The invention relates to a circuit containing a transimpedance amplifier for converting two input currents into two output voltages, having a first amplifier part containing a first input, to which a first input voltage is applied, and into which a first input current flows, and having a second amplifier part containing a second input, to which a second input voltage is applied and into which a second input current flows, wherein the first amplifier part and the second amplifier part are connected to a common supply voltage, the first amplifier part and the second amplifier part are connected to a common current source, the input of the first amplifier part and the input of the second amplifier part have a differing direct voltage, and the first amplifier part and the second amplifier part are designed such that an output voltage of the first amplifier part is proportional to the input current of the first amplifier part and an output voltage of the second amplifier part is proportional to an input current of the second amplifier part.

Provided is a temperature detection circuit that includes: a series connection circuit that is connected between a power supply voltage input terminal and ground and includes a temperature detection transistor and a first resistance element; and a current bypass circuit that includes a first transistor that is connected in parallel with the temperature detection element and allows a bypass current to flow therethrough. The temperature detection circuit outputs a temperature detection signal from a connection point between the temperature detection transistor and the first resistance element.

An apparatus includes a first amplifier, a second amplifier, and a compensation-setting generator to generate a first amplifier compensation setting and second amplifier compensation setting. A controller is operable to: i) apply the first amplifier compensation setting to the first amplifier and apply the second amplifier compensation setting to the second amplifier. The controller is further operable to switch between generating updates to the first amplifier compensation setting and the second amplifier compensation setting.

A amplifier circuit in some embodiment includes a differential amplifier have a pair of current sources. Each of the current sources includes two or more current-generating transistors and respective switching transistors, which can be turned on and off by a gain input code to tune the gain of the amplifier. A common-mode controller includes a similar pair of current sources as the differential amplifier. The common mode controller receives a common-mode signal of the input signal and a common-mode gain input code, and maintains the common-mode gain of the amplifier circuit when the differential gain changes. The amplifier circuit is switchable between a buffer mode and an equalizer mode.

Modern modulator drivers must be capable of delivering a large output voltage into a tens of ohms modulator, while minimizing the amount of distortion added by the driver. The driver should deliver the output voltage without exceeding a maximum distortion while minimizing the DC power consumption. Accordingly, a modulator driver includes a final stage amplifier with auxiliary transistors that turn on when the conventional differential pair of transistors approaches their maximum voltage of the linear region of their transfer function, thereby providing a more linear transfer function, in particular at large input voltages.

High bandwidth envelope trackers are provided herein. In certain embodiments, an envelope tracking system for a power amplifier includes a switching regulator that operates in combination with a high bandwidth amplifier to generate a power amplifier supply voltage for the power amplifier based on an envelope of a radio frequency (RF) signal amplified by the power amplifier. The high bandwidth amplifier includes an output that generates an output current for adjusting the power amplifier supply voltage, a first input that receives a reference signal, and a second input that receives an envelope signal indicating the envelope of the RF signal. The second input has lower input impedance than the first input to provide a rapid transient response and high envelope tracking bandwidth.

A chopper amplifier circuit includes a first amplifier path with chopper circuitry, a switched-capacitor filter, and multiple gain stages. The chopper amplifier circuit also includes a second amplifier path with a feed-forward gain stage. A chopping frequency of the chopper circuitry is greater than a threshold frequency at which the second amplifier path is used instead of the first amplifier path.

A summation circuit (1) for summing one or more signals received from a photomultiplier array is proposed. The summation circuit comprises one or more readout circuits (5) coupleable to one or more photodiodes of the photomultiplier array (2), respectively, and a channel summing module (50), coupled at one or more outputs of the one or more readout circuits, respectively, to sum the one or more signals provided by the one or more readout circuits. The one or more readout circuits are coupleable to the photodiode of the photomultiplier array. Each readout circuit (5) comprises one or more coefficient controllers (C1, C2) for controlling multiplying coefficients of the received signal. The coefficient controllers may be placed at the input and/or at the output of the readout circuits (5).

In conventional high data rate receivers, the transmitted optical signal has poor extinction ratio and translates into a small modulated current with a large DC current, which saturates the receiver TIA and amplifiers, and significantly degrades the gain and bandwidth performance. Consequently, cancelling PD DC current in high data rate receivers is desired for proper operation. Differential TIA schemes, i.e. providing separate AC-coupled and DC-coupled paths, in parallel, provide better linearity for large input currents and low gain settings. To AC couple the PD to the TIA using passive AC-coupling circuitry, an AC-coupling capacitor (C.sub.C) is positioned between the PD and the TIA to block the DC current, while passing the modulated AC current to the TIA. A DC cancellation circuit may be provided, without a capacitor, to maintain the receiver input bias while suppressing any DC component generated by the PD for the DC-coupled path.

One illustrative high bandwidth transimpedance amplifier includes a distributed amplifier having multiple transistors that receive a propagating input signal at respective nodes of an input signal line and drive corresponding nodes of an amplified signal line that propagates an amplified signal to an output voltage buffer. A feedback impedance couples the output voltage to a feedback node in the distributed amplifier, making the output voltage proportional to the input signal's current. An illustrative method includes: propagating an input signal current along an input signal line of a distributed amplifier, the distributed amplifier responsively propagating an amplified signal along an amplified signal line; buffering the amplified signal from a final node of the amplified signal line to produce an output voltage signal; and using the output voltage signal to draw the input signal current from a final node of the input signal line via a feedback impedance.