Sample and hold buffer
Granted: January 6, 2015
Patent Number:
8929102
This relates to sampling a feedback signal representative of an output of a power converter. The sampling is performed using a buffer sampling circuit having three sample and hold stages coupled in series to sense and store the feedback signal. The first stage is coupled to sample and hold the feedback signal on a capacitor. If the output diode is conducting, the sampled signal is transferred to the second stage. If the output diode is conducting, the first stage will sample the feedback…
Damper circuit for switched dimming
Granted: January 6, 2015
Patent Number:
8928235
A power converter includes dimmer circuit, a rectifier circuit, and a thyristor damper circuit. The dimmer circuit provides a dimmer voltage in response to an input voltage. The rectifier circuit provides a rectified voltage in response to the dimmer voltage. The thyristor damper circuit dampens an input current associated with the rectified voltage based on the input current and ceases dampening the rectified voltage based on the rectified voltage.
Vertical junction field effect transistors and diodes having graded doped regions and methods of making
Granted: January 6, 2015
Patent Number:
8928074
Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs) or diodes such as junction barrier Schottky (JBS) diodes or PiN diodes. The devices have graded p-type semiconductor layers and/or regions formed by epitaxial growth. The methods do not require ion implantation. The devices can be made from a wide-bandgap semiconductor material such as silicon carbide (SiC) and can be used in high temperature and high power…
Heterostructure power transistor with AlSiN passivation layer
Granted: January 6, 2015
Patent Number:
8928037
A heterostructure semiconductor device includes a first active layer and a second active layer disposed on the first active layer. A two-dimensional electron gas layer is formed between the first and second active layers. An AlSiN passivation layer is disposed on the second active layer. First and second ohmic contacts electrically connect to the second active layer. The first and second ohmic contacts are laterally spaced-apart, with a gate being disposed between the first and second…
Pulse width modulator with two-way integrator
Granted: December 30, 2014
Patent Number:
8922290
An example PWM includes a driver and a two-way oscillator. The oscillator includes, a first frequency adjust current source, a second frequency adjust current source, a capacitor, a switching reference and a comparator. The capacitor integrates a frequency adjust current by charging with the first frequency adjust current source. The capacitor subsequently integrates a second frequency adjust current by discharging with the second frequency adjust current source. The switching reference…
MOSFET having a JFET embedded as a body diode
Granted: December 23, 2014
Patent Number:
8916929
A field effect transistor, in accordance with one embodiment, includes a metal-oxide-semiconductor field effect transistor (MOSFET) having a junction field effect transistor (JFET) embedded as a body diode.
Method and apparatus to regulate an output voltage of a power converter at light/no load conditions
Granted: December 16, 2014
Patent Number:
8913407
An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit compares a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit outputs a switching signal having a switching period to control a switch to regulate an output of the power converter in response to the feedback signal and enables or disables a…
Feed forward imbalance corrector circuit
Granted: December 9, 2014
Patent Number:
8907577
A circuit includes an input to be coupled to receive a rectified line voltage having a controlled conduction phase angle in each half line cycle. An active device is coupled to a feedback terminal of a controller. The feedback terminal is coupled to receive a feedback signal representative of an output of a power supply. The active device includes a control terminal coupled to receive a signal representative of the input. The active device is coupled to adjust the feedback signal on the…
Method and apparatus for implementing an unregulated dormant mode with an event counter in a power converter
Granted: December 9, 2014
Patent Number:
8908395
An example power converter includes an energy transfer element, a switch, and a control circuit. The control circuit includes a drive signal generator and an unregulated dormant mode control circuit. The unregulated dormant mode control circuit renders dormant the drive signal generator thereby ceasing the regulation of the output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive…
Method and apparatus for regulating an additional output of a power converter
Granted: December 9, 2014
Patent Number:
8908391
An example post regulator controller for use in a power converter having a regulated output and an additional output is disclosed. The post regulator controller includes an inductor to be coupled between the regulated output of the power converter and a post regulator switch of the power converter. The inductor is to be coupled to drive the post regulator switch with an induced voltage across the inductor to redirect energy from the regulated output to the additional output of the power…
Vertical junction field effect transistors with improved thermal characteristics and methods of making
Granted: November 11, 2014
Patent Number:
8884270
Vertical junction field effect transistors (VJFETs) having improved heat dissipation at high current flow while maintaining the desirable specific on-resistance and normalized saturated drain current properties characteristic of devices having small pitch lengths are described. The VJFETs comprise one or more electrically active source regions in electrical contact with the source metal of the device and one or more electrically inactive source regions not in electrical contact with the…
Method and apparatus for controlling the maximum output power of a power converter
Granted: October 28, 2014
Patent Number:
8872500
An example control circuit for use in a power converter includes an input voltage sensor, a current sensor, and a drive signal generator. The input voltage sensor generates a first signal representative of an input voltage (Vin) of the power converter. The current sensor generates a second signal representative of a switch current through a power switch of the power converter. The drive signal generator generates a drive signal to control switching of the power switch in response to the…
Method and apparatus to control a power converter having a low loop bandwidth
Granted: October 21, 2014
Patent Number:
8867240
A controller for use in a power converter includes a comparator coupled to receive a signal representative of an output of the power converter. A counter is coupled to an output of the comparator to sample the output of the comparator a plurality of times within a period. A state machine is coupled to an output of the counter to control switching of the power converter according to one of a plurality of operating condition states in response to the output of the counter. The state…
High-voltage transistor device with integrated resistor
Granted: October 21, 2014
Patent Number:
8866201
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…
Half-bridge circuits employing normally on switches and methods of preventing unintended current flow therein
Granted: October 14, 2014
Patent Number:
8860494
A method for rendering a half-bridge circuit containing normally on switches such as junction field effect transistors (JFETs) inherently safe from uncontrolled current flow is described. The switches can be made from silicon carbide or from silicon. The methods described herein allow for the use of better performing normally on switches in place of normally off switches in integrated power modules thereby improving the efficiency, size, weight, and cost of the integrated power modules.…
Optically controlled silicon carbide and related wide-bandgap transistors and thyristors
Granted: October 7, 2014
Patent Number:
8853710
An optically active material is used to create power devices and circuits having significant performance advantages over conventional methods for affecting optical control of power electronics devices and circuits. A silicon-carbide optically active material is formed by compensating shallow donors with the boron related D-center. The resulting material can be n-type or p-type but it is distinguished from other materials by the ability to induce persistent photoconductivity in it when…
Delta-sigma modulator with high input impedance
Granted: September 30, 2014
Patent Number:
8847805
Measurement circuits having a delta-sigma modulator are disclosed. One example measurement circuit includes a low pass filter coupled to receive an input voltage, a switched-capacitor integrator circuit, and a switched comparator circuit. The measurement circuit may generate a digital output made up of a sequence of logic high and logic low levels that are representative of a scaled value of the input voltage output by the low pass filter circuit. Also, by virtue of its…
Enhanced active preload for high performance LED driver with extended dimming
Granted: September 9, 2014
Patent Number:
8829819
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…
Compact digital-to-analog converter
Granted: September 9, 2014
Patent Number:
8830102
An example digital-to-analog converter includes a reference scaling circuit receiving a first reference current and generating a second reference current. A first plurality of current sources is coupled to a summing node with a current of a first one of the first plurality of current sources proportional to the first reference current. A current of a second one of the first plurality of current sources is substantially equal to twice the current of the first one of the first plurality of…
Controller compensation for frequency jitter
Granted: September 9, 2014
Patent Number:
8829875
A controller for use in a power supply includes a drive signal generator, a jitter signal generator, a compensator signal generator, and an arithmetic operator. The drive signal generator is coupled to output a drive signal in response to an input signal. The jitter signal generator is coupled to provide a jitter signal that is representative of a first percentage amount to modulate a switching period of the drive signal. The compensator signal generator is coupled to provide a…
