A class-D amplifier includes measurement of speaker current via the low-side drive transistors of the amplifier. In one embodiment, a class-D amplifier includes two high-side transistors, two low-side transistors, a first sense resistor, a second sense resistor, and a sigma delta analog to digital converter (σΔ ADC). The two high-side transistors and two low-side transistors are connected as a bridge to drive a bridge tied speaker. The first sense resistor is connected between a first of the low-side transistors and a low-side reference voltage. The second sense resistor is connected between a second of the low-side transistors and the low-side reference voltage. The ΣΔ ADC is coupled to the bridge to measure voltage across the first sense resistor and the second sense resistor.

An image sensor may include an array of image sensor pixels. The array of image sensor pixels may be controlled by row driver circuitry. The row driver circuitry may include row drivers that receive power supply signals from transconductance amplifier circuitry. The transconductance amplifier circuitry may include multiple amplifiers with output ports shorted to one another. Each amplifier may include input transistors, cross-coupled transistors with a low threshold voltage, and additional transistors coupled in series with the cross-coupled transistors and having a moderate or high threshold voltage.

Transmitters and methods of transmitting a polar-modulated signal include a driver to output a polar-modulated signal according to a phase-modulation signal and an amplitude-modulation signal. A voltage regulator is connected to the driver, with the amplitude-modulation signal controlling an input of the voltage regulator and with the amplitude-modulation signal further being combined with an output of the voltage regulator to control an amplitude of the output of the driver to compensate for bandwidth cutoff noise in the voltage regulator.

The present invention discloses a CO alarm for a battery type generator, comprising a MCU control unit U2, configured to analyze and process signals, which is in a deep sleep state when the generator is not running, and enters a sleep plus timing wake-up working state after the engine is running; a CO sensor detection unit U3 connected to the MCU control unit, configured to convert the CO concentration in the environment into a corresponding electrical signal and output to the MCU control unit U2 for processing; an alarm indication unit U4 connected to the MCU control unit, configured to give an alarm prompt for the CO concentration and an alarm failure prompt.

In described examples, a circuit includes a first current mirror circuit. The first current mirror circuit is coupled to a power input terminal. A first stage is coupled to the first current mirror circuit, and a second stage is coupled to the first stage and to the first current mirror circuit. An amplifier is coupled to the first and second stages. The amplifier has first and second input terminals. The first input terminal is coupled to the first stage, and the second input terminal is coupled to the second stage. A second current mirror circuit is coupled to the first stage, the second stage and the amplifier.

A wideband envelope modulator comprises a direct current (DC)-to-DC switching converter connected in series with a linear amplitude modulator (LAM). The DC-DC switching converter includes a pulse-width modulator that generates a PWM signal with modulated pulse widths representing a time varying magnitude of an input envelope signal or a pulse-density modulator that generates a PDM signal with a modulated pulse density representing the time varying magnitude of the input envelope signal, a field-effect transistor (FET) driver stage that generates a differential PWM or PDM drive signal, a high-power output switching stage that is driven by the PWM or PDM drive signal, and an output energy storage network including a low-pass filter (LPF) of order greater than two that filters a switching voltage produced at an output switching node of the high-power output switching stage.

An automatic gain control system for a receiver, including: an automatic gain control loop (40) adapted to be coupled to both a first transimpedance amplifier (12) coupled to a first analog-to-digital converter (14) forming a first tributary and a second transimpedance amplifier (12) coupled to a second analog-to-digital converter (14) forming a second tributary; and an offset gain control voltage to gain balance a transimpedance amplifier gain of the first tributary and a transimpedance amplifier gain of the second tributary. The automatic gain control loop can be analog. Also, the automatic gain control loop can be implemented in hardware or firmware.

An operational amplifier 1 comprises transistors Q1 and Q2 forming an input stage, and input resistors R1 and R2 which form a filter together with parasitic capacitors C1 and C2 accompanying the transistors Q1 and Q2. Resistance values R of the resistors R1 and R2 may be set to R=1/(2π.Math.fc.Math.C), where C is the capacitance value of each of the parasitic capacitors C1 and C2, and fc is the target cutoff frequency of the filter. The operational amplifier 1 may also include a power supply resistor R0 which forms a filter together with a parasitic capacitor C0 accompanying a power supply line.

An apparatus for turning off a cascode amplifier having a common-base transistor and a common-emitter transistor is disclosed that includes the cascode amplifier, a feedback circuit, and a bias circuit. The feedback circuit is configured to receive a collector-voltage from the collector of the common-emitter transistor when the common-emitter transistor is switched to a first OFF state and produce a first feedback signal. The collector-voltage is equal to an emitter voltage of the common-base transistor and the collector-voltage increases in response to switching the common-emitter transistor to the first OFF state. The bias circuit is configured to receive the first feedback signal and produce a bias-voltage. A first base-voltage is produced from the bias-voltage. The cascode amplifier is configured to receive the first base-voltage and a second base-voltage. The common-base transistor is configured to switch to a second OFF state in response to receiving the second base-voltage.

A driver circuit includes: a current-controlling switching element electrically connected to a light emitting element; a differential amplifier circuit including: an output terminal electrically connected to the current-controlling switching element, a first input terminal configured to receive a reference signal as a reference for radiating light with a desired intensity from the light emitting element, and a second input terminal configured to receive a detection signal corresponding to a detection result of a current flowing in the light emitting element, wherein the differential amplifier circuit is configured to control the current flowing in the light emitting element and the current-controlling switching element based on a voltage of the first input terminal and a voltage of the second input terminal; and an adjustment part configured to adjust an overshoot amount of a rising edge of the current flowing in the light emitting element.