Texas Instruments Corporation

Roman Korsunsky

Larry J Wofford

Winthrop H McClure

Mark S Pieper

One embodiment of the present invention includes a current regulator circuit. The circuit includes at least one switch configured to periodically couple and decouple a respective at least one voltage rail to an inductor to maintain a current through the inductor. The circuit also includes a pulse-width modulation (PWM) controller configured to set a duty-cycle associated with a switching signal to control the at least one switch based on a feedback signal that is associated with a magnitude of the current. The circuit also includes a switch-controlled current path configured to shunt the current from a load in response to a control signal. The circuit further includes an error circuit configured to provide an error term to the PWM controller upon activating the control signal to adjust the duty-cycle substantially instantaneously in response to the control signal.

Pulse-width modulation current control with reduced transient time

Synchronization circuitry and synchronization system for synchronizing converters/controllers that are electrically-coupled to a common synchronization node. The synchronization system includes synchronization circuitry, oscillation circuitry, and a leading edge detector and pulse generator. The synchronization circuitry includes pull-up circuitry and pull-down circuitry for generating a voltage pulse-train at the synchronization node. The oscillation circuitry controls which of the pull-up and the pull-down circuitry is driven ON and which is driven OFF.

Synchronization circuitry for multiple power converters coupled at a common node

A battery protection circuit includes a moisture detection circuit, a temperature sensing circuit, and a high-temperature battery discharge circuit. The moisture detection circuit includes a pair of conductive traces closely spaced on a substrate such that a resistive path is formed between the traces when moisture forms on the substrate. The traces are connected between the positive battery terminal and a pull-down current source. When moisture forms on the substrate, pull-up current flows between the traces, and a resulting voltage change on one of the traces is detected by circuit element such as a logic inverter. The temperature sensing circuit includes a voltage reference circuit that generates a proportional-to-temperature voltage and temperature-independent voltage reference signals corresponding to various predetermined temperatures. A measuring circuit operates during a sampling interval to compare each temperature-dependent voltage to the proportional-to-temperature voltage and to store the result of each comparison until a subsequent temperature sampling interval. The measuring circuit includes multiplexing circuitry used to sequentially select each temperature-dependent voltage during a sampling interval. The high-temperature discharge circuit connects a discharge load across the battery when the voltage of the battery is above a high voltage threshold and the temperature of the battery is above the high temperature threshold. When no external charger is active, the discharge current flowing through this load works to reduce battery voltage. helping to prolong battery life.

Battery protector

A battery protection circuit includes back-to-back connected metal-oxide-semiconductor field-effect transistors (MOSFETs). Detection circuitry detects whether the battery is in a normal charge condition, an overcharged condition, or an over-discharged condition, and for the overcharged and over-discharged conditions the circuitry asserts a corresponding enable signal. For each MOSFET, a corresponding gate voltage regulating circuit controls the gate voltage such that (i) when the corresponding enable signal is de-asserted, the gate voltage is sufficient to enable the MOSFET to strongly conduct current in either direction, and (ii) when the corresponding enable signal is asserted, the gate voltage is a function of the polarity of drain-to-source voltage of the MOSFET. For each MOSFET, the corresponding gate voltage regulating circuit prevents the MOSFET from conducting when the drain-to-source voltage has an undesired polarity, and allows the MOSFET to conduct when the drain-to-source voltage has a desired polarity. One MOSFET prevents the flow of charge current, and the other prevents the flow of discharge current. When either MOSFET is conducting, its drain-to-source voltage is prevented from achieving a value sufficient to forward bias a parasitic diode associated with the source and drain terminals of the MOSFET. Current of correct polarity flows through the source-to-drain channel of a MOSFET rather than through the parasitic diode during the overcharged and over-discharged conditions.

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Downington, PA, United States of America

Roman Korsunsky