Abstract: A control circuit controls the output current of the power converter at the primary side of the transformer. The control circuit includes a current-detection circuit for generating a primary-current signal in response to the switching current of the transformer. A voltage-detection circuit is coupled to the transformer to generate a period signal and a discharge-time signal in response to the reflected voltage of the transformer. A signal-process circuit is utilized to generate a current signal in response to the primary-current signal, the period signal and the discharge-time signal. The period signal is correlated to the switching period of the switching signal of the power converter. The discharge-time signal is correlated to the duty cycle of switching current at the secondary-side of the transformer. The current signal is correlated to the output current of the power converter.

Abstract: A power converter according to the present invention comprises a resonant tank. The resonant tank is switched by a plurality of transistors. A control circuit generates a plurality of switching signals to control the transistors. The pulse widths of the switching signals are modulated for regulating an output voltage of the power converter. The control circuit is coupled to detect an input voltage of the power converter. The frequency of the switching signals is changed in response to the change of the input voltage or/and an output load of the power converter.

Abstract: A start up circuit of power converters is presented. It includes a first transistor, a resistive device, a second transistor, a third transistor and a diode. The first transistor is coupled to a voltage source. The third transistor is connected in serial with the first transistor to output a supply voltage to a control circuit of the power converter in response to the voltage source. The diode is connected from a transformer winding of the power converter to supply a further supply voltage to the control circuit of the power converter. The second transistor is coupled to control the first transistor and the third transistor in response to a control signal. The resistive device provides a bias voltage to turn on the first transistor and the third transistor when the second transistor is turned off. Once the second transistor is turned on, the third transistor is turned off and the first transistor is negative biased.

Abstract: A semiconductor structure of a high side driver includes an ion-doped junction. The ion-doped junction includes a substrate and a deep well. The deep well is formed in the substrate and has a first concave structure. The ion-doped junction includes a semiconductor region connected to the first concave structure of the deep well and having substantially the same ion-doping concentration as the substrate.

Abstract: A control circuit includes a detection circuit to detect the short-circuited of a current sense terminal of the power converter. It includes a comparator, a verification circuit and a timer circuit. The comparator receives an input signal for generating a sense signal. The input signal represents the switching current of a power switch. The sense signal is enabled when the input signal is lower than a threshold. The verification circuit generates a protection signal in response to the sense signal or/and -a delay signal. The protection signal is generated when the current sense terminal is short-circuited, in which the power switch and the sense signal are enabled after the time delay of the delay signal. The protection signal turns off the power switch for the protection.

Abstract: The present invention provides a low-cost resonant inverter circuit for ballast. The resonant circuit includes a transformer connected in series with a lamp to operate the lamp. A first transistor and a second transistor are coupled to switch the resonant inverter circuit. A second winding and a third winding of the transformer are used for generating control signals in response to a switching current of the resonant inverter circuit. The transistor is turned on once the control signal is higher than a high-threshold. Next, the transistor is turned off once the control signal is lower than a low-threshold. Therefore, soft switching operation for the first transistor and the second transistor is achieved.

Abstract: The high voltage integrated circuit comprises a P substrate. An N well barrier is disposed in the substrate. Separated P diffusion regions forming P wells are disposed in the substrate for serving as the isolation structures. The low voltage control circuit is located outside the N well barrier. A floating circuit is located inside the N well barrier. In order to develop a high voltage junction barrier in between the floating circuit and the substrate, the maximum space of devices of the floating circuit is restricted.

Abstract: A floating driving circuit according to the present invention comprises an input circuit to receive an input signal. A latch circuit receives a trigger signal for generating a latch signal. The latch signal is used to turn on/off a switch. A coupling capacitor is connected between the input circuit and the latch circuit to generate the trigger signal in response to the input signal. A diode is connected from a voltage source to a floating supply terminal of the latch circuit for charging a capacitor. The capacitor is coupled between the floating supply terminal and a floating ground terminal of the latch circuit to provide a supply voltage to the latch circuit. The latch circuit is controlled by the input signal via the coupling capacitor.

Abstract: A synchronous rectifier of a resonant switching power converter is provided to improve efficiency. The synchronous rectifier includes a power transistor and a diode connected to a transformer and an output of the resonant switching power converter for ratifications. A controller generates a drive signal to control the power transistor in response to an on signal and an off signal. A causal circuit is developed to generate the off signal in accordance with the on signal. The on signal is enabled once the diode is forward biased. The on signal is coupled to enable the drive signal for switching on the power transistor. The off signal is coupled to disable the drive signal for switching off the power transistor. The off signal is enabled before the on signal is disabled.

Abstract: A wall control interface for power management includes a transmitting circuit that generates a switching signal to control a switch and achieve a phase modulation to a power line signal in response to a transmitting-data. A receiving circuit is coupled to detect the phase of the power line signal for generating a data signal and a receiving-data in response to the phase of the power line signal. The receiving circuit further generates a control signal to control power of a load in accordance with the data signal or the receiving-data. The phase modulation is achieved by controlling a turn-on angle of the power line signal. The switch remains in a turn-on state during the normal condition, which achieves good power and low current harmonic. The phase modulation is only performed during the communication of the power management.

Abstract: A control circuit is developed to adaptively operate a power converter at quasi-resonance (QR) and in a continuous current mode (CCM) to achieve high efficiency. The control circuit includes a PWM circuit generating a switching signal coupled to switch a transformer. A signal generation circuit generates a ramp signal and a pulse signal. The pulse signal is generated in response to the ramp signal for switching on the switching signal. A feedback circuit produces a feedback signal according to an output load of the power converter. The feedback signal is coupled to switch off the switching signal. A detection circuit is coupled to the transformer for generating a valley signal in response to the waveform of the transformer. The valley signal is further coupled to generate the pulse signal when the ramp signal is lower than a threshold. The level of the threshold is correlated to the feedback signal.

Abstract: A synchronous rectifying circuit is provided for power converter. A pulse signal generator is utilized to generate a pulse signal in response to the leading edge and the trailing edge of a switching signal. The switching signal is used for switching the transformer of the power converter. An isolation device such as pulse transformer or small capacitors is coupled to the pulse signal generator for transferring the pulse signal through an isolation barrier of a transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is equipped in between the secondary side of the transformer and the output of the power converter for the rectifying. The control circuit having a latch is operated to receive the pulse signal for turning on/off the power switch.

Abstract: A circuit and a method for detecting a voltage of a transformer are provided. The circuit includes a current output circuit coupled to a winding of a transformer to generate a current signal. A current-to-voltage circuit is coupled to the current output circuit to generate a voltage signal in response to the current signal. A sample-and-hold circuit generates an output signal by sampling the voltage signal. An input voltage is applied to the transformer. The output signal is correlated to the input voltage of the transformer.

Abstract: A synchronous rectifying circuit is provided for resonant power converter. An integrated synchronous rectifier comprises a rectifying terminal, a ground terminal a first input terminal and a second input terminal. The rectifying terminal is coupled to the secondary side of a power transformer. The ground terminal is coupled to the output of the power converter. A power transistor is connected between the rectifying terminal and the ground terminal. The first input terminal and the second input terminal are coupled to receive a pulse signal for turning on/off the power transistor. A pulse-signal generation circuit includes an input circuit coupled to receive the switching signal for switching the power transformer of the power converter.

Abstract: A switching control circuit having a synchronous input for the synchronization of power converters is provided. It includes a synchronous input circuit for receiving a synchronous input signal. An oscillation circuit is connected to the synchronous input circuit for generating an oscillation signal in response to the synchronous input signal. A signal converter is coupled to receive a feedback signal of the power converter for modulating the oscillation signal in response to the feedback signal for achieving power savings. The oscillation signal is connected for enabling the switching signal of the power converter. The switching signal can be synchronized with the synchronous input signal immediately after the synchronous input signal is inputted. Otherwise, the switching signal will be running free.

Abstract: A circuit for detecting an input voltage of a transformer is provided. The circuit includes a current source circuit coupled to a winding of a transformer. A current-to-voltage circuit is coupled to the current source circuit to generate a first voltage in response to a current outputted from the current source circuit. A sample-and-hold circuit generates an output voltage by sampling the first voltage. The transformer is coupled to the input voltage, and the output voltage is correlated to the input voltage of the transformer.

Abstract: A semiconductor device for electrostatic discharge protection is disclosed, and at least comprises a high-voltage parasite silicon controlled rectifier (HVSCR) and a diode. The HVSCR has an anode and a cathode, and the cathode of HVSCR is coupled to a ground. The diode, coupled to the HVSCR in series, also has an anode and a cathode. The anode of the diode is coupled to the anode of the HVSCR, and the cathode of the diode is coupled to a terminal applied with a positive voltage. The diode has a second conductivity type zone that could be constructed to form several strips or small blocks spaced apart from each other. Those small blocks could be any shapes and arranged regularly or randomly.

Abstract: A slave switching circuit for a master-slave PFC converter is disclosed. The slave switching circuit includes a phase-detection circuit coupled to detect a master-switching signal and a slave-inductor signal for generating a start signal and a phase-lock signal. The start signal is coupled to enable a slave-switching signal. The slave-switching signal is coupled to switch a slave inductor. An on-time-adjust circuit is used to adjust the on-time of the slave-switching signal in accordance with the phase-lock signal. The slave-inductor signal is correlated to the demagnetization of the slave inductor. The phase-lock signal is coupled to minimize the period between the disablement of the slave-inductor signal and the enablement of the start signal.

Abstract: A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current.

Abstract: A switching controller having switching frequency hopping for a power converter includes a first oscillator generating a pulse signal and a maximum duty-cycle signal for determining a switching frequency of a switching signal, a pattern generator having a second oscillator and generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the first oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the first oscillator for generating the switching signal in accordance with the maximum duty-cycle signal. A maximum on-time of the switching signal is limited by the maximum duty-cycle signal. The switching signal is utilized to switch a transformer of the power converter.