Patent application number | Description | Published |
20080259655 | SWITCHING-MODE POWER CONVERTER AND PULSE-WIDTH-MODULATION CONTROL CIRCUIT WITH PRIMARY-SIDE FEEDBACK CONTROL - A pulse-width-modulation control circuit of a switching-mode power converter with a primary-side feedback control is disclosed. The switching-mode power converter includes a transformer, a power switch, a current sensing resistor and the pulse-width-modulation control circuit. The transformer includes a primary-side winding, a secondary-side winding and an auxiliary winding. The pulse-width-modulation control circuit includes a sample and hold circuit, a transconductor circuit, an error amplifier and a pulse-width-modulation generator. | 10-23-2008 |
20080298088 | DC TO DC CONVERTER WITH LOAD OPEN DETECTION AND RELATED METHOD THEREOF - Disclosed is a DC to DC converter, which comprises: a transforming circuit, for transforming an input voltage to an output voltage; a comparator, for comparing a reference voltage and a feedback voltage proportional to the output voltage to generate a comparing signal; a control circuit, coupled to the transforming circuit and the comparator, for controlling the transforming circuit according to the comparing signal; and a time-counting device, coupled to the control circuit, for counting the time of a specific voltage level of the comparing signal; wherein the time-counting device informs the control circuit that a load open situation occurs if the specific voltage level of the comparing signal lasts a predetermined time, then the control circuit turns off the transforming circuit. | 12-04-2008 |
20090180219 | APPARATUS FOR DETECTING ERROR OCCURRING TO POWER CONVERTER AND DETECTING METHOD THEREOF - An apparatus is applicable to a power converter comprising a primary winding for receiving an input voltage and a secondary winding for generating an output voltage to power a load. The apparatus comprises a detecting circuit, a comparing circuit, and a determining circuit. The detecting circuit is configured to generate a feedback signal according to the output voltage. The comparing circuit is coupled to the detecting circuit and configured to compare the feedback signal and a threshold and accordingly generates an indication signal indicative of the over high output voltage. The determining circuit, which is in response to the indication signal, is configured to trigger an over voltage protection mechanism preventing the power converter from powering the load. Since the feedback signal is instantly responsive to the output voltage, the occurrence of an error can be rapidly and correctly detected, allowing rapid and correct protection for the power converter. | 07-16-2009 |
20090279329 | DIGITAL LATCH CONTROL CIRCUIT FOR OVER-VOLTAGE PROTECTION AND POWER CONVERTER USING THE CONTROL CIRCUIT - An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level. | 11-12-2009 |
20090284180 | DRIVING CIRCUIT FOR LIGHT EMITTING DEVICE WITH COMPENSATION MECHANISM AND DRIVING METHOD THEREOF - A light emitting device driving circuit, includes: a switch device, a comparator, a driving module, a time counting circuit and a compensation module. The switch device is turned on or off according to a control signal for controlling a driving current flowing through the light emitting device. The comparator generates a comparison result according to a reference voltage and a feedback voltage corresponding to the driving current. The driving module generates the control signal according to the comparison result. The time counting circuit controls the driving module to turn on the switch device after the switch device turns off for a predetermined time. The compensation module detects a turn on time for the switch device and a delay time between the feedback voltage reaching the reference voltage value and the control signal varying correspondingly, and adjusts the reference voltage according to the turn on time and the delay time. | 11-19-2009 |
20100052742 | LIMIT SIGNAL GENERATOR, PWM CONTROL CIRCUIT, AND PWM CONTROL METHOD THEREOF - A PWM control circuit is disclosed. An oscillator generates a triangular signal, received by a limit signal generator to produce a limit signal accordingly. Corresponding to a rising period of the triangular signal, the limit signal sequentially experiences a first holding period, a rising period and a second holding period, wherein the limit signal has a first predetermined value during the first holding period and a second predetermined value during the second holding period. A compare/control circuit compares the limit signal with a detection signal corresponding to a current through a power switch, and controls the power switch accordingly. | 03-04-2010 |
20110211372 | COMPENSATION CIRCUITS AND CONTROL METHODS OF SWITCHED MODE POWER SUPPLY - A compensation circuit has a resistor, a switch and a compensation capacitor. The resistor and the switch are connected in series between a power node and a compensation node. The compensation capacitor is connected to the compensation node, whose voltage is responsive to the output power source. For a predetermined period of time after the voltage falls below a predetermined value, the switch is open and no current flows through the resistor from the power node to the compensation node. | 09-01-2011 |
20150207311 | CONTROL CIRCUIT APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF - A control circuit applied to a power converter includes a multi-functional pin, a zero-crossing signal generator, and an over-voltage detector. The multi-functional pin is used for receiving an auxiliary current generated by an auxiliary winding of the power converter, and an input current. The zero-crossing signal generator is used for generating a zero-crossing signal according to the auxiliary current. The over-voltage detector is used for generating an over-voltage signal according to the auxiliary current. The control circuit generates a switch control signal to the power switch according to the zero-crossing signal, or generates an over-voltage protection signal to the power switch according to the over-voltage signal. | 07-23-2015 |