A negative feedback inductor and a gate inductor are formed in different wiring layers of a substrate so as to be at least partially overlapped with each other in a plan view. When the lower wiring layer is thinner and the upper wiring layer is thicker, the negative feedback inductor Lc is formed in the lower wiring layer that is thinner.

A negative feedback inductor and a gate inductor are formed in different wiring layers of a substrate so as to be at least partially overlapped with each other in a plan view. When the lower wiring layer is thinner and the upper wiring layer is thicker, the negative feedback inductor Lc is formed in the lower wiring layer that is thinner.

An acoustic apparatus includes a class-D amplifier including a current feedback circuit, and a speaker system including a voice coil driven by the class-D amplifier. The speaker system is configured such that, in a case where the speaker system is driven by an ordinary amplifier having a first output resistance lower than a second output impedance of the class-D amplifier, a Q factor of the speaker system falls below a predetermined lower limit of an ordinary Q factor range of an ordinary speaker system. The current feedback circuit is configured to increase the second output impedance of the class-D amplifier by feeding a current flowing to the voice coil back to an input of the class-D amplifier so as to increase a Q factor as the acoustic apparatus higher than the predetermined lower limit of the ordinary Q factor range and within the ordinary Q factor range.

An acoustic apparatus includes a class-D amplifier including a current feedback circuit, and a speaker system including a voice coil driven by the class-D amplifier. The speaker system is configured such that, in a case where the speaker system is driven by an ordinary amplifier having a first output resistance lower than a second output impedance of the class-D amplifier, a Q factor of the speaker system falls below a predetermined lower limit of an ordinary Q factor range of an ordinary speaker system. The current feedback circuit is configured to increase the second output impedance of the class-D amplifier by feeding a current flowing to the voice coil back to an input of the class-D amplifier so as to increase a Q factor as the acoustic apparatus higher than the predetermined lower limit of the ordinary Q factor range and within the ordinary Q factor range.

Mechanisms for evaluating amplitude for current pulses provided to a transimpedance amplifier (TIA) for current levels beyond the linear range of the TIA where clipping circuit(s) may limit the input voltage of the TIA are disclosed. In one aspect, an example TIA arrangement includes a clipping arrangement that includes multiple clipping circuits. Each clipping circuit can be biased by different bias voltages such that the different clipping circuits are activated at different input current amplitudes. Different clipping circuits can have different impedances, which can result in different recovery time characteristics. With the multiple clipping circuits in clipping arrangements discussed herein, a saturated dynamic range of a TIA can be divided into sub-regions and different pulse widening characteristics for each region may be defined, which may enable determination of amplitude for current pulses provided to the TIA even for current levels beyond the linear range of the TIA.

Mechanisms for evaluating amplitude for current pulses provided to a transimpedance amplifier (TIA) for current levels beyond the linear range of the TIA where clipping circuit(s) may limit the input voltage of the TIA are disclosed. In one aspect, an example TIA arrangement includes a clipping arrangement that includes multiple clipping circuits. Each clipping circuit can be biased by different bias voltages such that the different clipping circuits are activated at different input current amplitudes. Different clipping circuits can have different impedances, which can result in different recovery time characteristics. With the multiple clipping circuits in clipping arrangements discussed herein, a saturated dynamic range of a TIA can be divided into sub-regions and different pulse widening characteristics for each region may be defined, which may enable determination of amplitude for current pulses provided to the TIA even for current levels beyond the linear range of the TIA.

A circuit for filtering a signal corresponding to a time of flight (TOF) of light from a laser reflected off an object to a photo detector, the circuit includes a preamplifier, a DC cancelation loop, and an AC cancelation loop. The preamplifier may be configured to receive the signal from the photo detector corresponding to an output of the laser reflected off an object remote from the laser and photo detector. The DC cancelation loop includes a current feedback DC servo loop. The AC cancelation loop includes a feedback network driven by a floating class AB output stage, and the preamplifier configured to drive the floating class AB output stage, wherein the preamplifier is driven by an error signal of the feedback network and creates an AC signal path with the feedback network and floating class AB output stage.

A system may include a first input for receiving a first signal for driving an amplifier that drives a load, a second input for receiving a second signal driven by the amplifier, and an instability detector for detecting instability of a feedback loop for controlling the first signal based on comparison of the first signal and the second signal.

This application relates to method and apparatus for driving acoustic transducers, such as speakers or haptic transducers. A transducer driver circuit (200) has a hysteretic comparator (201) configured to compare, with hysteresis, an input signal (S.sub.IN) received at a first comparator input to a feedback signal (S.sub.FB) received at a second comparator input. Based on the comparison the hysteretic comparator (201) generates a pulse-width modulation (PWM) signal (S.sub.PWM) at a comparator output (206). An inductor (203) is coupled between the comparator output and an output node (204). In use a resistive component (208), which may comprise the transducer (301) is coupled to output node (204). The inductor (203) and resistive component (208) provide filtering to the PWM signal (S.sub.PWM). A feedback path extends between the output node (204) and the second comparator input to provide the feedback signal (S.sub.FB).

This application relates to method and apparatus for driving acoustic transducers, such as speakers or haptic transducers. A transducer driver circuit (200) has a hysteretic comparator (201) configured to compare, with hysteresis, an input signal (S.sub.IN) received at a first comparator input to a feedback signal (S.sub.FB) received at a second comparator input. Based on the comparison the hysteretic comparator (201) generates a pulse-width modulation (PWM) signal (S.sub.PWM) at a comparator output (206). An inductor (203) is coupled between the comparator output and an output node (204). In use a resistive component (208), which may comprise the transducer (301) is coupled to output node (204). The inductor (203) and resistive component (208) provide filtering to the PWM signal (S.sub.PWM). A feedback path extends between the output node (204) and the second comparator input to provide the feedback signal (S.sub.FB).