Patent application number | Description | Published |
20080197924 | Variable gain amplifier circuit and filter circuit - This variable gain amplifier is provided with an operational amplifier. The non-inversion input terminal of the operational amplifier is connected to a reference potential. A feedback resistor is connected between the output terminal and inversion input terminal of the operational amplifier. An input resistor is inserted between the inversion input terminal of the operational amplifier and the input terminal of the variable gain amplifier circuit. An adjustment resistor is connected between the inversion input terminal of the operational amplifier and the reference potential. The resistance value of the adjustment resistor is controlled in such a way as to maintain constant against the resistance value change a combined resistance value in its parallel connection with the input resistor when changing the resistance value of the input resistor. | 08-21-2008 |
20080197926 | SOURCE FOLLOWER CIRCUIT AND SEMICONDUCTOR APPARATUS - Based on a result of comparing an output common mode direct-current voltage of a pair of source follower transistors when a direct-current voltage is applied to each gate of the pair of source follower transistors with a predetermined reference voltage, the direct-current voltage is controlled such that the output common mode direct-current voltage can match the reference voltage. | 08-21-2008 |
20080211597 | Filter Circuit - A filter circuit including first and second real filters of a zero-IF scheme. The first and second real filters receive an I component and a Q component separated from a reception signal, respectively; and a switch section for producing a complex filter by switchably connecting the first and second real filters through interconnection elements. The switch section further receiving a switching signal for connecting the first and second real filters, thereby switching from the zero-IF scheme to a low-IF scheme. | 09-04-2008 |
20080218244 | Analog switch - An analog switch comprises a first transistor, a second transistor, the drain and the source thereof being connected between said first input terminal and a second output terminal whereto said second signal is output and the gate thereof being grounded or connected to a supply voltage node, a third transistor, the drain and the source thereof being connected between a second input terminal whereto said second signal is input and said second output terminal and said third transistor being turned on and off by a control signal provided to the gate thereof; and a fourth transistor, the drain and the source thereof being connected between said second input terminal and said first output terminal and the gate thereof being grounded or connected to a supply voltage node. | 09-11-2008 |
20090108939 | AMPLIFYING APPARATUS AND BIAS STABILIZATION CIRCUIT - An amplifying apparatus including an amplifier having a first FET, a second FET having a source connected to a drain of the first FET, a load resistance connected to a drain of the second FET, a first bias circuit configured to supply a first bias voltage to a gate of the first FET, and a second bias circuit configured to supply a second bias voltage to a gate of the second FET. The second bias circuit includes a second comparison circuit configured to send a control signal to the gate of the second FET so that a bias voltage of a connection node between the first and second FETs changes in conjunction with an output voltage of the first bias circuit. | 04-30-2009 |
20090291661 | NOISE CANCELLATION CIRCUIT AND AMPLIFIER WITH NOISE CANCELLATION CIRCUIT - A noise cancellation circuit, which reduces noise in an output signal of an amplifier having an input resistance, a feedback resistance, and an operational amplifier, has: a first mixer circuit, which input an input signal across a first input terminal and a second input terminal of the operational amplifier, and performs frequency conversion of the input signal according to a first frequency signal; a noise cancellation amplifier, which amplifies an output signal of the first mixer circuit; a second mixer circuit, which performs frequency conversion of an output signal of the noise cancellation amplifier according to the first frequency signal; and a signal supply circuit, which supplies an output signal of the second mixer circuit to the first input terminal of the operational amplifier via an output resistance. | 11-26-2009 |
20090302925 | ORTHOGONAL SIGNAL OUTPUT CIRCUIT - An orthogonal signal output circuit having an error correction function for correcting an orthogonal error, including: first and second differential circuits; and first to fourth variable resistors, wherein the first variable resistor is connected to a positive output of the first differential circuit and a positive output of the second differential circuit; the second variable resistor is connected to the positive output of the first differential circuit and a negative output of the second differential circuit; the third variable resistor is connected to a negative output of the first differential circuit and the positive output of the second differential circuit; and the fourth variable resistor is connected to the negative output of the first differential circuit and the negative output of the second differential circuit. | 12-10-2009 |
20090302947 | SEMICONDUCTOR DEVICE - A semiconductor device including: a gain control circuit; a first circuit which is controlled a gain to be constant by the gain control circuit; and a bias circuit connected to the first circuit, wherein the first circuit including a first transistor; and a load resistance, an amplification factor or an attenuation factor of the first circuit is proportionate to a product of a transconductance of the first transistor and a resistance value of the load resistance, and a voltage applied to the load resistance is set as an output of the semiconductor device, the bias circuit generates and outputs a differential current of a current that is proportionate to a drain current flowing into the first transistor and a current that is inversely proportionate to the load resistance value, and an output of the bias circuit is connected to an output node of the first circuit. | 12-10-2009 |
20100171549 | Variable Gain Amplifier Circuit and Filter Circuit - This variable gain amplifier is provided with an operational amplifier. The non-inversion input terminal of the operational amplifier is connected to a reference potential. A feedback resistor is connected between the output terminal and inversion input terminal of the operational amplifier. An input resistor is inserted between the inversion input terminal of the operational amplifier and the input terminal of the variable gain amplifier circuit. An adjustment resistor is connected between the inversion input terminal of the operational amplifier and the reference potential. The resistance value of the adjustment resistor is controlled in such a way as to maintain constant against the resistance value change a combined resistance value in its parallel connection with the input resistor when changing the resistance value of the input resistor. | 07-08-2010 |
20100283527 | Analog Switch - An analog switch comprises a first transistor, a second transistor, the drain and the source thereof being connected between said first input terminal and a second output terminal whereto said second signal is output and the gate thereof being grounded or connected to a supply voltage node, a third transistor, the drain and the source thereof being connected between a second input terminal whereto said second signal is input and said second output terminal and said third transistor being turned on and off by a control signal provided to the gate thereof; and a fourth transistor, the drain and the source thereof being connected between said second input terminal and said first output terminal and the gate thereof being grounded or connected to a supply voltage node. | 11-11-2010 |
20110170628 | FILTER, AND TRANSMITTER AND RECEIVER HAVING THE SAME - In order to suppress the enlargement of the circuit layout area of an LSI together with the cost, even at the time when the variation width of the filter characteristic is narrow within a wide range, a filter varies an element value of at least one kind of elements ( | 07-14-2011 |
20120092085 | POLY-PHASE FILTER, AND A SINGLE-SIDE BAND MIXER INCLUDING THE SAME - A 4-phase filter includes four filter units including resistors and capacitors which inputs input signals, and provides the input signal via a switch buffer to a secondary capacitor provided in parallel to a primary capacitance of each filter unit, thus enabling a shift of an operational frequency band according to whether or not the switch buffer is in an output-high-impedance state. | 04-19-2012 |