Abstract: An apparatus for programmably adjusting output voltage of a constant-voltage battery charger is disclosed. The present invention includes a power circuit for generating an output voltage for charging batteries. This power circuit generates this output voltage as a function of an incoming power source and an incoming error signal. The invention further includes a controller for providing a pulse width modulated (PWM) signal operating at a pre-determined frequency. This PWM signal controls the effective divider ratio of a voltage divider network which is implemented, among other things, for generating the error signal to be fed to the power circuit. The present invention varies the effective divider ratio by programmably applying the pulse width modulated signal from the controller. As a result, the output voltage from the power circuit can be varied to optimally charge batteries of differing types and technologies.

Abstract: A technique is provided for substantially reducing clicks and pops caused by power cycling, in particular, the power cycling conservation strategy used in a portable computer. More specifically, an audio amplifier arrangement for a computer, in accordance with one embodiment of the present invention, includes a differential amplifier having a first input terminal, a second input terminal and an output terminal. A sound output connector may be connected to the output terminal through a signal path. First switching circuitry is responsive to a first mute signal for connecting together the first input terminal and the second input terminal through a low-impedance path. As a result, an output signal produced by the differential amplifier is essentially forced to zero. When power is removed from or applied to the differential amplifier, however, its behavior is not entirely predictable, and the output signal produced cannot be guaranteed to remain zero throughout the power-down transition.