Abstract: A fast battery charger in which each one of the battery charging sections comprises a charging branch and a bypassing branch, the battery charger is provided with enhanced charging monitory and control circuitry and method for performance elevation with minimal additional hardware overhead.

Abstract: In a method of acoustic feedback suppression, digitized time-domain samples of acoustic signals are obtained, and discrete time-frequency transformation is performed on the digitized time-domain samples to generate a plurality of frequency bins of a frequency resolution. A howling frequency bin is identified, where the howling frequency has the maximum magnitude among the plurality of frequency bins. A peak frequency within the howling frequency bin is detected, and this peak frequency is suppressed.

Abstract: An amplifier including a difference amplifier, said difference amplifier including a first output and a second output which are adapted for providing a PWM signal output to a load by signal difference between said first and said second outputs, said difference amplifier being adapted for operating in at least first and second alternative operating modes which are respectively characterised by first and second operating voltages, wherein during transition from one operating mode to another, the pulse area of the pulses of said first and second outputs of said difference amplifier are changed according to a pre-determined manner so that the pulse area of pulses of said first and second outputs at the end of said transitional mode is equivalent to the pulse area of the pulses of said first and second outputs immediately after the change of operating modes.

Abstract: An amplifier including a difference amplifier, said difference amplifier including a first output and a second output which are adapted for providing a PWM signal output to a load by signal difference between said first and said second outputs, said difference amplifier being adapted for operating in at least first and second alternative operating modes which are respectively characterised by first and second operating voltages, wherein during transition from one operating mode to another, the pulse area of the pulses of said first and second outputs of said difference amplifier are changed according to a pre-determined manner so that the pulse area of pulses of said first and second outputs at the end of said transitional mode is equivalent to the pulse area of the pulses of said first and second outputs immediately after the change of operating modes.

Abstract: A battery charger comprising an AC power input, isolation switching means, isolation control means, battery charging circuitry and battery receptacle, said isolation switching means substantially isolates said battery charging circuitry from said AC power input unless and until actuated by said isolation control means, said isolation switching means connects said battery charging circuitry to said AC power input for battery charging when actuated, wherein the operation of said isolation switching means being linked to the state of electrical insulation of said battery charging circuitry, said isolation control means and said isolation switching means being cooperatively configured so that said isolation switching means is actuated when said battery charging circuitry is electrically insulated from a user and said isolation switching means is caused to isolate said battery charging circuitry and said AC power input when said battery charging circuitry is not electrically insulated from a user.

Abstract: A fast battery charger in which each one of the battery charging sections comprises a charging branch and a bypassing branch, the battery charger is provided with enhanced charging monitory and control circuitry and method for performance elevation with minimal additional hardware overhead.

Abstract: A battery charger including a plurality of battery charging sections which are connected in series and a charging current source, said charging section includes at least a first branch and a second branch which are connected in parallel, said first parallel branch includes an electronically controllable bypassing switch, said second parallel branch includes terminals for receiving the positive and negative terminals of a battery and a one-way electronic device which are connected in series, said bypassing switch has a very low impedance when activated or turned-on and a very high impedance when deactivated or turned-off, wherein said one-way electronic device is characterised by a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said bypassing switch is activated, the battery in the charging section in which said bypassing switch is activated is substantially isolated electrically from the charging current, the other charging sections and t

Abstract: A battery charger including a plurality of battery charging sections which are connected in series and a charging current source, said charging section includes at least a first branch and a second branch which are connected in parallel, said first parallel branch includes an electronically controllable bypassing switch, said second parallel branch includes terminals for receiving the positive and negative terminals of a battery and a one-way electronic device which are connected in series, said bypassing switch has a very low impedance when activated or turned-on and a very high impedance when deactivated or turned-off, wherein said one-way electronic device is characterised by a very low-impedance when current flows from said charging section into said battery terminals and a high-impedance when said bypassing switch is activated, the battery in the charging section in which said bypassing switch is activated is substantially isolated electrically from the charging current, the other charging sections and t

Abstract: A serial battery charger including a number of serially connected battery charging sections in which the battery charging section is characterized by a first and second parallelly connected branches. The first branch includes terminals for connecting to the battery to be charged and a current blocking device and the second branch includes a by-passing switch which shunts across the terminals of the first branch when activated. The blocking device in the first branch prevents adverse reverse current flow from the battery to the charger when there is no power supply and also functions as a current block to prevent adverse flow of current from the battery into the shunting by-passing switch when the power supply to the charging section is in operation. This invention provides a simple solution to fulfil the conflicting requirements of an intelligent serial battery charger.

Abstract: A serial battery charger including a number of serially connected battery charging sections in which the battery charging section is characterized by a first and second parallelly connected branches. The first branch includes terminals for connecting to the battery to be charged and a current blocking device and the second branch includes a by-passing switch which shunts across the terminals of the first branch when activated. The blocking device in the first branch prevents adverse reverse current flow from the battery to the charger when there is no power supply and also functions as a current block to prevent adverse flow of current from the battery into the shunting by-passing switch when the power supply to the charging section is in operation. This invention provides a simple solution to fulfil the conflicting requirements of an intelligent serial battery charger.