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Patent Issued for Semiconductor Integrated Circuit and Electronic Apparatus Provided with Same

July 23, 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 Gotou, Tetsuji (Osaka, JP); Yamamoto, Hiroo (Kyoto, JP), filed on January 2, 2013, was published online on July 8, 2014.

The assignee for this patent, patent number 8774255, is Panasonic Corporation (Osaka, JP).

Reporters obtained the following quote from the background information supplied by the inventors: "The present disclosure relates to power supply control systems, and specifically to power supply control in an electronic apparatus including a power supply device, and a semiconductor integrated circuit which operates based on an output voltage of the power supply device.

"FIG. 22 illustrates an application circuit described in LM5005--High Voltage 2.5 Amp Buck Regulator, Datasheet, [online], National Semiconductor, March 2006, [retrieved on 2011 Apr. 28], Retrieved from the Internet: http://www.alldatasheet.com/datasheet-pdf/pdf/180844/NSC/LM5005.html>. In this power supply system, a smoothing coil 2203, a smoothing capacitor 2204, and a resistive voltage divider circuit 2205 which are mounted on substrates are connected to a power supply output terminal 2202 of a power supply IC 2201. Moreover, a power supply terminal 2208 of a system-on-a-chip (SoC) section 2207 is connected to a node 2206 to which the resistive voltage divider circuit 2205 is connected, thereby supplying a power supply voltage to the SoC section 2207. The power supply IC 2201 mainly composed of analog circuits generates an output voltage of a magnitude in accordance with a voltage VFB obtained by dividing an output voltage by the resistive voltage divider circuit 2205, and the SoC section 2207 operates in response to the output voltage as the power supply voltage received as a reference. In this type of electronic apparatus, the resistive voltage divider circuit 2205 includes a fixed resistor, and the divided voltage ratio is fixed, so that it is not possible to dynamically control a set output voltage. Moreover, accuracy of the power supply voltage is ensured only when the resistive voltage divider circuit 2205 is disposed in the immediate vicinity of the power supply IC 2201, and the power supply voltage is measured at the node 2206 near the power supply IC 2201. Thus, impedance of a power supply interconnect extending from the power supply IC 2201 to the SoC section 2207 or accuracy of components such as a resistive element of the resistive voltage divider circuit 2205 may cause variations in the power supply voltage of the SoC section 2207. As a result, the performance of the SoC section 2207 significantly depends on accuracy of the power supply potential of the power supply system. Thus, there has been demand to dynamically and accurately control the power supply voltage of the SoC section 2207 in accordance with the accuracy of the components and the impedance of the power supply interconnect.

"FIG. 23 illustrates a configuration of a system described in LP5552--PWI 2.0 and PowerWise Technology Compliant Energy Management Unit, Datasheet, [online], National Semiconductor, May 20, 2008, [retrieved on 2011 Apr. 28], Retrieved from the Internet: . This power supply system has a configuration as an electronic apparatus capable of dynamically and accurately controlling a power supply voltage. A power supply IC 2301 has a power management (PM) function by which the power supply voltage can be dynamically controlled. Moreover, a SoC section 2302 includes a performance monitor circuit (HPM) 2303 configured to monitor characteristics such as circuit delay. The power supply IC 2301 for PM includes a digital control circuit 2305 in which a digital feedback signal 2304 output from the SoC section 2302 is digitally processed. A signal 2306 obtained after the digital processing in the digital control circuit 2305 is converted to an analog signal 2307 by a built-in D/A converter (DAC) circuit, and is controlled so that an output voltage 2308 is a voltage according to demanded performance of the SoC section 2302. Based on a result of the monitoring by the performance monitor circuit 2303, the SoC section 2302 determines a voltage value necessary for normal circuit operation of the SoC section 2302, and outputs the voltage value as the digital feedback signal 2304 to the power supply IC 2301 for the PM. With this power supply system, the output voltage 2308 can be controlled so that Vdd is in the range from about 0.6 V to about 1.2 V.

"Japanese Patent Publication No. 2007-201455 proposes that a digital signal processing operation of a power supply voltage and a substrate voltage which minimize power of a power supply circuit (regulator) and a SoC section is performed, and a resistance value in a resistive voltage divider circuit of the regulator is changed to vary a reference voltage so that the power supply voltage has a desired power supply voltage value, thereby reducing power of a system."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The improved electronic apparatuses described above are only capable of performing discrete voltage control according to a bit width of a digital signal in accordance with the demanded performance of the SoC section 2302, and thus a variable step width of the power supply voltage supplied to the SoC section 2302 is necessarily large. Increasing the number of bits of the digital signal according to the demanded performance of the SoC section 2302 reduces a step width of voltage control, but increases sizes of a logic control circuit for performing digital processing, a DAC circuit for converting a digital signal from the logic control circuit to an analog signal, etc. which are built in the power supply IC 2301, thereby increasing cost.

"The present disclosure provides a power supply control system capable of performing dynamic and high-resolution voltage control with a relatively simple configuration.

"A semiconductor integrated circuit which operates based on a power supply voltage output from a power supply device configured to generate a voltage of a magnitude in accordance with an analog control signal includes: a first terminal to which the power supply voltage is applied; an internal interconnect connected to the first terminal to distribute the power supply voltage to sections in the semiconductor integrated circuit; and a second terminal from which the analog control signal is output, wherein the analog control signal is generated to have a magnitude in accordance with a potential of the internal interconnect.

"With this configuration, based on an internal voltage of the semiconductor integrated circuit, feedback control of the power supply device is performed by the analog control signal, so that it is possible to perform dynamic and high-resolution voltage control. Moreover, a circuit configuration is relatively simple due to analog control.

"For example, the semiconductor integrated circuit may include: a potential monitor circuit configured to detect the potential of the internal interconnect; and a potential control circuit configured to generate the analog control signal having a magnitude in accordance with the potential detected by the potential monitor circuit.

"Moreover, the semiconductor integrated circuit may include: a circuit block capable of being switched between a plurality of operation modes different in load, wherein before the circuit block is switched between the operation modes, the potential control circuit generates the analog control signal having a magnitude in accordance with an operation mode to which the circuit block will be switched.

"With this configuration, for example, when the circuit block will transition to, for example, a loaded state in which a high load is applied to the circuit block, an output voltage can be increased before the circuit block transitions to the loaded state. Thus, after the circuit block is switched between the operation modes, it is immediately possible to drive the circuit block under the high load.

"Alternatively, the semiconductor integrated circuit may include: a first IO circuit connected to the first terminal; and a second IO circuit connected to the second terminal, wherein the first and second IO circuits are electrically isolated from each other.

"For example, it is possible to configure an electronic apparatus, including: the above-described semiconductor integrated circuit; and a power supply device configured to generate a power supply voltage of a magnitude in accordance with the analog control signal output from the semiconductor integrated circuit, and supply the generated power supply voltage to the semiconductor integrated circuit.

"Preferably, in the above-described electronic apparatus, an interconnect through which the analog control signal is transmitted from the semiconductor integrated circuit to the power supply device may be shielded. With this configuration, it is possible to improve noise resistance characteristics of the analog control signal.

"Alternatively, a semiconductor integrated circuit which operates based on a power supply voltage output from a power supply device configured to generate a voltage of a magnitude in accordance with a control signal having three or more voltage values may include: a first terminal to which the power supply voltage is applied; an internal interconnect which is connected to the first terminal, and distributes the power supply voltage to sections in the semiconductor integrated circuit; and a second terminal from which the control signal is output, wherein the control signal is generated to have a magnitude in accordance with a potential of the internal interconnect.

"According to the present disclosure, it is possible to obtain a power supply control system capable of performing dynamic and high-resolution voltage control with a relatively simple configuration."

For more information, see this patent: Gotou, Tetsuji; Yamamoto, Hiroo. Semiconductor Integrated Circuit and Electronic Apparatus Provided with Same. U.S. Patent Number 8774255, filed January 2, 2013, and published online on July 8, 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=8774255.PN.&OS=PN/8774255RS=PN/8774255

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

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Source: Electronics Newsweekly


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