Abstract: An asymmetric multi-converter power supply including a first converter and a second converter coupled to provide power to an output node. A control circuit is coupled to the second converter and is configured to selectively enable the second converter depending upon a voltage at the output node. The control circuit may be configured to enable the second converter only in response to determining that the voltage at the output node is not within a predetermined range. Alternatively, the first converter is configured to provide power through a first series inductor and the second converter is configured to provide power to the output node through a second series inductor. The second series inductor having a smaller inductance than the first series inductor. Additionally, the second converter may be characterized by a transient response time that is faster than a transient response time of the first converter.

Abstract: An asymmetric multi-converter power supply including a first converter and a second converter coupled to provide power to an output node. A control circuit is coupled to the second converter and is configured to selectively enable the second converter depending upon a voltage at the output node. The control circuit may be configured to enable the second converter only in response to determining that the voltage at the output node is not within a predetermined range. Alternatively, the first converter is configured to provide power through a first series inductor and the second converter is configured to provide power to the output node through a second series inductor. The second series inductor having a smaller inductance than the first series inductor. Additionally, the second converter may be characterized by a transient response time that is faster than a transient response time of the first converter.

Abstract: An asymmetric multi-converter power supply including a first converter and a second converter coupled to provide power to an output node. A control circuit is coupled to the second converter and is configured to selectively enable the second converter depending upon a voltage at the output node. The control circuit may be configured to enable the second converter only in response to determining that the voltage at the output node is not within a predetermined range. Alternatively, the first converter is configured to provide power through a first series inductor and the second converter is configured to provide power to the output node through a second series inductor. The second series inductor having a smaller inductance than the first series inductor. Additionally, the second converter may be characterized by a transient response time that is faster than a transient response time of the first converter.

Abstract: An asymmetric multi-converter power supply including a first converter and a second converter coupled to provide power to an output node. A control circuit is coupled to the second converter and is configured to selectively enable the second converter depending upon a voltage at the output node. The control circuit may be configured to enable the second converter only in response to determining that the voltage at the output node is not within a predetermined range. Alternatively, the first converter is configured to provide power through a first series inductor and the second converter is configured to provide power to the output node through a second series inductor. The second series inductor having a smaller inductance than the first series inductor. Additionally, the second converter may be characterized by a transient response time that is faster than a transient response time of the first converter.

Abstract: An external universal battery charging apparatus which can include external universal battery charger circuitry having at least one universal battery charger circuitry input and at least one universal battery charger circuitry output. The universal battery charger circuitry output can include at least one battery charger output, which itself can include at least one universal battery connector and at least one universal battery charger cable. The at least one universal battery charger circuitry output can include at least one adapter pass through output, which itself can include at least one connector adapted to operably connect to an electronic device. The external universal battery charger circuitry can include at least one battery recognition and parameter adjustment circuit, battery current parameter adjustment circuit, charged voltage parameter adjustment circuit, and maximum power draw parameter adjustment circuit.

Abstract: A battery charge determination device including at least one battery cell voltage measurement device, at least one battery cell internal resistance measurement device, and at least one battery charge assessment device operably connected to the at least one battery cell voltage measurement device and the at least one battery cell internal resistance measurement device.

Abstract: A multiple stage sequential synchronous regulator including multiple switch stages activated in a sequential manner to reduce the frequency, stress and power loss per stage. In the preferred embodiment, each stage is implemented using buck regulator topology including an inductor and two synchronous switches, preferably comprising MOSFETs. A sequential logic circuit asserts corresponding enable signals to activate each of the stages one at a time in sequential manner. Each stage also receives a pulse width modulated (PWM) signal for activating the first synchronous switch during a power phase and then activating the second synchronous switch during a flux reversal phase for the enabled stage. The time sharing of multiple stages reduces the average current per stage and allows increased utilization of the switching parts per stage. Thus, the typically large and expensive power inductors and switches are replaced with significantly smaller, lighter and cheaper components.

Abstract: An external universal battery charging apparatus which can include external universal battery charger circuitry having at least one universal battery charger circuitry input and at least one universal battery charger circuitry output. The universal battery charger circuitry output can include at least one battery charger output, which itself can include at least one universal battery connector and at least one universal battery charger cable. The at least one universal battery charger circuitry output can include at least one adapter pass through output, which itself can include at least one connector adapted to operably connect to an electronic device. The external universal battery charger circuitry can include at least one battery recognition and parameter adjustment circuit, battery current parameter adjustment circuit, charged voltage parameter adjustment circuit, and maximum power draw parameter adjustment circuit.

Abstract: A circuit including bridge rectifier, switches across one or more of the diodes of the bridge rectifier, and a comparator providing control signals to the switch or switches can be constructed to apply a constant polarity voltage to an electrical load, regardless of the polarity of the input power applied to the circuit. The comparator produces a control signal depending upon a comparison of the input power voltages, and the control signal activates one or more of the switches to allow current flow through an appropriate path in the circuit to yield the constant polarity across the electrical load. Thus, the circuit can protect the electrical load from an inappropriately applied voltage by switching the applied voltage's polarity. Because an activated switch can short a diode in the bridge rectifier, power loss associated with current flow through the diode is reduced. Additionally, the circuit can provide constant polarity across the electrical load with either AC or DC input power.

Abstract: A switching flyback regulator circuit for providing a plurality of regulated DC voltage power supplies. The flyback regulator circuit includes a primary inductive element coupled in series with a first switch to turn charging current flow through the primary inductive element ON and OFF. A first secondary inductive element having a first end coupled to supply a first power source. A second secondary inductive element has a first end coupled to produce the second power source, and a second end coupled to a second switch to turn current flow through the second secondary inductive element ON and OFF. The first secondary inductive element and the second secondary inductive element are magnetically coupled to the primary inductive element.

Abstract: Following the constant-current portion of a rechargeable battery charging scheme with repeated current pulses having a lower current value than that of the constant current portion, for at least part of the period of the pulse, can increase the amount of time that elapses before the voltage of the rechargeable battery is at or above a threshold voltage, thereby decreasing the total charge time for the rechargeable battery. Various current pulse shapes can be used to reduce the total charge time for the rechargeable battery, including, for example, a ramped pulse that begins at a low current level and increases over some or all of the period of the pulse, and a constant current pulse whose current level is reduced from that of the constant-current portion of the rechargeable battery charging scheme by a specified amount.

Abstract: A limiting circuit for controlling overshoot in a charge current in a battery recharging system includes a current amplifier receiving input indicative of charge current in a rechargeable battery circuit and generating a current error signal, a voltage amplifier receiving input indicative of charge voltage in the rechargeable battery circuit and generating a voltage error signal, and a power amplifier receiving a first signal indicative of power in a switching voltage regulator and a second power signal indicative of power in the rechargeable battery circuit, and generating a power error signal. The limiting circuit compares the voltage error signal, the current error signal, and the power error signal to determine the error signal having the greatest value, and generates an input signal to a pulse width modulation comparator.

Abstract: An apparatus and method are provided for driving a cold cathode fluorescent lamp in a floating configuration with an inverter circuit having a transformer with a primary winding and two secondary windings. At least one sense resistor is coupled in series between terminals of the secondary windings. The other terminal of each secondary winding is coupled to a respective end of the fluorescent lamp. A rectifier is coupled to the secondary portion of the transformer to receive a signal indicative of the current in at least one end of the fluorescent lamp and generates a feedback signal. A control and drive circuit generates drive signals based on the feedback signal to control the current in the fluorescent lamp and outputs the drive signals to the primary transformer winding.

Abstract: For an electronic device having at least one power switch for each of two or more power sources such that the power switches can be selectively activated or deactivated depending on a signal supplied to them, a protection circuit having a current-sense circuit coupled to measure the current from the two or more power sources, and a latch for producing a switch deactivating signal and applying it to the switches in response to an over-current signal from the current-sense circuit can protect the switches and the electronic device from soft-short circuits and absolute short circuits. Bypass resistors coupled to the switches allow the electronic device to receive a small current ("pre-charge") before any of the switches are activated so that a comparator can test for the presence of various types of short circuits. Additionally, the precharging brings the electronic device to a higher voltage (as compared to no pre-charging) when one of the switches is activated, thereby helping to reduce in-rush currents.

Abstract: An adaptive battery charger for charging batteries used in portable electronic devices. The battery charger monitors power provided from an AC adapter to the portable electronic device, and adaptively utilizes all available power from the AC adapter for charging the batteries, both when the portable electronic device is off, and when it is in use. As the power required for the portable electronic device increases, the power provided to the batteries decreases. As the power required to power the portable electronic device decreases, the power available to charge the batteries increases.

Abstract: An inverter circuit having dual converters for driving a fluorescent lamp comprising a pulse width modulator coupled to receive a feedback signal indicative of current in the fluorescent lamp. The pulse width modulator generates driving signals that are received by a synchronously switching voltage regulator having a high side driver and a low side driver. A self-resonant converter is coupled between the synchronously switching voltage regulator and the fluorescent lamp and generates a voltage signal for illuminating the fluorescent lamp. The self-resonant converter includes a transformer having a primary winding and at least one secondary winding, a capacitor coupled in parallel with the primary winding, and a full bridge circuit. The full bridge circuit may include four switching transistors, such as MOSFETs coupled in an H-configuration to the primary winding and the capacitor.

Abstract: A switching flyback regulator circuit for providing a plurality of regulated DC voltage supplies, wherein one of the regulator circuits includes a saturable reactor for regulating one of the output voltages. The flyback regulator circuit includes a primary inductive element coupled to a first switch to turn charging current flow through the primary inductive element ON and OFF, a first secondary inductive element having a first end coupled to supply a first power source and magnetically coupled with the primary inductive element, and a second secondary inductive element magnetically coupled with the primary inductive element. The second secondary inductive element has a first end coupled to produce the second power source and a second end coupled in series with the saturable reactor and a second switch to control current flow through the second secondary inductive element.

Abstract: A current converter that includes stored information about the converter can provide that information to an electronic device, such as a computer system, when the current converter is in use with the device. The current converter information can include manufacturer and model identity information, compatibility information, electrical characteristics, current converter type information, and current source information. A storage device in the current converter is coupled to a data bus for connecting to the electronic device, or can make use of one or more of the existing power output terminals to provide current converter information to the electronic device. Based on the information provided to the electronic device, the device can determine whether to allow operation of the device, and if so, under what circumstances and conditions.

Abstract: A multiple stage sequential synchronous regulator including multiple switch stages activated in a sequential manner to reduce the frequency, stress and power loss per stage. In the preferred embodiment, each stage is implemented using buck regulator topology including an inductor and two synchronous switches, preferably comprising MOSFETs. A sequential logic circuit asserts corresponding enable signals to activate each of the stages one at a time in sequential manner. Each stage also receives a pulse width modulated (PWM) signal for activating the first synchronous switch during a power phase and then activating the second synchronous switch during a flux reversal phase for the enabled stage. The time sharing of multiple stages reduces the average current per stage and allows increased utilization of the switching parts per stage. Thus, the typically large and expensive power inductors and switches are replaced with significantly smaller, lighter and cheaper components.

Abstract: A system for charging dual battery packs. The system includes a charger for supplying current to charge a first battery pack when the first battery pack is electrically coupled to the computer system. The charger supplies current to charge a second battery pack when the second battery pack is electrically coupled to the computer system. The system also includes a charge controller, such as a keyboard controller executing a program stored in a memory, for controlling the charging of the first battery pack and the second battery pack such that the charger charges the first battery pack to a first level, the charger charges the second battery pack to a second level, and the charger simultaneously charges the first battery pack and the second battery pack when the first battery pack is charged above the first level and below a third level and the second battery pack is charged above the second level and below a fourth level.