A digital envelop tracker for a power amplifier. The digital envelop tracker includes a supply filter for filtering a supply voltage to a power amplifier, a level selection circuitry configured to determine a level of supply voltage based on an instantaneous power of an input data stream, schedule a series of switching events based on the determined level of supply voltage, and generate a level select signal based on the scheduled series of switching events, and a switch for connecting one of supply voltages to the supply filter based on the level select signal. The level selection circuitry schedules a primary switching event of the switch based on the determined level of supply voltage and secondary switching events of the switch delayed with respect to the primary switching event based on the determined level of supply voltage to generate a filter response of the supply filter with smaller peaking.

The present invention is in the field of booster stage circuit for a power amplifier, and an external supply voltage power amplifier comprising said booster stage circuit, such as for amplifying an electronic signal to a speaker system. These amplifiers may be provided with an external supply voltage.

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.

Some embodiments herein describe a radio frequency power semiconductor device that include a first non-linear filter network for compensating for lower frequency noise of a power amplifier. The first non-linear filter network can include a plurality of infinite impulse response filters and corresponding corrective elements to correct for a non-linear portion of the power amplifier. The radio frequency power semiconductor device can further include a second non-linear filter network for compensating for broadband distortion. The second non-linear filter network can be connected in parallel to the first non-linear filter network. The broadband distortion can include digital predistortion and the narrowband distortion can include charge trapping effects. The first non-linear filter network can comprise Laguerre filters. The second non-linear filter network can comprise general memory polynomial filters.

Disclosed is a filter bank die that includes a first acoustic wave (AW) filter having a first antenna terminal coupled to the antenna port terminal and a first filter terminal, wherein the first AW filter is configured to have a filter skirt with a slope that spans at least a 100 MHz gap between adjacent passbands, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

A multiplexer includes a transmission filter and a reception filter connected to a common terminal, a first inductor connected to the common terminal, and a multilayer substrate on which the transmission filter and the reception filter are mounted and which includes dielectric layers. The transmission filter includes a parallel-arm resonator connected to a path between the common terminal and a transmission terminal and a parallel-arm terminal, and a second inductor connected to the parallel-arm terminal and ground. The first inductor includes a first coil pattern on a first dielectric layer and a second coil pattern on a second dielectric layer. The second inductor includes a third coil pattern on the first dielectric layer and that is magnetically coupled to the first coil pattern. The inductance value of the second coil pattern is greater than that of the first coil pattern.

A transmission filter is arranged in a first filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. A reception filter is arranged in a second filter region and has one or more acoustic wave resonators, a plurality of terminal electrodes, and a plurality of wires. The first filter region and the second filter region are arranged adjacently to each other and have at least sides constituting a pair and opposing to each other. At least either one of the first filter region and the second filter region has no wire extending along one side in a forbidden region that is defined by a width including a terminal electrode nearest to the one side, along the one side and over the one side opposing to the other filter region.

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.

A class-D RF power amplifier (PA) architecture with duty cycle control has improved power efficiency while suppressing even-order harmonics. An inductor and capacitor (LC) low pass filter (LPF) can also be integrated on-chip to further suppress harmonics and provide impedance transformation between the PA and load. This eases the design for customers and reduce their bill of materials cost. The LPF can also match the PA to the load impedance to improve efficiency. The harmonic levels can also be controlled by adjusting the duty cycle of the PA output.

The, present application provides a filtering circuit and a. TV antenna amplifier, the filtering circuit includes a switching module, and the switching module includes a control unit and at least two filtering units. The present application switchably render one of the at least two filtering units conductive through the control unit, and filter the signals of different frequencies in the input signals through the at least two filtering units, so that different filtering units can be switched according to the filtering requirements of the frequency signal in different regions, which makes it a wide application range.