Infineon Technologies Canada Inc.

Texas Instruments Corporation

Yalong Li

Brent Alan McDonald

Yinglai Xia

Zhemin Zhang

Nan Xing

Abhishek Jain

Ashutosh Ravindra Joharapurkar

Edward MacRobbie

Maxim James Franke

John Christian Vogt

Ramesh G Karpur

Rohan Samsi

Robert Wayne Mounger

Ramkumar Sivakumar

Suraj Somashekara Kumar

Ashutosh Kumar

A power transistor current sense circuit. The control nodes of each of a power transistor and sense transistors are connected. The input nodes of the power transistor and each of the sense transistors are also connected. A voltage divider is connected between a reference voltage source and the output node of a second sense transistor. A negative feedback circuit is connected between the output of the voltage divider and the output node of the first sense transistor. The negative feedback circuit forces a voltage at the output node of the first sense transistor to be approximately equal to the divided voltage. A power transistor current determination component measures a sense current that passes through the first sense transistor, and from that detects the current passing through the power transistor.

Power current signal generation using sense transistors

A circuit that is capable of generating a negative voltage on a negative voltage supply node. The circuit includes a negative voltage generation circuit, an oscillator and an oscillator control signal generator. The negative voltage generation circuit generates a negative voltage on the negative voltage supply node in response to receiving a signal from the oscillator. The negative voltage generated by the negative voltage generation circuit depends upon the frequency of the signal from the oscillator. The oscillator control signal generator controls the frequency of the signal from the oscillator by sensing the negative voltage present on the negative voltage supply node, and by increasing or decreasing the frequency of the signal from the oscillator accordingly. Thus, charge is replenished to the negative voltage supply node to more closely match the drawing of charge from that negative voltage supply node, thereby more accurately generating the negative voltage.

Negative voltage generator

A circuit that includes a power transistor and at least one sense transistor and that uses the control drive terminal to not only control the power transistor and the sense transistor, but also to provide power to a current sense circuit. The control nodes of the power transistor and sense transistor are connected, and the input nodes of the power transistor and the sense transistor are also connected. The current sense circuit is connected to the sense transistor control node and is configured to detect current passing through the sense transistor. The current sense circuit is also connected to the control drive terminal and is configured to draw power from the control drive terminal when a high control signal is present on the control drive terminal. Accordingly, the current sense circuit does not require an independent fixed high voltage supply in order to operate.

Circuit with power transistor and current sense that uses control drive as power source

A method for operating a resonant converter in a burst mode includes determining the polarity of a transformer voltage across a secondary winding of a transformer. The method includes determining, from the polarity of the transformer voltage, on/off states of first and second transistors coupled to the secondary winding of the transformer. If the transformer voltage has a first polarity, the method includes commencing a burst period by alternately turning on/off high-side and low-side transistors electrically connected to a primary winding of the transformer.

Method of operating isolated resonant converter with synchronous rectifier

A circuit includes a first driver, a second driver, and a burst mode control circuit coupled to the first and second drivers. The burst mode control circuit is configured to implement a burst mode operation having a burst soft-on portion and a burst portion. During the soft-on portion of the burst mode operation, the burst mode control circuit is configured to cause the first and second drivers to produce a first set of pulses of increasing pulse width. During the burst portion of the burst mode operation, the burst mode control circuit is configured to cause the first and second drivers to produce a second set of pulses of a constant pulse width.

Burst mode operation for a resonant converter

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Allen, TX, United States of America

Yalong Li