233results about "Charge amplifiers" patented technology

An amplifier system with on-demand power supply boost includes an amplifier circuit for receiving an input signal and a charge pump connected to positive and negative power supplies and having predetermined supply voltages and being responsive to the input signal for increasing beyond the predetermined supply voltages the supply voltage applied to the amplifier in response to an increase in the input signal and a tracking charge pump usable in the amplifier system which includes a charge storage device; a unidirectional isolation device interconnecting the charge storage device and one pole of a power supply; a driver circuit responsive to an input signal and interconnected between both poles of the power supply; the power supply having predetermined power supply voltages; and a bias circuit for biasing the driver circuit to charge the charge storage device in the charge mode and in the boost mode, for increasing beyond the predetermined power supply voltages, the supply voltage supplied by the storage device to an external load in response to an increase in the input signal.

Provided is a radiation imaging apparatus, including: a first conversion element arranged to convert a radiation ray into electric charge in order to obtain a radiographic image; a first amplifier arranged to output a voltage corresponding to the electric charge of the first conversion element; a second conversion element arranged to convert the radiation ray into electric charge in order to detect radiation irradiation; a second amplifier arranged to output a voltage corresponding to the electric charge of the second conversion element; and a control circuit configured to control the first amplifier and the second amplifier, in which the control circuit is capable of controlling the second amplifier independently of control that is exerted over the first amplifier.

Systems and methods for insuring successful initiation of a resonating micro-electro mechanical systems (MEMS). An example system includes a resonating sensor, a drive device, a charge amplifier, and a voltage gain circuit. At start up, the charge amplifier and voltage gain circuit receives signals from the resonating sensor, compensates this signal for DC offsets, and generates a clock signal for the drive, thus placing the resonating sensor in a steady state operating mode. The circuit includes a plurality of gain switches that are toggled to produce a glitch in the signal associated with the received signal. The glitch overcomes the DC offset. A comparator generates the clock signal for the drive device if a signal associated with the received signal exceeds a reference signal.

The invention provides a microphone circuit. In one embodiment, the microphone circuit comprises a microphone, a self-biased amplifier with a finite gain, and a feedback capacitor. The microphone coupled between a ground and a first node generates a first voltage at the first node according to sound pressure. The self-biased amplifier has a positive input terminal coupled to the ground and a negative input terminal coupled to the first node and amplifies the first voltage according to the finite gain to generate a second voltage at a second node. The feedback capacitor coupled between the first node and the second node feeds back the second voltage to the first node. The second voltage is then output to a following module subsequent to the microphone circuit.

A charge pump circuit which uses a constant current from a constant current source for charging or discharging a capacitor and which obtains an output voltage by shifting a power supply voltage using a charged voltage of the charged capacitor. With this structure, a large current can be limited and generation of noise can be prevented.

The performance of precision analog integrated electronic circuits is directly related to the degree of matching between electrical circuit elements. Any residual mismatch of circuit elements after manufacturing must be calibrated out using numerous techniques such as adjusting potentiometers, trimming capacitors, modifying binary-weighted resistor strings, etc. Prior art matching techniques entail the use of large area circuit elements or a large number of elements arranged in a prescribed manner on the surface of a silicon die to minimize the residual calibration. The present invention utilizes a multiplicity of circuit elements that are interconnected in distinct groups to achieve a higher degree of element matching and the ensuing benefits thereof. The elements are interconnected to yield a prescribed minimum mismatch error.

A piezoelectric detector circuit has at least one input line, a piezoelectric transducer in the input line, an amplifier receiving signals on the input line and generating an output, and one or two feedback elements through which the output is sent back to the input line. The circuit may be a discrete time sampled operational amplifier (DTOA) based transconductance or “voltage output mode” circuit. In one embodiment, protection elements are associated with amplifier input lines to establish a reference voltage.

A transconductance monitoring and amplifying circuit for a piezoelectric transducer that may be used in, e.g., a motion detector system includes a FET, with the transducer (and, hence, the signal voltage reference) floating between the gate and source of the FET, as opposed to being connected to the common ground of the circuit. This permits the development of a larger detector signal and concomitantly the use of a relatively inexpensive FET instead of a relatively more expensive high impedance operational amplifier as must be used in conventional transconductance circuits. The FET and transducer can be held in a single four-pin package. A discrete time sampled operational amplifier may also be used.