US 2024/0186906 A1 · SWITCHING MODE POWER SUPPLY, CONTROL CIRCUIT AND CONTROL METHOD THEREOF

Abstract

A control circuit for a switching mode power supply is disclosed herein. The switching mode power supply has a primary-side circuit, the primary-side circuit has a first switch, a second switch, and a clamping capacitor. The control circuit includes a voltage detection circuit, an on-time adjustment circuit, and a driving circuit. The voltage detection circuit is coupled to the first terminal of the first switch and configured to detect a voltage signal at the first terminal of the first switch. The on-time adjustment circuit is configured to provide a first on-time signal to adjust an on-time of the first switch according to the voltage signal at the first terminal of the first switch. The driving circuit is configured to provide a driving signal to a control terminal of the first switch according to the first on-time signal.

Claims19

Dependent claims

A control circuit for a switching mode power supply, wherein the switching mode power supply has a primary-side circuit, the primary-side circuit has a first switch, a second switch, and a clamping capacitor, a first terminal of the first switch is coupled to a terminal of the clamping capacitor, a second terminal of the first switch is coupled to a first terminal of the second switch, and wherein the control circuit comprises:

a voltage detection circuit coupled to the first terminal of the first switch and configured to detect a voltage signal at the first terminal of the first switch;
an on-time adjustment circuit coupled to the voltage detection circuit and configured to provide a first on-time signal to adjust an on-time of the first switch according to the voltage signal at the first terminal of the first switch;
and
a driving circuit coupled to the on-time adjustment circuit and configured to provide a driving signal to a control terminal of the first switch according to the first on-time signal.

1 more element

A switching mode power supply, comprising:

a transformer having a primary winding and a secondary winding;
a primary-side circuit coupled to the primary winding and configured to receive an input voltage from a voltage input terminal, wherein the primary-side circuit comprises:
a clamping capacitor having a first terminal and a second terminal, wherein the first terminal of the clamping capacitor is coupled to the voltage input terminal;
a first switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal of the first switch is coupled to the second terminal of the clamping capacitor;
a second switch having a first terminal, a second terminal, and a control terminal, wherein the first terminal of the second switch is coupled to the second terminal of the first switch, and the second terminal of the second switch is coupled to a ground terminal;
and
a clamping control circuit, comprising:
a voltage detection circuit coupled to the first terminal of the first switch and configured to detect a voltage signal at the first terminal of the first switch;
an on-time adjustment circuit coupled to the voltage detection circuit and configured to, according to the voltage signal at the first terminal of the first switch, provide a first on-time signal to adjust an on-time of the first switch;
and
a driving circuit coupled to the on-time adjustment circuit and configured to provide a driving signal to a control terminal of the first switch according to the first on-time signal;
and
a secondary-side circuit coupled to the secondary winding and configured to provide an output voltage at a voltage output terminal.

10 more elements

Dependencies are inferred from the claim text.

Switching mode power supply, control circuit and control method thereof

Life of this patent

Switching mode power supply, control circuit and control method thereof

Life of this patent

Abstract

Claims19