Abstract: A switching amplifier is disclosed and comprises: a power supply (Vcc); input circuits (Va, Vb); switch transistors (M1, M2) connected with each other in series; driving circuits (I1, I2) coupled with the switch transistors (M1, M2) respectively; a bootstrap circuit for supplying operation voltage to the driving circuit (I1). The switching amplifier also comprises: leakage circuits (M1a, M2a) or auxiliary switching circuits (M1?, M2?). With the switching amplifier of the invention, the fluctuation of the bootstrap potential can be suppressed and the signal distortion of the switching amplifier can be prevented.

Abstract: A motion sensing process senses a mouse moving relative to a surface by taking a reference image and a sample image of the surface. The process shifts the reference image to neighboring pixel positions arranged in certain patterns and compares the sample image with the reference image at its original pixel position at the shifted pixel positions. A motion vector describing a displacement of the object with respect to the surface is generated from such comparisons. In one embodiment, the pattern includes the original pixel position and neighboring pixel position arranged five rows and five columns with the total number of the pixel positions less than twenty five. In another embodiment, the process selects one of four elongated patterns based on the orientation of a predicted motion vector. In yet another specific embodiment, the process selects one of eight directional patterns based on the direction of the predicted motion vector.

Abstract: An optical motion tracking device (10) includes a photo detector array (18) comprised of highly sensitive photo sensors coupled to a computational circuit (19) inside a casing (11). The photo detector array (18) detects optical features of a surface (25) using ambient light reflected from or propagated through the surface (25) and transmitted into the casing through an aperture (15). Protrusions (14) on the bottom (10) lifts the device (10) from the surface (25) and allow the ambient light to illuminate the surface (25). A nontransparent sidewall (17) encloses a light path from the aperture (15) to the photo detector array (18) to reduce light interference. A reflective band (32) near the aperture (15) to increases the illumination of the surface (25). The computational circuit (19) calculates the correlation between the images from the photo detector array (18) to track the motion of the device (10).

Abstract: A system (101) for clock signal synchronization includes a data analyzer (104) and a synchronized clock signal generator (105) coupled to an RC oscillator (103). The data analyzer (104) generates a digital control signal representing the number of cycles of a reference signal of the RC oscillator (103) during an eight-bit period of an incoming token packet. The synchronized signal clock generator (105) uses the digital control signal to lock a clock signal to packets that have the same bit rate as the token packet.

Abstract: The present invention discloses a switching amplifier and its modulations process, which belongs to the field of non-filters-type switching amplifier. The switching amplifier comprises: pulse-width modulation with dual comparator, multiple-loop feedback structure, only one integrating amplifier with dual-ends output needed for each loop, no less than two feedback loops set between the integrating amplifier and H-bridge, in addition, no any low-pass filters needed adding to the feedback path. Multiple feedback loops are adopted in the present invention, which can low the distortion of the switching amplifier to the extent. Furthermore, no any extra low-pass filters are needed adding to the feedback path, which making the products a higher cost effectiveness.

Abstract: A class-D amplifier (10) includes a logic circuit (40) for controlling the operation of a switching bridge (11). The logic circuit (40) transmits the differential mode of a differential pulse width modulation input signal and deletes a central portion of the common mode of input signal, while preserving pulses of a minimum pulse width following a rising edge and preceding a falling edge in common mode of the input signal. Deleting the central portion of the common mode signal improves the efficiency and reduces the electromagnetic interference radiation of the class-D amplifier (10). Preserving the pulses of the minimum pulse width ensures the proper operation of the switching elements (12, 14, 16, 18) in the switching bridge (11), thereby reducing the distortion in the signal amplification.

Abstract: An optical motion tracking device (10) includes a photo detector array (18) comprised of highly sensitive photo sensors coupled to a computational circuit (19) inside a casing (11). The photo detector array (18) detects optical features of a surface (25) using ambient light reflected from or propagated through the surface (25) and transmitted into the casing through an aperture (15). Protrusions (14) on the bottom (10) lifts the device (10) from the surface (25) and allow the ambient light to illuminate the surface (25). A nontransparent sidewall (17) encloses a light path from the aperture (15) to the photo detector array (18) to reduce light interference. A reflective band (32) near the aperture (15) to increases the illumination of the surface (25). The computational circuit (19) calculates the correlation between the images from the photo detector array (18) to track the motion of the device (10).

Abstract: The present invention discloses a switching amplifier and its modulations process, which belongs to the field of non-filters-type switching amplifier. The switching amplifier comprises; pulse-width modulation with dual comparator, multiple-loop feedback structure, only one integrating amplifier with dual-ends output needed for each loop, no less than two feedback loops set between the integrating amplifier and H-bridge, in addition, no any low-pass filters needed adding to the feedback path. Multiple feedback loops are adopted in the present invention, which can low the distortion of the switching amplifier to the extent. Furthermore, no any extra low-pass filters are needed adding to the feedback path, which making the products a higher cost effectiveness.