Method and apparatus for adjusting displacement current in an energy transfer element
Granted: April 10, 2012
Patent Number:
8154371
A method includes calculating a number of turns of a shield winding included in an energy transfer element of a power supply, where the calculating is to have a low noise current in an input conductor of the power supply. The method further includes: increasing the number of turns for the shield winding; operating the power supply; and adjusting a value of a shield impedance to substantially reduce the noise current. An apparatus includes a power supply having an energy transfer element…
Method and apparatus for time-differential comparison of an analog signal
Granted: April 10, 2012
Patent Number:
8154321
A time-differential analog comparator is disclosed. An example apparatus according to aspects of the present invention includes a source of a variable frequency signal having a frequency responsive to an analog input. A counting circuit is coupled to count cycles of the variable frequency signal. The counting circuit is coupled to count in a first direction for a first time interval and is coupled to count in a second direction opposite to the first direction for a second time interval…
Method and apparatus for a power supply controller responsive to a feedforward signal
Granted: April 3, 2012
Patent Number:
8148968
An apparatus and method of switching a switch of a power supply in response to an input voltage signal are disclosed. According to aspects of the present invention, a power supply controller includes a switch duty cycle controller coupled to receive a feedback signal and a duty cycle adjust signal. The switch duty cycle controller is coupled to generate a drive signal coupled to control switching of a switch, which is coupled to an energy transfer element, to regulate energy delivered…
Method and apparatus to limit output power in a switching power supply
Granted: March 27, 2012
Patent Number:
8143875
An example integrated circuit controller for a power supply includes a modulator, a drive signal generator, a comparator, and a variable current limit generator. The modulator generates an enable signal having logic states responsive to a feedback signal. The drive signal generator either enables or skips enabling a switch of the power supply during a switching period in response to the logic state of the enable signal. The comparator asserts an over current signal to disable the switch…
Electronic circuit control element with tap element
Granted: March 27, 2012
Patent Number:
8144484
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…
Apparatus and method for sensing of isolated output
Granted: March 27, 2012
Patent Number:
8144487
A controller for use in a power converter providing sensing of an isolated output is disclosed. An example controller includes a current controller to be coupled to an energy transfer element and an input of the power converter. A control circuit is included that generates a mode select signal coupled to be received by the current controller. A first, second or third current is enabled in the current controller in response to a selection of a first, second or third mode of operation,…
Method and apparatus for pulse width modulation
Granted: March 20, 2012
Patent Number:
8138810
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…
Method and apparatus for input charge control of a power supply
Granted: March 20, 2012
Patent Number:
8139384
An example controller includes a constant current control circuit and an integrator included in the constant current control circuit. The constant current control circuit is to be coupled to receive an input current sense signal, an input voltage sense signal, and an output voltage sense signal. The control circuit is adapted to regulate an output current of a power supply by generating a control signal to control switching of a switch. The integrator is coupled to integrate the input…
Electrostatic discharge conducting pathway having a noise filter spark gap
Granted: March 13, 2012
Patent Number:
8134817
A printed circuit board includes a primary region, a secondary region and an isolation region disposed between the primary region and the secondary region to galvanically isolate the primary region from the secondary region. The primary region is to be coupled to an AC source. The primary region also includes an electrostatic discharge (ESD) conducting pathway to redirect current to the AC source that crosses the isolation region. A spark gap is included in the ESD conducting pathway to…
Forward converter transformer saturation prevention
Granted: March 6, 2012
Patent Number:
8130517
A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, logic circuits and saturation prevention circuits. The saturation prevention circuits assert a first signal when a first integral value of the input voltage reaches a first threshold value and assert a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a…
High-voltage transistor device with integrated resistor
Granted: March 6, 2012
Patent Number:
8129815
A high-voltage device structure comprises a resistor coupled to a tap transistor that includes a JFET in a configuration wherein a voltage provided at a terminal of the JFET is substantially proportional to an external voltage when the external voltage is less than a pinch-off voltage of the JFET. The voltage provided at the terminal being substantially constant when the external voltage is greater than the pinch-off voltage. One end of the resistor is substantially at the external…
Temperature independent reference circuit
Granted: February 28, 2012
Patent Number:
8125265
A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the…
Method and apparatus for increasing the power capability of a power supply
Granted: February 28, 2012
Patent Number:
8125801
Techniques are disclosed to extend an on time period of switch to regulate a transfer of energy from an input of a power supply to an output of a power supply. One example integrated circuit includes an energy transfer element coupled between an input and an output of the power supply. A switch is coupled to the input of the energy transfer element. A controller is coupled to the switch to control switching of the switch to regulate a transfer of energy from the input of the power supply…
Method and apparatus for controlling a circuit with a high voltage sense device
Granted: February 21, 2012
Patent Number:
8120097
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 for implementing a power converter input terminal voltage discharge circuit
Granted: February 14, 2012
Patent Number:
8115457
A circuit to discharge a capacitance between input terminals of a power system is disclosed. An example circuit includes a control circuit coupled to an input of a power system. The control circuit is coupled to detect whether an electrical energy source is coupled to an input of the power system. A switch is also included and is coupled to the control circuit and to the input of the power system. The control circuit is coupled to drive the switch in a first operating mode when the…
Method and apparatus for a high voltage power supply circuit
Granted: February 14, 2012
Patent Number:
8115465
A power converter is disclosed. An example power converter includes an energy transfer element coupled between a power converter input and a power converter output. A power switch is coupled to the energy transfer element. A control circuit is coupled to receive a feedback signal representative of the power converter output during a feedback portion of an off time of the power switch. The control circuit is coupled to generate an output signal in response to the feedback signal. The…
Method and apparatus to select a parameter/mode based on a measurement during an initialization period
Granted: February 14, 2012
Patent Number:
8116106
Techniques are disclosed to select functional parameters and/or operating modes of a circuit based on a measurement during an initialization period. In one aspect an integrated circuit includes a threshold detection circuit coupled to measure during an initialization period of the integrated circuit a signal from a first external circuit comprising one or more components coupled to a first external terminal of the integrated circuit. A selection circuit is coupled to the threshold…
Power factor correction converter control offset
Granted: January 24, 2012
Patent Number:
8102164
Power factor correction converter control offset apparatus and methods are disclosed. In one aspect, an apparatus includes a control unit to generate a control signal to control a duty cycle of a PWM (Pulse Width Modulation) switching signal that controls a switch in a PFC (Power Factor Correction) converter. An offset unit is also included and is coupled to the control unit, to generate a variable offset signal to offset the control signal or a signal used by the control unit to…
Low profile coil-wound bobbin
Granted: January 24, 2012
Patent Number:
8102237
A low profile coil-wound bobbin is disclosed. A low profile coil-wound bobbin includes a spool and a terminal. The spool is configured to have a coil-wire arrangement wound around the spool. The terminals are to be coupled to the coil-wire arrangement and a first side of a circuit board. The terminal is configured to mechanically and/or electrically couple the low profile coil-wound bobbin to the first side of the circuit board such that the low profile bobbin extends through the circuit…
Phase angle measurement of a dimming circuit for a switching power supply
Granted: January 24, 2012
Patent Number:
8102683
An example controller for a switched mode power supply includes a zero-crossing detector, a feedback reference circuit, and a drive signal generator. The zero-crossing detector is coupled to generate a zero-crossing signal representative of a length of time that a zero-crossing condition of an input voltage of the power supply exists. The feedback reference circuit is to be coupled to receive a feedback signal and a reference signal, where the feedback signal is representative of an…
