Chengdu Monolithic Power Systems Co., Ltd.

Monolithic Power Systems, Inc.

Yuedong Chen

Lin Feng

Yiqing Jin

Sicong Lin

Hui Li

Haishi Wang

Zhiheng Hu

Jiayou Ye

Bin Xiao

A synchronous rectifier control circuit, used with a synchronous rectification circuit having a primary switch and a synchronous rectifier, having: a drain-source threshold setting circuit, configured to provide a dynamic drain-source voltage threshold based on a drain-source voltage across the synchronous rectifier; a primary switch detecting circuit, configured to provide a primary switch state indicating signal based on a comparison result of the drain-source voltage and the dynamic drain-source voltage threshold; and an on-control circuit, configured to provide a synchronous on signal to turn on the synchronous rectifier when the drain-source voltage decreases to the turn-on threshold, on the premise that the primary switch state indicating signal indicates an on state of the primary switch.

Circuit for generating a dynamic drain-source voltage threshold and method thereof

A switching mode power supply preventing a first switch from being falsely triggered. The switching mode power supply detects a peak of an input signal and starts timing a period of time since the arrival of the peak of the input signal is detected. The first switch starts performing the on and off switching operations when the period of time expires.

Switching mode power supply preventing false triggering of a switch

A discharge circuit for an X capacitor has a first voltage detection circuit providing a first indicating signal based on a voltage across two input terminals of a switching converter to indicate whether the two input terminals are connected to an AC power source, and a discharge module starting a discharge operation on the X capacitor based on first indicating signal, and the discharge operation discharges the X capacitor during a first time period, and stops discharging the X capacitor and compares a sampled signal with the voltage across the two input terminals during a following second time period.

X capacitor discharging circuit and method thereof

A switching mode power supply with an adaptive setting of a threshold valley voltage. The switching mode power supply decreases a reference auxiliary current when a valley value of a primary switching voltage across a primary switch is smaller than a first threshold valley voltage. And in addition, the switching mode power supply can increase the reference auxiliary current when the valley value of the primary switching voltage is larger than a second threshold valley voltage.

Switching mode power supply with adaptive threshold setting

A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable charging circuit and a slope sensing circuit. The slope sensing circuit may sense whether an abrupt rising change in a voltage drop from a sensing terminal to a reference ground terminal of the driving circuit is occurring, and provide a slope sensing signal in response to a rising edge of the abrupt rising change in the voltage drop. The controllable charging circuit may receive the slope sensing signal and provide a charging current to a supply terminal of the driving circuit in response to each rising edge of the abrupt rising change in the voltage drop.

Circuit with slope sensing for driving synchronous rectifier device

A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable clamping circuit having a first terminal coupled to a sensing terminal of the driving circuit, a second terminal coupled to a reference ground terminal of the driving circuit, a third terminal coupled to a driving terminal of the driving circuit, and a control terminal configured to receive a supply indication signal indicative of a voltage potential at a supply terminal of the driving circuit. The third terminal of the controllable clamping circuit may be connected to the second terminal of the controllable clamping circuit when the supply indication signal indicates that the voltage potential at the supply terminal has not been established to maintain the synchronous rectifier device off.

Circuit for driving synchronous rectifier device with false turn on prevention

A switching mode power supply preventing false triggering of an over current protection due to a surge pulse. The switching mode power supply has a switch and an inductor. An inductor current flows through the inductor. The switching mode power supply turns off the switch and meanwhile starts timing for a preset period of time when the inductor current is larger than a preset value. The switch is kept off during the preset period of time and is then turned on when the preset period of time expires.

Switching mode power supply providing an over current protection with anti-surge function

A control circuit having power limit for controlling an AC-DC voltage converter. The control circuit includes a first sensing circuit having an auxiliary winding used to sense a voltage on an inductive element of the converter to generate a first sensing signal, a second sensing circuit used to sense the current flowing through the inductive element to provide a second sensing signal, and a power limit circuit. The power limit circuit generates a power indication signal indicative of the input power of the converter based on the first sensing signal and the second sensing signal. When the power indication signal is larger than a power threshold, a controllable switch of the converter is turned off.

Control circuit having power limit for an AC-DC converter and integrated circuits thereof

An integrated circuit used for a switching converter has a power supply circuit for providing a power supply voltage, and a control circuit. The switching converter has a switching circuit converting a DC input voltage into an output signal. The power supply circuit has a protection circuit, an UVLO unit and a current source coupled to a power supply capacitor. The protection circuit detects whether the DC input voltage is at a brown-in state. The UVLO unit generates a lock out signal by comparing the power supply voltage with a upper threshold voltage and a lower threshold voltage. The lower threshold voltage is selectively limited to one of a first value or a second value based on the detection. The second value is less than the first value. The current source provides the power supply voltage under the control of the lock out signal.

Integrated circuit for switching converter and method for providing power supply voltage to the same

A current source generating a charging current and a supply voltage by charging a capacitor with the charging current. The current source has a conversion circuit converting a line voltage into a second voltage, a current generation circuit generating the charging current based on the second voltage, and a control circuit controlling the current generation circuit based on the supply voltage. The charging current is controlled to be at a first current value when the supply voltage is lower than a first threshold voltage, the charging current is controlled to be at a second current value when the supply voltage is higher than a second threshold voltage. The first threshold voltage is lower than the second threshold voltage, and the first current value is lower than the second current value.

High voltage current source with short circuit protection

Control method and circuit for resonant converters with capacitive protection. When a resonant converter enters into a capacitive mode, a high-side switch and a low-side switch of the resonant converter are turned off. After the high-side switch and a low-side switch are turned off for N switching cycles, the high-side switch is turned on once a current sense signal flowing through a resonant inductor of the resonant converter is increased to a zero-crossing threshold during an ascent stage of the current sense signal, and the low-side switch is turned on once the current sense signal is decreased to the zero-crossing threshold during a descent stage of the current sense signal.

Control method and circuit for resonant converters with capacitive protection

A control circuit used for controlling a resonant converter. The control circuit has a setting capacitor, N up thresholds and N low thresholds. If the resonant converter operates in the inductive mode, a setting voltage signal across the setting capacitor is respectively compared with the largest one of the N up thresholds and the smallest one of the N low thresholds in each operation cycle to generate a high-side control signal and a low-side control signal for controlling a high-side switch and a low-side switch of the resonant converter. If the resonant converter enters into the capacitive mode, the setting voltage signal is respectively compared with each of the N up thresholds and each of the N low thresholds operation cycle by operation cycle to generate the high-side control signal and the low-side control signal.

Resonant converter with capacitive mode control and associated control method

A switching mode power supply with resonant technology. The switching mode power supply current uses current polarity evaluation to avoid capacitive mode by triggering the capacitive protection if the evaluation indicates that the system will enter capacitive mode.

Switching mode power supply and the controller and the method thereof

A resonant converter has a switching circuit having a first switch and a second switch, a control circuit and a resonant circuit. The control circuit has a slope sensing circuit providing a slope sense signal based on a voltage variation at the common node of the first switch and the second switch, a slope judge circuit providing a slope judge signal, and a turn-ON control circuit providing a first reset signal to adjust a first dead-time period from turning OFF the first switch to turning ON the second switch based on the slope judge signal, the slope signal, and a current flowing through the resonant tank, and providing a second reset signal to adjust a second dead-time period from turning OFF the second switch to turning ON the first switch based on the slope judge signal, the slope signal, and the current flowing through the resonant tank.

Resonant converter, control circuit and associated control method with adaptive dead-time adjustment

A timing circuit used in lighting systems includes a first logic circuit, a first counter, a latching circuit and a judging circuit. The first logic circuit generates a first logic signal and a second logic signal based on a falling edge of a detecting signal. The first counter generates a first counting signal and a second counting signal based on the second logic signal, wherein the counting period of the first counting signal is longer than that of the second counting signal. The latching circuit samples and holds the first counting signal based on the first logic signal and provides a third counting signal. The judging circuit detects whether the second counting signal is equal to the third counting signal and provides a timing signal.

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Chengdu, China

Yuedong Chen