Linear Technology Corporation

Texas Instruments Corporation

David Charles Salerno

John Christopher Canfield

John P Bazinet

Mark G Jordan

Apparatus and method for a polarity independent step-up converter capable of operating with ultra low input voltage. The step-up converter as disclosed herein receives an input source having a variable polarity and includes a first core circuit coupled to the input source and an output of the step-up converter and a second core circuit coupled to the input source and the output of the step-up converter. The first core circuit is configured to be active for a first input voltage polarity to output a first step-up voltage and the second core circuit is configured to be active for a second input voltage polarity to output a second step-up voltage.

Method and system for polarity independent step-up converter capable of operating under ultra-low input voltage condition

A synchronous boost DC/DC conversion system comprises an input for receiving a DC input voltage, an output for producing a DC output voltage, a power switch controllable to adjust an output signal of the conversion system, and an inductor coupled to the input. A synchronous rectifier is configurable to create a conduction path between the inductor and the output to provide the inductor discharge. A control circuit is provided for controlling the synchronous rectifier as the input voltage approaches the output voltage, so as to adjust average impedance of the conduction path over a discharge period of the inductor.

Synchronous rectifier control for synchronous boost converter

A hysteretic regulator may be set to an active mode when voltage at an output falls to a first threshold level. In the active mode, charge is applied to an output node by a current having a set limit value. The regulator is set to an inactive mode when the voltage at the output node rises to a second threshold level. The current limit value is automatically adjusted as a function of average regulator current. An indication of average regulator current may be obtained by charging a sense capacitor during the active mode and discharging the sense capacitor during the inactive mode. The voltage of the sense capacitor, which is representative of the average regulator current, is used to generate an offset adjustment applied to a regulator controller.

Adaptive power control for hysteretic regulators

The present invention comprises a user-programmable control circuit for use in a power converter to automatically transition the converter into BURST mode when load current demand is low. The control circuit senses load current demand by monitoring the output current of the converter, and generating a signal representative of the monitored output current. The control circuit may automatically transition the converter into BURST mode when the signal indicative of the average monitored output current decreases below a user-programmable threshold. BURST mode may increase overall converter efficiency by turning OFF a plurality of electronic components, and maintaining the converter's output voltage at a regulated level by energy stored in an output capacitor.

Methods and circuits for programmable automatic burst mode control using average output current

A boost regulator circuit is designed to maintain nearly constant intensity from a flashlight lamp, compensating for the drop in battery voltage over an operating lifetime. The quality of the light output is improved, and battery life is extended. An asynchronous boost regulator circuit and two synchronous boost regulator circuits are shown. The regulator circuit begins boosting after battery voltage has fallen by 15-20%, and maintains output voltage at a substantially constant level until a major portion of the stored battery energy has been consumed. A circuit assembly is shown that can be used to retrofit existing flashlights. The circuit assembly resides on a disk-shaped circuit board that can be placed between the lamp and an adjacent battery. Contacts formed on the circuit board provide connections to the battery, the lamp, and to a common connection point such as ground.

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New Boston, NH, United States of America

David Charles Salerno