摘要:
A switching mode power supply, and a primary-side controlled PFM converter using the primary-side regulated PFM controller are discussed. In present embodiment, the primary side cycle by cycle switch peak current is no longer a constant. The time detector is added to monitor the waveform of primary-side sample voltage and then generate the duty cycle. The transfer function should be selected to satisfy a specific relationship of switching frequency and switch peak current against with output loading current. The new design shows higher switching frequency but lower value of switch peak current at light load condition. This resolves the audible noise and poor transient response issue from the prior art PFM controller.
摘要:
A switching mode power supply, and a primary-side controlled PFM converter using the primary-side regulated PFM controller are discussed. In present embodiment, the primary side cycle by cycle switch peak current is no longer a constant. The time detector is added to monitor the waveform of primary-side sample voltage and then generate the duty cycle. The transfer function should be selected to satisfy a specific relationship of switching frequency and switch peak current against with output loading current. The new design shows higher switching frequency but lower value of switch peak current at light load condition. This resolves the audible noise and poor transient response issue from the prior art PFM controller.
摘要:
The present invention relates to clamp protection circuit and a PFC control circuit employing such clamp protection circuit. Said clamp protection circuit comprises a high voltage isolation module used for receiving power from a high voltage power supply; a voltage clamp module used for receiving an output low voltage from the high voltage isolation module and realizing a clamp protection; and a low voltage bias module used for providing bias voltage to the high voltage isolation module and the voltage clamp module. By employing the clamp protection circuit, the precision of the clamp voltage is improved, the design is simplified and the silicon area is reduced. Meanwhile, the transient response is enhanced. Moreover, when the clamp protection circuit is applied in a PFC control circuit, the design of the whole PFC control circuit is simplified and the silicon area is reduced, and the precision and transient response of the clamp voltage of the clamp protection circuit inside the PFC control circuit are improved.
摘要:
The present invention relates to a frequency jittering device and method, and a switching power supply employing such frequency jittering device. Said method comprises: S1 generating a variable logic number; S2 generating a delay signal; S3 generating a PWM control signal according to the variable logic number and the delay signal; S4 generating an output signal according to the PWM control signal; and S5 generating a clock signal with variable frequency according to the output signal; wherein, the clock signal is fed back to update the variable logic number, and a jittering clock signal modified in each clock cycle is produced. The benefit of the present invention is not only can apply small low cost EMI filter but also can keep the noise floor level low enough at light load condition.
摘要:
The present invention relates to clamp protection circuit and a PFC control circuit employing such clamp protection circuit. Said clamp protection circuit comprises a high voltage isolation module used for receiving power from a high voltage power supply; a voltage clamp module used for receiving an output low voltage from the high voltage isolation module and realizing a clamp protection; and a low voltage bias module used for providing bias voltage to the high voltage isolation module and the voltage clamp module. By employing the clamp protection circuit, the precision of the clamp voltage is improved, the design is simplified and the silicon area is reduced. Meanwhile, the transient response is enhanced. Moreover, when the clamp protection circuit is applied in a PFC control circuit, the design of the whole PFC control circuit is simplified and the silicon area is reduced, and the precision and transient response of the clamp voltage of the clamp protection circuit inside the PFC control circuit are improved.
摘要:
The present invention relates to controller for reducing the harmonics contents in the AC-to-DC converter. The controller, capable of minimizing THD due to crossover distortion, comprises: a THD Reducer for setting an appropriate offset voltage to for THD reduction; an Error Amplifier for generating an output voltage error signal corresponding to a deviation in the output voltage of the power supply unit from a predetermined reference voltage; Multiplier for combining the divided down rectified signal with the output voltage error signal to generate a sinusoidal reference signal; Comparator for generating a logic signal for setting the Power NMOS on period by comparing the received current sense signal with the summation of offset voltage from THD Reducer and output of Multiplier; Zero Crossing Detector (ZCD) for generating an edge logic signal to turn on Power NMOS, RS Flip-Flop Register and Gate Driver combined to create required analog waveform pattern for driving Power NMOS and thereby approximating the shape of the current running through boost inductor to the sinusoidal waveform of the rectified line input voltage and in the meantime to keep the valley of rectified sinusoidal waveform line voltage close to local ground value.
摘要:
The present invention relates to a charge status indicator and a charger. The charger comprises a charging power supply and a charge status indicator, wherein, the charge status indicator comprises a detecting chip for monitoring charge status connected between the primary winding of transformer and ground, and a display module used for displaying the charge status, wherein, said detecting chip for monitoring charge status comprising: a detecting module for detecting the charging state of the charge power supply; a comparing module for determining the current charge status based on the detected charging state. By employing the charger or the charge status indicator for a charger, a primary-side feedback control Flyback SMPS may be employed, just a simple and reliable circuit is needed, and higher efficient can be achieved.
摘要:
The present invention relates to a frequency jittering device and method, and a switching power supply employing such frequency jittering device. Said method comprises: S1 generating a variable logic number; S2 generating a delay signal; S3 generating a PWM control signal according to the variable logic number and the delay signal; S4 generating an output signal according to the PWM control signal; and S5 generating a clock signal with variable frequency according to the output signal; wherein, the clock signal is fed back to update the variable logic number, and a jittering clock signal modified in each clock cycle is produced. The benefit of the present invention is not only can apply small low cost EMI filter but also can keep the noise floor level low enough at light load condition.
摘要:
A LED dimming device, and a LED dimming and a driving circuit using such LED dimming device are discussed. In present embodiment, the LED dimming device multiplexes an inputting switch and/or a sampling module of the LED driving circuit for dimming. such LED dimming device will not affect the sine waves of input current, in such a way, power factor and work efficiency will be increased while the harmonic coefficient and interference signal will be reduced.
摘要:
A LED dimming device, and a LED dimming and a driving circuit using such LED dimming device are discussed. In present embodiment, the LED dimming device multiplexes an inputting switch and/or a sampling module of the LED driving circuit for dimming. such LED dimming device will not affect the sine waves of input current, in such a way, power factor and work efficiency will be increased while the harmonic coefficient and interference signal will be reduced.