Patents Assigned to Micrel, Inc.
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Patent number: 7750736Abstract: An integrated circuit system comprising: forming a differential amplifier including: forming a first transistor, coupling a second transistor to the first transistor in a high gain configuration, and coupling a third transistor, having a low gain configuration, in parallel with the second transistor; and adjusting a gain of the differential amplifier by adjusting a ratio of the size of the second transistor to the size of the first transistor.Type: GrantFiled: April 25, 2008Date of Patent: July 6, 2010Assignee: Micrel, Inc.Inventor: Philip W. Yee
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Patent number: 7746053Abstract: For testing an RF device, such as an RF receiver/decoder chip that receives an RF signal via an antenna terminal and outputs a digital code at an output terminal, an inexpensive non-RF programmable tester is used. The programmable tester is a commercially available tester that need only generate and receive non-RF digital and analog signals. The RF signals needed for the testing of the RF device are totally supplied by RF generators on a single printed circuit board, external to the commercial tester housing. The board contains controllable RF generating circuitry whose possible output amplitudes and frequencies need be only those necessary for testing the particular DUT. The frequencies may be changed by switching in different crystal resonators mounted on the board.Type: GrantFiled: August 26, 2008Date of Patent: June 29, 2010Assignee: Micrel, Inc.Inventors: Carlos E. Ribeiro, Douglas Falco
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Patent number: 7738519Abstract: A laser driver circuit includes a laser APC circuit receiving a monitor current indicative of the average optical output power of a laser diode and providing a bias adjust signal for adjusting a bias current for the laser diode. The laser APC circuit includes a first non-linear impedance circuit receiving the monitor current and generating a first voltage using a first non-linear current-to-voltage transfer function, a second non-linear impedance circuit receiving a reference current and generating a second voltage and being implemented using the same or a scaled version of the first non-linear current-to-voltage transfer function, and a comparator for comparing the first voltage with the second voltage and providing the bias adjust signal indicative of the difference between the first and second voltages. The first non-linear current-to-voltage transfer function has difference resistance portions for increasing the dynamic range of the current-to-voltage conversion.Type: GrantFiled: July 10, 2007Date of Patent: June 15, 2010Assignee: Micrel, Inc.Inventor: Thomas S. Wong
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Patent number: 7714640Abstract: An optimized output voltage circuit and technique obtainable without trimming is set forth. A voltage reference circuit and method devoid of trim resistors comprising a high gain amplifier, a plurality of bandgap resistors, and at least a plurality of bipolar devices interconnected across circuitry in a predetermined configuration having emitter areas greater than traditional emitter areas of traditional bipolar devices is set forth.Type: GrantFiled: February 15, 2008Date of Patent: May 11, 2010Assignee: Micrel, Inc.Inventor: S. M. Sohel Imtiaz
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Patent number: 7705655Abstract: An input buffer circuit. In one embodiment, the input buffer circuit includes a first transistor operable to receive a first input signal, a second transistor operable to receive a second input signal, and a first mechanism coupled to the first transistor and to the second transistor. The first mechanism is operable to control the first and second transistors such that the first and second transistors can receive either single-ended input signals or differential input signals. According to the embodiments disclosed herein, the input buffer combines single-ended input and differential input functionalities without compromising performance.Type: GrantFiled: September 18, 2006Date of Patent: April 27, 2010Assignee: Micrel, Inc.Inventor: Thomas S. Wong
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Publication number: 20100065906Abstract: A device for providing a high power, low resistance, efficient vertical DMOS device is disclosed. The device comprises providing a semiconductor substrate with a source body structure thereon. The device further comprises a plurality of slots in the source/body structure and providing a metal within the plurality of slots to form a plurality of structures. A slotted PowerFET array is disclosed. This slotted approach results in a dense PowerFET, a low Ron due to the slotted design, an oxide isolated process without any due extra steps other than the slots, lower capacitance, lower leakage, smaller die, improved heat transfer, improved electro-migration, lower ground resistance, less cross talk, drops the isolation diffusion and the sinker diffusion, mostly low temperature processing and provides double metal with single metal processing.Type: ApplicationFiled: November 19, 2009Publication date: March 18, 2010Applicant: MICREL, INC.Inventors: Martin ALTER, John Durbin HUSHER
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Patent number: 7675278Abstract: A method for operating a current limit power switch for supplying power to a load include activating the power switch to start supplying power to the load; limiting the current drawn by the power switch to a first current limit for a first, fixed duration; after the first, fixed duration, limiting the current drawn by the power switch to a second current limit for a second duration where the second current limit is less than the first current limit; and after the second duration, limiting the current drawn by the power switch to a third current limit where the third current limit is less than the second current limit.Type: GrantFiled: September 28, 2007Date of Patent: March 9, 2010Assignee: Micrel, Inc.Inventor: Hardik D. Patel
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Patent number: 7676537Abstract: A method in an integrated circuit for generating an address value having a contiguous address range from a first selection result and a second selection result each being an one-of-k selection result includes selecting multiple multiplication factors being power-of-two multiplication factors and the sum of the multiplication factors being equal to k; shifting the first selection result towards the most significant bit by each of the multiplication factors to generate multiple shifted input values where each shifted input value is shifted towards the most significant bit by one of the multiplication factors; adding the shifted input values and the second selection result; and generating the address value having a contiguous address range. The method can be extended to combine more than two selection results by applying the shifting and addition steps in a hierarchical manner.Type: GrantFiled: September 27, 2005Date of Patent: March 9, 2010Assignee: Micrel, Inc.Inventor: Peter Chambers
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Publication number: 20100052708Abstract: For testing an RF device, such as an RF receiver/decoder chip that receives an RF signal via an antenna terminal and outputs a digital code at an output terminal, an inexpensive non-RF programmable tester is used. The programmable tester is a commercially available tester that need only generate and receive non-RF digital and analog signals. The RF signals needed for the testing of the RF device are totally supplied by RF generators on a single printed circuit board, external to the commercial tester housing. The board contains controllable RF generating circuitry whose possible output amplitudes and frequencies need be only those necessary for testing the particular DUT. The frequencies may be changed by switching in different crystal resonators mounted on the board.Type: ApplicationFiled: August 26, 2008Publication date: March 4, 2010Applicant: MICREL, INC.Inventors: Carlos E. Ribeiro, Douglas Falco
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Publication number: 20100032753Abstract: A MOS transistor includes a conductive gate insulated from a semiconductor layer by a dielectric layer, first and second lightly-doped diffusion regions formed self-aligned to respective first and second edges of the conductive gate, a first diffusion region formed self-aligned to a first spacer, a second diffusion region formed a first distance away from the edge of a second spacer, a first contact opening and metallization formed above the first diffusion region, and a second contact opening and metallization formed above the second diffusion region. The first lightly-doped diffusion region remains under the first spacer. The second lightly-doped diffusion region remains under the second spacer and extends over the first distance to the second diffusion region. The distance between the first edge of the conductive gate to the first contact opening is the same as the distance between the second edge of the conductive gate to the second contact opening.Type: ApplicationFiled: October 13, 2009Publication date: February 11, 2010Applicant: MICREL, INC.Inventor: Martin Alter
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Patent number: 7659783Abstract: A phase-locked loop (PLL) to provide clock generation for high-speed memory interface is presented as the innovate PLL (IPLL). The IPLL architecture is able to tolerate external long loop delay without deteriorating jitter performance. The IPLL comprises in part a common mode feedback circuit with a current mode approach, so as to minimize the effects of mismatch in charge-pump circuit, for instance. The voltage-controlled oscillator (VCO) of the IPLL is designed using a mutually interpolating technique generating a 50% duty clock output, beneficial to high-speed double data rate applications. The IPLL further comprises loop filter voltages that are directly connected to each VCO cell of the IPLL. Conventional voltage-to-current (V-I) converter between loop filter and VCO is hence not required. A tight distribution of VCO gain curves is therefore obtained for the present invention across process corners and varied temperatures.Type: GrantFiled: July 16, 2007Date of Patent: February 9, 2010Assignee: Micrel, Inc.Inventor: Gwo-Chung Tai
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Publication number: 20100020798Abstract: A method in a network device implements source address filtering, including gateway address filtering, to enable network devices to be configured in a true Ethernet ring network. By implementing source address filtering or source address filtering with gateway address filtering, a true ring network can be formed using Ethernet protocols where all the links between the network devices in the ring are active paths while avoiding data packets being switched endlessly around the ring. In one embodiment, a data packet in the true ring network is terminated when the source address of the data packet matches the local address of the network device. In another embodiment, a data packet in the true ring network is terminated when the source address of the data packet matches the address of the gateway switch connected to the network device.Type: ApplicationFiled: July 25, 2008Publication date: January 28, 2010Applicant: MICREL, INC.Inventor: Michael Jones
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Publication number: 20100020809Abstract: A method in a network device configured in a true ring network where the network device has a first port and a second port connected to the true ring network and a third port connected to a processor including: connecting the network device to transmit data packets in a single direction around the true ring network including an ingress port and an egress port; enabling ingress tag VLAN filtering on the ingress port only; configuring a VLAN table in the network device to terminate an incoming data packet when a VID tag (VLAN identifier tag) of the incoming data packet matches the local VID tag of the network device; and configuring the VLAN table in the network device to accept the incoming data packet when the VID tag of the incoming data packet does not match the local VID tag of the network device.Type: ApplicationFiled: July 25, 2008Publication date: January 28, 2010Applicant: MICREL, INC.Inventors: Michael Jones, Chung Chen Luan
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Publication number: 20100008378Abstract: A method of generating frame receive interrupts in an Ethernet controller including receiving incoming data frames and storing data frames into a receive queue, monitoring the number of received data frames, and when the number of received data frames exceeds a first threshold, generating a frame receive interrupt. In another embodiment, the method further includes monitoring the amount of received data stored in the receive queue and generating a frame receive interrupt when the first threshold is exceeded and when the amount of received data stored in the receive queue exceeds a second threshold. In yet another embodiment, the method further includes monitoring the time duration of the data frames stored in the receive queue, and generating a frame receive interrupt when the number of received data frames exceeds the first threshold or when the time duration of the data frames stored in the receive queue exceeds a third threshold.Type: ApplicationFiled: July 8, 2008Publication date: January 14, 2010Applicant: MICREL, INC.Inventor: Chung Chen Luan
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Publication number: 20100007316Abstract: A current sense device for a power transistor is described. The power transistor is formed in a cellular structure including a cellular array of transistor cells. The current sense device includes multiple transistor cells in the cellular array of transistor cells of the power transistor being used as sense transistor cells. The sense transistor cells are evenly distributed throughout the cellular array where the source terminal of each sense transistor cell is electrically connected to a first node through a metal line in the first metal layer and through a metal line in the second metal layer where the metal lines are electrically isolated from the metal lines connecting the transistor cells of the power transistor. The sense transistor cells measure a small portion of the current flowing through the power transistor based on the size ratio of the current sense device and the power transistor.Type: ApplicationFiled: July 8, 2008Publication date: January 14, 2010Applicant: Micrel, Inc.Inventors: Ira G. Miller, Eduardo Velarde
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Publication number: 20100007363Abstract: The present invention relates generally to semiconductor wafer fabrication and more particularly but not exclusively to advanced process control methodologies for measuring in-line contact resistance in relation to oxide formations. The present invention, in one or more implementations, include an in-line method of determining contact resistance across a semiconductor wafer and determining the contact resistance value and the number of monolayers of the wafer.Type: ApplicationFiled: December 3, 2007Publication date: January 14, 2010Applicant: Micrel, Inc.Inventors: Miles DUDMAN, Andrew LE, Daniel ANDERSON
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Publication number: 20100011140Abstract: An Ethernet controller has a host interface for coupling to a host processor and a physical layer transceiver for coupling to a data network and includes multiple data objects having different access times where the data objects communicate with the host interface over an internal data bus. The Ethernet controller includes a data object interface module coupled between the host interface and the internal data bus where the data object interface module has a first access time for handling data requests for the data objects received on the host interface from the host processor, and a control logic circuit coupled to control the operation of the data object interface module. Data requests from the host processor for accessing data stored in the multiple data objects are carried out through the data object interface module using the first access time, regardless of the different access times of the multiple data objects.Type: ApplicationFiled: July 8, 2008Publication date: January 14, 2010Applicant: MICREL, INC.Inventor: Chung Chen Luan
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Patent number: 7645691Abstract: A method for forming an ohmic contact and a zener zap diode in an integrated circuit includes forming a first contact opening in the insulating layer over a first diffusion region to expose the semiconductor substrate; forming a barrier metal layer on the insulating layer and in the first contact opening; forming a second contact opening in the barrier metal layer over a second diffusion region and the insulating layer to expose the semiconductor substrate; forming a third contact opening in the barrier metal layer and the insulating layer over a third diffusion region to expose the semiconductor substrate; forming an aluminum layer on the barrier metal layer and the insulating layer and in the first, second and third contact openings; and patterning the aluminum layer to form the ohmic contact over the first diffusion region and the zener zap diode over the second and third diffusion regions.Type: GrantFiled: December 11, 2008Date of Patent: January 12, 2010Assignee: Micrel, Inc.Inventor: Schyi-yi Wu
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Patent number: 7646185Abstract: A synchronous switching regulator controller incorporates a switch detection circuit to determine the presence or absence of a power switch at the output of a switch driver so that the switch driver can be disabled when it is left unused. In one embodiment, the synchronous controller includes a switch detection circuit receiving a power cycle signal and the PWM ramp clock signal and measuring a voltage at an output node of the switch driver. The switch detection circuit provides a driver enable signal in response to the assertion of the power cycle signal. The driver enable signal has a first logical state when the voltage at the output node of the switch driver is greater than a reference voltage and a second logical state when the voltage at the output node is less than a reference voltage. The switch driver can be disabled based on the driver enable signal.Type: GrantFiled: August 25, 2006Date of Patent: January 12, 2010Assignee: Micrel, Inc.Inventor: Sang Hoon Kim
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Patent number: RE41207Abstract: A monolithic AM transmitter is disclosed. An external antenna forms part of a resonance network so that the antenna resonance point is automatically tuned to the transmit frequency. This provides flexibility with no added cost to the transmitter.Type: GrantFiled: January 13, 2006Date of Patent: April 6, 2010Assignee: Micrel, Inc.Inventors: Joseph S. Elder, Joseph T. Yestrebsky, Mohammed D. Islam