Second order intermodulation canceller
Granted: July 9, 2013
Patent Number:
8483646
A technique for cancelling out target IM2 components in a wireless receiver's mixer output is disclosed. A differential RF signal and a differential local oscillator (LO) signal are mixed by a mixer to demodulate the RF signal. A first common node signal is generated between a first resistor and a second resistor coupled across the mixer's differential output terminals. A second common node signal is generated between a third resistor and a fourth resistor coupled across the differential…
System and methods to improve the performance of semiconductor based sampling system
Granted: July 9, 2013
Patent Number:
8482442
Circuits and methods that improve the performance of electronic sampling systems are provided. Impedances associated with sampling semiconductor switches are maintained substantially constant during sample states, at least in part, by compensating for encountered input signal variations in order to reduce or minimize signal distortion associated with sampled signals that pass through the sampling switch.
Current controlled fast low-side clamp
Granted: May 21, 2013
Patent Number:
8446203
A low side clamp circuit has a control portion, a sense portion, and a clamp portion. When the sense portion detects that the input voltage of an output stage of a buffer has gone below a threshold voltage, it triggers the control portion to quickly turn on a clamp transistor (in the clamp portion) to clamp the output voltage to the clamp voltage. The control portion and sense portion have cross-coupled transistors that create increased speed and a sharp response with little or no…
Current sensor using leadframe as sensing element
Granted: May 21, 2013
Patent Number:
8446159
A current sensor is disclosed. The current sensor includes a leadframe having a die paddle, a portion of the die paddle being configured as a resistive element through which current can flow, and an integrated circuit (IC) die attached and thermally coupled to the die paddle. The IC die includes a current sensing module configured to measure a voltage drop across the resistive element and convert the voltage drop measurement to a current measurement signal and a temperature compensation…
DC/DC converter having a fast and accurate average current limit
Granted: April 16, 2013
Patent Number:
8421432
Three modifications are provided to obtain a fast and accurate average current limit in a DC/DC converter. The first modification relates to providing a bias signal control configured to apply a variable DC bias signal to the compensation ramp signal generated in the DC/DC converter so that the compensating ramp signal is biased to zero at the end of each ON-time for each cycle so that the peak current limit is independent of the duty cycle of the pulse width modulation signal during…
Method and system for minimum output-voltage battery charger
Granted: March 26, 2013
Patent Number:
8405362
An apparatus and method for a portable device incorporating a battery and a battery charger. In the portable device, there are a plurality of system components configured to facilitate a plurality of functions that the portable device is designed to perform. The battery in the portable device is configured for providing an internal power supply to the plurality of system components in the absence of an external input power supply. The battery charger is configured for charging the…
Method and circuit for encoding and transmitting numerical values from an analog-to-digital conversion process
Granted: March 5, 2013
Patent Number:
8390497
An analog-to-digital converter system and methodology comprising an analog-to-digital converter circuit configured to provide sequentially a plurality of codes designating a numerical value in a first number system. The analog-to-digital converter system further comprising an encoder interface circuit configured to receive the plurality of codes and to derive a redundant digital representation. A portion of the redundant digital representation is transmitted during the conversion period.…
Circuit, trim and layout for temperature compensation of metal resistors in semi-conductor chips
Granted: March 5, 2013
Patent Number:
8390363
A temperature compensation circuit for generating a temperature compensating reference voltage (VREF) may include a Bandgap reference circuit configured to generate a Bandgap reference voltage (VBGR) that is substantially temperature independent and a proportional-to-absolute-temperature reference voltage (VPTAT) that varies substantially in proportion to absolute temperature. The circuit may also include an operational amplifier that is connected to the Bandgap reference circuit and…
Extending achievable duty cycle range in DC/DC forward converter with active clamp reset
Granted: February 26, 2013
Patent Number:
8385087
Novel system and methodology are provided for controlling a DC/DC forward converter having a transformer with primary and secondary windings, a reset switch, and a first switch coupled to the primary winding of the transformer. The control system involves a PWM control circuit responsive to an output signal of the converter for producing a PWM signal to control switching of the reset switch, and the first switch. A period of the PWM signal includes an on-time interval for enabling…
Paralleling voltage regulators
Granted: February 19, 2013
Patent Number:
8378657
Circuits and methods for paralleling voltage regulators are provided. Improved current sharing and regulation characteristics are obtained by coupling control terminals of the voltage regulators together which results in precise output voltages and proportional current production. Distributing current generation among multiple paralleled voltage regulators improves heat dissipation and thereby reduces the likelihood that the current produced by the voltage regulators will be temperature…
Third order intermodulation cancellation for RF transconductors
Granted: February 12, 2013
Patent Number:
8373503
A mixer in an RF demodulator includes a transconductance amplifier that converts an RF input voltage (Vin), applied to the base of a first bipolar transistor, to a first output current. The first output current contains third order intermodulation (IM3) products. An IM3 canceller is connected in parallel with the transconductance amplifier. The base of a second bipolar transistor in the IM3 canceller is coupled to the DC component of Vin, and the AC component of Vin is coupled to the…
Continuously switching buck-boost control
Granted: February 5, 2013
Patent Number:
8368365
A buck-boost converter with a switch controller may cause switches A, B, C, and/or D to cyclically close such that switches B and C are closed during at least one interval of each cycle during both the buck and boost modes of operation. The switch controller may in addition or instead cause switches A, B, C, and/or D to cyclically close based on a control signal such that switches A and D are closed during an interval of each cycle and such that these intervals are never both…
DC/DC converter overcurrent protection
Granted: January 1, 2013
Patent Number:
8345391
A DC/DC converter and a method protect a MOSFET driven by the converter from overcurrent conditions. No extra pins are required to sense the current, which saves IC package area and cost.
Current steering circuit with feedback
Granted: December 11, 2012
Patent Number:
8330633
A differential current steering (CS) circuit uses feedback from the differential output nodes A and B to cause current steering devices (e.g., MOSFETs) to effectively exhibit an infinite output impedance when conducting. Therefore, the signal on the output nodes A or B does not significantly change the voltage at the common node, This is particularly useful when the differential output nodes are connected to differential output buses in a digital-to-analog converter. The circuit…
Capacitively coupled switched current source
Granted: December 4, 2012
Patent Number:
8324957
A current source is switchable between two precisely defined output currents. A terminal of a coupling capacitor is coupled to the gate of an output MOSFET. The other terminal of the capacitor is switched between two reference voltages to toggle the output MOSFET to output the selected one of the two currents. A switchable bias voltage source is coupled to the gate only during the on state of the output MOSFET to set the gate voltage of the output MOSFET. The current output of the…
Extending input to output voltage range in multiple channel switching regulator applications
Granted: November 27, 2012
Patent Number:
8319485
Novel circuitry and methodology for operating a multiple channel switching regulator system to extend an input to output voltage ratio by setting individual constant switching frequencies to switching regulator channels. In the switching regulator system having at least first and second switching regulators, a first clock circuit supplies a first clock signal at a first clock frequency to define a switching frequency of one of the first and second switching regulators. A second clock…
Analog sampler with reduced input current
Granted: November 27, 2012
Patent Number:
8319527
Methods and systems for analog to digital converter and systems incorporating the same are provided. Specifically, an analog sampler that has a reduced input current is disclosed. According to the present teaching, an apparatus for sampling an input voltage includes a first switch having its first terminal connected to an input voltage, and a first pre-charging circuit, coupled to a second terminal of the first switch, that provides a first pre-charged voltage that is substantially equal…
Charge pump with reduced current variation
Granted: November 27, 2012
Patent Number:
8319545
Circuits and methods for maintaining a substantially constant input and output current for a charge pump circuit are provided which reduce current variation during switching intervals. The charge pump circuitry of the present invention maintains a current flow path from a current source to the charge pump output which minimizes or eliminates spikes normally associated with the switching intervals.
Method and system for improving limiting amplifier phase noise for low slew-rate input signals
Granted: November 27, 2012
Patent Number:
8319551
Apparatus and method for a limiting amplifier with improved phase noise. The improved limiting amplifier includes an input port, an output port, and one or more cascaded gain stages. The input of a first gain stage is connected to the input port of the limiting amplifier. The output of a last gain stage is connected to the output port of the limiting amplifier. Among the cascaded gain stages, an output of each gain stage is connected to an input of an adjacent gain stage. Each gain stage…
A/D converter with compressed full-scale range
Granted: November 27, 2012
Patent Number:
8319673
An embodiment of an analog-to-digital converter system is described wherein an analog voltage signal Vin(t) is provided by an input amplifier. The analog signal Vin(t) has a predetermined full-scale range that is less wide than a reference voltage (Vref) range used by a downstream ADC to derive a first digital (numerical) representation D1(k) of a sampled value Vin(k) of the analog signal Vin(t). The first digital representation has N bits. A digital circuit then converts the N-bit D1(k)…
