摘要:
Various apparatuses, methods and systems for boosting an amplifier slew rate are disclosed herein. For example, some embodiments of the present invention provide an apparatus including a pair of inputs connected to a pair of differential input devices in an amplifier, a current source, a first current path connected to the current source, a second current path connected to the current source and to the pair of differential input devices, a switch in the first current path, and a voltage difference signal connected between the pair of inputs and the switch. The voltage difference signal represents the voltage difference between the pair of inputs. The conductance of the switch is inversely proportional to the voltage difference signal.
摘要:
An amplifying circuit which may be useful in a diamond buffer amplifier or operational amplifier includes an input transistor including an emitter, a collector, and a base coupled to receive an input voltage. An adjustable current source circuit is coupled between a first reference voltage and the emitter of the input transistor. A current source is coupled between a second reference voltage and the collector of the input transistor. An isolation resistor has a first terminal coupled to an output terminal of the adjustable current source circuit and a second terminal coupled to the emitter of the input transistor. A current follower circuit is coupled between the collector of the input transistor and an input terminal of the adjustable current source circuit. A feed-forward capacitor is coupled between the collector of the input transistor and the first terminal of the isolation resistor.
摘要:
A bipolar rail-to-rail class-AB output stage that provides improved AC performance in low voltage applications. The bipolar output stage includes an input buffer stage, first and second complementary common emitter stages, and first and second control circuits biased and configured to assure class-AB operation of the first and second common emitter stages, respectively. The input of the bipolar output stage is applied to the input buffer stage, and the output of the bipolar output stage is provided by the second common emitter stage. The combination of the first common emitter stage and the first AB-control circuit operates as a current booster stage for the second common emitter stage, thereby obviating the need for a large power supply.
摘要:
A low noise charge pump circuit includes a first terminal of a first flying capacitor selectively coupled to a first voltage during a first recharging phase and a second terminal of the first flying capacitor selectively coupled to a second voltage during the first recharging phase. The second terminal of the first flying capacitor is coupled to a precharge control circuit during a first parasitic capacitance precharging phase that occurs after the first recharging phase to cause the voltage of the first terminal of the first flying capacitor to equal an output voltage. The first terminal of the first flying capacitor is coupled to an output conductor conducting the output voltage during a first discharging phase that occurs after the first parasitic capacitance precharging phase. The second terminal of the first flying capacitor is coupled to a discharge control circuit which increases the voltage of the second terminal of the first flying capacitor during the first discharging phase until the output voltage is equal to a regulated value.
摘要:
An amplifier circuit includes first (7A) and second (7B) operational amplifiers connected in a generally parallel configuration, each with inputs coupled through the same pair of matched input resistors which receive a differential input signal that may have both a positive and negative common mode range. An offset adjustment amplifier (17) receives a differential error signal representative of the difference between offset voltages of the first and second operational amplifiers and generates offset adjustment signals that are applied to input stages of the first and second operational amplifiers to adjust their respective offset voltages so as to equalize them. With the offset voltages equalized, the first and second operational amplifiers operate seamlessly as a common mode component of the differential input signal undergoes a transition from its positive to its negative range, so as to avoid inaccuracies and abrupt changes in an output voltage during the transition, the output voltage being produced in response to outputs of both first and second operational amplifiers.
摘要:
A high output current wideband output stage/buffer amplifier that has reduced quiescent current requirements. The output stage/buffer amplifier includes a diamond follower circuit having a pair of complementary output load-driving bipolar junction transistors (BJTs), a pair of pre-driver BJTs, and a plurality of current boost BJTs. As the base current of one of the driver transistors starts to increase in response to an increasing load current, the current through a corresponding pre-driver transistor decreases, thereby increasing the collector current of a corresponding boost transistor. The increased collector current of the boost transistor is fed back to a current mirror, causing a concomitant increase in the base current of the driver transistor.
摘要:
An amplifier circuit includes an pair of input transistors, the drains of which are connected to emitters of first and second cascode transistors. First and second controlled current sources are connected to the emitters of the first and second cascode transistors, respectively, and third and fourth controlled current sources are connected to the collectors thereof. A bias circuit controls the 4 controlled current sources in response to the emitter voltage of a pair of input transistors of an output stage the inputs of which are connected to the drains of the first and second cascode transistors.
摘要:
An amplifier (10) includes a first stage (4) including differentially coupled first (Q1) and second (Q2) input transistors and a controlled active load circuit (6). A second stage (8) includes differentially coupled third (Q5) and fourth (Q6) input transistors and a load circuit (Q7,8). A first output (2A) of the first stage (4) is coupled to a first input of the second stage (8), a second output (2B) of the first stage (4) being coupled to a second input of the second stage (8). A common mode feedback amplifier (12) has an input coupled to receive a common mode signal (3) from the second stage (8) for producing an amplified common mode signal (9) on a control input of the controlled active load circuit (6) to provide fast settling of an output (Vout) of the second stage without substantially increasing amplifier noise.
摘要:
A bipolar rail-to-rail class-AB output stage that provides improved AC performance in low voltage applications. The bipolar output stage includes an input buffer stage, first and second complementary common emitter stages, and first and second control circuits biased and configured to assure class-AB operation of the first and second common emitter stages, respectively. The input of the bipolar output stage is applied to the input buffer stage, and the output of the bipolar output stage is provided by the second common emitter stage. The combination of the first common emitter stage and the first AB-control circuit operates as a current booster stage for the second common emitter stage, thereby obviating the need for a large power supply.
摘要:
A high output current wideband output stage/buffer amplifier that has reduced quiescent current requirements. The output stage/buffer amplifier includes a diamond follower circuit having a pair of complementary output load-driving bipolar junction transistors (BJTs), a pair of pre-driver BJTs, and a plurality of current boost BJTs. As the base current of one of the driver transistors starts to increase in response to an increasing load current, the current through a corresponding pre-driver transistor decreases, thereby increasing the collector current of a corresponding boost transistor. The increased collector current of the boost transistor is fed back to a current mirror, causing a concomitant increase in the base current of the driver transistor.