发明名称 Dynamically biased output structure
摘要 A transconductance amplification stage (301) includes a differential pair (306) wherein a bias current flows through each transistor (302, 304) of the pair when input voltages are equal. Tail current boosting circuitry (320), which includes a tail transistor, provides a translinear expansion of tail current of the differential pair. A feedback loop (307) dynamically biases the differential pair to maintain current through one transistor (302) of the pair at the bias current value in spite of a difference between input voltages. Another transistor (304) of the pair provides an output current responsive to a difference between input voltages. The output current is not affected by a region of operation of the tail transistor. An output structure (300, 500) includes the transconductance amplification stage and a circuit (303) for mirroring the output current. An amplifier (800) includes the output structure as a buffer between other structures (801) and an output terminal.
申请公布号 US8890612(B2) 申请公布日期 2014.11.18
申请号 US201213656253 申请日期 2012.10.19
申请人 Freescale Semiconductor, Inc. 发明人 Coimbra Ricardo Pureza;Pereira da Silva, Jr. Edevaldo
分类号 H03F3/45 主分类号 H03F3/45
代理机构 代理人
主权项 1. An integrated circuit including a transconductance amplification stage, the transconductance amplification stage comprising: a differential pair of transistors, wherein a first input terminal of the amplification stage includes a control electrode of a first transistor of the differential pair, wherein a second input terminal of the amplification stage includes a control electrode of a second transistor of the differential pair, and wherein a current equal to a bias current flows through a conducting electrode of the first transistor and through a conducting electrode of the second transistor when a first input voltage at the first input terminal is equal to a second input voltage at the second input terminal; first circuitry, coupled to the conducting electrode of the first transistor and to a node, for providing a first current; second circuitry, coupled to the node, for sinking a second current from the node, wherein the second current is equal to the first current minus the bias current; tail current boosting circuitry, coupled to the node, for providing a translinear expansion of tail current of the differential pair, the tail current responsive to a voltage at the node; a feedback loop that dynamically biases the differential pair by controlling the voltage at the node by negative feedback during operation, wherein the current through the conducting electrode of the second transistor is maintained at a constant value during operation, and wherein a conducting electrode of the first transistor provides an output current responsive to a difference between the first input voltage and the second input voltage; and an output terminal for outputting the output current.
地址 Austin TX US