Abstract: To determine the temperature of a link capacitor (C) of a link converter (1) more accurately with less expenditure, a device and a method are described, in which the link capacitor (C) is modeled as a series interconnection of an equivalent capacitance (CS) and an equivalent series resistance (ESR), wherein a modeled capacitor current (iCm) flows across the equivalent series resistance (ESR). A modeled capacitor power loss (PC), from which the capacitor temperature (TC) is determined by means of a specified temperature model, is calculated from the modeled capacitor current (iCm) and the value of the equivalent series resistance (ESR) by means of a first relationship of the form PC=f(iCm, ESR). Direct measurement of the capacitor temperature (TC), of the capacitor current (iC), or of the capacitor power loss (PC) is not required. For example, a measurement of the capacitor voltage (uC) and a further calculation of the modeled capacitor current iCm and finally of the capacitor power loss (PC) are sufficient.
January 27, 2017
Date of Patent:
September 17, 2019
B&R INDUSTRIAL AUTOMATION GMBH
Klaus Doppelhammer, Johann Eder, Gerhard Mayrhofer-Huber
Abstract: Various embodiments relate to a flyback type SMPS including a primary side controller on a primary side, a first switch on the primary side and a transformer including a primary side winding on the primary side, a secondary side winding on a secondary side and an auxiliary winding on the primary side connected to a first switching regulator wherein the first switching regulator is supplied during a primary stroke from the auxiliary winding when the first switch is on.
Abstract: A switch mode power supply comprises a power converter including a transformer having a primary winding connected to a primary circuit, and a secondary winding connected to a secondary circuit delivering an output voltage to a load. The primary circuit comprises a controller for operating a switch element to chop the current flowing in the primary winding to transfer energy selectively to the secondary winding. The secondary circuit comprises a storage capacitor delivering the energy to the load, a first regulator receiving the output voltage and delivering a first control current for the controller via an isolator element, and a second regulator receiving an auxiliary output voltage that is an image of the output voltage and delivering a second control current for the controller. The second control current is added to the first control current to avoid any interruption in the chopping of the current flowing in the primary winding.
Abstract: In some examples, a controller device is configured to control power electronics circuitry and includes a high-voltage (HV) pin, a power supply (VCC) pin, a startup device configured to conduct electricity from the HV pin to the VCC pin, and comparator circuitry configured to determine whether a voltage level of the VCC pin is greater than a turn-on voltage threshold. In some examples, the comparator circuitry is further configured to cause the controller device to enter a normal-operation mode in response to determining that the voltage level of the VCC pin is greater than the turn-on voltage threshold. In some examples, the controller device also includes level detection circuitry configured to determine the turn-on voltage threshold based on a level of the HV pin.
Abstract: A diagnostic apparatus (101) for diagnosing faults within a lighting system comprising at least one luminaire (121), and at least one presence sensor (123, 151) configured to control the operation of at least one luminaire (121) when an object is within the presence sensor (123, 151) sensing range, the diagnostic apparatus (101) comprising: a user input (103) configured to receive at least one input to control the at least one luminaire (121); and a fault determiner (221) configured to determine at least one lighting system fault based on the at least one input and wherein an object is within the sensing range of a presence sensor (123, 151) expected to be associated with the at least one luminaire (121); and a fault reporter (223) configured to generate at least one fault report based on the determined at least one lighting system fault.
May 30, 2016
Date of Patent:
April 2, 2019
SIGNIFY HOLDING B.V.
Jurgen Mario Vangeel, John André Van Beurden, Robbert Martinus Andreas Driessen
Abstract: An LED driver, comprising: an inductive switch mode converter having an inductive component (16,22), an LED output (30) for an LED load and a main converter switch (18) for controlling a current flowing through the inductive component; a sensor (32) for generating a sensor signal indicative of the output current or voltage provided to the LED output; a feedback element (34) which provides a feedback path for feeding back the sensor signal for control of the main converter switch (18); and a processing circuit (50) for processing the sensor signal which has been fed back, wherein the processing circuit is adapted to generate an output when there is no sensor signal so as to limit the current flowing through the main converter switch when no sensor signal is present.
Abstract: Disclosed examples include flyback converters, control circuits and methods to facilitate secondary side regulation of the output voltage. A primary side control circuit operates a primary side switch to independently initiate power transfer cycles to deliver power to a transformer secondary winding in a first mode. A secondary side control circuit operates a synchronous rectifier or secondary side switch to generate a predetermined cycle start request signal via a transformer auxiliary winding to assume secondary side regulation and to cause the primary side controller to initiate new power transfer cycles.
July 6, 2016
Date of Patent:
June 26, 2018
TEXAS INSTRUMENTS INCORPORATED
Satish Kumar Vemuri, James M. Walden, Isaac Cohen
Abstract: A first power transistor of a DC-DC converter is connected between a voltage supply node and a common node, a second power transistor is connected between a reference node and the common node, and an inductor is connected between the common node and the output node of the DC-DC converter. A controller switches the first transistor off and the second transistor off during a step-down event at the load if current in the inductor exceeds a positive threshold value.
Abstract: A power supply circuit includes: an anti-electromagnetic interference circuit configured to receive input alternating current power and to output filtered alternating current power; a rectifier circuit configured to rectify the filtered alternating current power; a current correction circuit configured to perform passive power factor correction on the rectified alternating current power; a single-ended flyback converter circuit coupled to the output of the current correction circuit; and a dimming control circuit coupled between the output of the single-ended flyback converter circuit and a light load, wherein the current correction circuit is configured to control a waveform of the rectified alternating current power to follow a current output to the light load in order to provide passive power factor correction.
Abstract: A switching power supply device includes: a transformer; a first switch connected between a high potential terminal of an input DC voltage source and a primary winding; a second switch connected between a low potential terminal of the input DC voltage source and a primary winding; a control circuit outputting a driving pulse signal for synchronizing the first and second switches; first and second rectifying devices; a synchronous rectifier circuit; and a positive bias circuit that applies a positive bias to a control terminal of one of the first and second switches so as to constantly turn the one of the first and second switches ON. When the first and second switches stop a switching operation while an output voltage exists between the output terminals, the positive bias circuit applies the positive bias to the one of the first and second switches.
Abstract: In one embodiment, harmonic control method for a flyback switching power supply, can include: (i) generating a sense voltage signal based on an output signal of the flyback switching power supply; (ii) generating a first compensation signal by determining and compensating an error between the sense voltage signal and a reference voltage; (iii) generating a second compensation signal by regulating the first compensation signal based on a duty cycle of a main power switch in the flyback switching power supply; and (iv) generating a control signal based on the second compensation signal and a triangular wave signal, to control the main power switch such that the output signal is substantially constant and an input current follows a waveform variation of an input voltage of the flyback switching power supply.
Abstract: A controller for a power converter includes an edge detection circuit including a first circuit coupled to coupled to compare a voltage sense signal representative of an input voltage to a first reference, and a second circuit coupled to compare a current sense signal representative of an input current to a second reference. A slope sense circuit is coupled to measure a slope of the voltage sense signal over time. An edge driver circuit is coupled to generate an edge signal that indicates that an edge has been determined when the voltage sense signal is greater than the first reference, the current sense signal is lower than the second reference, and the slope is negative. A drive circuit is coupled to output a drive signal in response to the edge signal. The drive signal is for controlling a switch coupled to regulate an output of the power converter.
November 10, 2015
Date of Patent:
August 16, 2016
Power Integrations, Inc.
Mingming Mao, Ricardo Luis Janezic Pregitzer, Tiziano Pastore, Michael Yue Zhang
Abstract: A method for a power adapter to selectively provide a first and a second output voltage may comprise coupling a rectified and filtered transformer input signal to a primary winding of a transformer. The secondary winding thereof may comprise a first tap associated with the first output voltage and a second tap associated with the second output voltage, the first and second taps being configured to be selectively coupled to and uncoupled from an output of the power adapter. The output current drawn at the output of the power adapter may then be sensed. When the sensed output current is determined to have exceeded a predetermined threshold, the output of the power adapter may be switched from the first to the second tap by uncoupling the first tap from the output of the power adapter and coupling the second tap to the output of the power adapter.
Abstract: The power supply apparatus includes the feedback winding of a transformer having a first winding, and a second winding whose number of turns is larger than that of the first winding. A voltage output from the transformer is detected. Based on the detected voltage, connection between a switch element and the first winding or the second winding is switched.
Abstract: An external resistor is connected to a detection terminal. A pulse modulator is configured to generate a pulse signal SPWM having a duty ratio adjusted such that the output voltage VOUT of a DC/DC converter approaches a target value. A pulse modulator is configured to switch the pulse signal SPWM to a level that corresponds to the off level of the switching transistor according to a detection voltage VS that develops at the detection terminal. A short-circuit detection circuit is configured to generate a short-circuit detection signal which is asserted when the detection voltage VS is higher than a predetermined threshold voltage VTH after a judgment time elapses after the pulse signal SPWM is switched to an on level that corresponds to the on state of the switching transistor. When the short-circuit detection signal is asserted, the pulse modulator is configured to switch the pulse signal SPWM to the off level.
Abstract: A buck-boost regulation methodology operable, in one embodiment, with a single inductor, four-switch (S1-S4) buck-boost regulator configured for DCM. Buck-boost transition switching control is operable when inductor charge time exceeds a max charge time, and inductor discharge time exceeds a max discharge time, and includes: (a) during charge transition cycles, at the end of the max charge time, if IL is less than a predetermined peak current IL—MAX, switching S2 on (grounding the output side of the inductor) and S4 off, causing IL to increase (a rapid S1S2 charging current ramp), until IL reaches IL—MAX, and (b) during discharge transition cycles, at the end of the max charge time, if IL is greater than zero, switching S1 off and S3 on (grounding the input side of the inductor), causing IL to increase (a rapid S3S4 IL discharging current ramp), until IL reaches zero.
Abstract: A cascaded switching power converter for coupling a photovoltaic (PV) energy source to power mains provides a high-efficiency and a potentially simple control mechanism for AC solar energy conversion systems. The PV energy source charges a capacitive storage element through a DC-DC converter, and an inverter couples energy from the capacitive storage element to the mains supply. The DC-DC converter is controlled so that ripple present on the capacitive storage element due to current drawn by the inverter is not reflected at the input of the DC-DC converter, which is accomplished by varying the conversion ratio of the DC-DC converter with the ripple voltage present across the capacitor. The average voltage of the capacitor can also be increased with increases in the available power output from the PV energy source, so that a corresponding increase in power is transferred to the mains supply.
Abstract: A multilevel DC-DC converter includes a voltage source that provides a voltage Vout1 to at least one charge converter circuit and an output filter capacitor having an associated output voltage Vout2. The at least one charge converter circuit includes a transformer having at least one primary winding and at least two secondary windings, a primary and secondary circuit each having at least two switching elements, and a control unit which receives a control signal, such as but not limited to an envelope tracking signal, which represents a desired output voltage. The control unit is arranged to provide output control signals to the respective switching elements of the primary and secondary circuits to activate and deactivate the respective switching elements to obtain a desired output voltage Vout2. The multilevel DC-DC converter can be arranged to operate as a boost converter or as a buck-boost converter.
Abstract: A structure of a fly-back power converting apparatus is disclosed. The structure includes a power transistor, a current detector, a pulse width modulation (PWM) signal generator and a current limiter. The power transistor is coupled to an input voltage and receives a PWM signal. The current detector detects a current output from the power transistor and generates a detecting voltage according to the current. The PWM signal generator generates the PWM signal according to a comparing result by comparing the detecting voltage and a standard voltage. The current limiter generates the standard voltage according to a turn-on time of the power transistor.
Abstract: The present invention provides a multi-terminal power conversion device, a multi-terminal power transfer device, and a power network system which allows an existing power grid to be divided into a plurality of power grids that can be interconnected together and operated stably via existing or new transmission lines. An inter-power grid asynchronous interconnection network system includes a multi-terminal power conversion device characterized by connecting together a plurality of asynchronous power grids including a bulk power grid and controlling power so that the sum of inflow power and outflow power is zero. An intra-power grid synchronous network system includes a power apparatus control terminal device with means for controlling power for a power apparatus installed in an autonomous power grid. A plurality of inter-power grid asynchronous interconnection network systems are connected to an intra-power grid synchronous network system to integrate the power control with communication control.
Abstract: Disclosed is a circuit arrangement for determining a temporal change of an output voltage of a half-bridge circuit during a dead time. In one embodiment, the circuit arrangement includes a first input for applying the output voltage. A capacitive network includes a first and a second circuit node capacitively coupled to the input, and having a terminal for a reference potential. A recharging circuit during the switched-on phase of one of a first and second switching elements, adjusts electrical potentials of the first and second nodes, the electrical potentials each being different from the reference potential. A comparator arrangement, during the dead time, determines a time difference between such times at which the electrical potentials at the first and second node each assume a given potential value, the time difference being a measure for the change with time of the output voltage.
Abstract: A DC power supply (1) having a series regulator (2) for generating a fixed output DC voltage (VCC) at a variable input AC voltage (VAC) with low power loss. For this purpose, the DC power supply (1, 101, 201, 301) has a transformer (3, 103) having at least two auxiliary windings (W1, W2) having different numbers of windings that can each be connected via a switching device (4, 104, 204, 304) to the series regulator (2). Switching is effected such that the power loss is kept as low as possible.
Abstract: A switched-mode power supply with reduced electromagnetic interference (EMI) is described. This switched-mode power supply includes a modulation circuit that continuously frequency modulates a control signal over a bandwidth associated with a spread-spectrum modulation signal. By frequency modulating the control signal in the switched-mode power supply, spectral content associated with a modulated switching signal is spread evenly over the bandwidth, thereby reducing the EMI.
April 1, 2013
September 18, 2014
Yongxuan Hu, Keong W. Kam, Shimon Elkayam, Susan R. Schen
Abstract: Described are improvements in power factor control and systems embodying said improved power factor control. Improvements lie in a method of zero voltage switching in which a capacitor is placed in parallel with a switching device, and the switching device is operated responsive to a change in the polarity of the current through the capacitor. Switching therefore occurs at zero or close to zero voltage across the switching device in both on and off modes resulting in very low switching losses and electromagnetic interference. Systems employing the method include a power factor controller, LED light source, boost converter and a power source comprising one or more photovoltaic cells.
Abstract: An example power supply includes a first power converter, a second power converter, and a shared clamp reset circuit. The first power converter is adapted to convert an input to a first voltage output and includes a first diode and a first transformer having a first primary winding. The second power converter is adapted to convert the input to a second voltage output and includes a second diode and a second transformer having a second primary winding. The shared clamp reset circuit is included in the first power converter and is coupled to the cathode of the first diode. The shared clamp reset circuit also includes a clamp connection that is coupled to the cathode of the second diode. The shared clamp reset circuit is adapted to manage leakage inductance energy within the first transformer and within the second transformer.
Abstract: An example integrated circuit for use in a power supply includes a feedback terminal, a controller and a clamp. The feedback terminal is to be coupled to receive a feedback signal that is representative of a bias voltage across a bias winding of the power supply. The controller is to be coupled to control switching of a power switch included in the power supply in response to the feedback signal. The clamp is coupled to clamp the feedback terminal to a voltage for at least a time that the bias voltage is negative with respect to an input return of the power supply.
Abstract: A switching power source apparatus has a pulse generator of a first pulse. A first resonant series circuit receives the first pulse signal and passes a current having a 90-degree phase delay with respect to the first pulse signal. The current of the first resonant series circuit turns on/off a switching element Q21. A second resonant series circuit receives the second pulse signal and passes a current having a 90-degree phase delay with respect to the second pulse signal. The current of the second resonant series circuit turns on/off a switching element Q22. The pulse generator has a third transformer T3 that has secondary windings to output the first and second pulse signals according to a voltage that is applied to the third transformer and is synchronized with drive signals for the switching elements Q11 and Q12.
Abstract: A switching circuit for use in a power converter includes a first active switch coupled between a first terminal of an input of the power converter and a first terminal of a primary winding of a transformer. A second active switch is coupled between a second terminal of the input and a second terminal of the primary winding. An output capacitance of the first active switch is greater than an output capacitance of the second active switch. A first passive switch is coupled between the second terminal of the primary winding and the first terminal of the input. A second passive switch is coupled between the second terminal of the input and the first terminal of the primary winding. A reverse recovery time of the first passive switch is greater than a reverse recovery time of the second passive switch.
Abstract: A switching power supply apparatus includes a low-side switching control unit and a high-side switching control unit. The low-side switching control unit includes a low-side turn-off circuit that turns off a low-side switching element behind a delay time when reversal of the polarity of a winding voltage of a transformer is detected during a period in which a drive voltage signal is supplied to the low-side switching element. The high-side switching control unit includes a high-side turn-on delay circuit that delays a time from the time when the polarity of the winding voltage of the transformer is reversed to a time when a high-side switching element is turned on. The delay time of the low-side turn-off delay circuit is set so as to be shorter than the delay time of the high-side turn-on delay circuit.
Abstract: An example control element for use in a power supply includes a high-voltage transistor and a control circuit to control switching of the high-voltage transistor. The high-voltage transistor includes a drain region, source region, tap region, drift region, and tap drift region, all of a first conductivity type. The transistor also includes a body region of a second conductivity type. An insulated gate is included in the transistor such that when the insulated gate is biased a channel is formed across the body region to form a conduction path between the source region and the drift region. A voltage at the tap region with respect to the source region is substantially constant and less than a voltage at the drain region with respect to the source region in response to the voltage at the drain region exceeding a pinch off voltage.
Abstract: A switching control IC conducts on-off control on a first switching element. A second switching control circuit is provided between a high-side driving winding of a transformer T and a second switching element. The second switching control circuit discharges a capacitor in a negative direction with a constant current during an on period of the first switching element, and then after the second switching element is turned on, charges the capacitor in a positive direction with a constant current. A transistor controls the on period of the second switching element in accordance with the ratio of a charging current to a discharge current such that the ratio of the on period of the second switching element to the on period of the first switching element is substantially always constant.
Abstract: A power supply includes a forward converter having a first transformer coupled to an input of the power supply and to a first voltage output. The power supply also includes a separate flyback converter having a second transformer that is coupled to the input and to a second voltage output. A clamp reset circuit is coupled to the first transformer and to the second transformer. The clamp reset circuit includes a capacitor and a voltage limiting element. The voltage limiting element is coupled to prevent energy received at the capacitor from both the power converters from exceeding a threshold. The voltage limiting element limits a voltage on the capacitor.
Abstract: The present invention relates to a light emitting diode driver that integrates a light emitting diode control function and a power switching control function at a secondary side insulated from a primary side in a power supply circuit, without using a photo coupler to control power switching at the primary side.
May 27, 2011
Date of Patent:
November 12, 2013
Samsung Electro-Mechanics Co., Ltd.
Dae Hoon Han, Jeong In Cheon, Jae Shin Lee
Abstract: An integrated circuit for use in a power supply includes a drive signal generator, a first delay, a second delay, a comparator, a first logic, a first short on time detector, and a second logic. The drive signal generator generates a drive signal to control a switch in response to a clock signal. The short on time detector sets the first latch indicating that an on time of the switch is a short on time. The second logic is coupled to detect long pulses of the drive signal to reset the first latch indicating that the on time of the switch is not a short on time. An on time of the drive signal is a short on time if a switch current of the switch exceeds a current limit after a sum of a leading edge blanking period and a current limit delay time period.
Abstract: A power supply, which outputs a plurality of voltages in order to improve the cross regulation between output voltages and at the same time reduce the amount of electric power consumed, and an image forming device having the same are disclosed. The power supply includes a power converter, which generates a first output power source and a second output power source in response to an external power supply and a power control signal, respectively; a power output part, which includes output parts to rectify and smooth each of the first and second output power sources; a first output controller, which receives the first output power source feedback from the power output part to generate the power control signal; and a second output controller, which receives the second output power source feedback from the power output part to control to operate the power output part in stable mode.
Abstract: An AC-DC converter is disclosed. The AC-DC converter includes an OFF-time clamping circuit. The OFF time clamping circuit outputs a triggering signal when a main switch circuit of the AC-DC converter is switched from ON state to OFF state. When an input AC voltage is too small, and a terminal voltage at a first current-conducting terminal of the main switch circuit of the AC-DC converter is lower than a specific voltage such that a switching control circuit can not turn on the main switch circuit again, the switching control circuit can still turn on the main switch circuit again by the triggering signal. Therefore, the OFF time of the main switch circuit is clamped. The switching control circuit can control the switching operation of the main switch circuit.
Abstract: A switching circuit for use in a power supply includes a first active switch coupled to a first terminal of a primary winding of a transformer. A second active switch is coupled to a second terminal of the primary winding of the transformer. An output capacitance of the first active switch is greater than an output capacitance of the second active switch. A first passive switch is coupled to the second active switch and to the second terminal of the primary winding. A second passive switch is coupled to the first active switch and to the first terminal of the primary winding. A reverse recovery time of the first passive switch is greater than a reverse recovery time of the second passive switch. A recovery circuit is coupled to receive a current from the first passive switch.
Abstract: There is provided a self-excited switching power supply circuit which shifts to continuous oscillating operation immediately after the self-excited switching power supply circuit is connected to an AC power supply and started and which does not cause start-up failure while using a start-up resistor of a high resistance value to maintain standby power consumption at a low level. A bypass charging circuit connected in series to a start-up resistor is connected between a high-voltage side terminal of a DC input power supply and the gate of an oscillation field effect transistor. A charging current flowing in the start-up resistor, and additionally, a charging current to charge a start-up capacitor through the bypass charging circuit flow in a transitional period during which the voltage of the DC input power supply increases.
Abstract: An example integrated circuit for use in a power supply includes a feedback terminal and a controller having a variable time clamp (VTC). The feedback terminal is to be coupled to receive a feedback signal and the controller is to be coupled to enable or disable the conduction of a power switch during a switching cycle in response to the feedback signal. The controller includes a current limit comparator coupled to terminate the conduction of the power switch during an enabled switching cycle in response to a current through the power switch exceeding a variable current limit. The VTC is coupled to clamp the feedback terminal to a voltage for a clamp time that is responsive to the variable current limit.
Abstract: An example power supply includes a first power converter, a second power converter, and a shared clamp reset circuit. The first power converter is adapted to convert an input to a first output and includes a first transformer having a first primary winding. The second power converter is also adapted to convert the input to a second output and includes a second transformer having a second primary winding. The second primary winding of the second transformer is not the first primary winding of the first transformer. The shared clamp reset circuit is coupled to the first primary winding of the first transformer and is coupled to the second primary winding of the second transformer to manage leakage inductance energy within the first transformer and within the second transformer.
Abstract: A power supply includes a first power converter having a first transformer coupled to an input of the power supply and to a first output of the power supply. A clamp reset circuit is coupled to the first transformer. The clamp reset circuit includes a capacitor coupled to the first power converter and a Zener diode coupled to the capacitor. A second power converter is coupled to the clamp reset circuit. The second power converter includes a second transformer coupled to the clamp circuit and to a second output of the power supply. The capacitor is coupled to store energy received from the first power converter and the second power converter. The Zener diode is coupled to prevent the energy received from the first power converter and the second power converter from exceeding a threshold. The Zener diode limits voltage on the capacitor.
Abstract: A circuit for operating a household appliance includes a controller that controls processes of a household appliance, a switching power supply that supplies current to the controller, a pushbutton that couples the switching power supply to a supply grid, an electronic controller connected parallel to the pushbutton that is actuable by the switching power supply by a control connection, and a voltage storage connected between the control connection of the electronic controller and a reference potential.
Abstract: A switching power supply device includes a transformer, a switching unit which is connected with a primary winding of the transformer and configured to switch a current flowing to the primary winding, a start unit configured to start the switching unit, a voltage drop unit configured to lower output voltage from a secondary winding of the transform, and a current control unit configured to control an amount of a current flowing in the start unit when the switching unit is in an off state by lowering output voltage by the voltage drop unit.
Abstract: A power converter topology operates as a switching capacitor (capacitive voltage divider) converter during a first, preferably short portion of a switching cycle to provide excellent dynamic transient response and as a pulse width modulated converter during a second portion of a switching cycle to provide flexibility of voltage regulation and generality of application. This topology can be made self-driven and is capable of zero voltage switching. Therefore the power converter can be used as one of a plurality of branches of a multi-phase converter to enhance transient response. The respective branches can also be independently optimized for particular load levels and can be operated independently in a phase shedding manner to improve efficiency at low load. Further, the power converter or respective branches of a multi-phase power converter are compatible with non-linear control to further improve dynamic response.
December 15, 2009
Date of Patent:
December 11, 2012
Virginia Tech Intellectual Properties, Inc.
Abstract: A power supply may comprise a pulse-width-modulation (PWM) controller; a synchronous rectifier having a forward metal oxide field effect transistor (MOSFET) and a catch MOSFET; a forward gate driver; a catch gate driver; and the PWM controller connected so that a low output of the PWM controller facilitates operation of the catch MOSFET and so that the low output precludes operation of the forward MOSFET. The power supply may include a self powered synchronous rectifier that may be constructed with delay times that are independent of lot-to-lot and temperature-related timing variations of MOSFETS.
June 7, 2010
Date of Patent:
December 4, 2012
Honeywell International Inc.
Joseph Marotta, Xavier Enriquez, Stanislav Suchovsky, Steven Lawson
Abstract: An integrated circuit for use in a power supply includes a drive signal generator, a short on time detector, and an oscillator. The drive signal generator generates a drive signal in response to a clock signal. The short on time detector provides an output indicating that consecutive on times of the drive signal are short on times. An on time of the drive signal is a short on time if a switch current of the switch exceeds a current limit after a leading edge blanking period and if the on time of the switch is less than or equal to a sum of the leading edge blanking period and a current limit delay time period. The oscillator generates the clock signal and changes a frequency of the clock signal from a first frequency to a lower second frequency in response to the output of the short on time detector.
Abstract: Audible noise in resonant switching power converter during low-power burst mode operation is reduced by spreading the spectrum generated by the bursts, thereby reducing the amplitude of audio spectrum peaks in the current supplied through the resonant tank from a switching circuit. The spreading can be accomplished by varying the intervals between the bursts and/or by varying a pulse pattern within the bursts. The pulse pattern within the bursts can be varied by varying the number of pulses in the bursts, the polarity of the initial pulse of the bursts, and/or the duration of pulses within the bursts either uniformly or randomly. The burst pulse pattern may also be selected in alternation from a set of pulse patterns stored in a memory and the selection may be made randomly or systematically.
Abstract: A power supply circuit includes continuous conduction mode power factor correction (PFC). The PFC may be performed by generating a carrier signal voltage at a beginning of a switching cycle of the power supply, generating a sampling voltage indicative of drain current of a drive transistor, and detecting when the carrier signal voltage has decreased to the same level as the sampling voltage at an intersection time. The ON time of the drive transistor may be set to twice the intersection time.
Abstract: A power supply includes a first power converter, a second power converter, and a clamp reset circuit. The clamp reset circuit is electrically coupled to other components within the first power converter and the second power converter. A clamp standby connection can be provided to electrically couple the clamp reset circuit to components comprising the second power converter. The clamp reset circuit is coupled to reduce magnetizing energy of a transformer of the first power converter and limit voltage in a component of the second power converter. The clamp reset circuit may include a Zener diode and a resistor that are adapted to reduce magnetizing energy of the first power converter and voltage through the second power converter. The clamp reset circuit normally includes a capacitor that is adapted to store energy from the first power converter and the second power converter.
Abstract: 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 substantially proportional to a voltage between the first and second main terminals when the voltage is less than a pinch off voltage. The tap terminal is coupled to provide a substantially constant voltage that is less than the voltage between the first and second main terminals to the control circuit when the voltage between the first and second main terminals is greater than the pinch-off voltage.