US-20260128679-A1 - POWER SUPPLY CIRCUIT HAVING POSITIVE AND NEGATIVE OUTPUT VOLTAGES

US20260128679A1US 20260128679 A1US20260128679 A1US 20260128679A1US-20260128679-A1

Abstract

A power supply circuit having positive and negative output voltages is provided. The power supply circuit includes a primary side circuit, a transformer, and a secondary side circuit. The primary side circuit includes a resonant converter. The transformer includes a primary side winding and a secondary side winding. The secondary side circuit includes a positive voltage output circuit and a negative voltage output circuit. The resonant converter is connected to the primary side winding. The positive voltage output circuit and the negative voltage output circuit are connected to the secondary side winding. The positive voltage output circuit is configured to output a positive output voltage, and the negative voltage output circuit is configured to output a negative output voltage.

Inventors

Chih-Shan Chen

Assignees

LITE-ON TECHNOLOGY CORPORATION

Dates

Publication Date: 20260507
Application Date: 20250116
Priority Date: 20241105

Claims (11)

1 . A power supply circuit having positive and negative output voltages, comprising: a primary side circuit comprising: a resonant converter; a transformer, wherein the transformer comprises a primary side winding and a secondary side winding, and the resonant converter is connected to the primary side winding; and a secondary side circuit comprising: a positive voltage output circuit connected to the secondary side winding and configured to output a positive output voltage; and a negative voltage output circuit connected to the secondary side winding and configured to output a negative output voltage.
2 . The power supply circuit according to claim 1 , wherein the secondary side winding of the transformer comprises a first secondary side subwinding and a second secondary side subwinding; wherein a first terminal of the first secondary side subwinding is connected to the positive voltage output circuit, and a second terminal of the first secondary side subwinding is connected to ground; wherein a first terminal of the second secondary side subwinding is connected to ground, and a second terminal of the second secondary side subwinding is connected to the positive voltage output circuit and the negative voltage output circuit.
3 . The power supply circuit according to claim 2 , wherein the negative voltage output circuit comprises: a first inverter diode; and an inverter capacitor; wherein a cathode of the first inverter diode is connected to the second terminal of the second secondary side subwinding, an anode of the first inverter diode is connected to a first terminal of the inverter capacitor, and a second terminal of the inverter capacitor is connected to ground.
4 . The power supply circuit according to claim 3 , wherein a voltage of the inverter capacitor is the negative output voltage.
5 . The power supply circuit according to claim 3 , wherein the negative voltage output circuit further comprises: a second inverter diode, wherein a cathode of the second inverter diode is connected to the first terminal of the first secondary side subwinding, and an anode of the second inverter diode is connected to the first terminal of the inverter capacitor.
6 . The power supply circuit according to claim 2 , wherein the negative voltage output circuit further comprises: a first transistor; and an inverter capacitor; wherein a first terminal of the first transistor is connected to the second terminal of the second secondary side subwinding, a second terminal of the first transistor is connected to a first terminal of the inverter capacitor, a control terminal of the first transistor is coupled to a first control voltage, and a second terminal of the inverter capacitor is connected to ground.
7 . The power supply circuit according to claim 6 , wherein a voltage of the inverter capacitor is the negative output voltage.
8 . The power supply circuit according to claim 6 , wherein the negative voltage output circuit further comprises: a second transistor, wherein a first terminal of the second transistor is connected to the first terminal of the first secondary side subwinding, a second terminal of the second transistor is connected to the first terminal of the inverter capacitor, and a control terminal of the second transistor is coupled to a second control voltage.
9 . The power supply circuit according to claim 2 , wherein the positive voltage output circuit comprises: a first diode; and an output capacitor; wherein an anode of the first diode is connected to the first terminal of the first secondary side subwinding, a cathode of the first diode is connected to a first terminal of the output capacitor, a second terminal of the output capacitor is connected to ground, and a voltage of the output capacitor is the positive output voltage.
10 . The power supply circuit according to claim 9 , wherein the positive voltage output circuit further comprises: a second diode, wherein an anode of the second diode is connected to the second terminal of the second secondary side subwinding, and a cathode of the second diode is connected to the first terminal of the output capacitor.
11 . The power supply circuit according to claim 1 , wherein the power supply circuit further comprises a feedback circuit, a coupling circuit, a resonant control circuit, a protection circuit and a correction control circuit, and the primary side circuit further comprises a filter circuit, a bridge rectifier and a power factor correction circuit; wherein the feedback circuit is configured to output a feedback signal according to the positive output voltage or the negative output voltage; wherein the resonant control circuit is configured to receive the feedback signal from the feedback circuit through the coupling circuit and receive a voltage threshold from the protection circuit, and configured to compare the feedback signal with the voltage threshold to control the resonant control circuit; wherein the filter circuit is configured to filter an alternating current input voltage to form a filtered voltage, the bridge rectifier rectifies the filtered voltage to output a rectified voltage, and the power factor correction circuit is configured to output a direct current input voltage to the resonant control circuit according to the rectified voltage.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATION This application claims the benefit of priority to China Patent Application No. 202411562763.5, filed on Nov. 5, 2024. The entire content of the above identified application is incorporated herein by reference. Some references, which may include patents, patent applications and various publications, may be cited and discussed in the description of this disclosure. The citation and/or discussion of such references is provided merely to clarify the description of the disclosure and is not an admission that any such reference is “prior art” to the disclosure described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference. FIELD OF THE DISCLOSURE The disclosure relates to a power supply circuit, and more particularly to a power supply circuit having positive and negative output voltages. BACKGROUND OF THE DISCLOSURE Resonant converters are indispensable for electronic devices. Resonant converters such as inductor-inductor-capacitor (LLC) resonant converters are used to convert direct current (DC) input voltages into DC output voltages. However, conventional resonant converters are only capable of converting a single input voltage that may have a positive voltage value. Conventional resonant converters are unable to supply both the output voltage having the positive voltage value and an output voltage having a negative voltage value at the same time. Therefore, the conventional resonant converters are unsuitable for many applications. SUMMARY OF THE DISCLOSURE In response to the above-referenced technical inadequacies, the disclosure provides a power supply circuit having positive and negative output voltages. The power supply circuit includes a primary side circuit, a transformer and a secondary side circuit. The primary side circuit includes a resonant converter. The transformer includes a primary side winding and a secondary side winding. The resonant converter is connected to the primary side winding. The secondary side circuit includes a positive voltage output circuit and a negative voltage output circuit. The positive voltage output circuit is connected to the secondary side winding. The positive voltage output circuit is configured to output a positive output voltage. The negative voltage output circuit is connected to the secondary side winding. The negative voltage output circuit is configured to output a negative output voltage. As described above, the disclosure provides the power supply circuit having the positive and negative output voltages. In comparison with a conventional power converter that is only capable of supplying the positive output voltage, the power supply circuit of the disclosure is capable of supplying the positive output voltage and the negative output voltage at the same time. Therefore, the power supply circuit of the disclosure is more widely applicable than the conventional power converter. These and other aspects of the disclosure will become apparent from the following description of the embodiments taken in conjunction with the following drawings and their captions, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS The described embodiments may be better understood by reference to the following description and the accompanying drawings, in which: FIG. 1 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a first embodiment of the disclosure; FIG. 2 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a second embodiment of the disclosure; FIG. 3 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a third embodiment of the disclosure; FIG. 4 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a fourth embodiment of the disclosure; FIG. 5 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a fifth embodiment of the disclosure; FIG. 6 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a sixth embodiment of the disclosure; and FIG. 7 is a circuit diagram of a power supply circuit having positive and negative output voltages according to a seventh embodiment of the disclosure. DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS The disclosure is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Like numbers in the drawings indicate like components throughout the views. As used in the description herein an