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7630505 |
Loudspeaker system
There is provided a low-cost loudspeaker system which can adjust attenuation and provide protection against an excessive input. Between input terminals and a loudspeaker unit is provided a serial...
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7619481 |
Circuit for inhibiting over-current in power amplifier
A power amplifier drives a load connected to a first output terminal and a second output terminal. When generation of over-current is detected by the current detection section, the output amplifier...
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7595696 |
Power amplifier
A power amplifier including an active device having at least one heterjunction bipolar transistor based on a compound semiconductor; a diode connected between the base and the emitter of the...
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7586369 |
Pulse modulation type electric power amplifier
A pulse modulation type electric power amplifier includes a pulse modulator that receives as input a clock and an input signal, and converts the input signal to a pulse train, an output control...
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7570118 |
Thermal overload protection circuit and method for protecting switching power amplifier circuits
A thermal overload protection circuit and method for protecting switching power amplifier circuits provides protection against latch-up and other failures due to energy returned from an inductive...
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7567127 |
Automatic-gain control circuit
An automatic-gain control circuit includes a variable-gain amplifier, a peak-detecting circuit, and an adjustable charge/discharge circuit. The variable-gain amplifier receives an input signal and...
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7564310 |
Amplifier for improving electrostatic discharge characteristic
An amplifier for improving an electrostatic discharge (ESD) characteristic includes an operational amplifier, a first resistor circuit, a first fuse box, a second resistor circuit, and a second...
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7557660 |
Power amplification device
A power amplification device includes a BTL amplification circuit including a first amplification circuit and a second amplification circuit, the first amplification circuit including a first...
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7554409 |
Over-current protection circuit and method for protecting switching power amplifier circuits
An over-current protection circuit protection circuit and method for protecting switching power amplifier circuits provides protection against latch-up and other failures due to energy returned...
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7551034 |
Saturation handling
Saturation handling for preventing a power amplifier from going into a saturation condition is disclosed.
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7541865 |
EER high frequency amplifier
An EER high frequency amplifier wherein the dynamic range of the gain can be widened by performing a predetermined control of a device in a high frequency amplifying part and thereby enhancing the...
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7535305 |
Quiescent current detecting circuit for class AB amplifier
An operational transconductance amplifier is configured with an asymmetric output current capability. When current sunk from the output exceeds a rated load, the normally equal input voltages...
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7532076 |
Operational amplifier
An operational amplifier includes a differential amplifier circuit provided at an input stage and an amplifier circuit at a post stage. In the differential amplifier circuit, first and third...
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7525389 |
Signal amplifier circuit with a limiting voltage device
A signal amplifier circuit includes a negative feedback amplifier circuit having an output terminal, a first voltage limiting device for limiting the output voltage from the negative feedback...
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7495509 |
Audio power amplifier
A smart protection circuit to prevent possible circuit malfunction or damage due to sudden power source voltage fluctuation is introduced. In case of quick and large voltage fluctuation in power...
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7489199 |
Saturation detector and warning circuit including clamp
A saturation detection and warning circuit having an adaptive threshold voltage is disclosed. The disclosed circuit can also be used to detect the impending drop out of the low drop out linear...
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7486144 |
RF power amplifier protection
A circuit and method for protecting a radio frequency power amplifier against peak drain voltage. A detector circuit has an input connected to a drain of a power transistor of an amplification...
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7482878 |
Radio frequency power amplifier circuit
A radio frequency power amplifier, having a first amplifying transistor 103 - 1 and a second amplifying transistor 103 - 2 , comprises a detection circuit 101 that detects an output power and...
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7482877 |
Power protecting apparatus and method for power amplifier
A power protecting apparatus and method of a power amplifier for removing backward voltages and preventing a hard damage within a circuit by connecting an output terminal of a DC-DC converter with...
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7477107 |
Protection circuit and method for RF power amplifiers in WLAN transceivers
A protection circuit for a power amplifier of a radio frequency transmitter includes a sensing circuit that generates a sensed signal based on an output of the power amplifier. A reference signal...
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7459979 |
Semiconductor indicator for voltage diagnostics in power amplifiers
A semiconductor indicator for quantitatively diagnosing voltage conditions in high power transistor devices is provided. The semiconductor indicator includes a first transistor and a second...
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7449959 |
Methods and apparatus to detect impedance at an amplifier output
Methods and apparatus to detect impedance at an amplifier output are described. In one example, a method of determining a relative value of an amplifier output load may include determining a...
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7432766 |
Front end for an instrumentation amplifier
An amplifier system includes an instrumentation amplifier arrangement being designed to amplify the difference between two voltage inputs with a defined gain, and to produce a single-ended output...
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7423491 |
Semiconductor amplifier
A first power source 11 for supplying a bias voltage to a gate electrode G of a field effect transistor 13 , which amplifies high-frequency signals, and a second power source 15 for supplying...
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7391267 |
Output circuit
A patterning area of an output circuit is reduced while securing strong enough ESD tolerance. In the output circuit of this invention, an output of a first amplifier and an output of a second...
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7375589 |
Power amplifier system provided with improved protection function
The present invention provides a power amplifier system that includes a power terminal, a ground terminal, an output terminal, a ripple terminal, a control terminal, a power amplifier circuit...
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7362871 |
Audio amplifier circuit and audio IC having the same
In the present invention, in parallel with a resistor which determines an amplification rate being fed back from an output to an input of an output stage OP amp in an audio amplifier circuit,...
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7362181 |
Procedure for operating a high frequency amplifier
A procedure for operation of a high frequency amplifier having a power transistor—amplifier stage designed as a source or emitter circuit for amplifying a gate or base side high frequency signal...
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7362180 |
Protection circuit of digital amplifier
A protection circuit of a digital amplifier includes a DC voltage detection circuit for detecting a DC voltage occurring in a loudspeaker output terminal; a control circuit for performing...
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7355476 |
Input stage for an amplifier
In one embodiment, the present invention includes an amplifier having an input to receive a radio frequency (RF) signal from an output node of a source. An input stage coupled to the amplifier...
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7352240 |
Method and apparatus for protecting devices in an RF power amplifier
A method and apparatus are provided for use with a power amplifier for protecting active devices on the power amplifier. A peak detector is used by control circuitry to detect the presence of a...
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7348854 |
Automatic biasing and protection circuit for field effect transistor (FET) devices
A transistor biasing circuit is shown that utilizes a negative feedback loop control circuit to set the gate bias voltage in the output transistors of a power amplifier. This control circuit has a...
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7339424 |
Apparatus and method for controlling temperature of electronic apparatus
In an embodiment of this invention, if a state, in which duty ratio of a PWM signal is kept equal to or greater than a predetermined value, has been maintained for a first time period, the duty...
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7332969 |
Output offset protection for power amplifier
A output offset protection circuit provides protection of the load and the power amplifier through monitoring the temperature of the power transistor in the operational amplifier to detect fault...
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7327187 |
Method, circuit and power amplifier for detecting a fault, and method of protecting a circuit in a power amplifier from a fault occurrence
In a method of detecting a fault in a class D amplifier, an amplifier output signal is generated based on inverting a pulse width modulation signal corresponding to received audio data. The...
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7307478 |
Adjustable power amplifier and applications thereof
An adjustable power amplifier includes an input capacitor, an input transistor, an inductor, an output capacitor, and a gain module. The input capacitor includes a first plate and a second plate,...
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7301402 |
Soft saturation detection for power amplifiers
A soft saturation detection circuit for a radio frequency (“RF”) power amplifier is configured to detect the onset of soft saturation in an unambiguous and accurate manner. The circuit compares...
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7286010 |
Systems and methods for over-current protection
Systems and methods for over-current protection in all-digital amplifiers using low-cost current sensing mechanisms. An over-current hard clipping unit receives a digital audio signal, clips the...
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7276974 |
Method and apparatus for protecting RF power amplifiers
Method and apparatus are provided for protecting radio frequency (RF) power amplifiers. A circuit ( 10 ) is provided for limiting a supply current to a first stage (Q 3 ) of the RF power amplifier...
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7276968 |
Class D amplifier
A drive signal that matches the bias of a transistor is generated. A differential amplifier calculates the difference between a specified voltage of negative power supply and another input signal....
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7268990 |
Power amplifier protection
A power amplifier protection circuit that includes protection circuitry to variably shunt an input radio frequency (RF) signal to AC ground, turn off bias to an output transistor of a power...
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7262667 |
Radio frequency power amplifier
A radio frequency (RF) power amplification circuit including a power amplifier is provided for preventing breakdown of the power amplifier. The power amplifier includes an input for receiving RF...
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7256652 |
Differential input receiver having over-voltage protection
A differential receiver circuit. In one embodiment, the circuit includes first and second input transistors, each having a first terminal coupled to a bias node (a first and second bias node,...
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7253687 |
Clamping circuit for operational amplifiers
A differential input operational amplifier has a voltage clamp differential transistor pair coupled to an input differential transistor pair of the operational amplifier. The voltage clamp...
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7221227 |
Methods and apparatus for reducing output current oscillations of a driver provided with circuitry that senses and responds to excessive current draws of an output stage of the driver
In one embodiment, a method is provided for reducing output current oscillations of a driver provided with i) a current sensing circuit that senses excessive current draws of an output stage of the...
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7205843 |
Protection circuit for power amplifier
A directional coupler is provided on the output side of a power amplifier. An increase in reflected wave power from a load is detected through the directional coupler by an electric power detector...
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7205840 |
Wideband CMOS gain stage
A CMOS gain stage includes biasing circuitry configured to insure saturation of a subsequent stage without a source follower circuit. The CMOS gain stage is optionally powered by a supply voltage...
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7205834 |
Power amplifier
In a power amplifier driven by a pulse width modulation (PWM) signal, a first pair of drive pulses opposite in level to each other is formed from a first pulse width modulation signal whose...
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7202749 |
AC coupling technique for improved noise performance and simple biasing
A low noise amplifier (LNA), which utilizes an AC coupling technique that can internally bias diodes in such a way as to provide effective low noise amplification, is provided. The low noise...
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7196586 |
Oscillator amplifier circuit operable to provide symmetric current limiting and method of same
An amplifier circuit operable to provide symmetric current limiting. The amplifier circuit includes a common source amplifier for sourcing a current and receiving an voltage input, a current...
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