Bandgap reference circuits with isolated trim elements
Granted: December 9, 2008
Patent Number:
7463012
A bandgap reference circuit utilizes differential transistors to generate a temperature-independent bandgap voltage. In place of conventional trim elements that are connected in parallel to and adjust the resistance values of the bandgap reference circuit, current control circuits are placed in the current paths passing through the differential transistors (i.e., connected to the critical nodes located at the terminals of the differential transistors). Each current control circuit…
Single poly BiCMOS flash cell with floating body
Granted: November 11, 2008
Patent Number:
7449754
A BiCMOS integrated circuit (IC) includes a floating gate-type non-volatile memory (NVM) device that uses the polycrystalline silicon gate of a CMOS FET and the P-base and N-emitter diffusions of a bipolar transistor to provide an isolated P-type body and N-type source/drain diffusions. The P-body diffusion of the NVM device is isolated from a P-substrate by an N-well, thus facilitating the use of reduced positive and negative voltage levels to produce the onset of Fowler-Nordheim…
Lateral programmable polysilicon structure incorporating polysilicon blocking diode
Granted: October 28, 2008
Patent Number:
7443008
A programmable element includes a diode and a programmable structure formed in a polysilicon layer isolated from a semiconductor substrate by a dielectric layer. The diode includes a first region and a second region of opposite conductivity types. The programmable structure includes a third region and a fourth region of opposite conductivity types. The first region of the diode and the third region of the programmable structure are electrically connected. In operation, the programmable…
Constant on-time regulator with increased maximum duty cycle
Granted: October 28, 2008
Patent Number:
7443148
A buck switching regulator receives an input voltage and provides a switching output voltage on a switch output node using a minimum on-time, variable off-time feedback control loop. The buck switching regulator includes an on-time control circuit for generating a first signal for turning off the high-side switch at the expiration of a first on-time duration or at the expiration of a maximum on-time. The first on-time duration is at least a minimum on-time and is allowed to expand to a…
Light emitting diode driver circuit with high-speed pulse width modulated current control
Granted: October 21, 2008
Patent Number:
7439945
A Light-Emitting Diode (LED) driver circuit is disclosed that controls the brightness of light generated by a LED that is coupled between a first terminal and a second terminal in response to a user supplied brightness control signal. A constant current source generates a constant current that is supplied to the LED and to a shunt circuit, which his connected in parallel with the LED. A brightness control circuit generates a pulse signal having a duty cycle that is proportional to the…
Buck-boost control logic for PWM regulator
Granted: October 7, 2008
Patent Number:
7432689
A PWM regulator is operated either a buck mode or a boost mode depending on whether the input voltage is above or below the desired regulated output voltage. The technique uses two sawtooth ramps 180 degrees out of phase. Where the two ramps cross each other is a buck/boost transition level. An error voltage, corresponding to a required duty cycle to achieve a regulated voltage, is compared to the two ramps. The transition from one mode to the other occurs when the error voltage passes…
Ethernet network implementing redundancy using a single category 5 cable
Granted: October 7, 2008
Patent Number:
7433302
A method for providing redundancy in a daisy chain local area network employing Category 5 cabling for connecting network devices uses the normally unused twisted wire pairs in the single Cat 5 cable connecting adjacent network devices. The method includes forming in each network device a passive signal path connecting pins of an upstream port associated with the normally unused twisted wire pairs of the Cat 5 cable to pins of a downstream port associated with the normally unused twisted…
Automatic control of laser diode current and optical power output
Granted: September 9, 2008
Patent Number:
7423247
An automatic power control system provides a control signal that regulates the output power of at least one laser diode. Coarse adjustment of the control signal is provided by a first means, preferably a digital variable resistor, while fine adjustment and compensation is provided by a second means, preferably by a digital-to-analog converter that receives an input signal proportional to a sensed control system parameter. The control system includes an operational amplifier having a…
System and method for monitoring serially-connected devices
Granted: September 9, 2008
Patent Number:
7424348
A monitoring system comprising a plurality of devices, each including a shift register and a status register. The plurality of shift registers are coupled in a serial chain. The monitoring engine is configured to receive status information from the shift registers and monitor status of the connected devices. The monitoring engine has the capability to monitor fault and persistence counts for analog and digital artifacts. A method for monitoring a plurality of devices coupled in a serial…
PFM and current controlled switching regulator
Granted: August 26, 2008
Patent Number:
7417879
A circuit and method for controlling a switching regulator utilize a combination of variable off-time control (or frequency control) and variable peak current control to achieve high efficiency at a wide range of load conditions. A non-linear control circuit receives an error voltage and generates a first control signal for controlling a frequency control circuit and a second control signal for controlling a peak current control circuit. The frequency control circuit and the peak current…
Test mode for pin-limited devices
Granted: August 19, 2008
Patent Number:
7415647
A pin-limited device includes a pattern-recognition circuit that detects a predetermined signal pattern transmitted on a supply pin of the device. The predetermined signal pattern is generated within the acceptable operating voltage range of the IC device (e.g., between the minimum and maximum acceptable system voltage levels utilized to control the internal circuitry of the device). Accordingly, the pin-limited IC device continues to operate within specifications while the predetermined…
Intelligent soft start for switching regulators
Granted: August 5, 2008
Patent Number:
7408332
A circuit, method, and system for intelligently soft starting switching regulators are provided. The circuit, method, and system provide for a switching circuit operable to couple an input voltage to an output of the switching regulator in response to a control signal, a controller operable to generate the control signal to control the switching of the switching circuit based in part on a reference voltage, and a soft start circuit operable to provide the reference voltage to the…
AC coupling system for wide band digital data with dynamic AC load
Granted: August 5, 2008
Patent Number:
7408994
An interface system couples a fixed impedance device to a receiver for transmitting data signals at different data rates at different times. The interface system includes elements that are connected to provide different time constants of responsiveness to data signals of higher and lower data rates without distorting the data signals beyond usability.
Transmitter power level optimization and error correction technique
Granted: July 8, 2008
Patent Number:
7398101
A master transceiver automatically lowers its transmit power level at intervals until a slave transceiver no longer accurately receives the transmitted data. When the master detects an inaccurate transfer of data, the master incrementally increases the transmit power level until it is determined that there has been an accurate transfer of data. At that time, the master transmits an acknowledge signal to the slave. Since the automatic power adjust routine is performed using the…
Time constant based fixed parameter assignment
Granted: July 1, 2008
Patent Number:
7394729
A method for assigning a value to a fixed parameter in an electrical device where the fixed parameter has multiple states includes associating a time value to each state of the fixed parameter, driving a first input terminal of the electrical device to a first voltage value, receiving an input ramp signal on the first input terminal where the input ramp signal has a first time constant value and a voltage magnitude that varies from the first voltage value to a second voltage value,…
Numerical value conversion using a saturation limited arithmetic logic unit supporting variable resolution operands
Granted: July 1, 2008
Patent Number:
7395287
A device for performing numerical value conversion of a digital input value in a first unit to a second, natural unit where the digital input value is a digitized value of a first measurement parameter includes a look-up table storing an array of coefficients for performing the numerical value conversion for multiple measurement parameters. The look-up table is indexed using a first parameter indicative of the first measurement parameter to provide a selected coefficient. The device…
Analog internal soft-start and clamp circuit for switching regulator
Granted: May 27, 2008
Patent Number:
7378827
An analog soft-start circuit for a switching regulator (e.g., a buck converter) including an analog ramp circuit and an open-loop analog voltage clamp circuit. The voltage ramp circuit utilizes a two-stage current divider circuit to generate a very low, stable current signal, and an integrator circuit including a relatively small, integral capacitor to generate the ramp voltage signal in response to the very low current signal. The analog voltage clamp circuit clamps the regulated output…
Numerical value conversion using a look-up table for coefficient storage
Granted: May 6, 2008
Patent Number:
7370069
A device for performing numerical value conversion of a digital input value in a first unit to a second unit being a natural unit includes a look-up table storing an array of coefficients for performing the numerical value conversion. The look-up table is indexed using a first parameter to provide a selected coefficient. An arithmetic logic unit (ALU) is coupled to receive the digital input value and the selected coefficient and perform the numerical value conversion based on a first…
Amplifier turn-on speedup technique
Granted: April 15, 2008
Patent Number:
7358804
A method of reducing the settling time of an amplifier includes providing a pre-set voltage on a high gain node of the amplifier when the amplifier is disabled. This pre-set voltage can be slightly less than the regulated voltage. In this manner, when the amplifier is enabled, the high gain node can quickly reach this regulated voltage. The pre-set voltage can be applied to the high gain node by operating a switch, e.g. if the amplifier is enabled (disabled), then the switch is open…
Non-volatile memory cells
Granted: March 25, 2008
Patent Number:
7348621
A non-volatile memory cell and method of fabrication are provided. The non-volatile memory cell includes a substrate of a first conductivity type, a first dopant region of a second conductivity type in the substrate, a second dopant region of the first conductivity type in the first dopant region, a first isolation region overlaying a portion of the substrate, the first dopant region, and the second dopant region, a second isolation region overlaying another portion of the substrate, the…
