Abstract:
An analog-to-digital converter circuit having a simple design and capable of preventing an increase in surface area and other problems. An analog-to-digital converter circuit for converting an analog input signal to a digital quantity includes an analog-to-digital converter unit that converts analog input signals to pre-correction digital values, and a corrector unit that digitally corrects the pre-connection digital values output from the analog-to-digital converter unit. The corrector unit includes a weighting coefficient multiplier unit that outputs a post-correction digital value obtained by multiplying the weighting coefficients provided for each bit by each bit of the pre-correction digital value output from the A/D converter unit and summing them, and a weighting coefficient search unit that searches for weighting coefficients so as to minimize an error signal generated based on the post-correction digital value and an approximate value for the post-correction digital value.
Abstract:
A current generation circuit including a first and a second bipolar transistors, a current distribution circuit that makes a first current and a second current flow through the first and second bipolar transistors, respectively, the first current and the second current corresponding to a first control voltage, a first NMOS transistor disposed between the first bipolar transistor and the first current distribution circuit, a second NMOS transistor disposed between the second bipolar transistor and the first current distribution circuit, a first resistive element, a first operational amplifier that outputs the second control voltage to the gates of the first and the second NMOS transistors according to a drain voltage of the first NMOS transistor and a reference bias voltage, and a second operational amplifier that generates the first control voltage according to a drain voltage of the second NMOS transistor and the reference bias voltage.
Abstract:
A semiconductor communication device reduces influence of noise that is produced by applying a dither signal. The semiconductor communication device includes a Delta-Sigma analog-to-digital converter that converts input analog signals to digital signals, a power detecting unit that detects signal power of the digital signals, a gain control unit that changes a gain setting of analog signals to be input to the Delta-Sigma analog-to-digital converter depending on the signal power of the digital signals, and a dither signal control unit that causes the Delta-Sigma analog-to-digital converter to selectively add the dither signal when the gain setting changes.
Abstract:
A semiconductor device according to an aspect of the invention relates to an AD converter that converts a signal level of an analog signal into a digital value by using a comparator, and determines an amount of adjustment of an offset voltage of the comparator based on an offset determination result of the comparator obtained immediately after a least significant bit (LSB) of a digital value output as a conversion result is converted.
Abstract:
A semiconductor device according to an aspect of the invention relates to an AD converter that converts a signal level of an analog signal into a digital value by using a comparator, and determines an amount of adjustment of an offset voltage of the comparator based on an offset determination result of the comparator obtained immediately after a least significant bit (LSB) of a digital value output as a conversion result is converted.
Abstract:
A differential signal is amplified by passive amplification which does not a reference of a common-mode voltage. At this time, the voltage of the differential signal is passive-amplified twice before carrying out a successive approximation type analog-digital conversion operation. The passive amplification is attained by providing a plurality of capacitances which carry out a sampling operation, and switching these connection relation by using switches. Without being accompanied by the increase of the consumed power and the chip size, an influence by the noise of s comparator is reduced to a half so that the effective resolution can be increased for one bit.
Abstract:
Provided is a semiconductor device for wireless communication which achieves a reduction in leakage power and allows an improvement in power efficiency. For example, to external terminals, an antenna driver section for driving an antenna and a rectifying section for rectifying input power from the antenna are coupled. The antenna driver section includes pull-up PMOS transistors and pull-down NMOS transistors. In the rectifying section, a power supply voltage generated by a full-wave rectifying circuit is boosted by a voltage boosting circuit. For example, when a supply of a power supply voltage from a battery is stopped, a power supply voltage resulting from the boosting by the voltage boosting circuit is supplied to the bulk of each of the pull-up PMOS transistors.
Abstract:
A digital-correction-type A/D converter which is a charge sharing type and performing successive approximation is realized in a small area. The A/D converter is configured with an A/D conversion unit which is a charge sharing type and performing successive approximation, a digital correction unit which receives a digital output of the A/D conversion unit and performs digital correction to the digital output, and a holding unit which holds a test signal. A test signal of a common value from the holding unit is inputted into the A/D conversion unit in the first period and the second period. The A/D conversion correction coefficient for the digital correction unit is calculated on the basis of the digital correction result of the digital correction unit in the first period, and the digital correction result of the digital correction unit in the second period.
Abstract:
A differential signal is amplified by passive amplification which does not a reference of a common-mode voltage. At this time, the voltage of the differential signal is passive-amplified twice before carrying out a successive approximation type analog-digital conversion operation. The passive amplification is attained by providing a plurality of capacitances which carry out a sampling operation, and switching these connection relation by using switches. Without being accompanied by the increase of the consumed power and the chip size, an influence by the noise of s comparator is reduced to a half so that the effective resolution can be increased for one bit.
Abstract:
An analog-to-digital converter circuit having a simple design and capable of preventing an increase in surface area and other problems. An analog-to-digital converter circuit for converting an analog input signal to a digital quantity includes an analog-to-digital converter unit that converts analog input signals to pre-correction digital values, and a corrector unit that digitally corrects the pre-connection digital values output from the analog-to-digital converter unit. The corrector unit includes a weighting coefficient multiplier unit that outputs a post-correction digital value obtained by multiplying the weighting coefficients provided for each bit by each bit of the pre-correction digital value output from the A/D converter unit and summing them, and a weighting coefficient search unit that searches for weighting coefficients so as to minimize an error signal generated based on the post-correction digital value and an approximate value for the post-correction digital value.