Micrel Patent Grants

Field effect transistor with trench-isolated drain

Granted: August 23, 2011
Patent Number: 8004039
A MOS transistor includes a body region of a first conductivity type, a conductive gate and a first dielectric layer, a source region of a second conductivity type formed in the body region, a heavily doped source contact diffusion region formed in the source region, a lightly doped drain region of the second conductivity type formed in the body region where the lightly doped drain region is a drift region of the MOS transistor, a heavily doped drain contact diffusion region of the…

Method of accurate prediction of electrostatic discharge (ESD) performance in multi-voltage environment

Granted: July 26, 2011
Patent Number: 7987085
The present invention relates generally to semiconductor wafer fabrication and more particularly but not exclusively to predictive, pre-fabrication methodologies for determining inefficiencies in an integrated circuit (IC) design. The present invention, in one or more implementations, provides an effective pre-production methodology for predicting the efficiency and behavior of a designed ESD protective circuit and testing the ESD protective circuit with a simulated IC. The method of the…

System and method for matching silicon oxide thickness between similar process tools

Granted: July 19, 2011
Patent Number: 7983776
The present invention is one or more implementations is a method of fabricating a semiconductor for improved oxide thickness control, defining a process tool, determining and evaluating performance variables, determining a performance impact factor and thereafter modifying control of the process tool in the fabrication process to operate in direct relation to the determined results of the present invention. The present invention sets forth definitive advantages in reducing engineering…

Chip-scale package conversion technique for dies

Granted: July 12, 2011
Patent Number: 7979813
A method is described for converting an existing die, originally designed for a non-chip-scale package, to a chip-scale package die, where the die's bonding pads are located in positions within a defined grid of candidate positions. In the first step, the die's layout, comprising its outer boundaries and areas needed to be electrically connected to bonding pads, are shifted relative to a grid of candidate positions for the bonding pads until an optimal alignment is identified. Bonding…

Dynamic queue memory allocation with flow control

Granted: July 5, 2011
Patent Number: 7974190
A method in an Ethernet controller for allocating memory space in a buffer memory between a transmit queue (TXQ) and a receive queue (RXQ) includes allocating initial memory space in the buffer memory to the RXQ and the TXQ; defining a RXQ high watermark and a RXQ low watermark; receiving an ingress data frame; determining if a memory usage in the RXQ exceeds the RXQ high watermark; if the RXQ high watermark is not exceeded, storing the ingress data frame in the RXQ; if the RXQ high…

Diode having high breakdown voltage and low on-resistance

Granted: June 14, 2011
Patent Number: 7960754
A Schottky or PN diode is formed where a first cathode portion is an N epitaxial layer that is relatively lightly doped. An N+ buried layer is formed beneath the cathode for conducting the cathode current to a cathode contact. A more highly doped N-well is formed, as a second cathode portion, in the epitaxial layer so that the complete cathode comprises the N-well surrounded by the more lightly doped first cathode portion. An anode covers the upper areas of the first and second cathode…

Single chip radio receiver with decoder and controllable baseband filter

Granted: June 14, 2011
Patent Number: 7962117
A single chip receiver is disclosed herein. The chip only requires an external antenna for operation. A decoder is formed on chip for performing logical operations on demodulated digital data. A baseband filter is controlled by external control signals to have one of a plurality of discrete frequency response bandwidths depending on the type of signal to be received. To compensate for process variations in the implementation of the IC, bias currents setting the operating conditions for…

Laser turn-on accelerator independent of bias control loop bandwidth

Granted: May 10, 2011
Patent Number: 7940823
An accelerator circuit is incorporated in a laser diode system for accelerating the turn-on operation of the laser diode independent of the control loop bandwidth of the laser diode system. The accelerator circuit provides a boost current to a compensation capacitor upon laser turn-on which compensation capacitor operates to establish the control loop bandwidth of the laser diode system. The boost current enables the control loop to increase the bias current to the laser diode quickly.…

Automatic clock and data alignment

Granted: April 5, 2011
Patent Number: 7921321
A circuit is described for automatically adjusting a phase of an input register load clock to be synchronized with transitions of data bits forming an n-bit word. The circuit detects the first transition of a data bit in the n-bit word. The circuit then time-shifts the input clock, to generate a shifted clock, so that a triggering edge of the shifted clock occurs sometime after generation of the transition detect signal, such as in the middle third of a data cycle. Shifting the input…

PON burst mode receiver with fast decision threshold setting

Granted: April 5, 2011
Patent Number: 7920798
A receiver converts an analog signal, derived from light pulses in a GPON fiber optic system, to clean digital electrical signals. A photodetector and transimpedance amplifier (TIA) convert the light pulses to analog electrical signals. A reset signal generated by a media access controller (MAC) in the GPON system signifies the start of a new burst of data. The receiver has a switchable low pass filter that establishes the threshold voltage for determining whether the analog signal is a…

Boost LED driver not using output capacitor and blocking diode

Granted: April 5, 2011
Patent Number: 7919928
An LED driver is disclosed that boosts an input voltage to drive any number of LEDs in series. The driver includes a switch-mode current regulator that supplies regulated current pulses to the LEDs. No high voltage output capacitor is used to smooth the current pulses, so the LEDs are turned on any off at the switching frequency. Also, no blocking diode between the switching transistor and the LEDs is used. The cathode of the “bottom” LED in the string is connected to ground via a…

Controlling current through serial LEDs using a low voltage transistor when using a high voltage driver

Granted: February 1, 2011
Patent Number: 7880404
Various circuits are described herein where a series transistor used to control current through a string of LEDs, driven by a high voltage, is not subjected to the high voltage when the transistor is turned off pursuant to a PWM signal. To avoid the transistor experiencing the high voltage, the HV regulator is disabled shortly before the transistor is turned off and is enabled shortly after the transistor has turned back on. Control circuits for controlling the regulator and transistor…

Overcurrent protection circuit when setting current using a package control pin

Granted: February 1, 2011
Patent Number: 7881031
An overcurrent protection circuit for a current setting circuit is disclosed herein that prevents a user-selectable current from exceeding a current limit when an incorrect current selecting component (or current selecting circuit) is connected to an external control pin of a package by the user, or when the control pin is inadvertently grounded. The protection circuit senses a current (A1*Iset) mirrored from the user-set current (Iset). If the mirrored current is above a threshold, the…

Power budget management in power over ethernet systems

Granted: January 4, 2011
Patent Number: 7865754
A power budget monitoring circuit in a multi-port PSE includes a differential amplifier and a transistor for setting a reference voltage across a first resistor to establish a reference current, multiple current mirror output devices each associated with a power port of the PSE, a second resistor and a comparator. Each current mirror output device provides an output current indicative of the power demanded by the associated power port where the output currents are summed at a second node…

Voltage regulation system

Granted: December 28, 2010
Patent Number: 7859236
A voltage regulation system is provided including detecting a feedback voltage less than a reference voltage; asserting a current source gate output by the feedback voltage less than the reference voltage; activating a gated current source by the current source gate output; and waiting a delay interval before negating the current source gate output for turning off the gated current source.

Fast settling radio receiver automatic gain control system

Granted: December 14, 2010
Patent Number: 7853224
A fast settling AGC system includes a “fast settle” comparator that facilitates fast settling of strong radio receiver output signals from a maximum to an intermediate voltage level at the start of each transmission burst, and a “normal” AGC comparator that further settles the output signal from the intermediate voltage level to a desired target output voltage level at a slower “normal” rate. The gain control signal components generated by both the “fast settle”…

Seal ring for mixed circuitry semiconductor devices

Granted: November 30, 2010
Patent Number: 7843019
In mixed-component, mixed-signal, semiconductor devices, selective seal ring isolation from the substrate and its electrical potential is provided in order to segregate noise sensitive circuitry from electrical noise generated by electrically noisy circuitry. Appropriate predetermined sections of such a mixed use chip are isolated from the substrate through a non-ohmic contact with the substrate without compromising reliability of the chip's isolation from scribe region contamination.

LED driver circuits and methods

Granted: November 30, 2010
Patent Number: 7843147
An LED driver circuit may include dimming circuitry. In particular, the LED driver circuit may include a switching converter, an LED and a switch. The LED may be electrically connected to the switching converter and the switch may be connected in parallel with the LED. The switching converter and/or the switch may be configured to be controlled to achieve dimming of the LED. Current may be supplied to the LED and the switch may be turned on and off to dim the LED. The switching converter…

Driving multiple parallel LEDs with reduced power supply ripple

Granted: November 30, 2010
Patent Number: 7843148
An LED driver is disclosed that drives LEDs connected in parallel. Instead of applying current to all the parallel-connected LEDs at the same time, under control of a common PWM brightness control signal, the application of current to each parallel path is staggered by using staggered brightness control signals. The turning on of the LEDs in the different parallel paths will have the same duty cycle but will be out of phase. This reduces ripple in the power supply by reducing the…

Data slicer reference generator for multiple burst data signals

Granted: November 16, 2010
Patent Number: 7835470
A slice level reference generator and method for performing improved data slicing operations when gaps are present in a data stream is disclosed that involves applying a nominal reference signal to the comparator the during signal gaps. In one embodiment, a receiver circuit includes a slice level detector and a comparator that operate in a conventional manner, and control circuitry that utilizes a signal detector and a switch to store a slice level reference signal generated by the slice…