LEADTREND TECHNOLOGY CORPORATION Patent applications |
Patent application number | Title | Published |
20140146581 | Power Controller with Over Power Protection - A power controller with over power protection is disclosed, capable of providing a pulse-width-modulation signal to control a power switch. The power controller comprises a pulse width modulator, first and second oscillators, and an over power detector. The pulse width modulator generates the pulse-width-modulation signal. The first oscillator is coupled to the pulse width modulator, for determining a cycle time of the pulse-width-modulation signal. The second oscillator, independent from the first oscillator, determines a maximum over power duration. The over power detector detects the occurrence of an over power event. When the over power event lasts for the maximum over power duration, the pulse-width-modulation signal switches OFF the power switch constantly. | 05-29-2014 |
20140097755 | Drivers and Driving Methods for a LED String, Capable of Providing LED Short Protection or Avoiding LED Flickering - The disclosure regards to drivers and driving methods for a LED string consisting of LEDs. The LED string and a current switch are coupled in series between a power line and a ground line. The power line is powered to regulate a signal representing a current passing through the LED string. An enable signal capable of switching the current switch is provided. Whether a predetermined event occurs is detected. When the predetermined event occurs, the enable signal is clamped to have a predetermined logic value, the current switch thereby being kept either open or short. | 04-10-2014 |
20140009974 | Control Methods and Apparatuses for Switching Mode Power Supplies - Embodiments disclose control methods and control apparatuses for a switched mode power supply. The switched mode power supply comprises a current-controllable device. A driving current is provided to turn ON the current-controllable device. A conduction current passing through the current-controllable device is detected. The driving current is controlled according to the conduction current. The higher the conduction current the higher the driving current. | 01-09-2014 |
20130057234 | CONTROL METHODS AND POWER CONTROLLERS WITH LOAD COMPENSATION ADAPTED FOR A POWER SUPPLY - Disclosure includes control methods and power controllers with load compensation adapted for a power supply powering a load. A disclosed power controller comprises a converter and a control circuit. The converter converts the load signal at a first node to output a load-compensation signal at a second node. The load signal corresponds to an output power provided from the power supply to the load, and the converter includes a low-pass filter coupled between the first and second nodes. The control circuit is coupled to an inductive device via a feedback node, for controlling the output power to make a cross voltage of the inductive device approach a target voltage, based on a feedback voltage at the feedback node. The higher the load-compensation signal the higher the target voltage. | 03-07-2013 |
20130051086 | CONTROL CIRCUITS AND CONTROL METHODS FOR OVER VOLTAGE PROTECTION IN POWER SUPPLIERS - Disclosed include a control circuit adapted for a power controller powered by an operation voltage. When the operation voltage exceeds an over-voltage reference, the power controller stops power conversion provided by a power converter. The control circuit comprises a slope detector detecting a variation slope of the operation voltage. When the variation slope exceeds a drop rate, the slope detector recovers the power conversion. When the power conversion is recovered the power controller compares the operation voltage with the over-voltage reference. | 02-28-2013 |
20130038243 | CURRENT-CONTROLLED STAGES, CONSTANT CURRENT CONTROL SYSTEMS, AND CURRENT CONTROL METHODS FOR DRIVING LEDS - Disclosure has current-controlling stages, backlight systems and control methods for driving LEDs. A disclosed current-controlling stage has a current controller and a feedback apparatus. The current controller is coupled to a light-emitting device, for making the driving current through the light-emitting device substantially a predetermined value. The current controller has a control node, at which a control voltage substantially controls the driving current. The feedback apparatus influences a compensation voltage based on the control voltage to keep the control voltage substantially around a first predetermined value. The compensation voltage substantially determines an output power of a voltage-controlling stage. | 02-14-2013 |
20130033184 | POWER CONTOLLERS AND CONTROL METHODS - Disclosure has power controllers and control methods used therein. A disclosed power controller is adapted for a power converter to power at least one light emitting diode. The power converter includes a power switch with a control gate to make an inductive energized or de-energized. The power converter receives a dimming signal to substantially control the lighting of the light emitting diode. The power controller has a gate-driving circuit, for driving the control gate according to a pulse-width signal and the dimming signal. When the dimming signal is asserted the gate-driving circuit has a first driving force. When the dimming signal is deasserted the gate-driving circuit has a second driving force less than the first driving force. | 02-07-2013 |
20100046262 | Control Apparatus and Control Method for a Power Factor Correction Power Converter - A control apparatus and a control method for a power factor correction power converter are provided. The control apparatus is configured to reduce the variation rate of a reference signal with a rising portion and a falling portion. When the primary winding almost completely releases the stored energy, and the falling portion of the reference signal reaches a determined condition, the control apparatus turns on a switch for increasing the stored energy of the primary winding. | 02-25-2010 |
20100046261 | Apparatus and Method for Zero-Voltage Region Detection - An apparatus and a method for detecting zero-voltage region detection are provided. The apparatus for zero-voltage region detection is configured to detect whether an input voltage approaches a zero voltage through an auxiliary winding, and to detect whether a primary winding almost completely releases the stored energy through the auxiliary winding. | 02-25-2010 |