Temperature measurement with interleaved bi-level current on a diode and bi-level current source therefor
Granted: November 23, 1999
Patent Number:
5990725
Temperature measurement with interleaved bi-level current on a diode and bi-level current source therefor which provides a very accurate ratio of measurement currents through the diode without calibration and despite process and temperature variations. The bi-level current source uses a plurality N of individual current sources wherein the higher current is comprised of the sum of the N individual current sources and the lower current is comprised of one of the individual current…
Filter circuits for protecting against transient electrical pulses
Granted: November 23, 1999
Patent Number:
5990723
The present invention teaches a variety of filter circuits for protecting against transient electrical pulses such as those caused by electrostatic discharge (ESD) events. One aspect of the present invention teaches an integrated circuit package having primary circuitry, an ESD protection device, a filter circuit, and a conductive lead arranged to couple a point external to the integrated circuit package to a point internal to the integrated circuit package. The ESD device, coupled in…
Digital calibration for analog-to-digital converters with implicit gain proration
Granted: November 2, 1999
Patent Number:
5977894
A method of digital calibration for analog-to-digital converters providing implicit gain proration. In accordance with the method, the calibration begins at the center of the transfer curve rather from one end or the other. By beginning in the center, calibrating in the positive direction and then calibrating in the negative direction, the interstage gain errors are also corrected without an extra gain-proration cycle. In addition, the number of accumulated measurements is reduced by a…
Reverse current throttling of a MOS transistor
Granted: October 5, 1999
Patent Number:
5963067
The invention is a means for ensuring full current flow in the "forward" direction in a MOS transistor, and substantially reducing (and/or eliminating) current flow in the "reverse" direction. The forward voltage drop and reverse current are controllable and are determined by ratios of device size. In one embodiment, the present invention is a circuit coupled to an output stage transistor having an output voltage thereon to ensure current flow in one direction and to throttle current…
Low drop-out switching regulators
Granted: September 21, 1999
Patent Number:
5955872
A method for generating, in a switching power supply, an output voltage from an input voltage. The method includes the step of closing a switch in the switching power supply to permit current from the input source to flow through the inductor and the capacitor of the switching power supply, thereby building up an inductor current through the inductor and increasing the output voltage across the capacitor. If a combination of the output voltage and inductor current is satisfactory at the…
Gain enhancement for operational amplifiers
Granted: September 14, 1999
Patent Number:
5952882
Operational amplifiers with a gain enhancement apparatus and method result in a substantial improvement in the gain of such amplifiers without change in the gain of the signal amplifying transistors. The gain enhancement is achieved by providing a circuit for having one transistor in the folded cascode stage of the amplifier substantially track the operating conditions of another transistor in the folded cascode stage, thereby substantially eliminating the unbalanced differential drive…
Folded-cascode amplifier stage
Granted: May 25, 1999
Patent Number:
5907262
An amplifier circuit that offers high bandwidth operation and a high slew rate is disclosed. The amplifier circuit may also have an input voltage swing down to the negative rail which is particularly suitable for low voltage applications having a single power source. In one embodiment, the amplifier circuit amplifies a difference voltage between first and second input voltages to produce an output voltage, and includes: an analog voltage-to-current converter for receiving the first and…
Method and apparatus for enabling a step-up or step-down operation using a synchronous rectifier circuit
Granted: May 18, 1999
Patent Number:
5905368
A circuit for controllably coupling an input to an output. The circuit includes: (1) a pass transistor having an emitter, a collector and a base, the emitter being coupled to the input, the collector being coupled to the output; (2) a second transistor coupled to the pass transistor, and biased to operate with a collector-to-base voltage approximately equal to zero; and (3) a control circuit coupled to the input, the output and the base of the pass transistor, the control circuit…
Hybrid differential pairs for flat transconductance
Granted: May 11, 1999
Patent Number:
5903185
Hybrid differential pairs and methods of their hybridization by connecting and operating in parallel a degenerated differential pair with a multitanh. Proper matching of the degenerated differential pair and the multitanh results in higher linearity levels than can be attained with either approach individually. Also, the hybrid benefits from reduced process variation when compared with prior multitanh solutions. Increased gain, increased linearity, reduced noise and reduced supply…
Variable gain amplifier with improved linearity and bandwidth
Granted: April 20, 1999
Patent Number:
5896063
A variable gain amplifier having improved bandwidth and linearity, and having improved dynamic range by allowing the amplifier to be designed for low noise performance, while retaining the linearity normally lost with low noise designs. The amplifier is of the current steering type, having a differential current steering input stage coupled to a further current steering stage for controlling the gain responsive to a gain control signal. Current is maintained in a pair of common base…
Reset methods and apparatus for microcontrollers having bidirectional reset lines
Granted: April 13, 1999
Patent Number:
5894240
Method and apparatus for use in a microcontroller based system for detecting an active reset followed by the release of the reset line, and upon the release of the reset line, rapidly driving the reset line of the system to the inactive state to prevent the microcontroller from falsely interpreting the reset line voltage level as being a non-microcontroller initiated reset. The reset line is then released, after a short time delay so as to not interfere with any succeeding reset signal.
Switch-mode regulators and methods providing transient response speed-up
Granted: March 30, 1999
Patent Number:
5889392
Switch-mode regulators and methods providing transient response speed-up in the presence of large load transients. Speed-up is achieved by coupling a first MOSFET switch between the regulator output and the input voltage and a second MOSFET switch between the regulator output and the circuit common connection. During normal operation these MOSFETs are off, but in the event of a large load transient substantially disturbing the regulator output, one of the MOSFETs is momentarily turned on…
High speed semiconductor laser driver circuits
Granted: March 16, 1999
Patent Number:
5883910
A semiconductor laser driver circuit that provides single supply operation over a wide supply voltage range (e.g., 3 V to 5.5 V), is capable of high speed data transmission, and is programmable over a wide laser modulation current range (such as 5 mA to 60 mA). The circuit includes temperature sensitive circuits to adjust for changes in Vbe over the operating temperature range, and to adjust a bias current to maintain transistor g.sub.m in the presence of temperature changes. Also…
Rail-to-rail operational amplifier and method for making same
Granted: March 9, 1999
Patent Number:
5880638
Disclosed is an operational amplifier having a positive input terminal, a negative input terminal, an output terminal, a positive power supply input and a negative power supply input. The operational amplifier includes a transistor input pair being coupled to the positive input terminal and the negative input terminal. A first charge pump being coupled to positive supply circuitry contained within the operational amplifier. The first charge pump being configured to operate the positive…
Power level sense circuit
Granted: February 9, 1999
Patent Number:
5869986
A power level sense circuit which is substantially immune to variations in integrated circuit processing and operating temperature. The sense circuit uses a diode biased to a predetermined average conduction level as the primary element in an envelope detector to detect the envelope of the RF transmit signal. While the DC offset of the diode will vary with temperature and integrated circuit processing, the DC offset is eliminated by an auto zeroing procedure before each power sensing…
Dual interleaved DC to DC switching circuits realized in an integrated circuit
Granted: February 9, 1999
Patent Number:
5870296
Dual interleaved DC to DC switching circuits realizable in an integrated circuit form, capable of monitoring individual inductor current using only one current sense resistor and providing automatic duty cycle adjustment to keep the inductor currents in the interleaved DC to DC switching circuits balanced. The preferred embodiment includes a gain error amplifier, an integral error amplifier, and a differentiator error amplifier and circuits for controlling the nominal duty cycle, with…
Process tolerant NMOS transistor for electrostatic discharge protection
Granted: December 29, 1998
Patent Number:
5854504
An improved ESD cell provides in the worst case 2,000 volts HBM ESD protection using an NMOS transistor in a lightly-doped drain process. An NMOS transistor has its source connected to ground, and its drain connected through a polysilicon resistor to a pad of an integrated circuit. The pad is also connected by metal to an n+ pocket tap of an n-type epitaxial layer formed on a p-type substrate. The connection of pad metal to the pocket tap forms a second parasitic lateral bipolar junction…
Laser modulation control method and apparatus
Granted: December 15, 1998
Patent Number:
5850409
Laser modulation control apparatus and methods which provide direct control of the transmitted optical extinction ratio of a semiconductor laser. A relatively low frequency and low amplitude pilot tone is superimposed on the signal used to drive the laser. Setting the amplitude of the pilot tone to a fixed fraction of the laser modulation current causes the transmitted optical power to vary a fixed fraction of the optical data amplitude at the pilot tone frequency. By using feedback to…
Method and electronic device for reducing transition time of transistor switching circuits
Granted: October 13, 1998
Patent Number:
5821803
The present invention teaches a variety of electrical devices and methods for connecting a switch such as a transistor to decrease a voltage drop across an electrical coupling connecting the switch's source with a gate driver regulating operation of the switch, the voltage drop due, at least in part, to a change in current flowing through the switch. Decreasing the voltage drop from the switch's source to the gate driver tends to improve the operational characteristics of the switch. One…
Low drop out switching regulator
Granted: September 29, 1998
Patent Number:
5814979
A method for generating, in a switching power supply, an output voltage from an input voltage. The method includes the step of closing a switch in the switching power supply to permit current from the input source to flow through the inductor and the capacitor of the switching power supply, thereby building up an inductor current through the inductor and increasing the output voltage across the capacitor. If a combination of the output voltage and inductor current is satisfactory at the…
