprising a third capacitor and an inductor with a resistor,
- said output matching circuits of said first Darlington pair module and said second Darlington pair module separately connecting to a first output and a second output,
- said first Darlington pair module and said second Darlington pair module separately having an inductor serially connected with a resistor,
- said resistance capacitor electrically connecting to a bypass capacitor and a first voltage, said first voltage providing a working voltage;
- and
- a current mirror, said current mirror comprising a second resistor, two transistors and a second voltage,
- said current mirror providing a constant current source to have said first Darlington pair module and said second Darlington pair module operated in an active region,
- said second resistor controlling a collector bias of a four transistor,
- said second voltage providing a working voltage,
- wherein a phase imbalance of said first output of said first Darlington pair module is compensated through a fourth capacitor;
- wherein a phase imbalance of said second output of said second Darlington pair module is compensated through a second capacitor and said fourth capacitor;
- and
- wherein said fourth capacitor is a negative feedback capacitor serially connected between said third capacitor and said inductor.
14 more elements
Dependencies are inferred from the claim text.