Silergy Semiconductor Technology (hangzhou) Ltd

National Semiconductor Corporation

Hangzhou Silergy Semiconductor Technology Ltd

Xiaoru Xu

Wei P Chen

Yunlong Han

Jian Deng

Qiukai Huang

Shenglun Chen

Guojia Liu

Huiqiang Chen

Yongjiang Bai

Zhiliang Hu

Zhan Chen

Xiangdong Yang

Lu Zhang

Lawrence Hok Sun Ling

A controller of a switching power supply can include: a frequency-jittering control circuit configured to generate a frequency-jittering signal adaptively; a comparator having two input terminals for respectively receiving an inductor current sampling signal and a feedback control signal, and being configured to compare the signals of the two input terminals to generate a switching control signal, in order to control a power transistor in the switching power supply; and a superimposing circuit configured to superimpose the frequency-jittering signal on one of the two input terminals of the comparator, where a switching frequency of the switching power supply varies within a preset range under different load conditions.

Controller of switching power supply having a frequency-jittering control circuit and control method thereof

A controller of a switching power supply can include: a frequency-jittering control circuit configured to generate a first frequency-jittering signal and a second frequency-jittering signal; where a jittering range of an operating frequency of a power transistor in the switching power supply is adjusted by the first frequency-jittering signal; and where a jittering amplitude of a peak value of an inductor current of the switching power supply is adjusted by the second frequency-jittering signal.

Controller of switching power supply and control method thereof

A control circuit for a flyback converter is configured to adjust a conduction time of an auxiliary switch of the flyback converter in accordance with a drain-source voltage of a main switch of the flyback converter when the main switch is turned on, in order to achieve zero-voltage switching of the main switch. The flyback converter can include: a main power stage having the main switch to control energy storage and transmission of a transformer; and a clamp circuit having an auxiliary switch to provide a release path for releasing energy of leakage inductance of the transformer.

Flyback converter, control circuit and control method thereof

Control circuit for a flyback converter

A control circuit can include: a power supply circuit having a bias capacitor coupled between a power terminal and a common node, where the power supply circuit supplies power to the control circuit via the bias capacitor; a detection circuit coupled between the common node and a current output terminal of a main power switch of a power stage circuit, to detect current flowing through the main power switch; a current feedback circuit that generates a feedback signal according to a difference value between a sense value obtained from a voltage at the power terminal during an off state of the main power switch and a present voltage at the power terminal, where the feedback signal represents an inductor current of the power stage circuit; and a control signal generator that generates a control signal according to the feedback signal to control the main power switch.

Control circuit and related integrated circuit and switching-type converter

In one embodiment, a voltage peak detection circuit can include: (i) a voltage coupling circuit configured to inductively couple an input inductor voltage of a switching power supply, and to generate a first voltage that represents a DC input voltage of the switching power supply; (ii) a voltage conversion circuit configured to receive the first voltage, and to generate a second voltage that is proportional to the first voltage; and (iii) a holding circuit configured to hold a peak of the second voltage to generate a peak voltage signal that represents peak information of the DC input voltage.

Voltage peak detection circuit and detection method

In one embodiment, a zero-crossing detection circuit can include: (i) a first detection circuit configured to detect a current through a main transistor of a main circuit of a switching power supply, and to generate a voltage sense signal that represents the current through the main transistor; (ii) a second detection circuit configured to detect if quasi-resonance occurs in the main circuit, the second detection circuit being configured to generate at least one pulse signal when the quasi-resonance is detected; and (iii) a control circuit configured to receive the at least one pulse signal and the voltage sense signal, to turn the main transistor off when the current through the main transistor reaches a predetermined value, and to turn the main transistor on when the at least one pulse signal is active.

Zero-crossing detection circuit

In one embodiment, a method of controlling a switching power supply, can include: (i) generating a driving current signal that follows a waveform of a sense voltage signal, where the sense voltage signal is related to a current through a collector of a transistor that is configured as a power switch of the switching power supply, where the collector is coupled to an inductive element of the switching power supply; (ii) providing the driving current signal to a base of the transistor, where the transistor is in a saturated conduction state when a pulse-width modulation (PWM) signal is active; and (iii) releasing charge accumulated on the base when the PWM signal is inactive to turn off the transistor.

Control method and control circuit for switching power supply

In one embodiment, an undervoltage protection circuit for a switching power supply can include: (i) an undervoltage detection circuit that determines whether an input voltage of the switching power supply is in an undervoltage state; (ii) a selection circuit configured to select a first or a second control signal to be provided as a main control signal to a control circuit; (iii) the control circuit being configured, in response to the main control signal being the first control signal, to control a switching operation of a power transistor in the switching power supply such that an output voltage of the switching power supply is maintained as substantially stable; and (iv) the control circuit being configured, in response to the main control signal being the second control signal, to control the switching operation of the power transistor to reduce an input power of the switching power supply.

Undervoltage protection circuit, undervoltage protection method and switching power supply

The disclosure relates to a control circuit and a control method for a power converter. The power converter comprises a power switch and an inductor being coupled to the power switch. The control circuit controls operation of the power switch to charge and discharge the inductor for generating an inductor current and providing an output current. The control circuit controls the power switch to be turned on when or after an inductor current detection signal is zero, and controls the power switch to be turned off when the inductor current detection signal reaches a peak reference signal or when the power switch has been turned on for a maximum on time. The control circuit also adjusts the maximum on time in accordance with the inductor current detection signal, so that the power converter provides a constant output current to a load. The control circuit operates at a peak-value current mode and maintains the current of the power converter nearly stable without obtaining a compensation signal. The circuit structure is simplified and the number of peripheral components is reduced.

Peak-value current mode control for power converters

In one embodiment, a method of compensating for transmission voltage loss from a switching power supply, can include: (i) receiving a sampling signal that represents an output current of the switching power supply; (ii) delaying the sampling signal to generate a delayed sampling signal; (iii) converting the delayed sampling signal to generate a compensation signal; and (iv) regulating an output voltage of the switching power supply based on the compensation signal to compensate for the transmission voltage loss from the output voltage transmission to a load such that a voltage at the load is maintained as substantially consistent with an expected voltage at the load.

Transmission voltage loss compensation circuit, compensation method, controlling chip and switching power supply

In one embodiment, a light-emitting diode (LED) driver can include: (i) a reference voltage control circuit configured to provide a reference voltage signal in response to an enable signal; (ii) a current control circuit configured to control an output current of the LED driver in response to the reference voltage signal; and (iii) the LED driver being configured to drive an LED load when the enable signal is active.

High-precision LED control circuit, method and LED driver thereof

The present invention pertains to an inductor current detection circuit in a switching mode power supply, and a light-emitting diode (LED) driver thereof. In one embodiment, an inductor current detection circuit configured in a switching mode power supply under discontinuous conduction mode, can include: (i) a voltage detection circuit configured to generate a sampling voltage based on a drain-source voltage of a power switch in the switching mode power supply; (ii) a voltage holding circuit configured to receive the sampling voltage, and to generate a holding voltage through a sampling and holding operation; and (iii) a comparison circuit configured to compare the sampling voltage against the holding voltage, and to generate a zero-crossing signal when the sampling voltage is less than the holding voltage, where the zero-crossing signal is configured to represent an inductor current ending time of the switching mode power supply.

Growing community of inventors

Hangzhou, China

Xiaoru Xu