US 12,283,894 B2Granted

Push-pull converter with saturation prevention

AssigneeTexas Instruments Incorporated

InventorsAnant Kamath, Suvadip Banerjee

Life of this patent

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Abstract

In described examples, a converter circuit includes a primary-side ground, a current sensor, a control signal generator, first and second control switches, and a transformer with a center-tapped primary-side coil. A first terminal of the first control switch is coupled to a first terminal of the coil and a first input of the current sensor. A first terminal of the second control switch is coupled to a second terminal of the coil and a second input of the current sensor. Second terminals of the first and second control switches are coupled to ground. The control signal generator closes the first control switch and opens the second control switch in a first phase; opens the first control switch and closes the second control switch in a second phase that alternates with the first phase; and adjusts first phase duration in response to current sensor output, without changing converter period duration.

Claims15

Dependent claims

A converter circuit comprising:

a current sensor including a first input, a second input, and an output;
first and second capacitors, each respectively including a first terminal and a second terminal;
a first current source coupled to the first terminal of the first capacitor;
a second current source coupled to the first terminal of the second capacitor;
a first comparator including a first input, a second input, and an output, the first input of the first comparator coupled to the first terminal of the first capacitor, and the second input of the first comparator coupled to the output of the current sensor;
a second comparator including a first input, a second input, and an output, the first input of the second comparator coupled to the first terminal of the second capacitor;
and
a first control switch and a second control switch, each respectively including a first terminal, a second terminal, and a control terminal, the first terminal of the first control switch coupled to the first input of the current sensor, the first terminal of the second control switch coupled to the second input of the current sensor, the control terminal of the first control switch coupled to the output of the first comparator, and the control terminal of the second control switch coupled to the output of the second comparator.

5 more elements

A converter circuit comprising:

a current sensor including a first input, a second input, and an output;
a control signal generator including an input, a first output, and a second output, the input of the control signal generator coupled to the output of the current sensor;
and
a first control switch and a second control switch, each respectively including a first terminal, a second terminal, and a control terminal, the first terminal of the first control switch coupled to the first input of the current sensor, the first terminal of the second control switch coupled to the second input of the current sensor, the control terminal of the first control switch coupled to the first output of the control signal generator, and the control terminal of the second control switch coupled to the second output of the control signal generator;
wherein the control signal generator is configured to:
control the first control switch to be closed and the second control switch to be open in a first phase;
control the first control switch to be open and the second control switch to be closed in a second phase that alternates with the first phase;
and
adjust a duration of the first phase in response to the output of the current sensor, without changing a duration of a period of the converter;
wherein the current sensor includes:
a first sampling circuit including an input, an output, and a control terminal, the input of the first sampling circuit coupled to the first input of the current sensor, and the control terminal of the first sampling circuit coupled to the control terminal of the first control switch;
a second sampling circuit including an input, an output, and a control terminal, the input of the second sampling circuit coupled to the second input of the current sensor, and the control terminal of the second sampling circuit coupled to the control terminal of the second control switch;
and
an operational amplifier (op-amp) including a first input, a second input, and an output, the first input of the op-amp coupled to the output of the first sampling circuit, the second input of the op-amp coupled to the output of the second sampling circuit, and the output of the op-amp coupled to the output of the current sensor.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/153,249Filed 11 Jan 2023
Published: US 2024/0235422 A111 Jul 2024
Granted: 22 Apr 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H02M 3/3382
In a self-oscillating arrangement: in a push-pull circuit arrangement
H02M 1/0009
Details of control, feedback or regulation circuits: devices or circuits for detecting current in a converter
H02M 1/0064
Details of apparatus for conversion: magnetic structures combining different functions, e.g. storage, filtering or transformation
H02M 1/38
Details of apparatus for conversion: means for preventing simultaneous conduction of switches