High Q structure
Granted: August 13, 2002
Patent Number:
6433658
A structure (110, 150) for enhancing the quality factor (Q) of a capacitive circuit (112, 152). The capacitive circuit (112, 152) includes a first resistance (122, 164), a capacitance (124, 166), and a second resistance (126, 168). The capacitance (124, 166) represents the net capacitance of the capacitive circuit (112, 152), and the first resistance (122, 164) and second resistance (126, 168) represent elements of the intrinsic resistance of the capacitive circuit (112, 152). In a one…
Method to synchronize multiple switching regulators in out of phase mode without PLL
Granted: June 11, 2002
Patent Number:
6404657
The present invention is a method and apparatus to synchronize multiple switching regulators in out of phase mode without a phase locked loop. In the present invention, each multiple slave device is connected to a master device and to one another in series, as well as connected to a master clock signal. After a DH, LX or DL output from a preceding device is detected by a following connected slave device, the first subsequent edge of a master clock signal serves to reset the internal…
Hot swap current limit circuits and methods
Granted: June 4, 2002
Patent Number:
6400203
Hot swap current limit circuits and methods that provide soft start, current limiting and thermal limiting suitable for realization in a single integrated circuit. The circuits incorporate both a fast current limit loop to limit current spikes, and a slower current limit loop to more accurately limit the maximum or limit current to a predetermined value for longer periods, such as during start up or prolonged periods of excessive load conditions. Details of an exemplary embodiment…
Single-chip digital cable TV/cable modem tuner IC
Granted: June 4, 2002
Patent Number:
6400416
A television receiver is provided including a first mixer having a first input adapted for receiving an input signal in a predetermined frequency range. It should be noted that the input signal may take the form of either a broadcast television signal, a cable television signal, or a digital signal transmitted over a cable delivery system. The first mixer further includes a second input adapted for receiving a first reference signal having a first operating frequency. In use, the first…
Current limiting using capacitor charge measurement
Granted: June 4, 2002
Patent Number:
6400544
Current limiting using capacitor charge measurement to limit the supply current or load current of a circuit, or the current flowing through a device or switch, to prevent the time average current in the switch from exceeding a certain safe level. A replica circuit is used to provide a scaled version of the current in the main switch. The current output of the replica circuit is used to charge a capacitor during the first period of the clock signal so that the capacitor voltage, at any…
Methods and circuits for generating a preemphasis waveform
Granted: May 21, 2002
Patent Number:
6393062
The present invention overcomes ISI by precompensating for the anticipated high-frequency energy losses in the transmission media. This precompensation is accomplished using a preemphasis waveform, i.e., driving the differential signal to a value larger than normal on a signal edge. Preemphasis increases the slew rate of edges inside data with a lot of transitions relative to data with fewer transitions, thereby compensating for the low-pass effects of the transmission cable. The present…
Fast and precise current-sense circuit for high-voltage switch
Granted: May 7, 2002
Patent Number:
6384636
A current-sense circuit provides a fast and precise measure of current through a switch with the sensing circuit being protected from a high-voltage across the switch and from large transient currents through the switch when the switch is first closed. The sensed load current is connected through a first conductive path including the current switch and through a second conductive path for passing a scaled portion of the current and a scaled bias current. An output circuit is responsive…
Method and apparatus for digital to analog converters with improved switched R-2R ladders
Granted: April 30, 2002
Patent Number:
6380877
Operating range of R-2R ladders for digital to analog converters (DACs) is improved by increasing resistance in series with a termination switch in a termination leg to avoid transistor saturation for increasing DAC resolution, increasing reference voltage range, or other application. The switched R-2R ladder circuit is modified to compensate for increasing resistance to maintain proper resistor matching for generation of the appropriate range of analog output voltages for a digital…
Multi-phase switching converters and methods
Granted: March 26, 2002
Patent Number:
6362608
Multi-phase switching converters and methods that provide fast response and low ripple on the converter inputs and outputs. The converters include multiple converter stages that are normally operated in sequence into a common load. However upon sensing that operation of one of the converter stages does not bring the converter back into regulation, multiple converter stages are operated until regulation is reestablished, after which the converter stages are operated in sequence again. In…
System and method for optimal biasing of a telescopic cascode operational transconductance amplifier (OTA)
Granted: March 26, 2002
Patent Number:
6362688
A system and method of biasing a telescopic cascode operational transconductance amplifier is provided to prevent or reduce the likelihood that the inputs to the amplifier do exceed the input common mode voltage range for the amplifier. The system and method provides a bias control circuit for the differential input transistors and tail current transistor of the operational amplifier such that their respective Vds−Vdsat is maintained substantially constant. To accomplish this, the…
Method of modifying properties of deposited thin film material
Granted: March 19, 2002
Patent Number:
6358809
A method of modifying a layer of thin film composite material to achieve one or more desired properties for the thin film layer which cannot be achieved by heat treatment at all practical temperatures of operation allowable by particular integrated circuit processes. In particular, the thin film composite material is subjected to an ion implantation process. Depending on the doping species, the doping concentration, the doping energy, and other ion implantation parameters, one or more…
Switchable path power amplifier with combining network
Granted: March 19, 2002
Patent Number:
6359514
The present invention teaches a power amplifier having two output power devices and a mechanism for switching the output path between these two power devices. The first output power device is designed for power efficient signal amplification at the power amplifier's highest output power level. The second output power device is designed for power efficient signal amplification at the output power level that the power amplifier is most likely to operate. By switching between the two…
Dynamic element matching using current-mode butterfly randomization
Granted: March 19, 2002
Patent Number:
6359467
The present invention is a technique for dynamic element matching used in digital-to-analog converters (DAC's). An analog-to-digital converter (ADC) converts an analog signal into a digital code. A current-mode randomizer randomizes the digital code based on a control word provided by a pseudo random number generator. A digital-to-analog converter (DAC) converts the randomized digital code into an analog signal.
Linear regulators with low dropout and high line regulation
Granted: March 19, 2002
Patent Number:
6359427
Apparatus and method to provide high line regulation, which can be combined with a low dropout voltage, for linear regulators. The control for the regulators is referenced to ground rather than a relatively noisy power supply terminal so that the control is substantially free of power supply noise. The pass transistor forms the second transistor of a current mirror mirroring the current from the control. Referencing the control to ground and mirroring the control current to the pass…
Programmable electronic trim capacitor
Granted: March 12, 2002
Patent Number:
6356135
An electronically trimable capacitor (10) having a plurality of branch circuits (30) each including a capacitor (32) which may be selectively controlled by a switch (34) to contribute or not to the net capacitance exhibited by the trimable capacitor (10). Operation of the switches (34) is under direction of an interface (36), which can receive a program signal containing digital instruction for programming via a program terminal (22). An optional memory (38) permits storing a program of…
Averaging cell mismatches in integrated circuits
Granted: March 12, 2002
Patent Number:
6356225
An integrated circuit may include matched cells each having an active transconductor, wherein the matched cells are coupled together through respective active transconductor circuits to average the effect of comparator input-referred offsets. Each cell of the matched cells may have a first differential gain stage coupled to a second differential gain stage that is coupled to an output buffer stage, and an associated active transconductor circuit. The active transconductor of each cell is…
Direct-conversion tuner integrated circuit for direct broadcast satellite television
Granted: March 12, 2002
Patent Number:
6356736
A converter for the direct down-conversion of direct broadcast satellite signals such as those used for digital television. The direct broadcast satellite signal received from the satellite dish is amplified and then downshifted within the Low Noise Block (LNB), a subsystem contained with the satellite dish assembly, to a predetermined frequency band, typically in the L-band in the range 950 MHz to 2150 MHz. The signal is then sent via a coaxial cable to the set-top box unit located…
Hermetic packaging for semiconductor pressure sensors
Granted: March 5, 2002
Patent Number:
6351996
A hermetic media interface for a sensor package is disclosed. Preferably, the hermetic media interface is incorporated into a pressure sensor package for interfacing directly to fluid and/or gaseous media. In one embodiment, the pressure sensor package includes a semiconductor die and a pressure port that are housed in a pre-molded plastic package. A eutectic solder is coupled between the semiconductor die and the pressure port to solder the same to the semiconductor die. The…
Chip-scale packaged pressure sensor
Granted: February 12, 2002
Patent Number:
6346742
A chip-scale sensor package is described. In one embodiment, the chip-scale sensor package includes a semiconductor substrate having a sensor region, and a semiconductor cap having a recess. The semiconductor cap is bonded to the semiconductor substrate with a thermocompression bond to form a cavity therebetween. The semiconductor substrate is bonded to the semiconductor cap using different types of materials. The semiconductor substrate and/or the semiconductor cap may optionally…
Balanced input for temperature sensor
Granted: January 1, 2002
Patent Number:
6335661
A balanced input circuit which is used with an operational amplifier to obtain the difference between two input signals. In a temperature sensor application, one input signal is proportional to absolute temperature (PTAT) and one signal is complimentary to absolute temperature (CTAT) with the CTAT signal being the base-emitter voltage (Vbe) of a bipolar transistor. In this application the operational amplifier output is the PTAT signal minus Vbe times a scale factor determined by the…
