Abstract: A charging circuit includes a monitoring part configured to monitor a battery voltage applied to a battery and configured to output an overvoltage signal when the battery is in an overvoltage condition a protection part configured to electrically disconnect the battery from an adaptor when receiving the overvoltage signal, and a switch which, when the battery is electrically disconnected from the adaptor, switches a monitoring node for an adaptor voltage outputted from the adaptor, from a supply node of the battery voltage to a supply node of a system voltage, which is applied to a system electrically connected with the battery and the adaptor, based on the overvoltage signal to cause a control command for controlling the adaptor voltage based on the system voltage to be outputted.

Abstract: A voltage control method includes producing an error signal based on a difference between a reference signal and an adaptor voltage and an adaptor current corresponding to the adaptor voltage, regulating, based on the error signal, the adaptor voltage, comparing a reference voltage to a voltage proportional to a potential corresponding to an identifying voltage corresponding to the adaptor voltage, detecting, based on the comparison result, whether or not a couplable external power source is suitable, and setting based, on the detection result, a potential corresponding to the identifying voltage.

Abstract: A charging circuit includes a monitoring part configured to monitor a battery voltage applied to a battery and configured to output an overvoltage signal when the battery is in an overvoltage condition a protection part configured to electrically disconnect the battery from an adaptor when receiving the overvoltage signal, and a switch which, when the battery is electrically disconnected from the adaptor, switches a monitoring node for an adaptor voltage outputted from the adaptor, from a supply node of the battery voltage to a supply node of a system voltage, which is applied to a system electrically connected with the battery and the adaptor, based on the overvoltage signal to cause a control command for controlling the adaptor voltage based on the system voltage to be outputted.

Abstract: A voltage control method includes producing an error signal based on a difference between a reference signal and an adaptor voltage and an adaptor current corresponding to the adaptor voltage, regulating, based on the error signal, the adaptor voltage, comparing a reference voltage to a voltage proportional to a potential corresponding to an identifying voltage corresponding to the adaptor voltage, detecting, based on the comparison result, whether or not a couplable external power source is suitable, and setting based, on the detection result, a potential corresponding to the identifying voltage.

Abstract: A voltage control oscillation (VCO) circuit and an adjusting method for the same, which enables an adjustment for suppressing the dispersion of the output characteristic in spite of the manufacture-related dispersion of element characteristics, using a simple circuit configuration, are provided. A low-pass filter 15 and a high-pass filter 16 are composed of the elements that have the same structure as elements composing the VCO circuit 11, and a prescribed correlation is established between both elements. A corrective element 14 is connected in parallel to a main element, in which an oscillation frequency control signal VT is input, in the VCO circuit 11. Respective frequency-gain characteristic lines of the low-pass/high-pass filters 15 and 16 have gradients reverse to each other and cross at a target gain TG. When the capacitance value lowers in dispersion, the level of an output signal SL2 becomes higher than that of an output signal SH2 at a reference frequency fREF to form an output level difference LD2.

Abstract: An analog filter circuit in which filter characteristic deviation can be adjusted with simple circuitry and its adjustment method can be provided. The analog filter circuit includes a low pass filter and a high pass filter and output signals of both filters are input to a comparison and adjustment section from which an adjustment signal is fed back to the low pass and high pass filters and also input to a predetermined-band pass filter having predetermined correlation to the low pass and high pass filters. The low pass and high pass filters are tuned so that the frequency-gain characteristic line in an attenuation band of the low pass filter linearly falls, while that line of the high pass filter linearly rises, both the lines crossing at a reference frequency.

Abstract: An analog filter circuit in which filter characteristic deviation can be adjusted with simple circuitry and its adjustment method can be provided. The analog filter circuit includes a low pass filter and a high pass filter and output signals of both filters are input to a comparison and adjustment section from which an adjustment signal is fed back to the low pass and high pass filters and also input to a predetermined-band pass filter having predetermined correlation to the low pass and high pass filters. The low pass and high pass filters are tuned so that the frequency-gain characteristic line in an attenuation band of the low pass filter linearly falls, while that line of the high pass filter linearly rises, both the lines crossing at a reference frequency.

Abstract: Oscillators have capacitors, respectively, whose capacitances change according to an external force and generate first oscillating signals according to the capacitances. Each of the capacitors is disposed, for example, between a substrate and a mass body that is movably disposed to face the substrate and oscillates in a direction perpendicular to the substrate. A detecting unit detects a relative difference between the capacitances of the capacitors as a difference between frequencies of the first oscillating signals. An angular speed or acceleration applied in a horizontal direction of the substrate is calculated according to the frequency change detected by the detecting unit. Therefore, a capacitance difference detecting circuit and a MEMS sensor that detect a minute change in the capacitances of the two capacitors caused by the external force are formed.

Abstract: A voltage control oscillation (VCO) circuit and an adjusting method for the same, which enables an adjustment for suppressing the dispersion of the output characteristic in spite of the manufacture-related dispersion of element characteristics, using a simple circuit configuration, are provided. A low-pass filter 15 and a high-pass filter 16 are composed of the elements that have the same structure as elements composing the VCO circuit 11, and a prescribed correlation is established between both elements. A corrective element 14 is connected in parallel to a main element, in which an oscillation frequency control signal VT is input, in the VCO circuit 11. Respective frequency-gain characteristic lines of the low-pass/high-pass filters 15 and 16 have gradients reverse to each other and cross at a target gain TG. When the capacitance value lowers in dispersion, the level of an output signal SL2 becomes higher than that of an output signal SH2 at a reference frequency fREF to form an output level difference LD2.

Abstract: An analog filter circuit in which filter characteristic deviation can be adjusted with simple circuitry and its adjustment method can be provided. The analog filter circuit includes a low pass filter and a high pass filter and output signals of both filters are input to a comparison and adjustment section from which an adjustment signal is fed back to the low pass and high pass filters and also input to a predetermined-band pass filter having predetermined correlation to the low pass and high pass filters. The low pass and high pass filters are tuned so that the frequency-gain characteristic line in an attenuation band of the low pass filter linearly falls, while that line of the high pass filter linearly rises, both the lines crossing at a reference frequency.

Abstract: Oscillators have capacitors, respectively, whose capacitances change according to an external force and generate first oscillating signals according to the capacitances. Each of the capacitors is disposed, for example, between a substrate and a mass body that is movably disposed to face the substrate and oscillates in a direction perpendicular to the substrate. A detecting unit detects a relative difference between the capacitances of the capacitors as a difference between frequencies of the first oscillating signals. An angular speed or acceleration applied in a horizontal direction of the substrate is calculated according to the frequency change detected by the detecting unit. Therefore, a capacitance difference detecting circuit and a MEMS sensor that detect a minute change in the capacitances of the two capacitors caused by the external force are formed.