System and circuitry to provide stable transconductance for biasing
First Claim
1. An amplifier system comprising:
- an input amplifier configured to receive an analog input signal and provide an amplified signal corresponding to the analog input signal;
a tracking loop configured to employ delta modulation for tracking the amplified signal, the tracking loop providing a corresponding output signal; and
a biasing circuit configured to adjust a bias current to maintain stable transconductance over temperature variations, the biasing circuit providing at least one bias signal for biasing at least one of the input amplifier and the tracking loop, whereby circuitry receiving the at least one bias signal exhibits stable performance over the temperature variations.
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Abstract
An amplifier system can include an input amplifier configured to receive an analog input signal and provide an amplified signal corresponding to the analog input signal. A tracking loop is configured to employ delta modulation for tracking the amplified signal, the tracking loop providing a corresponding output signal. A biasing circuit is configured to adjust a bias current to maintain stable transconductance over temperature variations, the biasing circuit providing at least one bias signal for biasing at least one of the input amplifier and the tracking loop, whereby the circuitry receiving the at least one bias signal exhibits stable performance over the temperature variations. In another embodiment the biasing circuit can be utilized in other applications.
6 Citations
19 Claims
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1. An amplifier system comprising:
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an input amplifier configured to receive an analog input signal and provide an amplified signal corresponding to the analog input signal; a tracking loop configured to employ delta modulation for tracking the amplified signal, the tracking loop providing a corresponding output signal; and a biasing circuit configured to adjust a bias current to maintain stable transconductance over temperature variations, the biasing circuit providing at least one bias signal for biasing at least one of the input amplifier and the tracking loop, whereby circuitry receiving the at least one bias signal exhibits stable performance over the temperature variations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An integrated circuit comprising:
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an input amplifier configured to receive an analog input signal and provide an amplified signal corresponding to the analog input signal; a tracking loop configured to employ delta modulation for tracking the amplified signal, the tracking loop providing a corresponding output signal; and a bias generator for providing adaptive bias control that provides stabilization of transconductance over temperature for associated circuitry, the circuitry comprising; a first arrangement of transistors configured as a first current mirror portion, the first current mirror portion being connected to a first reference voltage; and a second arrangement of transistors and a resistor configured as a second current mirror portion having a non-linear characteristic to provide a bias current through the resistor that is inversely proportional to mobility, the first current mirror portion being connected with the second current mirror portion between the first reference voltage and a second reference voltage and being arranged in a feedback relationship to stabilize the bias current through the resistor, a bias voltage being provided from at least one of the first current mirror portion and the second current mirror portion based on the bias current, wherein each of the input amplifier and the tracking loop is biased by the bias voltage generated by the bias generator. - View Dependent Claims (17, 18, 19)
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Specification