摘要:
An amplifier including a P-channel transistor (P1) having current terminals coupled between a first node and a second node and having a control terminal coupled to a third node receiving an input voltage, an N-channel transistor (N1) having current terminals coupled between a fourth node developing an output voltage and a supply voltage reference and having a control terminal coupled to the second node, a first resistor (R1) coupled between the first node and a supply voltage, a second resistor (R2) coupled between the first and fourth nodes, and a current sink sinking current from the second node to the supply reference node. The amplifier may be converted to differential form for amplifying a differential input voltage. Current devices may be adjusted for common mode, and may be moved or added to improve headroom or to improve power supply rejection. Chopper circuits may be added to reduce 1/f noise.
摘要:
Die Erfindung betrifft eine Anordnung (1) zur Kompensation einer Offset-Spannung (U off ) eines elektronischen Verstärkers (2), umfassend - einen elektronischen Verstärker (2) mit einem ersten Eingang (E+), einem zweiten Eingang (E-), einem ersten Ausgang (A+) und einem zweiten Ausgang (A-), - einem Eingangsschaltmittel (10), - einem Ausgangsschaltmittel (20), - einer Steuerschaltung (30),
wobei die Eingangsschaltmittel (10) derart zwischen einem Signaleingang (X) und dem ersten Eingang (E+) und dem zweiten Eingang (E-) angeordnet sind, dass in einem ersten Schaltzustand (Z1) der erste Eingang (E+) mit dem Signaleingang (X) verbunden ist und in einem zweiten Schaltzustand (Z2) der zweite Eingang (E-) mit dem Signaleingang (X) verbunden ist, und wobei die Ausgangsschaltmittel (20) derart zwischen einem Signalausgang (Y) angeordnet sind, dass in dem ersten Schaltzustand (Z1) der erste Ausgang (A+) mit dem Signalausgang (Y) verbunden ist und in dem zweiten Schaltzustand (Z2) der zweite Ausgang (A-) mit dem Signalausgang (Y) verbunden ist, und wobei die Steuerschaltung (30) ausgestaltet ist das Eingangsschaltmittel (10) und das Ausgangsschaltmittel (20) synchron in den ersten Schaltzustand (Z1) bzw. in den zweiten Schaltzustand (Z2) zu schalten.
摘要:
A single stage current sense amplifier is described that generates a differential output that is proportional to a current through a sense resistor. The voltage across the sense resistor is Vsense. The current sense amplifier includes a differential transconductance amplifier having high impedance input terminals. An on-chip RC filter filters transients in the Vsense signal. A feedback circuit for each leg of the amplifier causes a pair of input transistors to conduct a fixed constant current irrespective of Vsense, which stabilizes the transconductance. A gain control resistor (Re) is coupled across terminals of the pair of input transistors and has Vsense across it. The current through the gain control resistor is therefore Vsensex1/Re. A level shifting circuit coupled to each of the input transistors lowers a common mode voltage at an output of the amplifier. Chopper circuits at the input and output cancel any offset voltages.
摘要:
A single-ended operational amplifier uses a plurality of chopper circuits (9, 16, 24) to alternately transpose matched transistor pairs for cancelling offset errors due to transistor mismatches from statistical process variations. The differential input signals are transposed while simultaneously transposing the currents in a current mirror (14, 15) and in the load devices (37). The matched devices comprising an output stage (36) remain untransposed since their contribution to offset error is minimal but their contribution to noise error would be substantial due to the potentially larger voltage differentials existing between them.
摘要:
The present disclosure relates to a first stage of an instrumentation amplifier. The instrumentation amplifier comprises a pair of input amplifiers, each comprising an input transistor and a feedback current amplifier configured to amplify and feedback an error current from the input transistor. The arrangement may enable a current efficient solution where the amplifier can operate with very low input signals that are close to, or potentially below ground, without requiring a negative power supply voltage.
摘要:
An amplifier circuit (12) having improved common mode rejection is provided. This can be achieved by estimating the common mode value of an input signal and using this to adjust a target common mode voltage at the output of the amplifier (12). This can help avoid the differential gain becoming modified by the common mode voltage.
摘要:
A circuit for generation of a reference voltage for an electronic system, which circuit comprises at least one digital buffer (U21, U31, U32, U41, U51), a low pass filter (R21, C21; R31, C31; R41, C41; R51, C51) and an operational amplifier (OA21, OA31, OA41, OA51)), which circuit is adapted to revive an input in the form of a bandgap reference voltage into the digital buffer, which digital buffer is adapted to receive a digital input from a Pulse Width Modulated (PWM) signal, which digital buffer is adapted to generate an output signal adapted to be fed to the low pass filter, which output signal after filtration is adapted to be fed to a positive input terminal of the operational amplifier, which operational amplifier comprises a feedback circuit, which feedback circuit comprises at least one capacitor (C22, C32, C44, C54) adapted to be connected from an output terminal of the operational amplifier towards a negative input terminal of the operational amplifier so as to form an integrator, wherein the feedback circuit further comprises at least one chopped signal path (R22, S21; R33, R34, S32; R33, R35, C35, S31), which chopped signal is adapted to be modulated by the output signal of the digital buffer.
摘要:
A signal processing circuit includes a chopper amplifier (1) that has a differential amplifier circuit (AMP1) that amplifies differential input signals Vsp(t) and Vsm(t), and an adder circuit (1B) that generates an addition signal Vfil(t) by addition of the chopper output signal Vsub(t) that the chopper amplifier (1) generates. Differential signals inputted into the differential amplifier circuit (AMP1) are interchanged for every first phase period and second phase period, and the adder circuit (1B) generates the addition signal by addition of the chopper output signal in the first phase period and in the second phase period.
摘要:
A sensor device is provided with a voltage detection type sensor unit (20) for converting a physical quantity into a voltage value and outputting a voltage signal indicating the voltage value; a chopper amplifier unit (10) for generating a modulation signal by chopping the voltage signal output from the sensor unit with a predetermined chopping frequency, amplifying the modulation signal into an amplification signal, then demodulating the amplification signal and outputting it as an output signal; an integration unit (13) including an operational amplifier (14) for amplifying a voltage difference between a voltage at a non- inverting input terminal and a voltage at an inverting input terminal, an input resistor (Rl) connected to the inverting input terminal of the operational amplifier and a capacitor (Cl) connected between the inverting input terminal and an output terminal of the operational amplifier (14) and adapted to sample the output signal output from the chopper amplifier unit (10) at a predetermined sampling frequency and integrate the sampled output signal.