Range compression in oversampling analog-to-digital converters
Granted: March 25, 2008
Patent Number:
7348907
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…
Methods and circuits for tracking and sequencing multiple power supplies
Granted: March 11, 2008
Patent Number:
7342328
The present invention relates to methods and circuits for controlling outputs of one or more slave power supplies in one or more defined relationships to a master signal. The defined relationships include but are not limited to coincident tracking, offset tracking, ratiometric tracking, and supply sequencing.
Systems and methods for reducing input current in photoflash chargers
Granted: March 11, 2008
Patent Number:
7342365
A circuit for charging a photoflash that preferably reduces the average input to the switching regulator in an efficient fashion is provided. The regulator includes a transformer. The transformer includes a primary winding and a secondary winding. The switching regulator also includes a switch that closes at the beginning of a first portion of the switching cycle and opens at the end of the first portion of the switching cycle. The second portion of the cycle may be to allow the…
Switching regulator with slope compensation independent of changes in switching frequency
Granted: March 11, 2008
Patent Number:
7342392
Compensation for a switching regulator is attained by developing a compensation signal for a switching regulator that is independent of changes in the switching frequency. The regulator operational frequency is established in accordance with a repetitive ramp signal of constant slope and adjustable frequency. The voltage of the ramp signal is monitored and an offset signal is derived therefrom. The peak value of the ramp signal, detected during monitoring, is used to derive the offset…
Low power wide dynamic range RMS-to-DC converter
Granted: March 11, 2008
Patent Number:
7342431
An RMS to DC converter squares an a-c input signal to obtain a squared direct current voltage signal. The squared direct current voltage signal is applied to successive stages, each stage amplifying its received signal and detecting the amplified level of the signal within a confined range. The detected levels detected in the successive stages are added to produce an output d-c signal that is variable in linear proportion to logarithmic change in RMS voltage of the input signal. The…
Ultra-wideband constant gain CMOS amplifier
Granted: March 4, 2008
Patent Number:
7339437
Circuitry and methods for improved amplifiers with large bandwidth and constant gain are provided. The combination of a synthetic inductive drain load and a bridged-T matching network provide amplifiers that can drive a substantial capacitive load with the above mentioned improvements over prior amplifiers. Additionally, circuits presented allow for improved rise time and insensitivity to temperature variations.
Inrush current slew control circuit and method
Granted: February 12, 2008
Patent Number:
7330065
Circuitry and methodology for controlling a FET or another transistor device provided to supply power to a circuit board insertable into a live backplane to provide inrush current slew rate control. The FET control circuit is responsive to an input signal variable in a preset manner to produce a FET control signal for controlling the FET so as to form an output signal corresponding to the input signal. The control circuit is configured to prevent the uncontrollable step in the output…
High capacitance integrated circuits
Granted: January 29, 2008
Patent Number:
7323928
An integrated circuit providing high equivalent capacitance ranging from a few tens of picofarads to a few nanofarads is presented. The integrated circuit includes active integrated circuit components, requires no external capacitor, and is substantially insensitive to transistor current gain variations. The high capacitance integrated circuit can be advantageously used to provide, for example, timing delay and servo loop compensation.
LED dimming control technique for increasing the maximum PWM dimming ratio and avoiding LED flicker
Granted: January 22, 2008
Patent Number:
7321203
Circuitry and methodology for providing LED dimming control in a LED driving system having a switching regulator for providing power supply to drive the LED. The switching regulator includes a switching circuit to which an oscillation signal is applied to control switching of the switching circuit. A dimming control input is supplied with a pulse-width modulation (PWM) dimming control signal to provide PWM dimming control of the LED. The dimming control input applies the PWM dimming…
High linearity low noise variable gain amplifier with continuous gain control
Granted: January 8, 2008
Patent Number:
7317357
A variable gain amplifier comprises a plurality of serially connected transistor cells, in which each of the transistor cells has a plurality of connecting terminals. The first terminals of the transistor cells are serially coupled together to receive a first input voltage. The second terminals of the transistor cells are serially connected via a first set of resistors between adjacent cells and coupled to a first gain control. Each of the second terminals is AC or virtual grounded. The…
Circuitry and methods for improving the performance of a light emitting element
Granted: December 25, 2007
Patent Number:
7312581
Light emitting elements with preselected or adjustable impedance characteristics are provided. Embodiments using a preselected impedance characteristic obtain significant performance benefits compared to the prior art. Embodiments having an adjustable impedance may alter the impedance associated with the light emitting component such that it has a substantially constant resistive or reactive impedance that improves certain performance attributes. This solution virtually eliminates the…
Squaring cell implementing tail current multipication
Granted: November 27, 2007
Patent Number:
7301387
A current squaring cell is provided for producing an output current that correlates to the square of an input signal current. The current squaring cell comprises a first circuit portion, which receives a first tail current that is positively proportional to the input signal current, and a second circuit portion, which connects to the first circuit portion and receives a second tail current that is negatively proportional to the input signal current.
Capacitor charging circuitry and methodology implementing controlled on and off time switching
Granted: November 6, 2007
Patent Number:
7292005
The present invention provides a capacitor charging circuit that efficiently charges capacitive loads. In particular, circuits and techniques are preferably provided for using current from both the primary and secondary windings of a transformer to control ON-time and OFF-time of a switch. This arrangement preferably yields an adaptable ON-time and adaptable OFF-time switch that is capable of rapidly charging capacitor loads ranging from as low as zero volts to several hundred volts. The…
Low voltage pull-down circuit
Granted: November 6, 2007
Patent Number:
7292076
A low voltage pull-down circuit for maintaining a node at a logic LOW voltage is provided. When a logic LOW is desired, the circuit provides a low-impedance path from the node to ground. The node may be pulled-up to a logic HIGH voltage, for example, by removing the low-impedance path and allowing a voltage source to reach the node through a resistor or transistor. A low voltage pull-down circuit may be provided in a power supervision circuit for systems that operate with, for example,…
Adaptive current reversal comparator
Granted: October 9, 2007
Patent Number:
7279877
An adaptive current reversal comparator for synchronous switching regulator comparison circuit for use in a switching regulator is provided. The comparison circuit includes a voltage offset that is used at least in part to compensate for a propagation delay of the comparison circuit. The switching regulator includes an inductor and a synchronous transistor. The comparison circuit also includes a timing circuit that provides a threshold amount of time and an offset adjustment circuit. The…
Wideband squaring cell
Granted: September 11, 2007
Patent Number:
7268608
A squaring cell comprises a first circuit responsive to an input voltage to produce a corresponding current, and a second circuit, preferably in the form of an absolute modulator circuit, responsive to the current produced by the first circuit and to the input voltage to produce an output current that corresponds to the square of the input voltage. In one embodiment, the first circuit comprises an absolute value voltage-to-current converter; in another, the first circuit comprises a…
Adaptive control for inducer based buck-boost voltage regulators
Granted: September 4, 2007
Patent Number:
7265524
Voltage regulators and methods for regulating voltages are disclosed. A switching circuit with an inductor and a plurality of switches may be used to produce a regulated voltage from an unregulated voltage source. A control circuit may be used to monitor the voltages at the input and output of the voltage regulator, and operate the switches in either a buck, boost, or buck-boost mode depending on the relationship between the voltages at the input and output of the voltage regulator.
CMOS driver with minimum shoot-through current
Granted: September 4, 2007
Patent Number:
7265591
A CMOS driver with minimum shoot-through current is disclosed. The potential for shoot-through current may be eliminated or reduced with a break-before-make circuit driving an output stage. The break-before-make circuit may include a first logic element followed by a first inverter and a second logic element followed by a second inverter. The inverters may be cross-coupled to one another and/or the internal transistors may be configured with different strengths. The logic elements may be…
Variable gain amplifier with temperature compensation and gain linearity enhancement
Granted: August 28, 2007
Patent Number:
7262661
A variable gain amplifier contains a plurality of differential transistor pairs. A temperature dependent current is generated in the current path of each differential transistor pair. A generated gain control current is converted to a temperature dependent gain control current and applied in circuit with control inputs of the transistors of the paired differential transistors. The temperature dependent gain control current is obtained from a gain control current corresponding to a…
Wide dynamic range switching variable gain amplifier and control
Granted: August 21, 2007
Patent Number:
7259620
A plurality of variable gain amplifier stages are coupled by an attenuation circuit that receives a voltage input to be amplified. A control circuit activates each of the variable gain amplifier stages in a seamless manner in accordance with a control signal applied to a voltage control node, while maintaining no more than one of the stages active at any time. Fractions of the reference signal voltage level are set to define boundaries between control voltage level ranges of the…
