Signal dependent current controlled amplifier and method of performing same
AssigneeNokia Mobile Phones Ltd.
InventorMarkus Nentwig
Life of this patent
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Abstract
A low-noise amplifier for radio frequency signals uses the magnitude of the input signal to adjust the output current of a current source if the input signal magnitude exceeds a predetermined value. The current source provides operating current to the low-noise amplifier. Compensation for gain reduction due to large input signal magnitude is therefore achieved by increasing the gain of the low noise amplifier in such situations by increased operating current. As a result, power consumption savings and better linearization are achieved, especially for such low-noise amplifiers used in mobile receivers.
Claims17
A method for reducing the power consumption of a differential amplifier for use in mobile radio frequency receivers having its operating current controlled by a current source, wherein an input signal which is or contains a desired subsequently detected;
- comprising the steps of:
- varying the output current of the current source to follow the instantaneous magnitude of the input signal if the input signal is greater than a predetermined value;
- and
- controlling the gain of the differential amplifier in response to the output current of the current source so that the gain of the differential amplifier is increased by the increased output current of the current source so as to compensate for the normal gain decrease of the differential amplifier in response to the input signal being greater than the predetermined value and so that the total power consumption of the amplifier is reduced when such input signal is below the predetermined value.
A method for reducing the power consumption of an amplifier having its operating current controlled by a current source, wherein an input signal is amplified, comprising the steps of:
- varying the output current of the current source to follow the magnitude of the input signal if the input signal is greater than a predetermined value;
- and
- controlling the gain of the amplifier in response to the output current of the current source;
- whereby the gain of the amplifier is controlled by the increased output current of the current source so as to compensate for the gain decrease of the amplifier in response to the input signal being greater than the predetermined value and so that the total power consumption of the amplifier is reduced when such input signal is below the predetermined value.
A circuit arrangement for reducing the power consumption of a differential amplifier for use in mobile radio frequency receivers, wherein an input signal which is or contains a desired signal received from an antenna is amplified and the amplified desired signal is subsequently detected, comprising:
- means for receipt of the input signal;
- a current source;
- means for varying the output current of the current source to follow the instantaneous magnitude of the input signal if the input signal is greater than predetermined value;
- and
- means for supplying the output current of the current source to the differential amplifier so that the gain of the differential amplifier is increased by the increased output current of the current source so as to compensate for the normal gain decrease of the differential amplifier in response to the input signal being greater than the predetermined valve so that the power consumption of the amplifier is reduced when such input signal is below the predetermined valve.
Dependencies are inferred from the claim text.