Patent application number | Description | Published |
20100283517 | CHARGE PUMP FOR PHASE LOCKED LOOP - A charge pump includes a charge pump core circuit having a first current source transistor, a second current source transistor and an output terminal ( | 11-11-2010 |
20110169553 | TEMPERATURE COMPENSATED CURRENT REFERENCE CIRCUIT - A temperature compensated current reference circuit has a differential amplifier and a first feedback transistor with a gate coupled to the differential amplifier output. The first feedback transistor couples a supply voltage line to an inverting input of the differential amplifier. There is also a second feedback transistor with a gate coupled to the differential amplifier output, which couples the supply voltage line to a non-inverting input of the differential amplifier. A first temperature dependent conductor couples the inverting input to ground. A primary reference resistor and a second temperature dependent conductor are connected in series and couple the non-inverting input to ground. An output current control transistor has a gate and one other electrode coupled together and a third electrode coupled to the supply voltage line. A secondary reference resistor and a conductivity change sensing transistor are connected in series and couple the gate of the output current control transistor to ground. The conductivity change sensing transistor has a gate coupled to the second one of the two differential inputs. There is a temperature compensation current reference output circuit that has a current reference transistor, an input coupled to the differential amplifier output and another input is coupled to the gate of the output current control transistor. | 07-14-2011 |
20110215849 | CHARGE PUMP FOR PHASE LOCKED LOOP - A charge pump includes a charge pump core circuit having a first current source transistor, a second current source transistor and an output terminal ( | 09-08-2011 |
20120033772 | SYNCHRONISER CIRCUIT AND METHOD - A synchronizer circuit and method for transferring data between mutually asynchronous source and destination clock domains. An input synchronizer cell clocked at an input clock frequency receives input data from the source domain and produces a corresponding intermediate signal. A frequency divider produces a divided clock signal whose frequency is equal to the input clock frequency divided by an integer. An output synchronizer module comprises first and second cascaded synchronizer cells clocked at the divided clock frequency, receives the intermediate signal and produces a corresponding output signal for the destination clock domain. | 02-09-2012 |
20120176169 | DIGITAL PHASE LOCKED LOOP WITH REDUCED SWITCHING NOISE - A method to operate a digital phase locked loop (DPLL) in which the DPLL includes a phase-frequency detector that compares the frequency of a reference signal with a feedback signal to generate an error signal. The error signal is used to generate first and second control words. Binary current control word bits and thermometric current control word bits are generated using the first and second control words, respectively. A binary controller switches a first set of binary current sources prior to a frequency lock being achieved using the binary current control word bits and the thermometric current control word bits are held at a predetermined value. After achieving the frequency lock, the binary current sources are fixed and then a thermometric controller switches a second set of thermometric current sources using the thermometric current control word bits. Operating the DPLL using the binary controller before the frequency lock and the thermometric controller after the frequency lock reduces switching noise and achieves stable loop dynamics. | 07-12-2012 |
20120249198 | DUAL LOOP PHASE LOCKED LOOP WITH LOW VOLTAGE-CONTROLLED OSCILLATOR GAIN - A dual loop PLL for generating an oscillator signal initially operates in a digital loop to achieve a frequency lock between an input reference signal and a feedback signal and then the PLL operates in an analog loop to achieve a phase lock. After attaining the phase lock, the analog loop is used to maintain the phase lock across frequency and phase variation due to changes in temperature and supply. | 10-04-2012 |
20120319788 | RELAXATION OSCILLATOR WITH LOW POWER CONSUMPTION - A relaxation oscillator for generating oscillator signal includes a ramp voltage generating circuit, a reference voltage generating circuit, a reference voltage switching circuit, and a digital logic circuit. The reference voltage generating circuit generates one or more reference voltages and the ramp voltage generating circuit generates one or more ramp voltages. The ramp voltages are compared with each of the reference voltages by sequentially switching the reference voltages using a reference voltage switching signal generated by the reference voltage switching circuit. The oscillator signal is generated by the digital logic circuit based on the results of the comparisons. | 12-20-2012 |
20140015509 | BANDGAP REFERENCE CIRCUIT AND REGULATOR CIRCUIT WITH COMMON AMPLIFIER - A bandgap voltage reference and voltage regulator system includes a bandgap voltage reference circuit and a voltage regulator circuit that share a single, common amplifier. The amplifier acts as a gain stage for the reference circuit and as an error amplifier for a driver stage of the regulator circuit. The regulator circuit has an input reference generated by the reference circuit, and the reference circuit acts as a load to the driver stage, obviating the need for a bias resistance network. By sharing the amplifier and obviating the need for a resistance network, the area and overall quiescent current of the system are reduced. The system can be implemented in CMOS/BiCMOS technology and is suited for low power applications. | 01-16-2014 |
20140118078 | RELAXATION OSCILLATOR - A relaxation oscillator for generating an output clock signal includes a RC circuit, a bias generation stage, first and second comparator stages, and a logic circuit. The RC circuit generates first and second comparator input signals that are transmitted to the first and second comparator stages. The bias generation stage generates first and second bias voltages that are provided to each of the first and second comparator stages. The first and second comparator stages generate first and second comparator output signals, respectively, based on the first and second comparator input signals and the first and second bias voltages. The first and second comparator output signals are provided to the logic circuit that generates the output clock signal. | 05-01-2014 |
20140139201 | LOW-POWER VOLTAGE TAMPER DETECTION - Systems and methods for low-power voltage tamper detection are described. In some embodiments, an integrated circuit may include source-follower circuitry configured to produce a scaled down supply voltage. The integrated circuit may also include undervoltage detection circuitry coupled to the source-follower circuitry, the undervoltage detection circuitry configured to output a first signal having a first logic value if the scaled down supply voltage is greater than a low threshold voltage or a second logic value if the scaled down supply voltage is smaller than the low threshold voltage. Additionally or alternatively, the integrated circuit may include overvoltage detection circuitry coupled to the source-follower circuitry, the overvoltage detection circuitry configured to output a second signal having the first logic value if the scaled down supply voltage is smaller than a high threshold voltage or the second logic value if the scaled down supply voltage is greater than the high threshold voltage. | 05-22-2014 |
20140197806 | CAPACITOR CHARGING CIRCUIT WITH LOW SUB-THRESHOLD TRANSISTOR LEAKAGE CURRENT - A capacitor charging circuit has input, output and control nodes, first and second series connected primary FETs, and first and second leakage current reduction FETs. All of the FETs have their gates coupled to the control node. The first primary FET is coupled between the input and output nodes, and the second primary FET is coupled between the output node and a leakage current reduction node. The first leakage current reduction FET is coupled between a supply line and the leakage current reduction node, and the second leakage current reduction FET is coupled between the leakage current reduction node and ground. When a control signal at the control node is low, the first primary FET and the first leakage current reduction FET are conductive, and the second primary FET and the second leakage current reduction FET are non-conductive, which eliminates sub-threshold leakage current flowing through the second primary FET. | 07-17-2014 |
20140210564 | RELAXATION OSCILLATOR WITH SELF-BIASED COMPARATOR - A relaxation oscillator for generating an output clock signal includes an RC circuit, a self-biased comparator stage, and a logic circuit. The RC circuit generates first and second comparator input signals that are provided to the self-biased comparator stage. The self-biased comparator stage includes first and second input stages and a voltage reference circuit. Each of the first and second input stages in conjunction with the voltage reference circuit forms a comparator, i.e., first and second comparators corresponding to the first and second input stages, respectively. The self-biased comparator stage generates first and second comparator output signals, based on the first and second comparator input signals. The first and second comparator output signals are provided to the logic circuit that generates the output clock signal. | 07-31-2014 |