Leakage compensation for sample and hold devices
Granted: June 29, 2010
Patent Number:
7746119
A sample and hold circuit in one aspect includes first and second switches. The first switch can be coupled to receive an input signal and to sample the input signal using a first capacitor. A first leakage current flows between first and second conductive terminals of the first switch and accumulates as a first leakage charge in the first capacitor. A second leakage current flows between the first and second conductive terminals of the second switch and accumulates as a second leakage…
Method and apparatus for controlling the maximum output power of a power converter
Granted: June 29, 2010
Patent Number:
7746050
A controller for a power converter is disclosed. An example circuit controller according to aspects of the present invention includes an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter. A current sensor is also included and is to be coupled to sense a current flowing in a power switch. A drive signal generator is to be coupled to drive the power switch into an on state for an on time period and an off state for an…
Gate metal routing for transistor with checkerboarded layout
Granted: June 8, 2010
Patent Number:
7732860
In one embodiment, a transistor fabricated on a semiconductor die is arranged into sections of elongated transistor segments. The sections are arranged in rows and columns substantially across the semiconductor die. Adjacent sections in a row or a column are oriented such that the length of the transistor segments in a first one of the adjacent sections extends in a first direction, and the length of the transistor segments in a second one of the adjacent sections extends in a second…
Method and apparatus to reduce audio frequencies in a switching power supply
Granted: June 8, 2010
Patent Number:
7733673
A controller for use in a power supply regulator is disclosed. One controller includes a feedback circuit coupled to generate an equivalent switching frequency signal in response to a sense signal from a power supply regulator output. A comparator is coupled to compare the equivalent switching frequency signal with a reference signal. A period modulation circuit is coupled to the feedback circuit to generate a period modulation switching signal in response to the equivalent switching…
Method and apparatus to reduce maximum power from a power supply with transition region regulation
Granted: June 1, 2010
Patent Number:
7728572
Techniques are disclosed to regulate the output power of a power supply. An example technique for regulating a power supply output includes regulating in response to a feedback signal an output current of a power supply in a regulated current region of operation if an output voltage of the power supply is less than a second transition voltage. The output voltage and the output current of the power supply are regulated in a transition region current region of operation in response to the…
Variable inductive power supply arrangement for cold cathode fluorescent lamps
Granted: May 25, 2010
Patent Number:
7723929
A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second inductor inductively coupled to the first inductor, and an AC switch for selectively shorting the second inductor. A capacitor in parallel with the first inductor forms a resonant circuit tuned to…
Graphical interface for configuring a power supply controller
Granted: May 18, 2010
Patent Number:
7721213
Information for configuring control apparatus for a power system including a plurality of controlled power supplies is produced using a graphical interface which displays the topology and sequencing of the power supplies in the power system. A database is used to select power supplies to add in determining the power system topology. Sequencing is represented by displacing icons representing the power supplies along lines representing their input and output voltages, and arrows…
Method and apparatus providing final test and trimming for a power supply controller
Granted: May 4, 2010
Patent Number:
7710705
A power supply controller having final test and trim circuitry. In one embodiment, a power supply controller for switched mode power supply includes a selector circuit, a trim circuit, a shutdown circuit and a disable circuit. The trim circuit includes a programmable circuit connection that can be selected by the selector circuit by toggling a voltage on an external terminal such as for example a power supply terminal, a control terminal or a function terminal of the power supply…
Power supply output voltage trimming
Granted: April 27, 2010
Patent Number:
7705570
A power supply trim control signal is produced by integrating differences between monitored and target values of the output voltage of a power supply. Register storage requirements are reduced by producing the target value from a nominal voltage value and one of a plurality of margin offsets selected in accordance with control data. The control data also selects between open and closed loop trim control. Stability is enhanced by changing the target value slowly in response to any change…
Method and apparatus for reducing audio noise in a switching regulator
Granted: April 20, 2010
Patent Number:
7701186
A switching regulator utilizing on/off control that reduces audio noise at light loads by adjusting the current limit of the switching regulator. In one embodiment, a switching regulator includes a state machine that adjusts the current limit of the switching regulator based on a pattern of feedback signal values from the output of the power supply for a preceding N cycles of the drive signal. The state machine adjusts the current limit lower at light loads such that cycles are not…
Method and apparatus for controlling a circuit with a high voltage sense device
Granted: April 13, 2010
Patent Number:
7696566
A control circuit with a high voltage sense device. In one embodiment, a circuit includes a first transistor disposed in a first substrate having first, second and third terminals. A first terminal of the first transistor is coupled to an external voltage. A voltage provided at a third terminal of the first transistor is substantially proportional to a voltage between the first and second terminals of the first transistor when the voltage between the first and second terminals of the…
Method and apparatus to control two regulated outputs of a flyback power supply
Granted: March 9, 2010
Patent Number:
7675761
A flyback power supply method and apparatus is disclosed. An apparatus according to aspects of the present invention includes an energy transfer element having a primary winding and first and second output windings. The first and second output windings are coupled to produce first and second output values, respectively. A primary switch is coupled to the primary winding. A control circuit is coupled to the primary switch to regulate a sum of the first and second output values. A steering…
Transformer data coupler with high common mode immunity
Granted: March 9, 2010
Patent Number:
7675978
A data coupler includes a transformer having primary and secondary windings, a data transmitter coupled to the primary winding of the transformer, and a data receiver coupled to the secondary winding. The data transmitter includes a first driver and a second driver having outputs coupled to respective ends of the primary winding. The first driver is responsive to a data signal and the second driver is responsive to a delayed version of the data signal, such that the primary winding is…
Method and apparatus for robust mode selection with low power consumption
Granted: February 23, 2010
Patent Number:
7667518
A low power method and apparatus for selecting operational modes of a circuit. One circuit according to the teachings of the disclosed method and apparatus includes a first current limiting circuit coupled between a selector terminal and a first voltage bus. The first current limiting circuit is adapted to vary a current limit out of the selector terminal in response to a voltage on the selector terminal. The circuit also includes a second current limiting circuit coupled between the…
Output feedback and under-voltage detection system
Granted: February 16, 2010
Patent Number:
7663852
A switched mode controller for properly handling an under-voltage condition in a power line which includes a current mirror for receiving current from the power line; a reference current source coupled to the current mirror for supplying a reference current; and a power transistor coupled to the reference current source, the power transistor generating a pulse width modulated signal when current from the power line exceeds the reference current, the power transistor being disabled when…
Method and apparatus for sensing a current in a circuit
Granted: February 2, 2010
Patent Number:
7656304
Techniques are disclosed to sense a current in a circuit. For instance, current sense circuit according to the teachings of the present invention includes a current sense resistor coupled to an input of the current sense circuit. The current sense resistor is coupled to receive a current to be sensed from the input of the current sense circuit. The current to be sensed is converted to a current sense voltage. A first PN junction diode is coupled to the current sense resistor. A light…
High-voltage vertical transistor with a multi-gradient drain doping profile
Granted: January 19, 2010
Patent Number:
7648879
A high-voltage transistor includes first and second trenches that define a mesa in a semiconductor substrate. First and second field plate members are respectively disposed in the first and second trenches, with each of the first and second field plate members being separated from the mesa by a dielectric layer. The mesa includes a plurality of sections, each section having a substantially constant doping concentration gradient, the gradient of one section being at least 10% greater than…
Method and apparatus for maintaining a constant load current with line voltage in a switch mode power supply
Granted: January 12, 2010
Patent Number:
7646184
A power supply including a regulation circuit that maintains an approximately constant load current with line voltage. In one embodiment, a regulation circuit includes a semiconductor switch and current sense circuitry to sense the current in the semiconductor switch. The current sense circuitry has a current limit threshold. The regulation circuit current limit threshold is varied from a first level to a second level during the time when the semiconductor switch is on. One embodiment of…
Electronic circuit control element with tap element
Granted: December 22, 2009
Patent Number:
7636247
A technique for controlling a power supply with power supply control element with a tap element. An example power supply control element includes a power transistor that has first and second main terminals, a control terminal and a tap terminal. A control circuit is coupled to the control terminal. The tap terminal and the second main terminal of the power transistor are to control switching of the power transistor. The tap terminal is coupled to provide a signal to the control circuit…
Method and apparatus for pulse width modulation
Granted: December 8, 2009
Patent Number:
7629823
An apparatus and method of providing a pulse width modulated signal that is responsive to a current are disclosed. A circuit according to aspects of the present invention includes a capacitor to convert a first current to a first voltage on the capacitor during a first time duration and to discharge a second current from the capacitor to change the first voltage to a second voltage during a second time duration. A comparator is also included and is coupled to an output of the capacitor…
