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Patent Issued for Supplying Voltage in a Circuit Using a First Voltage Source and an Adjustable Second Voltage Source

July 16, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Jochmann, Sven (Dresden, DE); Dathe, Lutz (Dresden, DE), filed on October 16, 2009, was published online on July 1, 2014.

The assignee for this patent, patent number 8766618, is Atmel Corporation (San Jose, CA).

Reporters obtained the following quote from the background information supplied by the inventors: "The present invention relates to a circuit, a use, and a method for operating a circuit.

"Linear voltage regulators are known per se. Different circuits with regulated voltage sources as linear voltage regulators are known from 'Halbleiterschaltungstechnik' (Semiconductor Technology), U. Tietze and C. Schenk, 12.sup.th ed., 2002, pages 926 to 936."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "It is an object of the present invention to improve a circuit as much as possible. Accordingly, a circuit is provided which can be monolithically integrated on a semiconductor chip. The circuit can be formed for operation via a battery.

"The circuit can have a regulated first voltage source for providing a supply voltage for a subcircuit. The first voltage source can have an output which is connected to the subcircuit and at which the supply voltage is provided. The first voltage source can have a control amplifier and a reference voltage source. In this regard, the control amplifier regulates the supply voltage to a target value.

"The circuit can have an adjustable second voltage source, which is formed to provide an output voltage to supply the subcircuit. The second voltage source can be formed to provide the output voltage in the case of a deactivated first voltage source. The second voltage source can have a switch for connecting the output voltage. The second voltage source can be formed to take over the supplying of the subcircuit, when the first voltage source is turned off. The second voltage source can have a series regulator, for example, an emitter follower or a source follower. The second voltage source can be formed to adjust at least the output voltage by a digital control signal. Further, an adjustment algorithm can be set up for adjusting the output voltage of the second voltage source to the output voltage of the first voltage source, whereby the adjusted voltage value can deviate, for example, by an LSB (lowest significant bit).

"The circuit can have an evaluation circuit, which is connected to an output of the second voltage source, particularly for measuring an output voltage of the second voltage source. A control output of the evaluation circuit can be connected to a control input of the second voltage source. An input of the evaluation circuit is connected to an output of the first voltage source.

"The evaluation circuit can be formed to adjust the output voltage of the second voltage source by a control signal, particularly a digital control signal, at the control input of the second voltage source. The evaluation circuit is formed to perform the adjustment of the output voltage of the second voltage source with evaluation of the supply voltage at the output of the first voltage source. The voltage at the output of the first voltage source is used in particular as a reference for the adjustment.

"The evaluation circuit and/or the second voltage source can have a memory for storing a value of the adjustment. The memory can be connected or formed in such a way that the value of the adjustment is retained if the first voltage source is deactivated. Also, the memory can be connected to an input voltage connection of the circuit, particularly for connecting a battery.

"A further object of the invention is to provide as improved a method as possible. Accordingly, a method for operating a circuit in an operating mode and a sleep mode is provided. Circuit current consumption in a sleep mode is reduced in comparison with the current consumption in the operating mode. Preferably, the number of functions of the circuit in the sleep mode is reduced in comparison with the operating mode.

"In the operating mode, a subcircuit is supplied by a regulated first voltage source with a supply voltage. Preferably, the first voltage source is activated for the operating mode.

"In a sleep mode, the first voltage source is deactivated. The subcircuit in the sleep mode is supplied by a second voltage source. The second voltage source is activated at least in the sleep mode.

"In the operating mode, an output voltage of the second voltage source is adjusted automatically as a function of the supply voltage of the first voltage source. The adjustment of the output voltage in this case occurs preferably to a voltage value that enables retention of logical information in the subcircuit. The adjustment occurs by setting of a resistance value of a resistance device of the second voltage source. In this case, the output voltage depends on the resistance value. The resistance value can be set by connection or disconnection of ohmic resistors or preferably by connection or disconnection of active resistance elements, such as field-effect transistors.

"An even further object of the invention is to provide a use. Accordingly, a use of a regulated first voltage source and an adjustable second voltage source for operating a subcircuit is provided. The operation of the subcircuit occurs in an operating mode by means of the first voltage source and in a sleep mode by means of the second voltage source. An output voltage of the second voltage source is adjusted during the operating mode as a function of a voltage at the output of the first voltage source and an output current of the second voltage source. The output current of the second voltage source is matched to a quiescent current which flows through the subcircuit in the sleep mode. The quiescent current in this case is made up of different partial currents, such as the leakage currents through the analog and/or digital subcircuit or a small quiescent supply current for a subcircuit with a low current take-up, such as, for example, a slow counter or a clock circuit (RTC--real-time clock).

"The embodiments described hereinafter relate to the circuit, as well as to the use and to the method for operating a circuit. The functions of the circuit in this case emerge from the methods features. Likewise, the methods features emerge from the functions of the circuit.

"According to an embodiment, the subcircuit is formed for an operating mode and a sleep mode. In the operating mode, the subcircuit is formed to draw an operating current. In the sleep mode, in contrast, a quiescent current, reduced compared with the operating current, flows through the subcircuit.

"The first voltage source can be activated in the operating mode. Preferably, in the sleep mode, the first voltage source is deactivated and the second voltage source activated. The evaluation circuit can be set up for adjustment in the operating mode. In this case, the adjustment can occur at least during the first initiated operating mode.

"In another embodiment, it is provided that the evaluation circuit has a current source as a load for the output of the second voltage source during the adjustment in the operating mode. Preferably, the current of the current source is on the order of the quiescent current through the subcircuit in the sleep mode. The current through the current source does not deviate from the quiescent current flowing in the sleep mode through the subcircuit by more than the factor of twenty, preferably by more than the factor of ten. The current can flow through the current source in a current strength between 0.1 .mu.A and 10 .mu.A. Too large deviations between the current of the current source and the quiescent current in the sleep mode could have the result that the output voltage of the second voltage source is no longer within the desired normal range.

"According to an embodiment, the evaluation circuit has a comparator. For comparison of the output voltage of the second voltage source, the comparator can be connected to the supply voltage, provided by the first voltage source, and to the output of the second voltage source, as well as to the output of the first voltage source.

"Preferably, the evaluation circuit has an arithmetic logic unit for evaluating the output voltage of the second voltage source and the supply voltage provided at the output of the first voltage source. The arithmetic logic unit can be formed as a state machine. It is also possible to form the arithmetic logic unit such that it is programmable. For example, the arithmetic logic unit can be formed as a microcontroller core. The arithmetic logic unit can be connected or is connected to an input voltage of the circuit, particularly to a battery voltage.

"According to an embodiment, an input of the arithmetic logic unit can be connected to an output of the comparator to evaluate an output signal of the comparator.

"In an embodiment, the evaluation circuit can be set up for adjusting the output voltage of the second voltage source preferably by means of particularly successive approximation. Alternatively, the output voltage of the second voltage source can be increased from a lowest voltage also stepwise until the necessary output voltage is reached.

"According to an embodiment, the evaluation circuit can have a temperature sensor element for determining a circuit temperature, particularly of the subcircuit. Preferably, the evaluation circuit is set up to map the values of the adjustment onto the circuit temperature. If the temperature response of the circuit is known, the evaluation of the temperature as a temperature current value or temperature voltage value can be eliminated.

"In an embodiment, it is provided that the second voltage source can have a current source and a resistance device for generating a reference voltage. Preferably, the evaluation circuit can be formed to match a current source temperature response as a function of an adjustment result.

"According to an embodiment, the circuit can have a semiconductor switch for switching the output voltage of the second voltage source to the output of the second voltage source. To this end, the switch can be connected to an output driver transistor and to an output terminal.

"The second voltage source can have a resistance device with a variable resistance value for setting the output voltage. A resistance device can have a plurality of resistance elements. A resistance element can be, for example, an ohmic resistor or an active element, such as a field-effect transistor, whose drain is connectable to the gate.

"The second voltage source can have a transistor wired as a source follower or emitter follower. Preferably, a control input (gate/base) of the transistor is connected to the resistance device. A source or emitter of the transistor can be or is connected to an output of the second voltage source.

"Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description."

For more information, see this patent: Jochmann, Sven; Dathe, Lutz. Supplying Voltage in a Circuit Using a First Voltage Source and an Adjustable Second Voltage Source. U.S. Patent Number 8766618, filed October 16, 2009, and published online on July 1, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8766618.PN.&OS=PN/8766618RS=PN/8766618

Keywords for this news article include: Electronics, Semiconductor, Digital Control, Atmel Corporation.

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Source: Electronics Newsweekly


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