Abstract: Recently, there has been an increased desire to measure load currents of class-D amplifiers to improve performance. The traditional solution has been to include one or more discrete components in series with the load, but this degrades performance. Here, however, circuit is provided (which includes sample-and-hold circuit) that accurately measures load currents without inhibiting performance and that is not inhibited by the phase differences between the load voltage and load current.

Abstract: Recently, there has been an increased desire to measure load currents of class-D amplifiers to improve performance. The traditional solution has been to include one or more discrete components in series with the load, but this degrades performance. Here, however, circuit is provided (which includes sample-and-hold circuit) that accurately measures load currents without inhibiting performance and that is not inhibited by the phase differences between the load voltage and load current.

Abstract: A power converter receiving a single-sided supply which is ground-terminated and providing a regulated positive supply and a regulated negative supply that is optimized to the expected output range of a class AB amplifier, as well as providing excellent efficiency. The converter finds application as a compact converter to power an audio amplifier driving an audio device which is ground terminated, such as a speaker.

Abstract: Audio amplifiers and methods of generating audio signals are disclosed. A disclosed example amplifier comprises a first driver to receive a first signal; a second driver to receive a second signal; a configurable signal delivery circuit; and a mode selector in communication with the first and second drivers to selectively configure the signal delivery circuit in a voltage boost mode or a voltage buck-boost mode based on a characteristic of the input signal.

Abstract: Audio amplifiers and methods of generating audio signals are disclosed. A disclosed example amplifier comprises a first driver to receive a first signal; a second driver to receive a second signal; a configurable signal delivery circuit; and a mode selector in communication with the first and second drivers to selectively configure the signal delivery circuit in a voltage boost mode or a voltage buck-boost mode based on a characteristic of the input signal.

Abstract: An apparatus for regulating a switching device that couples an output locus with one of a first voltage locus and a second voltage locus in response to a driver unit includes: a voltage feedback unit coupling the driver unit with at least one of the first voltage locus and the second voltage locus. The feedback unit provides a voltage feedback signal to the driver unit. The driver unit responds to the voltage feedback signal to affect the coupling by the switching device.

Abstract: A power converter receiving a single-sided supply which is ground-terminated and providing a regulated positive supply and a regulated negative supply that is optimized to the expected output range of a class AB amplifier, as well as providing excellent efficiency. The converter finds application as a compact converter to power an audio amplifier driving an audio device which is ground terminated, such as a speaker.

Abstract: A penetrating washer for use with a carriage bolt. The penetrating washer includes a flat section with a non-circular hole and one or more prongs, ridges, or other protrusions extending from a face of the flat section. A size of the non-circular hole preferably corresponds to a size of a top shaft of the carriage bolt. The non-circular hole can be a polygonal hole with round or sharp corners, for example a square hole with round or sharp corners. Any number of prongs, ridges, or other protrusions can be used, for example four. The non-circular hole preferably is in a center of the flat section. Also, methods of making and using the penetrating carriage bolt washer.

Abstract: A high voltage output stage amplifier that maximizes the output voltage swing when the peak-to-peak output voltage signal is higher than the supply voltage used in the signal conditioning circuits of the amplifier. The amplifier allows the maximum peak-to-peak swing on the output stage by shifting the quiescent voltage of the output stage to the midpoint of the output supply voltage. The shift is accomplished by tapping an offset current at the input of the error integrating stage of the amplifier proportional to the difference in the two power supply voltages.

Abstract: A tunable high voltage trigger silicon controlled rectifier (SCR) with a high holding voltage is disclosed. The source of a drain extended MOS serves as the remote cathode for the SCR, while the drain of the drain extended MOS serves to generate avalanche currents to trigger the SCR.

Abstract: An improved waveform generator (10) permits digital spectrum spreading by employing circuitry for controlling the charging and discharging of a load capacitor (24) to alter the generator's base frequency. A charge/discharge circuit (22) modulates the currents into the capacitor (24) to effect the slope of the triangle signal waveform (202). A threshold detector (26) determines the amplitude of the base frequency. Switch logic (28) controls an array of 1/N current switches (18) that provide incremental values of a reference source (12) to a summing function (16) which, in turn, feeds a charge/discharge circuit (22). The energy of the triangle waveform (202) remains approximately the same only it is now spread over a range of frequencies with the amplitude of the signal at a given point less than the amplitude of the base.

Abstract: A Class-D switching amplifier (30, 40) having a ternary mode of operation. Signal processing (21, 22) is provided to eliminate the potential of crosstalk within one channel by introducing a time delay into the system. A susceptible crosstalk point is moved away from a zero-crossing point to a higher power level, which is advantageous in low-end audio applications. A time delay is introduced to one ramp signal (RAMPB) in the first implementation (30), and an in-sync generator (42) is utilized in another implementation (40) using offset switching in the comparitors (40, 42) to create the time delay (&Dgr;t).

Abstract: A Class-D switching amplifier (20) having a terinary modulation scheme implemented in an H-bridge configuration. The present invention has four states of operation, and achieves increased efficiency and reduced cost by delivering current to the load only when needed, and once delivered, maintaining the current. The Class-D switching amplifier eliminates the need for post amplifier filters.

Abstract: A charge pump uses switching transistors including a PMOS transistor (P1), a first transistor (N1), and a second transistor (N2) instead of diodes (D1, D2) to control the transfer of charge from a pump capacitor (14) to a storage capacitor (20). The voltage (60) at the storage capacitor (20) is applied to a level shifter (13) and to the source of the PMOS transistor (P1) which, in turn, biases the first transistor (N1) during low state of an oscillating waveform (30B). A supply rail (140) charges the pump capacitor (14) when the first transistor (N1) is in its active region during the low state of the oscillating waveform (30B) and turns OFF during the high state of the waveform (30B) causing the charge on the pump capacitor (14) to be transferred to the storage capacitor (20). The level shifter (13) is used to synchronize the oscillating waveform (30B) so that no charge is lost from the pump capacitor (14) back to the supply and minimal charge is conducted through a parasitic diode (55).

Abstract: A high current power transistor is provided that comprises a drain region that includes a highly-doped drain region (54) and a lightly-doped drain region (50). The channel region (52) is activated by a gate conductor (32). The channel region separates the lightly-doped drain region (50) from a D-well region (40). A sidewall insulator body (44) is used to form the lightly-doped drain region (50) and the lightly-doped drain region (54). The transistor is formed in an active region (20) which comprises a portion of an n-type epitaxial layer (12) formed outwardly from a p-type substrate (10). The isolation structures (14) and (16) as well as the epitaxial layer (12) provides for a transistor that can be used in both source follower and common source configurations.

Abstract: A concrete screed rail having generally parallel spaced top and bottom edges, at least the upper one of which is provided with a finished surface, there being at least one and preferably a plurality of recesses in a web portion of the rail. The recesses in the web portion preferably are closed off by a thin layer of concrete, the concrete including that of said recess being reinforced by a mesh or plurality of short fibers. The screed rail may be in the form of a straight beam of I-section or alternatively of generally L-shaped cross-section. If desired, additional reinforcement may be incorporated in the rail.