Abstract: Disclosed boost amplifiers are used with a BTL amplifier that outputs balanced audio signals and that has an output current capacity and a dynamic power capacity. Disclosed amplifiers include an audio amplifier with a dynamic power capacity and that amplifies the balanced audio signals and applies them to a load, at least one diode that receives audio signals and produces single-ended input power signals, and at least one regulator that converts the single-ended input power signal into a regulated power signal of a higher magnitude. The boost regulator presenting a variable input impedance to the BTL amplifier such that the output current capacity of the BTL amplifier is not exceeded. Disclosed amplifiers also include a DC power reservoir that stores power from the regulated power signal and supplies sufficient power that the dynamic output power capacity of the audio amplifier exceeds the dynamic power capacity of the BTL amplifier.

Abstract: Methods and apparatus for audio signal clip detection are disclosed. The clip detectors may receive audio signals, from which peak reference signals, indicative of the highest voltage of the received audio signals, may be derived. The received audio signals may also be differentiated and phase-lagged to produce differentiated audio signals which may, in turn, be rectified to produce rectified differentiator signals. The rectified differentiator signals and the peak reference signals may be compared to thereby produce clip detect signals indicative of whether the received audio signals are clipped. The clip detect signals may then be used to indicate whether the received audio signal are clipped.

Abstract: A method to more accurately monitor remaining battery life under varying load conditions. The measured battery voltage is adjusted for the current load and then used to determine the remaining battery life according to the battery voltage discharge curve for the battery type and chemistry. Advantageously, in an embodiment the present invention the remaining battery life can be determined despite fluctuations in the current due to a changing load and without monitoring current flow so that the determination of battery life is independent of the battery charging process.

Abstract: A method to more accurately monitor remaining battery life under varying load conditions. The measured battery voltage is adjusted for the current load and then used to determine the remaining battery life according to the battery voltage discharge curve for the battery type and chemistry. Advantageously, in an embodiment the present invention the remaining battery life can be determined despite fluctuations in the current due to a changing load and without monitoring current flow so that the determination of battery life is independent of the battery charging process.

Abstract: A hardware latch for limiting access to protected system memory. An N-bit bus provides the instructions executed by the system to a combinatorial logic block (204). The combinatorial logic block (204) provides eight separate outputs and functions as a series of comparators. One input of each comparator is connected to the instruction bus, the other input of each comparator is hardwired to indicate the pattern that appears on the bus when a particular instruction is executed. The output from a given comparator is active when that particular instruction is applied to the instruction bus (202). A counter (208) counts the instructions and selects which output from the combinatorial logic block should be selected by multiplexer (206). If the output of the multiplexer is logic false, the sequence of instructions is broken and the counter (208) is reset. If the output of the multiplexer is logic true, the counter is allowed to continue incrementing.

Abstract: An inflatable pillow for use with a halo-type head immobilization brace having a generally circular head-encircling member secured to a patient's head and a plurality of post members extending from the head-encircling member. The inflatable pillow includes a flexible, generally rectangular base portion, a generally oval inflatable bladder portion connected to the base portion, and means for removably securing the base portion to the post members. The bladder portion is inflatable to expand to fit snugly between the patient's head and the head-encircling member.

Abstract: A hardware latch for limiting access to protected system memory. An N-bit bus provides the instructions executed by the system to a combinatorial logic block (204). The combinatorial logic block (204) provides eight separate outputs and functions as a series of comparators. One input of each comparator is connected to the instruction bus, the other input of each comparator is hardwired to indicate the pattern that appears on the bus when a particular instruction is executed. The output from a given comparator is active when that particular instruction is applied to the instruction bus (202). A counter (208) counts the instructions and selects which output from the combinatorial logic block should be selected by multiplexer (206). If the output of the multiplexer is logic false, the sequence of instructions is broken and the counter (208) is reset. If the output of the multiplexer is logic true, the counter is allowed to continue incrementing.