Leadtrend Technology Corporation

Wen-Chung Yeh

Yi-Lun Shen

Ren-Yi Chen

Chung-Wei Lin

Ming-Nan Chuang

Kuo-Chien Huang

Da-Chun Wei

Yang-Sheng Lin

Tsung-Hsiu Wu

A timing controller provides adaptive timings to control a synchronous rectifier with a body diode. The timing controller has a ramp generator providing a ramp signal at a first capacitor. The ramp signal corresponds to a discharge time when the body diode is forward biased. A second capacitor records an estimated duration signal. An update circuit is connected between the first and second capacitors, for shorting the first and second capacitor to update the estimated duration signal by charge sharing. A comparator with two inputs coupled to the ramp signal and the estimated duration signal respectively compares the ramp signal and the estimated duration signal to control the synchronous rectifier.

Timing control method and apparatus for synchronous rectifier using estimated duration signal

In a switching mode power supply, a power controlling circuit includes a phase generator and a phase controller. The phase generator provides a clock signal. The phase controller detects phases of a phase reference signal and a burst initialization signal so as to generate a burst signal, and causes a phase of the burst signal to not be earlier than the phase of the group reference signal. The burst signal is utilized for switching the power supply between a non-switching state and a switching state. The group reference signal is generated according to the clock signal and has a lower frequency than the clock signal. The burst initialization signal is controlled by an output voltage source of the power supply.

Power control circuit detecting a phase of a burst initializing signal and power controlling method detecting a phase of a burst initializing signal

An embodiment provides a control method capable of controlling a switching-mode power supply to provide an output power source. The switching-mode power supply has a winding coupled to an input power source and controlled by a switch to be energized or de-energized. The maximum current peak through the winding is set to be a predetermined value. A discharge time of the winding in a switching cycle period is detected. The switching cycle period of the switch is controlled to keep the ratio of the discharge time to the switching cycle period as a constant.

Control methods for switching power supplies

A frequency-jittering apparatuses includes an oscillator and a frequency control circuit. The oscillator generates a signal. When the magnitude of the signal exceeds a magnitude of a reference signal, the oscillator operates substantially in a first state; and when the magnitude of the signal is lower than the magnitude of the reference signal, the oscillator operates substantially in a second state different from the first one. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator.

Frequency-jittering apparatuses, frequency-jittering methods and power management devices

Control methods and controller thereof for a power supply including a power switch and an inductor. The power switch is turned on to increase the inductor current through the inductor, which is sensed to generate a current-sense signal. The current-sense signal is added up with an adjusting signal to generate a summation signal. The power switch is turned off if the summation signal is higher than a peak limit. The turn-on time of the power switch is detected to update the adjusting signal.

Over current protection method used in a switched-mode power supply and related controller

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.

Compensation circuits and control methods of switched mode power supply

A switch controller for switching power supply is coupled to an auxiliary winding of the switching power supply through a detecting resistor. The switch controller provides a detecting current passing through the detecting resistor for keeping the voltage level of a detecting signal transmitted by the detecting resistor higher than a predetermined voltage. In this way, the switch controller can avoid the latch-up phenomenon caused by receiving the detecting signal of the negative voltage level. In addition, the switch controller can detect the magnitude of an input voltage of the switching power supply by means of the detecting current, and accordingly control the operation of the switching power supply.

Switch controller for switching power supply and method thereof

Current control method and apparatus are disclosed. A current limiter is coupled to a switch connected in series with an energy transfer element of a power supply. The current limiter detects a current flowing through the switch and, when the current exceeds a current limit signal, turns off the switch. A limit signal generator provides the current limit signal, detects the maximum current value of the current, and updates the current limit signal according to the maximum current value and an ideal current limit value.

Growing community of inventors

Hsin-Chu, Taiwan

Wen-Chung Yeh