Power Integrations, Inc.

Frank Joseph Schulz

Robert J Mayell

Roger Colbeck

Hartley Fred Horwitz

Apparatus and methods for sensing resonant circuit signals to enhance control in a resonant converter are described herein. A buffer circuit coupled in parallel with or across a resonant component (e.g., a transformer) input port avails a buffered primary port signal for use in resonant conversion. The buffered primary port signal is a comprehensive signal including information relating to both input voltage and input power; and it may be used to advantageously enhance switching and power conversion in an inductor-inductor capacitor (LLC) converter. Additionally, the LLC converter uses a sense interface circuit to provide a scaled replica of the buffered primary port signal. In one example the scaled replica can advantageously be used with a secondary side controller to control output power based on the comprehensive information contained within the buffered primary port signal.

Apparatus and methods for sensing resonant circuit signals to enhance control in a resonant converter

A resonant converter includes a resonant transformer having a leakage inductance and a magnetizing inductance coupled in series to form a resonant transformer input port. The resonant transformer has an output that is coupled to provide an output power to a load. A primary bridge circuit is coupled to provide an input power to the resonant transformer input port. A buffer circuit is coupled in parallel with the resonant transformer input port. A control module is coupled to receive a buffered primary port signal from the buffer circuit to control the primary bridge circuit to control the output power to the load in response to the buffered primary port signal.

An IC for power conversion includes bias circuitry that generates one or more bias voltages. An adaptive biasing circuit adaptively shifts an input signal having a negative value to a positive value. An operational transconductance amplifier (OTA) receives a supply bias current and the first and second bias voltages. The OTA has first and second input terminals coupled to the input signal and ground, respectively. The OTA has first and second transistors coupled to the first and second input terminals through first and second resistors at first and second internal nodes, respectively. Additional circuitry of the OTA is coupled to the second internal node. The additional circuitry insures that the voltage at the second internal node follows the voltage at the first internal node. The OTA generates an output current signal responsive to a differential input voltage applied across the first and second input terminals.

Voltage-to-current transconductance operational amplifier with adaptive biasing

Measurement circuits having a delta-sigma modulator are disclosed. One example measurement circuit includes a low pass filter coupled to receive an input voltage, a switched-capacitor integrator circuit, and a switched comparator circuit. The measurement circuit may generate a digital output made up of a sequence of logic high and logic low levels that are representative of a scaled value of the input voltage output by the low pass filter circuit. Also, by virtue of its switched-capacitor configuration, the electric charge received by the switched difference amplifier circuit may be returned to the input in a manner such that the input to the delta-sigma modulator takes little to no average current from the voltage it measures. In other words, the delta-sigma modulator may have a high input impedance by virtue of its switched-capacitor circuit configuration.

Delta-sigma modulator with high input impedance

An operational amplifier includes a selective differential stage including a first current mirror and a current distribution circuit. First and second legs of the first current mirror are responsive to current in first and second paths of the current distribution circuit, which distributes a tail current in response to a first signal received by a first input of the operational amplifier. Current in a first path of a selection circuit in the second path of the current distribution circuit is responsive to a second signal received by a second input of the operational amplifier. Current in the second path of the selection circuit is responsive to a third signal received by a third input of the operational amplifier. An output stage generates an output signal responsive to a difference between the first signal and one of the second and third signals.

Operational amplifier with selective input

Apparatus and methods of controlling operating states of multi-stable electronic circuits are disclosed. In one aspect, an apparatus includes a bandgap reference circuit having an operating state and a latched off state. The bandgap reference circuit includes an amplifier to provide a bandgap reference voltage when the bandgap reference circuit is in the operating state. A state control circuit is also included and is coupled to sense an output signal of the bandgap reference circuit. The state control circuit is also coupled to provide a drive signal to an input of the amplifier in response to the sensed output signal. The drive signal is coupled to cause the bandgap reference circuit to avoid the latched off state.

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Ottawa, Canada

Frank Joseph Schulz