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US 7,031,684 B2Granted
Variable gain amplifier device
AssigneeKabushiki Kaisha Toshiba
InventorsShoji Otaka, Takafumi Yamaji
Life of this patent
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Abstract
A variable gain amplifier device controlled by a first gain control signal comprises a gain controlled amplifier having a gain and including a differential pair of first and second MOS type transistors configured to operate in a weak inversion region; and a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal.
Claims19
A variable gain amplifier device controlled by a first gain control signal, comprising:
- a gain controlled amplifier having a gain and including a differential pair of first and second MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- wherein the control signal converter comprises a differential pair of third and fourth MOS type transistors including a common source terminal to which a direct current Io is supplied and configured to operate in the weak inversion region, the third MOS type transistor including a drain terminal and a gate terminal which are connected to each other, a current Io·exp(−b·Vc/VT) (where, Vc is the first gain control signal, VT is the thermal voltage, and b>0) being applied to the drain terminal of the third MOS type transistor, the fourth MOS type transistor including a gate terminal fixed to a constant direct current level, and a potential difference between the gate terminal of the third MOS type transistor and the gate terminal of the fourth MOS type transistor corresponding to the second gain control signal.
1 more element
A variable gain amplifier device controlled by a first gain control signal, comprising:
- a gain controlled amplifier having a gain and including a first differential pair of first and second MOS type transistors configured to operate in a weak inversion region, and a second differential pair of third and fourth MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- wherein the control signal converter comprises a differential pair of fifth and sixth MOS type transistors including a common source terminal to which a direct current Io is supplied and configured to operate in the weak inversion region, the fifth MOS type transistor including a drain terminal and a gate terminal which are connected to each other, a current Io·exp(−b·Vc/VT) (where, Vc is the first gain control signal, VT is the thermal voltage, and b>0) being applied to the drain terminal of the fifth MOS type transistor, the sixth MOS type transistor including a gate terminal fixed to a constant direct current level, and a potential difference between the gate terminal of the fifth MOS type transistor and the gate terminal of the sixth MOS type transistor corresponding to the second gain control signal.
1 more element
A wireless communication apparatus comprising:
- a baseband signal generator configured to generate first and second transmission baseband signals orthogonal to each other;
- first and second baseband signal amplifiers each including a variable gain amplifier device including,
- a gain controlled amplifier having a gain and including a differential pair of first and second MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- and configured to amplify the first and second transmission baseband signals, respectively;
- a quadrature modulator configured to multiply the amplified first transmission baseband signal by a first local signal to produce a first radio frequency signal, multiply the amplified second transmission baseband signal by a second local signal having a π/2-phase difference from the first local signal to produce a second radio frequency signal, and combine the first radio frequency signal and the second radio frequency signal into a transmission radio frequency signal;
- and
- a transmitter configured to transmit the transmission radio frequency signal.
6 more elements
A wireless communication apparatus comprising:
- receivers configured to receive a radio frequency signal;
- a quadrature modulator configured to multiply the received radio frequency signal by a first local signal to produce a first reception baseband signal, and multiply the received radio frequency signals by a second local signal having a π/2-phase difference from the first third local signal to produce a second reception baseband signal having a π/2-phase difference from the first baseband signal;
- first and second baseband amplifiers each including a variable gain amplifier device including,
- a gain controlled amplifier having a gain and including a differential pair of first and second MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain
- controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- and configured to amplify the first and second reception baseband signals, respectively;
- and
- a baseband signal processor configured to process the amplified first and second reception baseband signals.
7 more elements
A wireless communication apparatus comprising:
- a baseband signal generator configured to generate first and second transmission baseband signals orthogonal to each other;
- first and second baseband signal amplifiers each including a variable gain amplifier device including,
- a gain controlled amplifier having a gain and including a first differential pair of first and second MOS type transistors configured to operate in a weak inversion region, and a second differential pair of third and fourth MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- and configured to amplify the first and second transmission baseband signals, respectively;
- a quadrature modulator configured to multiply the amplified first transmission baseband signal by a first local signal to produce a first radio frequency signal, multiply the amplified second transmission baseband signal by a second local signal having a π/2-phase difference from the first local signal to produce a second radio frequency signal, and combine the first radio frequency signal and the second radio frequency signal into a transmission radio frequency signal;
- and
- a transmitter configured to transmit the transmission radio frequency signal.
6 more elements
A wireless communication apparatus comprising:
- receivers configured to receive a radio frequency signal;
- a quadrature modulator configured to multiply the received radio frequency signal by a first local signal to produce a first reception baseband signal, and multiply the received radio frequency signals by a second local signal having a π/2-phase difference from the first local signal to produce a second reception baseband signal having a π/2-phase difference from the first baseband signal;
- first and second baseband amplifiers each including a variable gain amplifier device including, a gain controlled amplifier having a gain and including a first differential pair of first and second MOS type transistors configured to operate in a weak inversion region, and a second differential pair of third and fourth MOS type transistors configured to operate in a weak inversion region;
- and
- a control signal converter configured to convert the first gain control signal into a second gain control signal, and supply the second gain control signal to the gain controlled amplifier to exponentially vary the gain with respect to the first gain control signal,
- and configured to amplify the first and second reception baseband signals, respectively;
- and
- a baseband signal processor configured to process the amplified first and second reception baseband signals.
5 more elements
Dependencies are inferred from the claim text.