Analog signal sampling system and method having reduced average input current
Granted: September 2, 2008
Patent Number:
7420491
A novel sampling system having a sampling device responsive to an analog input signal and a reference signal for providing corresponding charges. A switching circuit is provided to supply the input signal and the reference signal to the sampling device. The switching circuit is controlled to supply the input signal and the reference signal to the sampling device so as provide a substantially zero total charge taken by the sampling device from a source of the input signal. One application…
Spread spectrum modulation of a clock signal for reduction of electromagnetic interference
Granted: August 26, 2008
Patent Number:
7417509
A spread spectrum frequency modulated oscillator circuit usable as a clock comprises a reference component such as a resistor, a voltage controlled oscillator and a first circuit coupled to the reference component and voltage controlled oscillator and configured to supply a first control signal to the oscillator to cause the oscillator to oscillate at a frequency corresponding to a value of the reference component. A second circuit configured to supply a random signal to the oscillator…
Flashless lead frame with horizontal singulation
Granted: August 19, 2008
Patent Number:
7414302
A lead frame is configured for use with a singulation apparatus that eliminates flash. A die pad is attached to sides of the frame by tie bars and peripheral portions. The peripheral portions have cutout sections defining openings that are bridged by lead frame segments. The apparatus applies a downward force to the lead frame segments and translates the downward force to a horizontal force applied to the tie bars. The singulation process confines movement of the lead frame metal to…
Class AB folded-cascode amplifier having cascode compensation
Granted: August 19, 2008
Patent Number:
7414473
A class AB folded-cascode amplifier having improved gain-bandwidth product, comprises a differential input circuit including a differential transistor pair coupled to a source of tail current and responsive to a differential input signal for conducting a first current, a cascode circuit coupled to the differential input circuit for supplying a second current thereto, and a class AB output stage. A compensation circuit is configured for feeding back mutually complementary compensation…
Gradient insensitive split-core digital to analog converter
Granted: August 19, 2008
Patent Number:
7414561
Digital to analog converter circuits and methods are provided for producing an analog output voltage indicative of a digital input signal with at least partial insensitivity to error gradients. Described are split-core resistive elements, which include a plurality of one-dimensional or multi-dimensional resistive strings, that may be used to reduce or substantially eliminate the effects that error gradients have on the linearity of the analog output voltages of a resistive string or…
Method of fabricating a semiconductor device with multiple gate oxide thicknesses
Granted: July 22, 2008
Patent Number:
7402480
The individual performance of various transistors is optimized by tailoring the thickness of the gate oxide layer to a particular operating voltage. Embodiments include forming transistors with different gate oxide thicknesses by initially depositing one or more gate oxide layers with intermediate etching to remove the deposited oxide from active regions wherein transistors with relatively thinner gate oxides are to be formed, and then implementing one or more thermal oxidation steps.…
Range compression in oversampling analog-to-digital converters using differential input signals
Granted: July 8, 2008
Patent Number:
7397403
An analog-to-digital converter according to the invention is provided. The analog-to-digital converter preferably includes an analog input signal, a first reference signal, a second reference signal, and a range compression signal. The range compression signal is preferably characterized by a magnitude greater than the first reference signal and smaller than the second reference signal. In addition, when the analog input signal is sampled N times and the range compression signal is…
Current-mode control for switched step up-step down regulators
Granted: July 1, 2008
Patent Number:
7394231
A switched regulator circuit provides step-up and step-down operation in which the level of the input voltage can be greater, equal to, or less than a preset controlled output voltage. A four switch arrangement or two switch arrangement provides buck, boost, and buck-boost regulation under constant frequency valley-peak current mode control. A single sense resistor may be utilized for sensing inductor current during only a short period during each duty cycle. As an alternative to the…
Switching regulator duty cycle control in a fixed frequency operation
Granted: June 17, 2008
Patent Number:
7388444
A clock oscillator system for use in providing the switching regulator duty cycle control in a fixed frequency (no cycle skipping) operation is provided. In one embodiment, the circuit according to the invention uses an analog feedback loop to extend the switch ON time of the clock cycle by controlling the oscillator charging current and, thereby, increase the duty cycle. Preferably, this circuit can achieve very high switching duty cycle and/or very low switching duty cycle in a PWM…
Non-perturbing power supply margin controller
Granted: June 3, 2008
Patent Number:
7382303
A power supply margin controller may alter the voltage of a control signal used to control the output voltage of a power supply. The controller may include a digital-to-analog converter having an input and an output, and a comparator having a first input coupled to receive the control signal, a second input coupled to the output of the digital-to-analog converter, and an output. The controller may include a processing system configured to deliver data to the input of the…
Circuit and method for controlling hysteresis for bilevel signal transitions
Granted: June 3, 2008
Patent Number:
7382167
An output signal is controlled with adjustable hysteresis in response to a variable voltage input signal. One or more signals derived from the input signal are respectively compared with first and second reference voltages of different magnitudes. The output signal changes from a first state to a second state when one of the derived signals reaches a first reference voltage level threshold, and changes from the second state to the first state when a second one of the derived signals…
Switching regulator slope compensation generator circuit
Granted: May 27, 2008
Patent Number:
7378822
A slope compensation circuit that provides slope compensation in a switching regulator is provided. The slope compensation circuit preferably is adapted to receive an oscillator pulse train from a pulse width modulator oscillator and a modulator pulse train from a pulse width modulator. The circuit preferably includes a feedback loop that is responsive to the oscillator pulse train. The circuit preferably provides a slope compensation pulse train of ON and OFF states that is responsive…
Methods and circuits for output over-voltage reduction in switching regulators
Granted: May 27, 2008
Patent Number:
7378826
Switching regulator Burst Mode control circuitry is provided for limiting voltage overshoot at the output of a switching regulator operating in power saving Burst Mode. The Burst Mode control circuitry may include regulator load current sensing circuitry which may be operative to put and maintain the regulator in the SLEEP state when the load current amplitude is below a threshold. The control circuitry may also include gated over-voltage comparator circuitry operative to reduce…
High voltage MOS transistor with gate extension
Granted: May 20, 2008
Patent Number:
7374982
A high voltage MOS transistor with a gate extension that has a reduced electric field in the drain region near the gate is provided. The high voltage MOS transistor includes a first and second gate layers, and a dielectric layer between the gate layers. The first and second gate layers are electrically coupled togther and form the gate of the transistor. The second gate layer extends over the drain of the transistor above the dielectric and gate oxide layers to form the gate extension.…
Systems and methods for reducing transient errors on digital to analog converters (DACs) deglitcher
Granted: May 20, 2008
Patent Number:
7375671
A digital to analog converter that receives a digital signal and that converts the digital signal to an analog input signal is provided. The converter may include a group of most significant bits. The group is decoded to drive a plurality of equivalent most significant segments. The converter may also include a second group of bits. The second group is decoded to drive a second plurality of equivalent segments.
Protection for switched step up/step down regulators
Granted: April 29, 2008
Patent Number:
7365525
A four switch voltage converter is regulated for buck mode and boost mode under constant frequency valley-peak current mode control. Protection circuits are responsive to output voltage and regulator current to prevent excessive current that otherwise might result from abnormally low output voltage short circuit, or spurious switching abnormalities during low duty cycle operation. The regulator control circuit is responsive to the protection circuits to automatically connect a regulator…
Non-feedback implemented control of the output-common mode of a differential amplifier
Granted: April 29, 2008
Patent Number:
7365600
A differential amplification circuit includes a differential amplifier and common mode control circuitry configured to control output common mode of the differential amplifier. However, this control circuitry does not use feedback. The circuitry controls the output common mode in either, or in a combination of two ways, neither of which employs feedback from the output common mode. One control technique uses a dummy circuit and comparator to cancel out the effect of variations in…
Methods and circuits for frequency modulation that reduce the spectral noise of switching regulators
Granted: April 22, 2008
Patent Number:
7362191
The present invention comprises methods and circuits for spread spectrum frequency modulation that reduce peak spectral noise at the outputs or inputs of switching regulators. More specifically, the present invention modulates the operating frequency of the switching regulator in accordance with a frequency modulation waveform having a shape coordinated to a peak noise amplitude waveform that describes the correlation between the operating frequency of a switching regulator and the peak…
Circuits and methods for detecting the presence of a powered device in a powered network
Granted: April 8, 2008
Patent Number:
7356588
Circuits and methods for detecting the presence of a powered device in a powered network connection and removing power from the powered network connection when no powered device is present are disclosed. The circuits and methods involve applying a time-varying voltage signal into an analog amplifier circuit that converts the voltage into a current indicative of the impedance of the connection. The analog amplifier circuit may be implemented with a dual-output trans-conductance amplifier…
Bidirectional power conversion with multiple control loops
Granted: March 25, 2008
Patent Number:
7348767
Bidirectional power conversion systems provide the ability to change power attributes to and from a component. Current bidirectional power conversion systems use a unidirectional power converter for each direction. The integration of the two normally independent power converters results in a bidirectional power converter with nearly half the size, weight, volume, cost and complexity. Described are embodiments of bidirectional power conversion systems that allow power transfer between two…
