Amplifiers with wide input range and low input capacitance are provided. In certain embodiments, an amplifier input stage includes a pair of input terminals, a pair of n-type input transistors, a first pair of isolation switches connected between the input terminals and the n-type input transistors, a pair of p-type input transistors, and a second pair of isolation switches connected between the input terminals and the p-type input transistors. The amplifier input stage further includes a control circuit that determines whether to use the n-type input transistors and/or the p-type input transistors for amplification based on a detected common-mode voltage of the input terminals. The control circuit opens the first pair of isolation switches to decouple the input terminals from the n-type input transistors when unused, and opens the second pair of isolation switches to decouple the input terminals from the p-type input transistors when unused.

A novel comparison circuit, a novel amplifier circuit, a novel battery control circuit, a novel battery protection circuit, a power storage device, a semiconductor device, an electronic device, and the like are provided. The semiconductor device includes a capacitor, a first amplifier circuit including a first output terminal electrically connected to a first electrode of the capacitor, and a second amplifier circuit including an input terminal, a second output terminal, a first transistor, and a second transistor; a second electrode of the capacitor is electrically connected to the input terminal; the input terminal is electrically connected to a gate of the first transistor and one of a source and a drain of the second transistor; one of a source and a drain of the first transistor is electrically connected to the second output terminal; the second transistor has a function of supplying a potential to the input terminal and holding the potential; and a channel formation region of the second transistor includes a metal oxide containing at least one of indium and gallium.

Embodiments relate to sensing a current provided by a power supply circuit. The current sensing circuit includes a sense transistor for sensing the current provided by a main transistor, a driver for controlling a bias provided to the sense transistor and the main transistor, and a sense resistor for converting the sensed current to a voltage value. Moreover, the current sensing circuit includes a controller that modifies at least one of: (a) a resistance of the main transistor by adjusting the bias voltage provided by the driver, (b) a gain ratio between a load current and a sensing current by adjusting a number of individual devices that are active in the sense transistor, and (c) a resistance of the sense resistor.

Chopper amplifiers with tracking of multiple input offsets are disclosed herein. In certain embodiments, a chopper amplifier includes chopper amplifier circuitry including an input chopping circuit, an amplification circuit, and an output chopping circuit electrically connected along a signal path. The amplification circuit includes two or more pairs of input transistors, from which a control circuit chooses a selected pair of input transistors to amplify an input signal. The chopper amplifier further incudes an offset correction circuit that senses the signal path to generate an input offset compensation signal for the amplification circuit. Furthermore, the offset correction circuit separately tracks an input offset of each of the two or more pairs of input transistors.

Embodiments relate to sensing a current provided by a power supply circuit. The current sensing circuit includes a sense transistor for sensing the current provided by a main transistor, a driver for controlling a bias provided to the sense transistor and the main transistor, and a sense resistor for converting the sensed current to a voltage value. Moreover, the current sensing circuit includes a controller that modifies at least one of: (a) a resistance of the main transistor by adjusting the bias voltage provided by the driver, (b) a gain ratio between a load current and a sensing current by adjusting a number of individual devices that are active in the sense transistor, and (c) a resistance of the sense resistor.

An amplifier device includes a regulator circuit, a first voltage converting circuit, a first control circuit, and an amplifier circuit. The regulator circuit is configured to output a first driving voltage. The first voltage converting circuit is coupled to the regulator circuit, and is configured to output one of the first driving voltage and at least one first voltages related to the first driving voltage, as a first operating voltage. The first control circuit is coupled to the first voltage converting circuit through a first node, and is configured to receive the first operating voltage and generate a first operating signal according to the first operating voltage and a first control signal. The amplifier circuit is coupled to the first control circuit and the regulator circuit, and is configured to receive the first driving voltage, and is controlled by the first operating signal to generate an output voltage.

Embodiments relate to sensing a current provided by a power supply circuit. The current sensing circuit includes a sense transistor for sensing the current provided by a main transistor, a driver for controlling a bias provided to the sense transistor and the main transistor, and a sense resistor for converting the sensed current to a voltage value. Moreover, the current sensing circuit includes a controller that modifies at least one of: (a) a resistance of the main transistor by adjusting the bias voltage provided by the driver, (b) a gain ratio between a load current and a sensing current by adjusting a number of individual devices that are active in the sense transistor, and (c) a resistance of the sense resistor.

Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are possible where the amplifier is configured to operate in at least an active mode and a standby mode. Circuital arrangements can reduce bias circuit and stacked transistors standby current during operation in the standby mode and to reduce impedance presented to the gates of the stacked transistors during operation in the active mode while maintaining voltage compliance of the stacked transistors during both modes of operation.

A transistor circuit includes a transistor having a gate terminal and first and second conduction terminals, a first circuit configured to convert an AC input signal of the transistor circuit to a gate bias voltage and to apply the gate bias voltage to the gate terminal of the transistor, a second circuit configured to convert the AC input signal of the transistor circuit to a control voltage, and a switching circuit configured to apply a first voltage to the first conduction terminal of the transistor in response to the control voltage.

Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are possible where the amplifier is configured to operate in at least an active mode and a standby mode. Circuital arrangements can reduce bias circuit and stacked transistors standby current during operation in the standby mode and to reduce impedance presented to the gates of the stacked transistors during operation in the active mode while maintaining voltage compliance of the stacked transistors during both modes of operation.