Patent application number | Description | Published |
20100007394 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal. A waveform generator generates a waveform signal in response to a switching signal and a second-sampling signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a first-sampling signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to the second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-14-2010 |
20100033991 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - 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. | 02-11-2010 |
20100232187 | OUTPUT VOLTAGE CONTROL CIRCUIT OF POWER CONVERTER FOR LIGHT-LOAD POWER SAVING - A control circuit of a power converter for light-load power saving according to the present invention comprises a first feedback circuit coupled to an output voltage of the power converter to receive a first feedback signal. A second feedback circuit is coupled to the output voltage to receive a second feedback signal. A control circuit generates a switching signal for switching a transformer of the power converter and regulating the output voltage of the power converter in response to the first feedback signal and the second feedback signal. The switching signal is generated in accordance with the first feedback signal when an output load is high. The switching signal is generated in accordance with the second feedback signal during a light-load condition. | 09-16-2010 |
20110116287 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - A switching controller having switching frequency hopping for a power converter includes an oscillator generating a pulse signal for determining a switching frequency of a switching signal, a maximum duty-cycle circuit generating a maximum duty-cycle signal in response to the switching signal for determining the switching frequency of the switching signal, a pattern generator generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the oscillator and the maximum duty-cycle circuit for generating the switching signal in accordance with the pulse signal and 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. | 05-19-2011 |
20110176341 | START-UP CIRCUIT TO DISCHARGE EMI FILTER OF POWER SUPPLIES - A start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter. | 07-21-2011 |
20110182090 | SWITCHING CONTROLLER FOR POWER CONVERTERS - A switching controller for power converter comprises a current-sense circuit and a PWM circuit, The current-sense circuit receives high-voltage signal across a first switch to generate a current-sense signal. The PWM circuit generates a switching signal to control the first switch in response to the current-sense signal. The switching controller further comprises a delay circuit. The delay circuit receives the switching signal to generate a delayed switching signal. The current-sense signal and the high-voltage signal ramp up with the same slope during the delayed switching signal is enabled. The current-sense signal will be pulled down to a level of a ground reference during the delayed switching signal is disabled. A delay time provided by the delay circuit avoids the high-voltage signal at the instance which the first switch is being turned off being conducted to a first comparator and a second comparator via a second switch. | 07-28-2011 |
20110211281 | POWER SUPPLY WITH OPEN-LOOP PROTECTION - A power supply with an open-loop protection according to the present invention comprises a transformer, a switch, a signal generation circuit, a feedback detection circuit, a brown-out detection circuit, and a delay circuit. The transformer receives an input voltage. The switch is coupled to the transformer for switching the transformer. The signal generation circuit generates a switching signal to control the switch. The feedback detection circuit generates a pull-high signal in response to a feedback signal of the power supply. The brown-out detection circuit generates a delay signal in response to the pull-high signal and the input voltage. The delay circuit counts a delay time in response to the delay signal for generating a disabling signal coupled to the signal generation circuit to latch the switching signal. The brown-out detection circuit is utilized to detect whether the input voltage is in the brown-out condition for determining whether the open-loop protection is executed. | 09-01-2011 |
20110305051 | START-UP CIRCUIT WITH LOW STANDBY POWER LOSS FOR POWER CONVERTERS - A start-up circuit with low standby power loss for power converters according to present invention comprises a first diode and a second diode coupled to an input voltage of the power converter. A start-up resistor is coupled to the join of the first diode and the second diode. A high-voltage switch is coupled to the start-up resistor to generate a power source. A control circuit generates a switching signal for switching a transformer. A detection circuit generates a disable signal in response to the input voltage to disable the switching signal. A winding of the transformer is coupled to the power source to generate the power for the power source. The high-voltage switch is turned off to cut off the start-up resistor for saving the power loss once the voltage of the power source is higher than a threshold. | 12-15-2011 |
20120008352 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal and an oscillation signal. A waveform generator generates a waveform signal in response to the oscillation signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a switching signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to a second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-12-2012 |
20130235627 | START-UP CIRCUIT TO DISCHARGE EMI FILTER FOR POWER SAVING OF POWER SUPPLIES - A start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter. | 09-12-2013 |
20140043002 | CONTROL CIRCUIT WITH DEEP BURST MODE FOR POWER CONVERTER - A control circuit with deep burst mode for power converter according to the present invention comprises a load detection circuit and a PWM circuit. The load detection circuit generates a switching control signal in response to a feedback signal. The feedback signal is correlated to a load condition of the power converter. The PWM circuit generates a switching signal to regulate an output of the power converter in response to the switching control signal and the feedback signal. The control circuit performs a deep burst mode to switch the switching signal only one time during each deep burst period when the load condition of the power converter is a very light-load. Therefore, switching loss is reduced so that the power consumption of the power converter is also reduced. | 02-13-2014 |