A voltage-to-current converter can be configured to generate a current based on an input voltage and for part of the time use the generated current as the output current of the voltage-to-current converter, and for part of the time use the generated current as a current source for the operation of the voltage-to-current converter. This arrangement can reduce the need for high performance current mirror circuits within the voltage-to-current converter, thereby reducing the cost and complexity of the voltage-to-current converter and improving precision and accuracy.

An instrumentation amplifier including a pair of input amplifiers, each including an input transistor and a feedback current amplifier configured to amplify and feedback an error current from the input transistor. The arrangement can 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.

A buffer amplifier comprises a source follower and a feedback amplifier. The feedback amplifier may be configured to control a drain current of the source follower to remain substantially constant independent of a load.

In a general aspect, a circuit can include an amplifier circuit including a first amplifier, a first feedback path, and a second feedback path. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier, The circuit can also include a loop circuit including a second amplifier, The loop circuit can be configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and into the negative input of the first amplifier.

An apparatus may include a delta sigma modulator. A first portion of the delta sigma modulator may form a digital predictor while a second portion of the delta sigma modulator may form an analog approximator. An output of the analog approximator may be coupled with a quantizer. The digital predictor, the analog approximator, and the quantizer may form a digitizing loop configured to convert an analog input into a digital output. The digital predictor may be configured to generate, based on a polarity of one or more digital outputs from the quantizer, a digital prediction of an expected amplitude of the analog input. The quantizer may be configured to respond to the digital prediction by adjusting a dynamic range of the digitizing loop including by changing a quantization step size used by the quantizer to quantize the analog input. Related methods are also provided.

A high side current sensing amplifier architecture is simplified and improved over prior art current sensing amplifier circuits by using chopping only, without requiring auto-zeroing, and by using a simpler (and faster) switched capacitor filter instead of an auto-zeroing integrator filter. Also, VIP (positive DC sense node) is merged with the VDDHV (power supply) node, such that the integrated circuit package requires only a single node (package pin) to accommodate both the VIP and VDDHV connections for the current sensing amplifier circuit, resulting in being able to use a smaller integrated circuit package. A small resistor is coupled between VIP and VDDHV to reduce the offset considerably. A low latency time high voltage level shifter is provided which is essential for precise chopping operation.

A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

A device for analysis of cells comprises: an active sensor area (104) presenting a surface for cell growth; a microelectrode array (102) comprising a plurality of pixels (110) in the active sensor area (104), wherein each pixel (110) comprises at least one electrode (120) at the surface, wherein each pixel (110) is configured to control the configuration of the pixel circuitry and set a measurement modality of the pixel; recording circuitry having a plurality of recording channels (130), wherein each pixel (110) is connected to a recording channel (130), wherein each recording channel (130) comprises a reconfigurable component (131), which is selectively controlled between being set to a first mode, in which the reconfigurable component (131) is configured to amplify a received pixel signal, and being set to a second mode, in which the reconfigurable component (131) is configured to selectively pass a frequency band of the received pixel signal.

An amplifier circuit 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. This can help avoid the differential gain becoming modified by the common mode voltage.