Leadtrend Technology Corporation

Weltrend Semiconductor Inc.

Grenergy Opto Inc.

Ren-Yi Chen

Yi-Lun Shen

Kuo-Chien Huang

Yi-Shan Chu

Chun-Teh Chen

Wen-Chung Yeh

Ming-Ying Kuo

Yuan-Wen Chang

Chin-Ho Wu

Ming-Chang Tsou

Yu-Yun Huang

Chen-Lun Yang

Jeng-Cheng Liu

Shun-Chin Chou

Mu-Chih Lin

Jiun-Sheng Huang

A control method is introduced to operate an ACF power converter under a non-complimentary mode. A high-side switch is turned ON at least twice within a switching cycle of a low-side switch, to provide at least two high-side ON times. One of the high-side ON times follows the end of demagnetization time of a transformer in the ACF power converter, and the other follows the end of the blanking time that controls the maximum switching frequency of the low-side switch.

Control method in use of active-clamp flyback power converter

Power supplies together with related over voltage protection methods and apparatuses. A power supply has a transformer including a primary winding and an auxiliary winding. A power switch is coupled to the primary winding and a sensing resistor coupled between the power switch and a grounding line. A multi-function terminal of a controller is coupled to the sensing resistor. A diode and a first resistor is coupled between the auxiliary winding and the multi-function terminal.

Controller and power supply

A power control device includes a switch control circuit, a first resistor, a second resistor, a third resistor, a sense node, a first comparator, a second comparator, a transformation circuit, and a logic control circuit. The switch control circuit outputs a driving signal according to a set signal and a reset signal. The first resistor, the second resistor, and the third resistor generate a reference voltage according to a feedback current. The sense node receives a current sample voltage. The first comparator outputs a first control signal according to the current sample voltage and the reference voltage. The transformation circuit outputs a short detection voltage according to the current sample voltage. The second comparator outputs the second control signal according to the current sample voltage and the short detection voltage. The logic control circuit gate outputs the reset signal according to the first control signal and the second control signal.

Power control device capable of detecting the condition of the sensing resistor

A control circuit includes a set of alternating-current (AC) power receiver terminals, a rectification unit, a transistor, a switch, a detection unit, a comparison unit and a logic control circuit. The AC power receiver terminals receive and send external AC power to the rectification unit. The rectification unit outputs an operation voltage accordingly. The transistor is coupled between the rectification unit and the switch. The detection unit is coupled to the rectification unit to generate a first detection voltage and a second detection voltage according to the operation voltage. When the first detection signal is equal to the second detection signal, the comparison unit sends a comparison signal. The logic control circuit turns on the transistor and the switch if the comparison signal still has not been received after a predetermined time interval has elapsed.

Control circuit capable of detecting status of receiving power and decreasing voltage of capacitor accordingly

Controllers, power supplies and control methods

Power supplies and power controllers are disclosed. A disclosed power supply has a power controller, a power switch, an auxiliary winding, a first circuit and a second circuit. The power controller is a monolithic integrated circuit with a multi-function pin and a gate pin. A control node of the power switch is coupled to the gate pin. The first circuit is coupled between the multi-function pin and the auxiliary winding and has a diode. The second circuit is coupled between the multi-function pin and a ground line, and has a thermistor.

Power controller with multi-function pin and power supply using the same

A power controller provides a block time in response to an output current to an output load, and the block time determines a maximum switching frequency of a switching mode power supply. An exemplifying power controller has an output current estimator, a block time generator, and a pulse width modulator. The output current estimator provides a load representative signal in response to a discharge time of the inductive device and a current sense signal, wherein the current sense signal represents a current through an inductive device. The block time generator provides a block time based on the load representative signal. The pulse width modulator generates a pulse-width-modulation signal to control a power switch in response to a compensation signal, which is in response to the output voltage to the output load. The cycle time of the pulse-width-modulation signal is limited to be not less than the block time.

Switching mode power supply capable of providing a block time in response to an output current

A controller of a power converter with adjustable jitter amplitude includes a feedback pin, a logic circuit, an auxiliary pin, and a current sensing pin. The feedback pin is used for receiving a feedback voltage from a secondary side of the power converter. The feedback voltage corresponds to an output voltage of the secondary side of the power converter. The logic circuit is used for generating a jitter signal according to a clock, the feedback voltage, and a first resistor. The auxiliary pin is used for receiving a voltage corresponding to an auxiliary winding of the power converter. The current sensing pin is used for generating a detection voltage according to a current flowing through a primary side of the power converter. The voltage, the jitter signal, and the detection voltage determine turning-on time of the primary side of the power converter.

Controller of a power converter with adjustable jitter amplitude and method of generating adjustable jitter amplitude thereof

Disclosure includes a control method for over voltage protection, suitable for a power converter. The power converter has a rectifier for rectifying an alternative-current voltage into a direct-current input voltage. The direct-current input voltage is sensed and determined whether it locates in a valley. A detection voltage is provided, capable of representing the direct-current input voltage. The detection voltage is compared with a predetermined reference voltage. When the detection voltage exceeds the predetermined reference voltage and the direct-current input voltage is in the valley, an OVP signal is provided to stop the power conversion of the power converter.

Control methods for over voltage protection and relevant power controllers

A method for controlling voltage crossing a power switch of a switched-mode power converter includes the steps of: controlling a switch frequency of the power switch of the switched-mode power converter to a first frequency as activating the switched-mode power converter; and then changing the switch frequency of the power switch to a second frequency after the switched-mode power converter is activated for a predetermined time; wherein the first frequency is lower than the second frequency.

Control circuit of a switched-mode power converter and method thereof

A power supply can provide brown-out protection and overheat protection. The power supply includes a rectifier, a transformer, and a power management device. The rectifier is used for receiving an alternating current voltage. The alternating current voltage has a voltage cycle. The transformer coupled to the rectifier has an inductor coupled to a switch for supplying an output voltage. The power management device is used for controlling the switch to make the inductor save power or release power. The power management device has a multi-functional pin coupled to the rectifier for receiving a detection voltage corresponding to a positive half cycle of the alternating current voltage. The multi-functional pin is also coupled to a thermistor for receiving an overheat protection signal.

Power supply, power management device applied to a power supply, and method for performing brown-out protection and overheat protection of a power management device

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.

Control methods and power controllers with load compensation adapted for a power supply

A sample-and-hold circuit for generating a variable sample delay time of a transformer includes a discharge detection unit, a sample delay time generation unit, and a comparator. The discharge detection unit generates a first voltage according to a first turning-on signal and a first reference current. Length of the first turning-on signal is varied with a discharge time of a present period of the transformer. The sample delay time generation unit generates a second voltage according to the first turning-on signal and a second reference current. The comparator generates a sample signal to a control circuit of the transformer according to a first voltage corresponding to a previous period of the transformer and a second voltage corresponding to the present period of the transformer. The first reference current is K times the second reference current, and 0&#x3c;K&#x3c;1.

Sample-and-hold circuit for generating a variable sample delay time of a transformer and method thereof

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.

Growing community of inventors

Hsin-Chu, Taiwan

Ren-Yi Chen