Abstract: A light-emitting diode (LED) tube including a ballast compatible buffer circuit for interfacing with a ballast circuit and for driving a light-emitting diode LED tube. The LED tube includes an LED driver circuit with first and second input terminals coupled to receive an ac input signal from the ballast circuit, an input rectifier circuit coupled to receive the ac input signal and output a rectified voltage signal, a switching regulator including a regulator switch controlled by a controller that regulates transfer of energy to the LED load through an energy transfer element and the ballast compatible buffer circuit.

Abstract: A circuit to be utilized for an LED driver bleeder activation. The circuit comprises a circuit block for timing a duration of any removed portion of a rectified line signal. The input of the circuit to be coupled to receive the phase controlled rectified line signal through a voltage divider. Comparing the divided rectified line signal with a threshold voltage and output a comparison result. A timer coupled to the comparator and responsive to the comparison result to time the duration of the removed portion of the rectified line signal and activate the bleeder activation circuitry to turn on the switching element of the bleeder to sink a controlled current from the input line.

Abstract: A circuit to be utilized for an LED driver bleeder activation. The circuit comprises a circuit block for timing a duration of any removed portion of a rectified line signal. The input of the circuit to be coupled to receive the phase controlled rectified line signal through a voltage divider. Comparing the divided rectified line signal with a threshold voltage and output a comparison result. A timer coupled to the comparator and responsive to the comparison result to time the duration of the removed portion of the rectified line signal and activate the bleeder activation circuitry to turn on the switching element of the bleeder to sink a controlled current from the input line.

Abstract: Enhanced active preload circuits for an LED driver implementing phase-angle dimming are disclosed. The enhanced active preload circuits may be used with any type of phase-angle control dimmer that either controls the leading edge or trailing edge of the line voltage cycle. In one example, the enhanced active preload circuitry may be used with an isolated or non-isolated LED driver converter having a Triac leading edge phase-angle control dimmer by directly sensing (e.g., by sensing the dimming level using an output/load voltage signal or output/load current signal) or indirectly sensing (e.g., by sensing a signal of output or bias winding) the Triac conduction angle. The enhanced active preload circuitry may advantageously improve performance of the LED driver by extending the dimming ratio at deep dimming and by adjusting the preload sinking current in response to a preload control signal.

Abstract: A low profile coil-wound bobbin includes a spool, a terminal, a lower flange, and a terminal base member. The spool is configured to have a coil-wire arrangement wound around an axis the spool. The terminal is to be coupled to the coil-wire arrangement and a first side of a circuit board such that the axis of the spool is substantially normal to the circuit board and the bobbin extends completely through the circuit board. The lower flange is coupled to the spool to at least partially contain the coil-wire arrangement. The terminal base member is coupled to the lower flange and the terminal. A vertical member of the terminal base member includes a chamfer region on a top edge of the vertical member to guide and reduce stress on a wire end of the coil-wire arrangement.

Abstract: Example methods include calculating a first number of turns of a shield winding included in an energy transfer element of a power supply. A first number of turns of the shield winding is calculated for the power supply to have a low noise current in an input conductor of the power supply. The method then includes increasing the first number of turns to a second number of turns. The power supply is then operated, which generates a first voltage waveform of a voltage between the input conductor and an output conductor of the power supply. An impedance is then inserted between the shield winding and the input conductor. The noise current is reduced by adjusting a value of the impedance until a second voltage waveform of the voltage between the input conductor and the output conductor reverses polarity to be the opposite of a polarity of the first voltage waveform.

Abstract: Example methods include calculating a first number of turns of a shield winding included in an energy transfer element of a power supply. A first number of turns of the shield winding is calculated for the power supply to have a low noise current in an input conductor of the power supply. The method then includes increasing the first number of turns to a second number of turns. The power supply is then operated, which generates a first voltage waveform of a voltage between the input conductor and an output conductor of the power supply. An impedance is then inserted between the shield winding and the input conductor. The noise current is reduced by adjusting a value of the impedance until a second voltage waveform of the voltage between the input conductor and the output conductor reverses polarity to be the opposite of a polarity of the first voltage waveform.

Abstract: A low profile coil-wound bobbin includes a spool, a terminal, a lower flange, and a terminal base member. The spool is configured to have a coil-wire arrangement wound around an axis the spool. The terminal is to be coupled to the coil-wire arrangement and a first side of a circuit board such that the axis of the spool is substantially normal to the circuit board and the bobbin extends completely through the circuit board. The lower flange is coupled to the spool to at least partially contain the coil-wire arrangement. The terminal base member is coupled to the lower flange and the terminal. A vertical member of the terminal base member includes a chamfer region on a top edge of the vertical member to guide and reduce stress on a wire end of the coil-wire arrangement.

Abstract: 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 and a shield impedance. The energy transfer element includes a shield winding having an end terminated externally to the energy transfer element. The shield impedance is coupled between the externally terminated end of the shield winding and an input conductor of the power supply, where the shield impedance has a non-zero finite impedance value to substantially reduce a noise current in the input conductor.

Abstract: 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 board to another side of the circuit board.

Abstract: 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 and a shield impedance. The energy transfer element includes a shield winding having an end terminated externally to the energy transfer element. The shield impedance is coupled between the externally terminated end of the shield winding and an input conductor of the power supply, where the shield impedance has a non-zero finite impedance value to substantially reduce a noise current in the input conductor.

Abstract: 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 board to another side of the circuit board.

Abstract: A thermal conduit to extract heat from an electrical component on a circuit board is disclosed. An electronic assembly according to aspects of the present invention includes an integrated circuit mounted on a circuit board and a thermal conduit having a first and a second portion. The first portion of the thermal conduit is thermally coupled to one or more electrical terminals of the integrated circuit through an opening defined in the circuit board while the second portion of the thermal conduit is thermally coupled to a first material of the circuit board.

Abstract: A thermal conduit to extract heat from an electrical component on a circuit board is disclosed. An electronic assembly according to aspects of the present invention includes an integrated circuit mounted on a circuit board and a thermal conduit having a first and a second portion. The first portion of the thermal conduit is thermally coupled to one or more electrical terminals of the integrated circuit through an opening defined in the circuit board while the second portion of the thermal conduit is thermally coupled to a first material of the circuit board.