Abstract: Devices, systems, and methods for self-testing event devices of a building alarm system are described herein. One self-test alarm system device having a self-testing capability includes a first independent power source connected to a detector module and a second independent power source connected to a self-test module.

Abstract: A multi-port USB Type-C® Power Delivery (USB-C/PD) power converter for switching clock phase shifts is described herein. The multi-port USB-C/PD power converter includes a first PD port, a second PD port, and a power controller coupled to the first and second PD ports. The power controller includes a first phased clock generator to generate a first phase-shifted clock signal by shifting a clock signal by a first phase with respect to a reference clock signal, and a second phased clock generator to generate a second phase-shifted clock signal to generate a second phased-shifted clock signal by shifting the clock signal by a second phase with respect to the reference clock signal. The first PD port and the second PD port output power in response to a first control signal based on the first phase-shifted clock signal and a second control signal based on the second phase-shifted clock signal, respectively.

Abstract: A hysteretic current control switching power converter with a clock-controlled switching frequency is disclosed. A power converter includes a switching circuit including a high side switch and a low side switch coupled to one another at a switching node, with an inductor being coupled between the switching node and a regulated supply voltage node. The power converter further includes a control circuit configured to alternately cause activation of the high side switch and the low side switch, wherein the control circuit is configured to activate the low side switch in response to a first voltage reaching peak threshold value, the first voltage corresponding to a current through the inductor. A ramp voltage circuit is configured to, in response to a clock signal, generate a ramp voltage, wherein the peak threshold value is based on the ramp voltage.

Abstract: A building automation system that is comprised of a plurality of network connected electrical modules contained in standard receptacle gang boxes for outlets and switches is described. The system includes an AC to DC power supply, a bidirectional solid state dimmer switch, a microprocessor, and, interconnected sensors that are powered and controlled by microprocessors within the electrical modules. The electrical modules include a user interface for programming and control. The system provides enhanced safety and security, power metering, power control, and home diagnostics. The apparatus replaces existing outlet receptacles and switches with a familiar flush but elegantly updated and seamlessly integrated faceplate.

Abstract: A current switch control system includes a first controllable switch, a first current switching controller, a second controllable switch, a second current switching controller, and a reference value controller. Each current switching controller generates a pulse width modulated switching signal to change the state of one of the respective controllable switches based on a current reference value and a current measured value corresponding to current flow through the respective controllable switch. The reference value controller changes the current reference values used by the current switching controllers based on the pulse width modulated switching signals for the controllable switches.

Abstract: A position determination device comprises data input circuitry configured to obtain magnetic field sensor data sensed by a magnetic field sensor, separation circuitry configured to separate the obtained magnetic sensor data into low frequency sensor data including frequencies below a frequency threshold and high frequency sensor data including frequencies above the frequency threshold, fingerprint combining circuitry configured to determine a combined magnetic fingerprint based on the low frequency sensor data and the high frequency sensor data, and position determination circuitry configured to determine the sensor position of the magnetic field sensor by comparing the combined magnetic fingerprint with a magnetic map.

Abstract: A temperature computing parameter providing circuit, configured to generate sensing voltage values and calibrated voltage values as temperature computing parameters for a target electronic device, including: a parameter computing circuit, configured to compute a reference voltage, which is a cross voltage of a reference resistor coupled to the target electronic device in series, to generate a reference voltage value, and to compute the sensing voltage, which is a cross voltage of the target electronic device, to generate the sensing voltage value; a reference temperature sensing circuit, configured to sense a current reference temperature of the reference resistor; and a computing circuit, configured to calibrate the reference voltage value to generate the calibrated voltage value according to a calibrating function and the current reference temperature. The calibrating function corresponds to a resistance-temperature variation function.

Abstract: A lighting control device is provided which includes a microcontroller, at least one wireless transceiver, at least one dimmer, one or more lighting terminals powered by the at least one dimmer, at least one environmental sensor, and at least one input device. In operation, the microcontroller obtains environmental data from the at least one environmental sensor, obtains input data from the at least one input device, transmits the environmental data and the input data to an external server, obtains a lighting operating schedule based on the environmental data and the input data from the external server, and executes the lighting operating schedule from the external server by controlling one or more smart bulbs via the at least one wireless transceiver and controlling the electrical current output to lighting terminals.

Abstract: There is presented a boost converter and an associated method for starting the boost converter. The boost converter includes an input terminal for receiving an input voltage, an output terminal for providing an output voltage, a low-side power switch and a high-side power switch coupled at a switching node, and a voltage regulator coupled to the high-side power switch. The boost converter is also provided with a controller for operating the boost converter in a start-up phase. In the start-up phase the controller controls the boost converter to generate an intermediate voltage and increase the intermediate voltage to a predetermined value. The intermediate voltage is then provided to the voltage regulator to obtain a drive voltage. The high side power switch is then driven to increase the output voltage linearly up to a start-up voltage.

Abstract: Methods and apparatus for reducing electromagnetic interference in a power converter using phase hopping in conjunction with pulse width modulation are disclosed. An example power converter includes an input voltage to, when a control switching device receives a first voltage, increase an output voltage; and when the control switching device receives a second voltage, decrease the output voltage. The example power converter further includes a phase hopping generator to generate a phase varying signal corresponding to two or more phases, the phase varying signal corresponding to a reference voltage; and output the phase varying signal to control the control switching device.

Abstract: One example includes a pipelined analog-to-digital converter device. The pipelined analog-to-digital converter device includes a capacitive digital-to-analog converter, a first analog-to-digital converter, and a second analog-to-digital converter. The capacitive digital-to-analog converter includes a capacitor comprised of a top plate and a bottom plate, the capacitive digital-to-analog converter sampling an analog input signal applied to the pipelined analog-to-digital converter device while the capacitor is grounded, holding the sampled analog input while the top plate is floated, and outputting a residue voltage. The second analog-to-digital converter is coupled to the top plate of the capacitor, the second analog-to-digital converter producing a second digital representation of voltage on the top plate of the capacitor after the top plate is floated, wherein the second digital representation represents fine bits produced by the first stage of the pipelined analog-to-digital converter device.

Abstract: An over-voltage protection circuit for a transistor switch has an error detecting circuit, a dummy load circuit and a driving circuit. The error detecting circuit has a first input terminal; and a second input terminal configured to receive a reference signal. The dummy load circuit is configured to establish a conductive path between the output terminal of the transistor switch and ground. The driving circuit is configured to increase the on-resistance of the transistor switch if the voltage difference between the second terminal of the error detecting circuit and the first terminal of the error detecting circuit is smaller than a calculated value.

Abstract: A boost converter circuit able to sense current comprises an inductor connected with a power source; an active switch; a passive switch; a capacitor connected with one end of the passive switch, which is not connected with the active switch; a center-tapped current transformation element; and a signal rectification unit. The center-tapped current transformation element includes a primary winding and a secondary winding. Two ends of the primary winding are respectively connected with the active switch and the passive switch. The primary winding is connected with the inductor through a tapped terminal. The secondary winding is magnetically induced by the primary winding to generate a magnetic induction signal while the primary winding receives an inductor current. The signal rectification unit is connected with the secondary winding, receiving the magnetic induction signal and rectifying the magnetic induction signal to generate a sensed current signal corresponding to the inductor current.

Abstract: In accordance with an embodiment, switch driver includes a first switch driver configured to be coupled to a control node of a first switch, a second driver configured to be coupled to a control node of a second switch, and a first terminal and a second terminal configured to be couple to a boot capacitor. The first terminal is coupled between a boot input of the first switch driver and the second terminal is configured to be coupled to outputs of the first switch and the second switch. The switch driver further includes a voltage measurement circuit coupled to the first terminal and the second terminal, and a control circuit configured to activate the second switch driver when the voltage measurement circuit indicates that a voltage across boot capacitor is below a first threshold.

Abstract: A DC-DC converter includes an input terminal Pin receiving an voltage input, switching circuits connected in parallel between the input terminal Pin and ground, an output terminal Pout from which converted voltage is output, and a controller that turns the switching circuits on in a predetermined cycle by inputting, into each of the switching circuits, a control signal that turns the switching circuits on individually.

Abstract: A DC/DC converter is disclosed. The DC/DC converter includes a first heavy-load electronic switch and a second heavy-load electronic switch connected in series between an input terminal and ground at a first output portion, a third light-load electronic switch and a fourth light-load electronic switch connected in series between the input terminal and ground at a second output portion, an output circuit, an output current measurement circuit, and a control circuit. The output circuit includes an inductor connected to the first and second output portions. The output current measurement circuit measures an output current. The control circuit, in response to an output of the output current measurement circuit, selects a combination of the first and second heavy-load electronic switches during a heavy load state, and selects a combination of the third and fourth light-load electronic switch during a light load state.

Abstract: A controller of the power converter according to the present invention comprises a gate driver. The gate driver generates a gate-drive signal. The gate-drive signal is coupled to drive a power transistor to switch a transformer of the power converter for regulating an output of the power converter. The gate driver has a charge-pump circuit for charging pump a voltage level of the gate-drive signal. Therefore, the gate-drive signal can fully turn on the power transistor.

Abstract: A two-wire load control device (such as, a dimmer switch or an electronic switch) for controlling the power delivered from an AC power source to an electrical load includes a controllably conductive device for controlling the power to the load, a microprocessor operable to generate a control signal that is representative of whether the load should be controlled on or off, a capacitor operable to produce a supply voltage for powering the microprocessor, a power supply that charges the capacitor when the controllably conductive device is non-conductive, and a control circuit that receives the control signal from the microprocessor. The control circuit is operatively coupled to the controllably conductive device for maintaining the controllably conductive device non-conductive after the beginning of each half-cycle until the magnitude of the supply voltage exceeds a predetermined threshold.

Abstract: A discharging circuit includes a filter unit connected between the input lines of a commercial AC power supply, a switch whose operations are controlled by the filter unit; and a discharging unit which discharges voltage of the capacitance element when the switch unit is turned on.

Abstract: A bootstrap capacitor detecting circuit includes a current source, for providing a discharging current; a first switch, for conducting connection between a system voltage and a bootstrap voltage node according to a power-on-reset signal, to charge the bootstrap voltage node; a second switch, for conducting connection between a current source and the bootstrap voltage node according to the power-on-reset signal, to discharge the bootstrap voltage node; and a detecting unit, for determining whether a bootstrap capacitor is connected normally according to a bootstrap voltage of the bootstrap voltage node after the current source discharges the bootstrap voltage node.

Abstract: An error amplification circuit includes an integrated circuit and a phase compensation capacitor. The integrated circuit includes an error amplifier to amplify a difference between a predetermined reference voltage and an input feedback voltage for output; a current generator circuit to generate a bias current for supply to the error amplifier; a phase compensation resistor; a bias-current control terminal; and a phase compensation terminal connected to an output terminal of the error amplifier via the phase compensation resistor. The phase compensation capacitor is connected to the phase compensation terminal, the phase compensation capacitor being provided outside the integrated circuit.

Abstract: The present invention discloses an adaptive phase-shifted synchronization clock generation circuit and a method for generating phase-shifted synchronization clock. The adaptive phase-shifted synchronization clock generation circuit includes: a current source generating a current which flows through a node to generate a node voltage on the node; a reverse-proportional voltage generator coupled to the node for generating a voltage which is reverse-proportional to the node voltage; a ramp generator receiving a synchronization input signal and generating a ramp signal; a comparator comparing the reverse-proportional voltage to the ramp signal; and a pulse generator for generating a clock signal according to an output from the comparator.

Abstract: Circuitry and method for providing a signal indicative of instances of conduction of average inductor current in a DC-to-DC voltage converter. Such signal identifies a time when the instantaneous average current being conducted by the inductor in a DC-to-DC voltage converter can be measured by providing a signal edge approximately halfway through one of the increasing and decreasing current conduction intervals of the inductor.

Abstract: A DC-DC converter control circuit includes: a slope signal generation circuit that generates a reference voltage by superimposing a slope voltage onto a standard voltage; a comparator that performs comparison of the reference voltage with an output voltage and generates a signal according to a result of the comparison; an oscillator that generates a pulse signal with a substantially constant cycle; and a control signal generation circuit that generates a control signal that turns on a switch based on a comparator output signal and turns off the switch based on the pulse signal.

Abstract: A first pump circuit generates a first voltage for decreasing the distance between primary electrodes. The first voltage is limited to a predetermined limit by a first limiter circuit. A second pump circuit generates a second voltage for keeping the distance between the primary electrodes constant. A third pump circuit generates the second voltage and has a supplying capacity smaller than the first one. The second voltage is limited by second and third limiter circuits. A ripple capacitor is charged up to the second voltage by the second pump circuit and the second limiter circuit within a period of time the first voltage is being generated. When a supplying voltage of the first pump circuit reaches to the first voltage, and a deformation stops, the second voltage is supplied by the third pump circuit and the third limiter circuit instead of the second pump circuit and the second limiter circuit.

Abstract: Provided is a switching regulator capable of performing stable start-up with a soft-start operation without causing excessive extension of a soft-start time period. In a start-up period, a voltage approximating a feedback voltage (FB) is provided as an initial value of a soft-start reference voltage. The feedback voltage (FB) and the soft-start reference voltage become substantially equal to each other at a moment when the start-up is completed, to thereby realize a smooth transition of an operating state from the start-up to normal control.

Abstract: System and method for regulating a power converter. The system includes a first signal generator configured to receive a first sensed signal and generate an output signal associated with demagnetization. The first sensed signal is related to a first winding coupled to a secondary winding for a power converter, and the secondary winding is associated with at least an output current for the power converter. Additionally, the system includes a ramping signal generator configured to receive the output signal and generate a ramping signal, and a first comparator configured to receive the ramping signal and a first threshold signal and generate a first comparison signal based on at least information associated with the ramping signal and the first threshold signal. Moreover, the system includes a second comparator configured to receive a second sensed signal and a second threshold signal and generate a second comparison signal.

Abstract: Disclosed are apparatus and methodology for providing a capacitive voltage divider configured to reduce a relatively high level alternating current (AC) to a lower level direct current (DC). The apparatus provides a series of capacitors and diodes configured for series charging of the capacitors and parallel discharge thereof by way of a single switching element. In operation, the capacitor series is charged during the negative half cycle of the AC source and then discharged during the positive half cycle thereof.

Abstract: Rather than operating in asynchronous mode during turn-on ramps, a switching power regulator system may be configured to synthesize a digital waveform, which may protect against a pre-bias condition and maintain the desired ramp-up time and rate. The desired turn-on ramp may be generated digitally by counter logic, beginning with an initial value and incrementing at a programmed rate until a digital value equivalent to the desired output voltage is reached. When a pre-bias condition is not present, the output of the digital ramp generator may control a digital-to-analog converter (DAC), which may be configured to generate the reference voltage for the power regulator. To correct for a pre-bias condition, the pre-bias output of the power regulator may be measured prior to turn-on, using an analog-to-digital converter. The digital pre-bias value may be used to control the DAC until the value of the digital waveform generated by the ramp generator reaches the pre-bias value.

Abstract: In an induction motor group control system, magnetic energy recovery switches (3) are connected in series to an induction motor (2) directly driven by a commercial power supply, and a plurality of induction motor control devices (10) enabling voltage control and reactive power control of the induction motor 2 are employed to control generation of reactive power so as to maximize a power factor of the entire plurality of AC loads including the induction motor or compensate variations in voltage of an AC power supply (1).

Abstract: A photovoltaic (PV) energy system includes a pulsed bus defined by a non-zero average value voltage that is proportional to a rectified utility grid AC supply voltage. The PV energy system also includes a plurality of PV modules, each PV module including a bucking circuit configured to convert a corresponding PV voltage into a pulsing current, wherein the pulsating bus is configured to sum the pulsing currents produced via the plurality of PV modules such that a resultant pulsing current is injected into the pulsating bus in phase with the non-zero average value voltage. A current unfolding circuit is configured to control the amount of AC current injected into the utility grid in response to the resultant pulsing current.

Abstract: A first capacitor is arranged such that the electric potential at a first terminal is fixed. A first discharging circuit discharges the first capacitor at a timing that corresponds to a cyclic synchronization signal received from an external circuit. A first comparator compares the voltage at a second terminal of the first capacitor with a predetermined threshold voltage, and generate a judgment signal that corresponds to the comparison result. A charging circuit generates a charging current the current value of which is adjusted according to the level of the judgment signal at a timing that corresponds to the synchronization signal, and supplies the charging current thus generated to the first capacitor.

Abstract: A stepwise voltage ramp generator includes a tank capacitor, a terminal of which is coupled to a reference potential to be charged with a voltage ramp. A transistor couples the tank capacitor to a supply line. A diode-connected transistor, biased with a bias current is coupled to the transistor to form a current mirror. A by-pass switch is electrically coupled in parallel to the diode-connected transistor, and is controlled by a PWM timing signal, the duty-cycle of which determines a mean slope of the generated voltage ramp.

Abstract: Provided is a voltage regulator capable of stable operation under a light load so as to cover a wide range of load capacitances. The voltage regulator includes a circuit for charging a phase compensation capacitor for the voltage regulator, and a zero due to a resistor (104) and a capacitor (106) appears at low frequency.

Abstract: A circuit and method are proposed for constant on-time control for an interleaved multiphase voltage regulator, which monitor the channel currents of all the channels of the interleaved multiphase voltage regulator to select one from the channels to drive and so achieve interleaved phase operation.

Abstract: A first pump circuit generates a first voltage for decreasing the distance between primary electrodes. The first voltage is limited to a predetermined limit by a first limiter circuit. A second pump circuit generates a second voltage for keeping the distance between the primary electrodes constant. A third pump circuit generates the second voltage and has a supplying capacity smaller than the first one. The second voltage is limited by second and third limiter circuits. A ripple capacitor is charged up to the second voltage by the second pump circuit and the second limiter circuit within a period of time the first voltage is being generated. When a supplying voltage of the first pump circuit reaches to the first voltage, and a deformation stops, the second voltage is supplied by the third pump circuit and the third limiter circuit instead of the second pump circuit and the second limiter circuit.

Abstract: The present invention relates to temperature compensation of HID lamps in automobiles. The invention concerns the manner in which the temperature of the HID lamp is accounted for in order to drive the lamp is at appropriate power from hot to cold conditions. In the present invention, the voltage across a capacitor in the temperature compensation circuit is sensed and used as a command signal to anticipate lamp temperature, and accordingly the reference power to the HID lamp is modulated depending on the temperature of the lamp. In the present invention, the lamp is driven with a higher power setting when the lamp is cold and with lower power setting when hot. This adaptive generation of reference power setting depending on the temperature of the lamp is implemented using the voltage across a capacitor in the temperature compensation circuit.

Abstract: A first pump circuit generates a first voltage for decreasing the distance between primary electrodes. The first voltage is limited to a predetermined limit by a first limiter circuit. A second pump circuit generates a second voltage for keeping the distance between the primary electrodes constant. A third pump circuit generates the second voltage and has a supplying capacity smaller than the first one. The second voltage is limited by second and third limiter circuits. A ripple capacitor is charged up to the second voltage by the second pump circuit and the second limiter circuit within a period of time the first voltage is being generated. When a supplying voltage of the first pump circuit reaches to the first voltage, and a deformation stops, the second voltage is supplied by the third pump circuit and the third limiter circuit instead of the second pump circuit and the second limiter circuit.

Abstract: A charging circuit charges a secondary battery by using a first direct current power supply that generates and outputs a first voltage. A highest voltage among the first voltage of the first direct current power supply, a second voltage generated from power supplied from outside, and a secondary battery voltage of the secondary battery is supplied as a power supply to the charging circuit.

Abstract: Methods of reducing peak electrical demand at a single customer location of an electrical service provider during at least one time interval during a day can include shifting the activation of a first electrical appliance located at the single customer location from the at least one time interval during a day to a second time interval during which a second electrical appliance is not activated for at least part of the second time interval. Related systems, circuits, and computer program products are disclosed.

Abstract: A modulator for providing control pulses on a pulse control signal for controlling operation of a DC-DC converter is disclosed which includes a comparator, pulse control logic, a memory circuit and a switch circuit. The comparator compares a timing waveform with a compensation signal and provides a comparison signal with preliminary pulses. The pulse logic circuit receives the comparison signal and provides normal pulses on a normal pulse signal. The pulse logic circuit selects only those preliminary pulses which are provided during a permissible time window of each period of the periodic timing waveform. The memory circuit provides a pulse indication whenever a normal pulse does not occur on the pulse signal during any switching period. The switch circuit selects between the normal pulse signal and the comparison signal based on the pulse indication for providing the control pulses.

Abstract: A power supply includes a first switch to establish a first path to charge an output of the power supply by a voltage source, a second switch to establish a second path to discharge the output, and a third switch connected between the output and a capacitor. When to discharge the output, the third switch is turned on before the second switch turns on, to transfer a portion of energy on the output to the capacitor. When to charge the output, the third switch is turned on before the first switch turns on, to transfer a portion of the energy on the capacitor to the output.

Abstract: A device, such as a pump capacitor or an energy storing inductor, is charged by coupling it to a voltage source. Thereafter, the device is connected in parallel to one of the capacitors or capacitance cells to be charged, and the charging of the device and successive connections of it in parallel to a selected capacitor of the series of capacitors for charging it are replicated for all the capacitors of the series. The sequence of different connections of the device to the charge voltage source and to the selected one of the capacitors of the series is actuated through a plurality of coordinately controlled switches that establish distinct current circulation paths, according to a switched-capacitor or switched inductor techniques driven by respective periodic control signals that may be generated from a master clock signal.

Abstract: In one embodiment, an apparatus is provided for a system including an integrated circuit coupled to a node to receive a supply voltage and having bypass capacitors coupled in parallel with the integrated circuit to the node. The apparatus comprises a first capacitor, a switch coupled to the first capacitor, and a voltage source configured to charge the first capacitor. The switch is coupled to receive a control signal that is asserted, during use, if the supply voltage to an integrated circuit is to be increased. The switch is configured to electrically couple the first capacitor to the node in response to an assertion of the control signal. When electrically coupled to the node, the first capacitor supplies charge to the bypass capacitors. A system comprising the apparatus, the node, the integrated circuit, and the bypass capacitors is also contemplated in some embodiments.

Abstract: To accurately regulate output of a high-frequency power with a simple configuration. A high-frequency power supply circuit includes: a basic drive square wave generation circuit unit (5) for generating a basic drive square wave having an output frequency; a differential signal generation circuit unit (9) for generating a front edge differential signal of the basic drive square wave; a vibrator circuit unit (15) having a square wave signal generator (10) for outputting a square wave signal having a signal width within a period corresponding to a half cycle of the output frequency upon input of a trigger signal from outside and signal width control circuits (11, 12) varying/controlling the signal width of the square wave signal according to the control signal; and a switching amplification circuit unit (6) for amplifying the amplification source signal based on the output signal from the vibrator circuit unit (15).

Abstract: The present invention is intended to prevent the flow of a large input current into a DC/DC converter, to which power is fed from a power supply, before a supply voltage delivered from the power supply reaches a rated output voltage. A control unit included in the DC/DC converter includes a steady state detection block that detects a condition in which an input voltage to be applied to the DC/DC converter has been stabilized, and inhibits the power feed from the DC/DC converter until the input voltage delivered from a power supply in a preceding stage is stabilized.

Abstract: A load control device is adapted to be disposed in series with an AC voltage source and an electrical load and is operable to provide substantially all voltage provided by the AC voltage source to the load. The load control device comprises a controllably conductive device, a controller, a zero-crossing detector, and a power supply for generating a substantially DC voltage for powering the controller. The power supply is operable to charge an energy storage device to a predetermined amount of energy each half-cycle. The controller is operable to determine when the power supply has stopped charging from the zero-crossing detector each half-cycle, and to immediately render the controllably conductive device conductive to conduct the full load current. Before the controllably conductive device begins to conduct each half-cycle, only a minimal voltage develops across the power supply to allow the energy storage device to charge.

Abstract: Rather than operating in asynchronous mode during turn-on ramps, a switching power regulator system may be configured to synthesize a digital waveform, which may protect against a pre-bias condition and maintain the desired ramp-up time and rate. The desired turn-on ramp may be generated digitally by counter logic, beginning with an initial value and incrementing at a programmed rate until a digital value equivalent to the desired output voltage is reached. When a pre-bias condition is not present, the output of the digital ramp generator may control a digital-to-analog converter (DAC), which may be configured to generate the reference voltage for the power regulator. To correct for a pre-bias condition, the pre-bias output of the power regulator may be measured prior to turn-on, using an analog-to-digital converter. The digital pre-bias value may be used to control the DAC until the value of the digital waveform generated by the ramp generator reaches the pre-bias value.

Abstract: A control loop system is provided that employs an active DC output control circuit that more accurately calibrates the desired voltage at a load, e.g. 3.3 volts, by adjusting a trim pin on a DC/DC converter.

Abstract: A control circuit having a programmable waveform for the output power limit comprises an oscillation circuit to generate an oscillation signal. The oscillation signal is used for producing a switching signal to control a switching device in response to a feedback signal of the power converter. A waveform generator generates a waveform signal in accordance with the oscillation signal. The waveform signal controls the control signal and limits the output power of the power converter. A resistor is coupled to the waveform generator to program the waveform of the waveform signal. By properly selecting the resistance of the resistor, which can be used to achieve an identical output power limit of the power converter for the low line and high line voltage input.