Ami Semiconductor, Inc.

J Marcos Laraia

Greg Scott

A double-sided extended drain field effect transistor that includes a gate terminal overlying a channel region in a substrate. The substrate includes a drain region of a first carrier type that is laterally separated from the channel region by a first RESURF region of the first carrier type, and a source region of the first carrier type that is laterally separated from the channel region by a second RESURF region of the first carrier type. Regions of the first carrier type may also be disposed laterally adjacent to the source and drain regions on the opposite lateral side as compared to the RESURF regions. This configuration improves the reverse bias breakdown voltage of the transistor.

Double-sided extended drain field effect transistor

An integrated overvoltage and reverse voltage protection circuit. The protection circuit includes a field-effect transistor having a source terminal coupled to an input terminal of the protection circuit, and a drain terminal coupled to an output terminal of the protection circuit. A resistor is coupled between the source terminal and the body terminal of the field-effect transistor to inhibit reverse current flow during a reverse voltage condition. A voltage-current dependent circuit is coupled between the gate terminal and the source terminal of the field-effect transistor, and is configured to apply a voltage between the gate terminal and the source terminal that is dependent on the current passing through the voltage-current dependent circuit. A current application circuit is coupled to the voltage-current dependent circuit and is configured to apply a current that limits or even altogether stops an applied overvoltage condition from reaching a load circuit.

Integrated overvoltage and reverse voltage protection circuit

An integrated overvoltage and reverse voltage protection circuit that includes two p-channel double-sided extended drain transistors coupled to a high voltage source, each having their n-well coupled through a resistor to the high voltage source. For voltage regulation, a voltage divider is coupled in series with a first of these transistors, while the drain of the second transistor is coupled to the gate of the first transistor. For voltage blocking, the voltage divider may span the entire supply voltage. An n-channel transistor couples the second p-channel transistor to a low voltage source. A middle node in the voltage divider is coupled to one input of a comparator, with a reference voltage coupled to the second input. The comparator output drives the gate terminal of the n-channel transistor. A load to be protected may be disposed in parallel with the voltage divider.

Double-sided extended drain field effect transistor, and integrated overvoltage and reverse voltage protection circuit that uses the same

A current reference circuit provides a reference current that has a controlled temperature coefficient and is relatively stable with supply voltage fluctuations. The reference leg includes a series of MOS transistors including at least one PMOS transistor that is electrically closer in the series to a high voltage source, at least one NMOS transistor that is electrically closer in the series to the low voltage source. The series composite resistor comprises at least two resistors coupled in series within the current path. The size of the resistors may be designed so as to lower the temperature dependency of the circuit. A bipolar transistor is also coupled in the reference leg. The mirror leg is similar to the reference leg except that no series resistor is provided, and the emitter area of the bipolar resistor in the reference leg is larger than the emitter area of the bipolar transistor in the mirror leg.

Circuits and methods for providing a current reference with a controlled temperature coefficient using a series composite resistor

A bandgap voltage reference circuit includes a current source and a bipolar transistor that are coupled together such that current from the current source passes through the bipolar transistor to a low voltage source such as ground. A composite resistor is coupled in series between the current source and the bipolar transistor. The composite resistor of this voltage reference leg of the circuit is composed of at least two component resistors that may be fabricated so as to adjust the temperature coefficient of the bandgap voltage reference as a whole.

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Pocatello, ID, United States of America

J Marcos Laraia