Power Integrations, Inc.

Manoj Bhasin

Antonius Jacobus Johannes Werner

Matthew David Waterson

Adrian Kirilov Lefedjiev

Karl Moore

Paul Thomas Ryan

Johan Piper

A controller for use in a power converter with multiple outputs includes a discharge detect circuit coupled to receive a voltage signal from a transformer winding of the power converter to output a discharge signal in response to the voltage signal. A multi-output signal process and interface block is coupled to output request signals to the output selection drive and idle ring visibility logic circuit. An output selection drive and idle ring visibility logic circuit is coupled to receive the discharge signal from the discharge detect circuit and the output request signals from the multi-output signal process and interface block. An idle ring detection circuit is coupled to one of the plurality of output switches and coupled to output an idle ring output signal to generate a next request pulse.

Idle ring detection for a multi-output power converter

A method of dynamically adjusting a storage time of a bipolar junction transistor (BJT) in a switched mode power converter during a switching cycle includes generating a storage time reference signal responsive to an input voltage signal. A collector off signal is generated responsive to a comparison of a current sense signal to a collector off reference threshold signal. The current sense signal is representative of a switch current of the BJT. A base off reference threshold signal is generated responsive to the storage time reference signal and the collector off signal. A base off signal is generated responsive to a comparison of the current sense signal and the base off reference threshold signal. Charging of a base terminal of the BJT is discontinued responsive to the base off signal, and the base terminal of the BJT is discharged responsive to the collector off signal.

BJT driver with dynamic adjustment of storage time versus input line voltage variations

A controller for a power converter includes a driver circuit that generates a control signal to switch a power switch in response to an output, and a control circuit that controls the switching of the power switch. The control circuit includes a storage time reference circuit generates a storage time reference signal responsive to an input. A first comparator generates a collector off signal in response to a comparison of a switch current sense signal and a collector off reference signal. A storage time regulator circuit generates a base off reference signal in response to the storage time reference signal and the collector off signal. A second comparator generates a base off signal in response to a second comparison of the switch current sense signal and the base off reference signal. The driver circuit is coupled to discontinue and start charging a base terminal of the BJT power switch.

The invention generally relates to switch mode power converters (SMPCs). and methods for providing supplementary base drive to a bipolar transistor of an SMPC, and more particularly to a switching control circuit for a SMPC, a said SMPC having an inductive component coupled to receive power from an input to the SMPC, a bipolar transistor coupled to control current flow in the inductive component, an auxiliary power rail, a charge store for supplying power via the auxiliary rail to a switching control circuit for driving the bipolar transistor, and a bootstrap circuit for bleeding current from the input to the bipolar transistor to thereby provide an amplified current to the charge store, the switching control circuit comprising: a base current line for coupling to a base terminal of a said bipolar transistor, an emitter current line for coupling to an emitter terminal of a said bipolar transistor, an auxiliary line for coupling to a said auxiliary power rail, and at least one reference line for coupling to a reference voltage; a base current switch configured to controllably couple a base current source to the base current line; an emitter current switch configured to controllably couple the emitter current line to a said reference line; a bootstrap element for bleeding current from the emitter current line to the auxiliary line, the bootstrap element further operable to block a said current according to a current or voltage bias; a base discharge switch configured to controllably bleed current from the base current line to a said reference line; and a supplementary base drive line for coupling to a series circuit comprising a supplementary base drive resistor and current control element coupled in series, a said series circuit for bleeding current from a said input to a said base terminal, a said current control element for blocking current flow from a said bootstrap circuit to a said supplementary base drive resistor.

BJT drive scheme

A power converter controller includes a storage time reference circuit to generate a storage time reference signal in response to an input voltage signal. A first comparator generates a collector off signal in response to a current sense signal of a BJT and a collector off reference threshold signal. A storage time regulator circuit generates a base off reference threshold signal in response to the storage time reference signal and the collector off signal. A second comparator generates a base off signal in response to the current sense signal and a base off reference threshold signal. A driver circuit controls switching of the BJT in response to an output voltage signal, discontinues charging a base terminal of the BJT in response to the base off signal, and starts discharging the base terminal of the BJT in response to the collector off signal during a switching cycle of the BJT.

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Cambridge, United Kingdom

Manoj Bhasin