Analog Devices Global

Analog Devices,inc.

Hynetek Semiconductor Co., Ltd.

Renjian Xie

Yingyang Ou

Qingyi Huang

Huailiang Sheng

Jun Duan

Liuqing Yang

Zhijie Zhu

Xudong Huang

Bo Yuan

Jerry Zhai

Ling Ren

An fault detection circuit includes a first comparison unit, a second comparison unit, an impedance unit and a digital control unit, the first comparison unit is configured to output a first judgment signal based on the voltage across a sampling resistor; the second comparison unit is configured to output a second judgment signal based on the voltage across the impedance unit, or the second comparison unit is configured to output a second judgment signal based on the voltage across the circuit in which the sampling resistor is connected in series with the impedance unit, and the digital control unit is configured to determine the working state of the sampling resistor based on the first judgment signal and the second judgment signal. Through the above method, the accuracy of overcurrent protection can be improved under the condition where the sampling resistor fails.

Fault detection circuit, method and power adapter

A circuit for sampling current includes a current transformer, a reset resistor, a diode, a sampling switch, and a current sampling resistor. The current transformer includes a primary winding and a secondary winding. The reset resistor and two ends of the secondary winding are connected in parallel. The sampling switch, the diode, and the current sampling resistor are connected in series and then connected to two ends of the reset resistor in parallel. The primary winding is for connecting to a circuit to be sampled. When a current flows through the primary winding and the circuit to be sampled and the sampling switch is turned on at a negative AC half cycle, the circuit for sampling current samples the current flowing through the circuit to be sampled.

Circuit for sampling current and system for sampling current of Totem-Pole bridgeless circuit

A power converter can include an electrical isolation circuit between input and output nodes. An input signal monitor node can be provided, such as on a converter output side of the isolation circuit. In an example, a peak detection circuit can be coupled to the input signal monitor node. The output node of the power converter can be configured to supply an output power signal that is a function of an input signal at the input node. The power converter can include multiple, independently-switchable switches at one or more of the input and output sides of the isolation circuit. In an example, the power converter with the input signal monitor node can be configured as a bias supply to provide power, at the output node, to a controller circuit for a main stage power converter circuit.

Isolated power supply with input voltage monitor

This application provides methods and apparatus for controlling aspects of a synchronous rectifier power converter. In an example, an apparatus can include a minimum duty cycle control circuit configured to receive first control signals for one or more switches associated with the synchronous rectifier power converter, to compare a duty cycle of the first control signals to a minimum duty cycle threshold, and to provide second control signals having at least the minimum duty cycle for an active snubber switch of the synchronous rectifier power converter.

Minimum duty cycle control for active snubber

In certain example embodiments, a system is provided that includes a circuit. The system also includes a reverse current control module that provides an isolated power supply in order to protect one or more devices in a power chain during one or more testing activities having one or more requirements.

Reverse current control for an isolated power supply having synchronous rectifiers

An apparatus comprises a power converter circuit and a control circuit. The power converter circuit includes a primary circuit side and a secondary circuit side. The primary circuit side includes a plurality of primary switches, and the secondary circuit side includes a plurality of synchronous rectifiers and an inductor. The control circuit is configured to operate the synchronous rectifiers synchronously with the primary switches when inductor current at the inductor is greater than or equal to a reference inductor current, and operate the synchronous rectifiers in a bidirectional mode when the inductor current is less than the reference inductor current, wherein energy is delivered from the primary side to the secondary side and from the secondary side to the primary side during the bidirectional mode.

Synchronous rectifier control for a double-ended isolated power converter

A duty cycle balance module (DCBM) for use with a switch mode power converter. One possible half-bridge converter embodiment includes a transformer driven to conduct current in first and second directions by first and second signals during and second half-cycles, respectively. A current limiting mechanism adjusts the duty cycles of the first and second signals when a sensed current exceeds a predetermined limit threshold. The DCBM receives signals representative of the duty cycles which would be used if there were no modification by the current limiting mechanism and signals Dand Drepresentative of the duty cycles that are actually used for the first and second signals, and outputs signals Dand Dwhich modify signals Dand Das needed to dynamically balance the duty cycles of the first and second signals and thereby reduce flux imbalance in the transformer that might otherwise arise.

Duty cycle balance module for switch mode power converter

An adaptive dead time (ADT) control scheme for use with a switch mode power converter having a full bridge with synchronous rectifiers topology. A controller which implements the control scheme includes an input circuit arranged to receive a signal representative of the converter's output voltage, and an output circuit arranged to operate the converter's switching elements and synchronous rectifiers to produce a desired output voltage. The controller is further arranged such that the converter's 'dead time' is adaptively varied in an inverse relationship to the magnitude of the load current. In a preferred embodiment, the signals used to operate the synchronous rectifiers are PWM signals, and the controller adaptively varies the dead time in a linear inverse relationship to the magnitude of the load current by modulating the rising and falling edges of the signals used to operate the synchronous rectifiers.

Adaptive dead time control scheme for switch mode power converter with synchronous rectifiers topology

A switching power converter includes a voltage source that provides an input voltage Vin to an unregulated DC/DC converter stage and at least one buck-boost converter stage to produce a desired output voltage Vout. The unregulated DC/DC converter stage is adapted to provide an isolated voltage to the at least one regulated buck-boost converter stage, wherein the unregulated DC/DC converter stage comprises a transformer having a primary winding and at least one secondary winding and at least one switching element coupled to the primary winding. The at least one buck-boost converter stage is arranged to operate in a buck mode, boost mode or buck-boost mode in response to a mode selection signal from a mode selection module. By influencing the pulse width modulation output power controller the at least one buck-boost converter stage is arranged to produce one or multiple output voltages.

Wide output voltage range switching power converter

An OVP system which includes a plurality of OVP circuits coupled to respective parallel-connected switching power supplies. Each OVP circuit comprises a bus voltage overvoltage detection circuit having a first output which toggles when the voltage on the common power bus exceeds a reference voltage, a modulation flag detection circuit which receives a value that varies with a parameter associated with the PWM or PFM drive signals generated for the switching power supply to which the OVP circuit is coupled and has a second output which toggles when the parameter value exceeds a reference parameter value, logic circuitry which toggles an output when both the first and second outputs toggle, and an overvoltage response circuit which initiates a course of action such as latching or shutting down the switching power supply to which the OVP circuit is coupled when the logic circuitry's output toggles.

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Shenzhen, China

Renjian Xie