Abstract: A protection module (4) for a RF-amplifier (2) is efficient against overvoltage due to load impedance mismatch when said RF-amplifier is connected to a load RF-element (3). The protection module comprises a branch with at least one diode-like operating component (D1, D2, . . . , Dn) and a resistor (R2) which starts conducting when a RF-signal on a transmission link (6) between the RF-amplifier and the load RF-element is higher than a threshold set by the diode-like operating component. Such protection may be implemented in MOS technology only.

Abstract: The power amplifying apparatus includes a first comparator that compares the first detection signal and the fourth detection signal and outputs a first comparison signal depending on whether or not a difference between the first current and the fourth current is equal to or greater than a first predetermined value. The power amplifying apparatus includes a second comparator that compares the second detection signal and the third detection signal and outputs a second comparison signal depending on whether or not a difference between the second current and the third current is equal to or greater than a second predetermined value.

Abstract: Semiconductor devices are disclosed including a bulk substrate, an epitaxial collector layer, an epitaxial base layer, an epitaxial emitter layer and an electrical insulator layer in direct thermal contact with at least a portion of the base layer, emitter layer, and/or collector layer. At least a portion of the electrical insulator layer has high thermal conductivity properties, which can provide for dissipation of undesirable thermal energy through the electrical insulator layer.

Abstract: A protection device includes: a serial element unit that includes a first switching element and a resistive element, one end being connected to a control terminal of a protection-target switching element, the other end being connected to a first voltage line, the protection-target switching element including a first terminal connected to the first voltage line, a second terminal connected to a second voltage line and an inductor unit, and the control terminal, the protection-target switching element switching a conduction state at the normal time to a non-conduction state between the first terminal and the second terminal when an off-voltage is applied to the control terminal; a capacitance provided at the protection-target switching element and has a predetermined capacitance value; and a controller that performs control such that the first switching element is in a conduction state if the protection-target switching element is put into a non-conduction state.

Abstract: A method for processing signals may include comparing an output voltage signal in an output stage of an amplifier with a reference voltage signal. If the output voltage signal is greater than the reference voltage signal, a comparator voltage signal may be generated. Bias voltage for at least one output stage transistor may be increased by increasing current generated by a first bias current source of the at least one output stage transistor. The current may be increased in proportion to the generated comparator voltage signal. The output voltage signal may be divided prior to the comparing. The at least one output stage transistor may be dynamically biased based on the generated comparator voltage signal. The comparator voltage signal may be generated using at least one differential pair with a current mirror load.

Abstract: Systems and method that provide short circuit protection for a power amplifier are described. The system can include, for example, a sense network that receives an output current from the power amplifier that is to be protected. The sense network can include, for example, a first resistor and a second resistor in series. The sense amplifier has a first input and a second input in which the first input is coupled to a first end of the first resistor and in which second input is coupled to a second end of the first resistor. The sense amplifier amplifies a voltage across the first resistor of the sense network in which the voltage is based on the output current from the power amplifier. Based on the amplified voltage of the sense amplifier, the feedback network reduces the output current from the power amplifier to protect the power amplifier from damage due to a short circuit condition.

Abstract: Systems and methods for protecting circuits from short-circuit events are described. The system may include, for example, first circuitry that receives an output signal from a power amplifier to be protected from a short-circuit event. The first circuitry mirrors an output stage of the power amplifier and provides a mirrored current that mirrors an output stage current of the power amplifier. Second circuitry is operatively coupled to the first circuitry and to the power amplifier. The second circuitry includes, for example, a comparator circuit that compares the mirrored current to a reference current. A first transistor of the comparator circuit is in a mirror configuration with respect to a second transistor of the power amplifier. The second transistor sinks or sources current into the power amplifier to protect the power amplifier from the short-circuit event.

Abstract: A mismatch protection circuit for high frequency power amplifiers includes a waveguide coupler connected to the output of the high frequency power amplifier. The waveguide coupler includes a first detector diode, which supplies, according to the power level being applied, a first voltage, which corresponds to the effective power that is fed in. The waveguide coupler also includes a second detector diode, the outputted second voltage of which corresponds to the power that is reflected due to the mismatch. The protection circuit further includes a control circuit, with which the amount of a mismatch is determined from the difference between the voltage value at the second diode and a reference voltage. The output stage(s) of the high frequency power amplifier(s) is and/or are switched on or off, depending on whether the voltage difference drops below or exceeds a given reference value.

Abstract: There is provided a radio frequency amplifying apparatus having a protection voltage varying function, including a radio frequency amplifying unit amplifying a radio frequency signal, and a protection circuit unit connected between an output node of the radio frequency amplifying unit and a ground and limiting a voltage in the output node to a level of a preset protection voltage or less when the voltage in the output node is higher than the preset protection voltage, wherein the protection voltage is varied with a control signal.

Abstract: A semiconductor integrated circuit that is efficiently reduced in a noise level is offered. P-channel type MOS transistors M1 and M2 serving as differential input transistors have a thin gate oxide film in order to reduce the noise level. A protection circuit to protect the P-channel type MOS transistors M1 and M2 from overvoltage is formed including P-channel type MOS transistors M3 and M4. The P-channel type MOS transistor M3 is a first protection transistor to protect the P-channel type MOS transistor M1 from overvoltage, and is connected to a drain of the P-channel type MOS transistor M1. The P-channel type MOS transistor M4 is a second protection transistor to protect the P-channel type MOS transistor M2 from overvoltage, and is connected to a drain of the P-channel type MOS transistor M2.

Abstract: The apparatus and method thereof accurately sense and convert a radio frequency (RF) current signal to direct current (DC) independent of process variation and temperature, and without requiring high speed, high voltage amplifiers for its operation. The apparatus comprises an AC coupled circuit that couples the RF signal from the main device to a sense device with an N:M ratio, a low pass filter system that extracts the DC content of the RF current signal, and a negative feedback loop that forces the DC content of the main device and the sensed device to be equal. Exemplary embodiments include a current sensor that provides feedback to protect an RF power amplifier from over-current condition, and a RF power detection and control in a RF power amplifier (PA) that multiplies the sensed output current by the sensed output voltage to be used as a feedback to control the PA's bias.

Abstract: Exemplary embodiments are directed to providing electrostatic discharge (ESD) protection of a cascode device of an amplifier. In an exemplary embodiment, a transistor is configured to receive a bias voltage and at least one circuit element coupled to the transistor and configured to receive an input voltage via an input pad. Additionally at least one diode can be coupled to a drain of the first transistor and configured to limit a voltage potential at an internal node of the amplifier caused by the input pad.

Abstract: Systems, methods and apparatus are disclosed for amplifiers for wireless power transfer. In one aspect a method is provided for controlling operation of an amplifier, such as a class E amplifier. The method may include monitoring an output of the amplifier. The method may further include adjusting a timing of an enabling switch of the amplifier based on the output of the amplifier.

Abstract: A power amplifier includes a power amplifier core including a plurality of gain stages to receive a radio frequency (RF) signal and to output an amplified RF signal, an output network coupled to the power amplifier core to receive the amplified RF signal and output a transmit output power signal, and a directional coupler coupled to the output network to obtain a coupled signal proportional to the transmit output power signal. Each of these components can be configured on a single semiconductor die, in an embodiment.

Abstract: The present invention relates to an integrated amplification circuit for a transducer signal comprising a semiconductor substrate. The semiconductor substrate comprises a signal limiting network comprising first and second parallel legs coupled between an input of a preamplifier and a first predetermined electric potential of the integrated amplification circuit. The first leg comprises a plurality of cascaded semiconductor diodes coupled to conduct current in a first direction through the limiting network and the second leg comprises a plurality of cascaded semiconductor diodes coupled to conduct current in a second direction through the limiting network. A current blocking member is configured to break a parasitic current path between an anode or a cathode of a semiconductor diode of the first leg or the second leg and the semiconductor substrate.

Abstract: Embodiments of the present application disclose a power amplifier protection circuit, communication device, and method, to protect a power amplifier when an abnormal signal, such as a burr or a pulse, occurs in a circuit. The method according to an embodiment of the present application comprises: detecting and comparing, by an input detection circuit, an abnormal signal in an input signal, outputting a protection control signal, and after processing performed by a delay circuit, controlling a power amplifier to be in an off state in a pulse width of the delayed protection control signal, so that the abnormal signal passes through the power amplifier when the power amplifier is in the off state, thereby preventing the power amplifier from burning, and achieving the effect of protecting the power amplifier.

Abstract: The low-noise amplifier with through mode is configured such that a source grounded transistor and a gate grounded transistor are connected in cascode, and a load impedance element and a switching transistor are serially connected between the drain of the gate grounded transistor and a power supply, and a through pass circuit is connected between an input terminal and an output terminal. The gate voltage of the gate grounded transistor is regulated by a bias circuit and the voltage of a mode control terminal is converted by a level shifter to control the gate voltage of the switching transistor, whereby, in the case of using only transistors whose terminal-to-terminal breakdown voltages are each equal to or less than the power supply voltage, it becomes feasible to prevent voltages equal to or more than the terminal-to-terminal breakdown voltages from being applied between the terminals of each transistor.

Abstract: A system for power amplifier over-voltage protection includes a power amplifier configured to receive a system voltage, a bias circuit configured to provide a bias signal to the power amplifier, and a power amplifier over-voltage circuit configured to interrupt the bias signal when the system voltage exceeds a predetermined value, while the system voltage remains coupled to the power amplifier.

Abstract: An output stage of an integrated class-A amplifier in a technology adapted to a first voltage and intended to be powered by a second voltage greater than the first one, including: one or several transistors of a first channel type between a first terminal of application of the second voltage and an output terminal of the stage; transistors of a second channel type between this output terminal and a second terminal of application of the second voltage, wherein: a first transistor of the second channel type has its gate directly connected to an input terminal of the stage; at least a second and a third transistors of the second channel type are in series between the output terminal and said first transistor, the gate of the second transistor being connected to the midpoint of a resistive dividing bridge between said output terminal and the gate of the third transistor, and the gate of the third transistor being biased to a fixed voltage.

Abstract: A thermally regulated amplifier system includes an amplifier unit, a temperature-sensing unit and a controller. The amplifier unit includes a power amplifier that has an adjustable gain function. The controller receives temperature readings from the temperature-sensing unit, computes the gain G(n) of the amplifier unit, and provides the computed gain of the amplifier G(n) to the power amplifier unit.

Abstract: A transmitter includes a Power Amplifier (PA), an antenna, at least one passive component and control circuitry. The PA is controlled by a PA control voltage, is operative to amplify a Radio Frequency (RF) signal and has input and output amplifier terminals. The passive component has an input component terminal coupled to the output amplifier terminal of the PA and an output component terminal coupled to the antenna. The control circuitry is configured to determine an interim power level at the output amplifier terminal that causes the signal at the output component terminal to have a target output power level, to determine, based on the interim power level, a given PA control voltage that makes the interim power level producible by the PA, so that the signal at the output component terminal has the target output power level, and to apply the given PA control voltage to the PA.

Abstract: Embodiments of the present application disclose a power amplifier protection circuit, communication device, and method, to protect a power amplifier when an abnormal signal, such as a bun or a pulse, occurs in a circuit. The method according to an embodiment of the present application comprises: detecting and comparing, by an input detection circuit, an abnormal signal in an input signal, outputting a protection control signal, and after processing performed by a delay circuit, controlling a power amplifier to be in an off state in a pulse width of the delayed protection control signal, so that the abnormal signal passes through the power amplifier when the power amplifier is in the off state, thereby preventing the power amplifier from burning, and achieving the effect of protecting the power amplifier.

Abstract: The present invention relates to audio amplifier and a method for protecting the audio amplifier. The audio amplifier includes a pre-amp circuit, an output stage power amplifier, a temperature detector and a gain adjusting circuit. The pre-amp circuit receives an audio signal for amplifying the audio signal to generate an amplified audio signal. The output stage power amplifier receives the amplified audio signal to drive a load. The temperature detector is used for detecting a temperature of the output stage power amplifier to output a temperature signal. The gain adjusting circuit adjusts amplitude of the amplified audio signal of the pre-amp circuit according to the temperature signal.

Abstract: Embodiments of circuits, apparatuses, and systems for a protection circuit to protect against overdrive or overvoltage conditions. Other embodiments may be described and claimed.

Abstract: One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

Abstract: An apparatus (20) for use as an amplifier has a transistor (26) for providing signal amplification, a heat pipe or circulated fluid heat sink (22) and a thermal interface device (24) for providing mechanical and thermal connection between the transistor (26) and the heat sink (22). In use, to facilitate efficient transfer of heat/thermal energy from the transistor (26) to the heat sink (22), the plate (24) is provided between the heat sink (22) and the transistor (26). The plate (24) connects the heat sink (22) to the transistor (26) and provides a thermal conduit therebetween.

Abstract: In an example embodiment, a method for bidirectional signal propagation comprises: a) sensing a voltage level of a first signal at a first port; b) coupling the first port to an output of an amplifier with a solid state switch if the voltage level of the first signal is less than a threshold voltage, whereby a second signal applied to a second port coupled to an input of the amplifier is propagated in a first direction from the second port to the first port; and c) bypassing the amplifier if the voltage level of the first signal is greater than the threshold voltage such that the first signal is propagated in a second direction from the first port to the second port.

Abstract: A signal amplifier includes an inverting amplification circuit, a first switching element, a second switching element, and a control section. The inverting amplification circuit includes a first voltage terminal, a second voltage terminal, an inverting input terminal, an output terminal, a first protected switching element, and a second protected switching element. The control section controls such that when an overcurrent has flowed in the first voltage line, the first and second protected switching elements are switched to a non-conducting state after switching the first switching element in a conducting state and switching the second switching element in a non-conducting state, and when an overcurrent has flowed in the second voltage line, the first the second protected switching elements are switched to a non-conducting state after switching the first switching element in a non-conducting state and switching the second switching element in a conducting state.

Abstract: An oscillator having: (A) a transistor for producing an oscillating output signal at an output electrode of the transistor. The oscillator includes; (B) a bias circuit for producing a bias signal for the transistor, said bias circuit including an amplifier coupled to the output electrode of the transistor; and (C) a circuit coupled between an output of the amplifier and a control electrode of the transistor, for isolating the bias signal provided by the amplifier from the oscillating signal.

Abstract: Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.

Abstract: Systems and methods for implementing over-current protection include reducing a clip level while an over-current condition is being detected. Once the over-current condition is no longer detected, the clip level is maintained for a specified period before allowing the clip level to be increased. In an embodiment, the specified period, for which the clip level is maintained before the clip level is allowed to be increased, starts when the over-current condition is no longer detected, and ends when each of N immediately preceding sample(s) of the audio signal are not clipped to the clip level, where N is an integer ?1. After an over-current condition is no longer detected, and after the clip level has been maintained for the specified period, the clip level can be increased if an over-current condition is not detected for a sample and the clip level is below a specified maximum clip level.

Abstract: A method of providing electrostatic discharge (ESD) protection for a read element in a magnetic storage system comprises coupling a first terminal of a shunting device to a first terminal of the read element; coupling a second terminal of the shunting device to a second terminal of the read element; providing a conductive path between the first and second terminals of the shunting device when the read element is disabled; and providing a nonconductive path between the first and second terminals of the shunting device when the read element is enabled.

Abstract: Aspects of embodiments according to the present invention are directed toward a circuitry and a method to accurately measure the junction temperature of power amplifier and uses the measurement to enable optimization of performance in the presence of a mismatched load via control of the power amplifier such that corrective action to mitigate effects of the mismatched load can be performed.

Abstract: The system contains a first input receiving a signal from the amplifier input. A second input receives a signal from the amplifier output. A gain modification device is connected to the second input thereby reducing an amplitude of the signal from the amplifier output. A difference element connected to the gain modification device and the first input subtracts one of the first input and the second input from the other of the first input and the second input and outputting a difference voltage. A comparator, connected to the difference element and a threshold voltage source, compares the difference voltage to a threshold voltage. A disabling device is connected to the comparator and an output stage of the amplifier, wherein an output stage of the amplifier is disabled when the threshold voltage exceeds the difference voltage.

Abstract: A signal processing apparatus includes: a digital processing unit to which a digital input signal is supplied, which performs a digital process on the digital input signal to produce a digital signal, and which produces a control signal designating a specific time period when an amplitude of an analog output signal is to be lowered; a DA-conversion unit which converts the digital signal to produce an analog signal; and a variable gain unit which adjusts an amplitude of the analog signal to produce the analog output signal, and which lowers the amplitude of the analog output signal during the specific time period designated by the control signal.

Abstract: This disclosure relates generally to radio frequency (RF) amplification devices and methods of limiting an RF signal current. Embodiments of the RF amplification device include an RF amplification circuit and a feedback circuit. The RF amplification circuit is configured to amplify an RF input signal so as to generate an amplified RF signal that provides an RF signal current with a current magnitude. The feedback circuit is used to limit the RF signal current. In particular, a thermal sense element in the feedback circuit is configured to generate a sense current, and thermal conduction from the RF amplification circuit sets a sense current level of the sense current as being indicative of the current magnitude of the RF signal current. To limit the RF signal current, the feedback circuit decreases the current magnitude of the RF signal current in response to the sense current level reaching a trigger current level.

Abstract: A device including a gain control element coupled prior to or within a radio frequency (RF) power amplifier (PA) with an adaptive parametric PA protection circuit is described. In an exemplary embodiment, the device includes a gain control element coupled prior to a radio frequency power amplifier with a power stage with corresponding transistor breakdown threshold values, having an adaptive parametric PA protection circuit configured to receive at least one power stage drain-source voltage parameter value, at least one power stage drain-gate voltage parameter value, and at least one power stage drain-source current parameter value, and including an adaptive parametric PA protection circuit having a first section for processing the parameter values and a second section for generating a gain correction signal to adjust the gain control element with optimal power added efficiency (PAE) for the power stage within the corresponding transistor breakdown threshold values.

Abstract: A power amplifier, for example a class-E switching power amplifier, and corresponding method, comprising: a plurality of power transistors (16), for example twelve power transistors, providing a partitioned power transistor; and a voltage sensing module (22), comprising for example voltage dividers and inverters, digitally sensing the drain voltage (2) of the partitioned power transistor to control the number of power transistors of the plurality of power transistors (16) that are switched on or off thereby controlling the drain voltage (2) which is varying for example due to antenna mismatch. The power amplifier may further comprise a memory (24) coupled to the voltage sensing module (22) for storing a history of the drain voltage (2), e.g. a history of antenna mismatch.

Abstract: Apparatus and methods for biasing a power amplifier are provided. In one embodiment, a packaged circuit includes a power amplifier, a bond wire electrically connected between a system voltage source and a supply input of the power amplifier, a current source, a reference resistor electrically connected between the system voltage source and the current source, and a comparator. The comparator is configured to compare a sense voltage that is based on a voltage across the bond wire to a reference voltage that is based on a voltage across the reference resistor. The comparator is configured to generate a saturation control signal for clamping a bias current of the power amplifier when the sense voltage exceeds the reference voltage.

Abstract: There is provided a current sense circuit (134). An exemplary current sense circuit (134) comprises a voltage-to-current converter circuit (218) that is adapted to receive a voltage that is proportional to a load current drawn from a battery (110) by a load (202) and to produce a current proportional to the load current, and a current-to-voltage converter circuit (228) that is adapted to receive the current proportional to the load current and to produce a voltage proportional to the load current based on a regulated voltage source (230).

Abstract: A class D amplifier includes an amplifier that generates a digital signal for driving a load based on an input signal, an attenuator that attenuates the input signal according to an attenuation command signal, and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.

Abstract: When an output voltage from the amplifying circuit includes a positive DC voltage, an electric current continuously flows in a power source voltage, a load, and a reference voltage in this order. As a result, the reference voltage increases so as to be a first threshold voltage or more . The detecting section detects that the reference voltage is the first threshold voltage or more. When the output voltage from the amplifying circuit includes a negative DC voltage, an electric current continuously flows in the reference voltage, the load, a grounding potential in this order. As a result, the reference voltage reduces so as to be a second threshold voltage or less. The detecting section detects that the reference voltage is the second threshold voltage or less.

Abstract: 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 peak voltage that exceeds a threshold voltage. In response to the detection of a peak voltage, the gain of the power amplifier is reduced.

Abstract: Detection accuracy of a short circuit state in a load driving circuit is improved thereby operation efficiency of a motor may be enhanced. A gate control circuit 25 turns off NMOS transistors Q1 and Q4, turns on an NMOS transistor Q3, and turns on and off an NMOS transistor Q2 intermittently so as to control rotation of a motor 10. A detection circuit 30a detects a voltage Va at a connection node a between the NMOS transistor Q2 and the motor 10 a predetermined time after the NMOS transistor Q2 is turned on. A control circuit 20 turns off the NMOS transistor Q2 so as to cut off a current from a power supply to the motor 10 if the voltage Va at the connection node a is within a range in which the motor 10 is determined to be short-circuited.

Abstract: A protection circuit for a power amplifier connected as a negative feedback loop around the power amplifier. The negative feedback loop comprises a detector circuit, a driver circuit and an attenuator circuit. The detector circuit receives output voltage from the power amplifier and generates a signal when the output voltage exceeds a predefined threshold. The driver circuit filters the signal received from the detector circuit to maintain feedback loop stability and adjusts the feedback loop bandwidth and gain to provide a filtered signal. The attenuator circuit receives the filtered signal and attenuates the input voltage of the power amplifier to reduce the output voltage of the power amplifier to a level below the predefined threshold.

Abstract: Disclosed is a high efficiency amplifier operable to substantially reduce electromagnetic interference (EMI). The high efficiency amplifier comprises an output stage to provide a high powered signal to a load. The high efficiency amplifier further comprises an overlap protection circuit to produce a timing non-overlap in a control signal for the output stage, and an edge control circuit to reduce a transient portion of the high powered signal to substantially reduce the EMI. The overlap protection circuit and the edge control circuit may be implemented with resistive source degeneration. Also disclosed is a related method. In one embodiment, the high efficiency amplifier and the related method may be incorporated into a cellular telephone or a mobile audio device.

Abstract: When an output voltage from the amplifying circuit includes a positive DC voltage, an electric current continuously flows in a power source voltage, a load, and a reference voltage in this order. As a result, the reference voltage increases so as to be a first threshold voltage or more . The detecting section detects that the reference voltage is the first threshold voltage or more. When the output voltage from the amplifying circuit includes a negative DC voltage, an electric current continuously flows in the reference voltage, the load, a grounding potential in this order. As a result, the reference voltage reduces so as to be a second threshold voltage or less. The detecting section detects that the reference voltage is the second threshold voltage or less.

Abstract: An RF power amplifier includes an RF choke coil, a power amplification circuit unit, and an electrostatic discharge (ESD) protection unit. The RF choke coil is connected to a voltage terminal through which an operating voltage is applied. The RF choke coil supplies the operating voltage and interrupts an RF signal. The power amplification circuit unit is supplied with the operating voltage through the RF choke coil. The power amplification circuit unit amplifies an input signal inputted through an input terminal and outputs the amplified input signal through an output terminal. The ESD protection unit is connected between a first connection node and a ground. The ESD protection unit bypasses an ESD voltage from the first connection node to the ground, the first connection node being a node between the voltage terminal and the RF choke coil.

Abstract: 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 input may include one or more components to aid in processing of incoming signals. One such component coupled between the source and the input of the amplifier is a coupling capacitor used to maintain a bias voltage of the amplifier at a different potential than a DC voltage of the output node. In certain applications, the amplifier and the coupling capacitor may be integrated on a single substrate.

Abstract: 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 signal according to a clip level, and provides the signal to a modulator. The modulator modulates the signal to produce, e.g., a PWM signal and provides the modulated signal to an output stage which generates an output current to drive a speaker. An over-current sensing unit is compares the output current to a threshold value and generates a binary signal indicating whether the output current exceeds the threshold value. The hard clipping unit receives the binary signal and ramps down the clip level during time periods in which the binary signal indicates that the output current exceeds the threshold. When the binary signal indicates that the output current does not exceed the threshold value, the hard clipping unit ramps up the clip level.