Voltage-to-current converters that include two current mirrors are disclosed. In an example voltage-to-current converter each current mirror is a complementary current mirror in that one of its input and output transistors is a P-type transistor and the other one is an N-type transistor. Such voltage-to-current converters may be implemented using bipolar technology, CMOS technology, or a combination of bipolar and CMOS technologies, and may be made sufficiently compact and accurate while operating at sufficiently low voltages and consuming limited power.

A method and a detection circuit. The detection circuit may include (a) a photodiode that is configured to convert radiation to a photodiode current; (b) a photodiode bias circuit that is configured to bias the photodiode; (c) a dynamic resistance circuit that has a first terminal and a second terminal; (d) a transimpedance amplifier that is configured to amplify an output current of the dynamic resistance circuit to provide an output voltage, wherein the second terminal is coupled to a negative input port of the amplification circuit; and (e) a conductor that is coupled between the first terminal and an anode of the photodiode.

A transimpedance amplifier and photodiode that has a bias voltage node established at a bias voltage and a ground node/plane that connects, over a short distance as compared to the prior art, to a photodiode and a transimpedance amplifier. The photodiode is in a substrate and configured to receive and convert an optical signal to an electrical current. The photodiode has an anode terminal and a cathode terminal which is connected to the bias voltage node. One or more capacitors in or on the substrate and connected between the bias node and the ground node. The transimpedance amplifier has an input connected to the anode terminal of the photodiode and an output that presents a voltage representing the optical signal to an output path. The transimpedance amplifier and the photodiode are both electrically connected in a flip chip configuration and the ground plane creates a coplanar waveguide.

A detection circuit that may include (i) a photosensor that is configured to convert light to current; wherein the photosensor has an output node and is configured to operate as a current source, (ii) an adder, and (iii) multiple amplification branches that are coupled in parallel between the adder and the output node of the photosensor. The multiple amplification branches do not share a feedback circuit, wherein all amplification branches of the multiple amplification branches comprise an amplifier of a same type, wherein the type is selected out of a transimpedance amplifier and a current amplifier.

Disclosed herein are transimpedance circuits, as well as related methods and devices. In some embodiments, a transimpedance circuit may include a current source bias terminal, a current source output terminal, and a transimpedance amplifier coupled to the current source output terminal, wherein voltage signals at the current source bias terminal are correlated with voltage signals at the current source output terminal. In some embodiments, the current source may be a photodiode.

A CMOS trans-impedance amplifier includes an inverting amplifier circuit and a feedback resistor. The inverting amplifier circuit includes an input end and an output end, and the feedback resistor is coupled therebetween. The inverting amplifier circuit includes at least three sequentially-connected amplifier units, and each amplifier unit includes at least three sequentially-connected nFETs, namely an input signal receiving part nFET, an intermediate part nFET and a DC signal receiving part nFET. A common connection terminal of the input signal receiving part nFET and the intermediate part nFET is configured to output an amplified voltage signal.

An embodiment of this disclosure provides an automated payment apparatus. The apparatus includes a photodiode current integrator configured to charge an integration capacitor. The photodiode current integrator includes a first feedback resistor connected along a negative feedback path of an operational amplifier between an output of the operational amplifier and a negative input of the operational amplifier. The photodiode current integrator also includes a second feedback resistor connected along a positive feedback path of the operational amplifier between the output of the operational amplifier and a positive input of the operational amplifier. The photodiode current integrator also includes an integration capacitor connected to the positive input of the operational amplifier and to common circuit ground. The photodiode current integrator also includes a reset switch connected to the positive input of the operational amplifier and to common circuit ground or to additional voltage source. The photodiode current integrator also includes a photodiode connected to the positive input and the negative input of the operational amplifier.

A programmable transimpedance amplifier (TIA) includes a plurality of signal paths between an output of a common emitter amplifier and the output of the TIA. The TIA is programmed by selecting one of the signal paths, because the paths have different parameters (e.g. different bandwidth). Thus, the bandwidth or other parameter can be programmed by selecting the appropriate path. The common emitter amplifier's output is coupled to the inputs of common base amplifiers in each path. The inputs have low impedance. Also, each path has a separate buffer amplifying the common base amplifier output in the path. Therefore, having multiple paths does not significantly degrade the amplifier performance. High bandwidth can be provided.

An amplifier arrangement comprises a sensor input and a first and a second amplifier. The first amplifier has a first amplifier output and a first input connected to a first reference potential terminal and a second input connected to the sensor input in a direct fashion and to the first amplifier output via a feedback path having a switched integration capacitor that is charged by the feedback path during a first switching phase and discharged during a second switching phase. The second amplifier has a second amplifier output, a first input connected to a second reference potential terminal and a second input. A first feedback capacitor is connected in-between two pairs of feedback switches. A second feedback capacitor is connected between the second amplifier output and the second input of the second amplifier. An impedance element is coupled between the second amplifier output and the sensor input.

An amplifier includes an amplification circuit including an input circuit receiving an input signal and configured to output an output signal by amplifying the input signal; and an offset cancelling circuit configured to cancel offset by controlling the input circuit according to activation control signal and offset control signal, wherein the offset cancelling circuit cancels the offset according to the offset control signal after the activation control signal is activated.