18results about "Volume compression/expansion having semiconductor devices" patented technology

Aspects of the subject disclosure may include, for example, first and second operational amplifiers; and a differential pair of NPN transistors in a feedback path of the TLA configured to convert an input current signal into an output voltage signal, where a first emitter of a first NPN transistor of the pair of NPN transistors is connected to an inverting input of the first operational amplifier, and where a second emitter of a second NPN transistor of the pair of NPN transistors is connected to a non-inverting input of the second operational amplifier. Other embodiments are disclosed.

An audio system, including at least one approximating circuit, the at least one approximating circuit configured to apply an approximated gain to the input signal, the least one approximating circuit outputting an approximated signal; a limiter configured to reduce a magnitude of the input signal by a gain determined by an amount the magnitude of the approximated filtered signal exceeds a predetermined threshold, the limiter outputting a limited input signal; a filter being respectively configured to receive the limited input signal and to respectively apply a filter gain, the filters outputting a plurality of filtered signals, wherein the approximated gain is substantially similar to the filter gain of one of the plurality of equalization filters; and a speaker array comprising a plurality of speakers, each speaker configured to receive a respective filtered signal of the plurality of filtered signals and to transduce the filtered signal to an audio signal.

An example detector cell includes a first current source circuit having a terminal. The detector cell includes a first transistor having a control terminal, a first terminal, and a second terminal coupled to the terminal of the first current source circuit. The detector cell includes a second current source circuit having a terminal coupled to the first terminal of the first transistor. The detector cell includes a first current mirror having a first terminal and a second terminal, the first terminal coupled to the terminal of the second current source circuit and the first terminal of the first transistor. The detector cell includes a second transistor having a control terminal, a first terminal, and a second terminal coupled to the terminal of the first current source circuit. The detector cell includes a third current source circuit having a terminal coupled to the first terminal of the second transistor. The detector cell includes a second current mirror having a first terminal coupled to the terminal of the third current source circuit and the first terminal of the second transistor and a second terminal coupled to the second terminal of the first current mirror.

This application relates to methods and apparatus for clipping prevention. A driver apparatus for driving a load with an output signal has a switching driver with a switch network and a modulator configured to control the switch network to switch output nodes between different switching voltages with a controlled duty-cycle. A quantizer controller receives a quantizer input signal based on an input signal and a feedback signal and controls the duty-cycle of the switch network. A clipping prevention controller is configured to control a gain applied to the input signal so as to provide limiting of the input signal to avoid clipping, wherein the clipping prevention controller is configured to dynamically control at least one limiting threshold used to determine when to apply limiting of the input signal based on an indication of said quantizer input signal.

This application relates to methods and apparatus for voltage monitoring of switching drivers. A modulator is configured to receive a modulator input signal and to controlling switching of an output stage of the switching driver to generate a first drive signal. A voltage monitor is configured to receive a first digital signal tapped from the modulator and to generate an indication of output voltage of the first drive signal from the first digital signal by controllably applying an adjustment from the first digital signal to compensate for inaccuracy between the first digital signal and the output voltage. The adjustment is based on monitored operation of the modulator. In some cases the monitored operation may be clipping of the switching driver. In some cases the monitored operation may be a signal generated by the modulator that include a contribution from a feedback signal of output voltage.

An audio system is provided. The aspects include a notification appliance circuit (NAC) having one or more speakers configured to reproduce sound. The aspects include an amplifier circuit configured to drive the one or more speakers. The aspects include a relay circuit configured to selectively connect or disconnect the speakers to or from the amplifier circuit responsive to an enable amplifier control signal or a disable amplifier control signal, respectively. The aspects include a logic element configured to generate the enable amplifier control signal or the disable amplifier control signal responsive to an absence or a presence of an overcurrent condition in an output of the amplifier circuit, respectively. The aspects include an overcurrent detection circuit configurated to detect the absence or the presence of the overcurrent condition.

The disclosure relates to a current converter circuit (600) for converting a linear input current (lctrl_lin) to an exponential output current (lctrl_sum), the current converter circuit (600) comprising first and second current converters (601, 602), each of which comprises: an input current branch (6031, 6032) with an input current source (6041, 6042) connected in series with a tuning voltage circuit (6051, 6052) and a tuning resistor (6061, 6062) between a supply voltage line (607) and a common voltage line (608); and an output current branch (6091, 6092) with an output transistor (6101, 6102) having a collector connected to an output node (6111, 6112), a emitter connected to the common voltage line (608) and a base connected to the tuning voltage circuit (6051, 6052), wherein the output nodes (6111, 6112) of the first and second current converters (601, 602) are connected to a summing output node (612) of the current converter circuit (600).

A logarithmic amplifier (200) includes a logarithmic current preamplifier circuit (202) and a logarithmic amplifier circuit (204). The logarithmic current preamplifier circuit (202) includes an inverting input terminal (206A), an output terminal (206B), and a first diode (210). The first diode (210) is coupled between the inverting input terminal (206A) and the output terminal (206B) of the logarithmic current preamplifier circuit (202). The logarithmic amplifier circuit (204) includes an inverting input terminal (212A), an output terminal (212B), and a second diode (214). The inverting input terminal (212A) of the logarithmic amplifier circuit (204) is coupled to the output terminal (212B) of the logarithmic current preamplifier circuit (202). The second diode (214) is coupled between the inverting input terminal (212A) and the output terminal (212B) of the logarithmic amplifier circuit (204).

A driver apparatus 100a for driving a transducer (Fig.1, 102) has a switching driver 101 configured to switch at least one output node (Fig.1, 103a, 103b) between different switching voltages with a c

Hybrid variable gain amplifiers and methods of controlling hybrid VGAs are disclosed. The hybrid VGA includes a first portion that provides a current path between a positive input and a positive output, and a current path either between the positive input and a negative output, in a first mode of operation, or between the positive input and a voltage source, in a second mode of operation. A second portion of the VGA provides a current path between a negative input and the negative output, and a current path either between the negative input and the positive output, in the first mode of operation, or between the negative input and the voltage source, in the second mode of operation. Control voltages selectively enable the paths in the first or second mode of operation. The control voltages further control amount of current flow in the enabled paths.

This application relates to methods and apparatus for clipping prevention. A driver apparatus for driving a transducer has a switching driver configured to switch at least one output node between different switching voltages with a controlled duty-cycle to drive an output signal across the transducer. A clipping prevention controller is configured to control a gain applied to the input signal so as to provide limiting of the input signal to avoid clipping of the output signal. The clipping prevention controller is configured to dynamically control at least one limiting threshold used to determine when to apply limiting of the input signal based on an indication of load resistance of the transducer and the input voltage to the switching driver.

The disclosure relates to a current converter circuit. Example embodiments include a current converter circuit (600) for converting a linear input current (Ictrl_lin) to an exponential output current (Ictrl_sum), the current converter circuit (600) comprising first and second current converters (601, 602), each of which comprises: an input current branch (6031, 6032) with an input current source (6041, 6042) connected in series with a tuning voltage circuit (6051, 6052) and a tuning resistor (6061, 6062) between a supply voltage line (607) and a common voltage line (608); and an output current branch (6091, 6092) with an output transistor (6101, 6102) having a collector connected to an output node (6111, 6112), a emitter connected to the common voltage line (608) and a base connected to the tuning voltage circuit (6051, 6052), wherein the output nodes (6111, 6112) of the first and second current converters (601, 602) are connected to a summing output node (612) of the current converter circuit (600)

The invention relates to a method for protecting a component (6) within an audio device (4) from the exceedance of a maximum internal temperature (TI), wherein a power loss (V) of the component (6) is determined, a measurement temperature (TM) is measured on the component (6), a temperature difference (DT) for the component (6) between the measurement temperature (TM) on the component and the internal temperature (TI) is determined from the power loss (V) by means of a thermal model (14) of the component (6), the internal temperature (TI) is determined as the sum of the measurement temperature (TM) and the temperature difference (DT), a permissible maximum value (VM) for the power loss (V) is determined on the basis of the internal temperature (TM) and known component data (16) of the component (6), and the component (6) is operated in a normal operating mode (N) if the power loss (V) does not exceed the maximum value (VM) or the component (6) is otherwise operated in reduced-power economy operating mode (S) such that the power loss (V) is limited to the maximum value (VM). An audio apparatus (2), having an audio device (4) that internally contains a component (6) that should be protected from the exceedance of a maximum internal temperature (TI), contains a protection module (8) for carrying out the method according to the invention.

Method for adjusting the dynamic range of a receiver amplifier (100) in an environmental sensor device, comprising the step of injecting (S200) an additional electrical signal (S g ) into the input (11, 12) of the receiving amplifier (100) to reduce an output signal generated due to a first electrical signal (u a ) of the receiving amplifier (100), wherein the additional electrical signal (S g ) by a current source (ig, B) drives a current towards a negative terminal of an operational amplifier (1) inside the receiver amplifier (100) and / or a voltage source (ug, A) is driven to couple a voltage to the positive terminal of the operational amplifier (1) of the receiver amplifier (100).

A driver apparatus 100c for driving a load (Fig.1, 102) with an output signal has a switching driver 101 with a switch network (Fig.1, 105) and a modulator 106 configured to control the switch network

The present disclosure relates to a first circuit for measuring a first current, the first circuit including a current step-down circuit, a logarithmic comparator circuit, and a differential voltage amplifier circuit. A first input of the current step-down circuit is configured to receive the first current, and a first output of the current step-down circuit is configured to provide a ratiometric step-down current to a first logarithmic amplifier via a current mirror assembly. The logarithmic comparator circuit includes the first logarithmic amplifier, configured to convert the ratiometric step-down current into a logarithmic first voltage, and a second logarithmic amplifier, configured to provide a logarithmic reference voltage. The differential voltage amplifier circuit is configured to compare the logarithmic first voltage with the logarithmic reference voltage.

Current measuring circuit The present description relates to a circuit for measuring a current (Imeas200) between 1 mA and 100 A comprising: - a first logarithmic amplifier (LogAmp200) adapted to convert said current (Imeas200) into a first voltage (LogAmpOut200); and - a second logarithmic amplifier (Amp203, TB202) adapted to provide a second reference voltage (Vref200). Figure for abstract: Fig. 2