Richtek Technology Corporation

Wen-Wei Chen

Kuo-Chi Liu

Yen-Te Lee

Jian-Rong Huang

Yi-Cheng Wan

Kuang-Feng Li

Wei-Yuan Ting

Yi-Fan Chen

A constant on time mode power supplier uses longer constant on time when the output voltage of the constant on time mode power supplier is drooped due to load variation, to increase energy provided to the output of the constant on time mode power supplier for preventing the output voltage from undershooting and shortening the time for the output voltage to recover stable.

Load transient of a cot mode power supply

A control circuit of a power converter includes: a periodical signal generating circuit for generating a first filtered signal, a second filtered signal, and a periodical signal according to a second feedback signal corresponding to an inductor voltage of the power converter; a comparison circuit for comparing the error signal and the periodical signal to generate a comparison signal; a control signal generating circuit for generating a control signal to control power switches of the power converter according to the comparison signal; and a signal adjusting circuit. During a load transient period at which the load of the power converter changes from a relatively light load to a relatively heavy load, when a lower switch of the power converter is turned on, the signal adjusting circuit reduces an output current of the periodical signal generating circuit to increase a loop response of the power converter.

Control circuit for dynamically adjusting off time of power switch in power converter

An independent bleeding integrated circuit device is provided to replace the bleeding resistor for an EMI filter capacitor, to establish a discharge path between the two terminals of the EMI filter capacitor when the EMI filter capacitor is disconnected from an AC power source, for discharging the EMI filter capacitor. When the EMI filter capacitor is connected with an AC power source, the discharge path is cut off to avoid power loss.

Self-discharge control for an EMI filter capacitor

A control circuit and method for a PWM voltage regulator combine a high frequency feedback technique with a constant on-time or constant off-time topology to improve the transient performance of the PWM voltage regulator. The PWM voltage regulator generates a constant on-time or constant off-time depending on a current for generating a PWM signal, and dynamically adjusts the current according to the droop-voltage at its output during a transient period. Therefore, the PWM voltage regulator boosts its transient response without any threshold for load step detection.

Control circuit and method for providing a signal for a PWM voltage regulator to convert an input voltage into an output voltage

A control device is disclosed, having a signal generating circuit and a mode decision circuit. The signal generating circuit is used to generate a first control signal and a second control signal according to an output voltage of a buck-boost converter. The first control signal is used to conduct a first switch and a second switch of the buck-boost converter. The second control signal is used to conduct a third switch and a fourth switch of the buck-boost converter. When the duty cycle of the first control signal is greater than a first predetermined value and the duty cycle of the second control signal is less than a second predetermined value, the mode decision circuit configures the signal generating circuit to generate the first control signal and the second control signal with substantially the same duty cycle.

Control device for buck-boost converter

A control circuit and method for a buck-boost switching converter provides a mode determinative circuit to judge the timing of an operation under buck-boost mode based on the input voltage, the output voltage and the mode reference voltage; meanwhile, the control signal generating circuit is provided to turn off the second switch during the first switch being on, turn on the second switch during the first switch being off, turn off the fourth switch during the third switch being on, turn on the fourth switch during the third switch being off, wherein the duty cycles of the first and third switches are identical, and duty cycles of the second and fourth switches are identical.

Control circuit and method for a buck-boost switching converter

A control circuit and method for a current mode controlled power converter to convert an input voltage into an output voltage, dynamically adjust the peak or the valley of a ramp signal depending on either or both of the input voltage and the output voltage. Under different conditions of the input voltage and the output voltage, the current mode controlled power converter can generate stable output voltages with an invariant inductor and an invariant compensation circuit, without sub-harmonic which otherwise may happen.

Control circuit and method for a current mode controlled power converter

A control circuit and method are proposed to generate a control signal to operate a buck-boost power stage of a buck-boost power converter to convert an input voltage to an output voltage. The control circuit and method detect the output voltage to generate an error signal, control the frequency of two ramp signals according to the error signal, generate two pulse width modulation signals according to the error signal and the two ramp signals, and generate the control signal according to the two pulse width modulation signals. When the loading of the buck-boost power converter transits from heavy to light, the frequency of the two ramp signals is decreased to improve the efficiency of the buck-boost power converter. The peaks and valleys of the two ramp signals may be adjusted by signals related to the input voltage and the output voltage.

Growing community of inventors

Taipei, Taiwan

Wen-Wei Chen