83results about "DC-isolation amplifier" patented technology

A power amplifier comprises a series stack of power amplifier devices, connected in parallel to the amplifier input for receiving an RF input signal, and having output terminals being connected in series to the amplifier output. An intermediate coupling capacitor is connected between each adjacent pair of power amplifier devices in the series stack of power amplifier devices for DC isolation of said power amplifier devices. This reduces the required DC supply voltage, as well as allowing shorting of individual power amplifier devices in response to variation in the DC supply voltage.

A wide bandwidth, high power amplifier system for amplifying a signal in a radio frequency (RF) system in a specific bandwidth within the frequency range from 1 MHz to 100 GHz. The system includes a number of amplifier modules and an equal number of input transformers connected in series, with each input transformer providing an input signal to one amplifier module. It also includes an equal number of output transformers connected in series with each output transformer receiving an input signal from one amplifier module. The series of input transformers, the series of output transformers and the amplifier modules each provide an impedance matched approximately to the impedance of the RF system.

Systems and methods implemented in a switching amplifier for providing consistent, matching switching between top and bottom switching devices in a switching amplifier. One embodiment includes a half-bridge circuit output stage, a driver stage and a transformer. The driver stage, which drives the switches of the output stage, is very fast, has a low propagation delay, and has minimal input capacitance. The transformer drives the drive paths from the transformer inputs to the switches. The transformer avoids resonances within the audio band and at the amplifier switching frequencies, has low and spread free leakage inductance, has enough magnetizing inductance to keep transformer currents low in proportion to the total driver stage current drain, has low core losses at the switching frequency, has minimal inductance change and operates well below its saturation point. The amplifier stage provides a substantially constant amplitude drive signal to the output power switching devices.

The signal detecting circuit has a first amplifier which amplifies the supplied signals and outputs the amplified signals from first and second output terminals; a switch unit which supplies the signals to the first amplifier such that the polarity thereof is reversed between the first and second periods; a first capacitor, one end of which is connected to the first output terminal; a second capacitor, one end of which is connected to the second output terminal; a first switch, one end of which is connected to the other end of the second capacitor; a second amplifier having an inverting input terminal connected to the other end of the first capacitor, a non-inverting input terminal connected to the other end of the first switch, and an output terminal; a second switch which is connected to between the output terminal and the inverting input terminal, a third switch, one end of which is connected to the other end of the second capacitor; a fourth switch, one end of which is connected to the other end of the non-inverting input terminal; a threshold voltage source which is connected to between the other end of the third switch and the other end of the fourth switch; and a reference voltage source which is connected to either one of the other end of the third switch and the other end of the fourth switch. In the first period, the first switch is off, and the second to fourth switches are on; in the second period, the first switch is on, and the second to fourth switches are off.

The invention discloses a chopper amplification circuit adopting a negative impedance compensation technology. The chopper amplification circuit comprises a differential input end, a first-stage chopper switch, a first-stage amplification circuit, a second-stage chopper switch, a second-stage amplification circuit, a negative impedance conversion circuit, a negative feedback unit, an input capacitor and a differential output end, the differential input end is connected with the first-stage chopper switch and is used for accessing a differential voltage signal; an output terminal of the first-stage chopper switch is connected with the first-stage amplifying circuit through an input capacitor; the first-stage amplification circuit is connected with the second-stage chopper switch, the second-stage chopper switch is connected with the second-stage amplification circuit, and the second-stage amplification circuit is connected with the differential output end and is further connected with the feedback input end of the first-stage amplification circuit through the negative feedback unit, and the negative impedance conversion circuit is connected to the signal input end of the first-stageamplification circuit in parallel for reducing the equivalent input capacitance of the first-stage amplification circuit. The circuit has the advantages of high input impedance and high stability, and can be suitable for occasions requiring high input impedance.

Circuitry for providing improved pulse-type enhancement of the voltage supplied to a power amplifier (101) that is fed by a power supply that is connected to the power amplifier (101) at a feeding point through a main supply path that is connected via an inductor (L1). A second feeding point is used for enhancement by a capacitor that is discharged. A transformer L2, L3, M) is formed by mutually coupling an additional inductor (L3), through which an additional supply path is connected. Enhancement power is provided partially through the transformer L2, L3, M) and the remaining part thorough the capacitor (C1). This way, the total level of possible enhancement is increased, while minimizing distortion of the envelope of the amplified RF signal.

A semiconductor circuit comprising an input block having a first chopper providing a chopped voltage signal, a first transconductance converting said chopped voltage signal into a chopped current signal, a second chopper providing a demodulated current signal, a current integrator having an integrating capacitor providing a continuous-time signal, a first feedback path comprising: a sample-and-hold block and a first feedback block, the first feedback path providing a proportional feedback signal upstream of the current integrator. The amplification factor is at least 2. Charge stored on the integrating capacitor at the beginning of a sample period is linearly removed during one single sampling period. Each chopper operates at a chopping frequency. The sample-and-hold-block operates at a sampling frequency equal to an integer times the chopping frequency.