International Rectifier Corporation

Linear Technology Corporation

Muthu Subramanian

Talbott Mead Houk

Ravindran Mohanavelu

Iulian Mirea

Goran Perica

Control circuitry controls a boost regulator during a start-up period. The control circuitry may comprise an oscillator for generating a clock signal. The oscillator may be configured for ramping up a frequency of the clock signal in accordance with an voltage to be applied to the oscillator and varied during the start-up period. The control circuit may further include a switching circuit configured for controlling a power switch of the boost regulator in response to the clock signal from the oscillator. The switching circuit can control the power switch to have an on-time which is largely independent of the operating frequency of the oscillator. The voltage to be applied to the oscillator may have the same initial voltage level upon startup of the control circuit, independent of an output voltage of the boost regulator.

DC/DC converter startup with frequency ramping

An input voltage sensing circuit comprising a circuit input terminal; a comparator having first and second input terminals, the first of said input terminals being coupled to a reference voltage; a switch circuit provided between the circuit input terminal and the second of the input terminals of the comparator, the switch being provided to protect the comparator from voltages exceeding a predetermined voltage at which the switch turns off; and an electrostatic discharge circuit coupled to the circuit input terminal for discharging electrostatic induced voltages exceeding a predetermined value.

Input voltage sensing circuit

A level shifting device having an input side operating at a first voltage level, an output side operating at a second voltage level and a level shifting circuit which connects the input and output sides. The input circuit receives an input signal referenced to the first voltage level and provides separate outputs corresponding to transitions of the input signal. The level shifting circuit includes MOSFETS having the gates connected respectively to each output of the input circuit; and the source-drain path coupled between the second voltage and a reference for the first voltage. The output side has a differential topology, and includes a first circuit which samples signals corresponding to the transitions of the input signal, holds the sample between transitions, and an output circuit which receives the held sample signal in differential form and converts it to single-ended form for use by other circuits. The circuit also blocks input signals when common mode transients are present. The device is realized as an integrated circuit using exclusively n-channel MOSFETS in the critical path of operation.

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Fremont, CA, United States of America

Muthu Subramanian