Dell USA L P

Dell Computer Corporation

Advanced Micro Devices Corporation

Other

Dell Usa, D.p.

Barry K Kates

John A Cummings

Edward P Sheehan, Jr

Greg R Fiebrich

Alan E Brown

Edward C Guerrero, Jr

Christopher Eric Tressler

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.

Asymmetric multi-converter power supply including a fast response converter

A clamping circuit and method for use in a computer system are provided. In the computer system, a voltage regulator supplies a voltage rail to various components in the system. This voltage rail may be susceptible to voltage spikes or other over-voltage conditions, such as when the voltage rail provides the input voltage to a switching regulator. The clamping circuit comprises a detecting stage and a clamping stage. The detecting stage detects when the voltage rail increases beyond a first voltage level. If this increase is detected, the detecting stage activates the clamping stage, which begins reducing the voltage rail. Once the voltage rail decreases beneath the first voltage level, the detecting stage stops activating the clamping stage. In this way, the clamping circuit protects the computer system from voltage spikes on the voltage rail.

Clamping circuit for use in computer system

Asymmetric power supply including a fast response converter

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. The external universal battery charging apparatus can include a maximum rated power supply determination unit. The method can include detecting a battery, identifying characteristics of the battery, and adjusting at least one parameter in universal battery charger circuitry in response to the characteristics of the battery such that optimum battery charging is achieved.

External universal battery charging apparatus and method

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.

Battery charge determination

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. Furthermore, each switched device can be pushed past its rated limits due to smaller average current, thereby increasing the efficiency of each of the parts. A single output capacitor is coupled to all of the stages for filtering the output voltage. The output capacitor can remain small since it sees the cumulative frequency of all of the switch stages combined.

Method and apparatus for a multiple stage sequential synchronous regulator

A battery charging apparatus, computer system and method provide current from a single power line to charge either a first battery or multiple batteries in an independent mode or a simultaneous mode. The apparatus includes an AC-to-DC adapter, the power line, and a battery charging control system that measures the charge of the individual batteries and compares the measured charge. If the charging system detects a difference in charge between the batteries, the lowest or the lower charged batteries are charged until the charging system detects no difference in charge, and then resumes simultaneous charging. The battery charging control system also includes a comparator circuit that determines whether to enable charging in the independent mode or the simultaneous mode based on input from a user or input from a computer system. The computer system includes a processor, a memory, a bus, a power line, and a battery charging apparatus coupled to the power line. The battery charging apparatus capable of simultaneously charging a plurality of batteries with a single power line and allowing current from the power line to charge either a first battery or multiple batteries in either an independent mode or a simultaneous mode. The method includes simultaneously charging a plurality of batteries using a power line, providing a battery charging apparatus with an AC-to-DC adapter and a power line, providing a battery system, and enabling current from the power line to charge either a first battery or a plurality of batteries simultaneously or independently.

Adaptive multiple battery charging apparatus

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.

Constant polarity input device including synchronous bridge rectifier

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. A control circuit generates a ramped voltage signal having a negative slope to control the ON and OFF duty cycle of the second switch such that when the first switch is operated to allow the primary inductive element to discharge, current flows through the first secondary inductive element before current flows in the other secondary inductive element. The current through the second switch is zero when the second switch is turned OFF and ON, thereby eliminating switching losses and improving efficiency of the flyback regulator circuit.

Redirected sequential flyback regulator

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. The specified amount of reduction can, for example, be a fixed percentage of the current level of the constant-current portion of the rechargeable battery charging scheme, or it can be based on the parameters of the battery being charged.

Adaptive fast charging of lithium-ion batteries

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. The limiting circuit also includes an internal current source, a first transistor coupled to the current amplifier, a second transistor coupled to the voltage amplifier; and a third transistor coupled to the power amplifier. The first transistor, the second transistor, and the third transistor are coupled to the internal current source to determine the error signal having the greatest value. To prevent reverse current flow in the switching voltage regulator, a low current comparator receives a signal indicative of the current flowing in the switching voltage regulator, and generates an output signal. A transistor receives the output signal from the low current comparator, and generates a signal to maintain the current flowing in the switching regulator circuit above a threshold value.

Reverse current protection/current overshoot control for two quadrant

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.

Balanced feedback system for floating cold cathode fluorescent lamps

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. Blanking logic allows the protection circuit to tolerate certain in-rush currents by preventing the latch from triggering (e.g., supplying the latch with an under-current signal) for an appropriate time period.

Protection circuit for electronic devices

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.

Growing community of inventors

Austin, TX, United States of America

Barry K Kates