阅读说明：本技术 一种宽范围输入的dc-dc隔离转换功率电路及其控制方法 (Wide-range input DC-DC isolation conversion power circuit and control method thereof ) 是由 徐立平 应站标 黄恒华 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种宽范围输入的DC-DC隔离转换功率电路,包括耦合电感Sepic电路、推挽隔离电路,耦合电感Sepic电路包括一对电压输入端Vin,该对电压输入端之间连接有耦合电感L11-1、耦合电感L11-2,耦合电感L11-2的两端两端跨接有一极性电容C22,极性电容C22的两极上连接有一USB供电端子Vbus并通过该USB供电端子Vbus与推挽隔离电路连接；推挽隔离电路包括两极连接在USB供电端子Vbus上的极性电容C1,极性电容C1的阳极上连接有变压器T1。(The invention discloses a wide-range input DC-DC isolation conversion power circuit, which comprises a coupling inductance Sepic circuit and a push-pull isolation circuit, wherein the coupling inductance Sepic circuit comprises a pair of voltage input ends Vin, a coupling inductance L11-1 and a coupling inductance L11-2 are connected between the pair of voltage input ends, two ends of the coupling inductance L11-2 are connected with a polarity capacitor C22 in a crossing manner, and two poles of the polarity capacitor C22 are connected with a USB power supply terminal Vbus and connected with the push-pull isolation circuit through the USB power supply terminal Vbus; the push-pull isolation circuit comprises a polarity capacitor C1 with two poles connected to the USB power supply terminal Vbus, and a transformer T1 is connected to the anode of the polarity capacitor C1.)

1. A DC-DC isolation conversion power circuit with wide-range input is characterized by comprising a coupling inductance Sepic circuit and a push-pull isolation circuit, wherein the coupling inductance Sepic circuit comprises a pair of voltage input ends Vin, a coupling inductance L11-1 and a coupling inductance L11-2 are connected between the pair of voltage input ends, two ends of the coupling inductance L11-2 are connected with a polarity capacitor C22 in a cross-connection mode, and two poles of the polarity capacitor C22 are connected with a USB power supply terminal Vbus and connected with the push-pull isolation circuit through the USB power supply terminal Vbus;

the push-pull isolation circuit comprises a polar capacitor C1 with two poles connected to a USB power supply terminal Vbus, a transformer T1 is connected to the anode of the polar capacitor C1, the transformer T1 comprises a transformer primary T1-1, a transformer primary T1-2 and a transformer secondary T1-3, the transformer primary T1-1 and the transformer primary T1-2 are connected to the anode of the polar capacitor C1 in parallel, two ends of the transformer secondary T1-3 are respectively connected with a capacitor C3 and a coupling inductor L1-1 to form a resonant network, and the transformer secondary T1-3 is connected with a voltage output end Vout through the resonant network.

2. The wide-range input DC-DC isolated conversion power circuit as claimed in claim 1, wherein a diode D11 is connected between the anode of the polar capacitor C22 and the coupling inductor L11-2, and the cathode of the diode D11 is connected to the anode of the polar capacitor C22.

3. The wide-range input DC-DC isolated conversion power circuit as claimed in claim 1, wherein the turn ratio of the coupling inductor L11-1 to the coupling inductor L11-2 is 1: 1.

4. The wide-range input DC-DC isolated conversion power circuit of claim 1, wherein a capacitor C33 is connected between the coupling inductor L11-1 and the coupling inductor L11-2, a polar capacitor C11 is connected across two ends of the voltage input terminal Vin, an anode of the polar capacitor C11 is connected with the coupling inductor L11-1, and a MOS switch Q11 is connected between the capacitor C33 and a cathode of the polar capacitor C11.

5. The wide-range input DC-DC isolation conversion power circuit as claimed in claim 1, wherein a polarity capacitor C2 is connected across the two ends of the voltage output terminal in the push-pull isolation circuit, a diode D1 is connected between the anode of the polarity capacitor C2 and the coupling inductor L1-1, a diode D3 is connected between the anode of the polarity capacitor and the capacitor C3, wherein the cathodes of the diode D1 and the diode D3 are both connected with the anode of the polarity capacitor C3;

a diode D2 is connected between the cathode of the polar capacitor C2 and the coupling inductor L1-1, a diode D4 is connected between the cathode of the polar capacitor and the capacitor C3, and the anodes of the diode D1 and the diode D3 are both connected with the cathode of the polar capacitor C3.

6. A control method of a wide-range input DC-DC isolation conversion power circuit, which is applied to the wide-range input DC-DC isolation conversion power circuit as claimed in claims 1-5, and is characterized by comprising the following steps:

s1: according to the voltage relation between a voltage input end Vin and a USB power supply terminal Vbus in a coupling inductance Sepic circuit:

wherein Vbus is the voltage at the USB power supply terminal Vbus,

vin is the voltage at the voltage input terminal Vin,

d is the duty cycle of the MOS switch-on Q11,

setting a voltage threshold value at a voltage input end Vin;

s2: and establishing a frequency-gain relation chart of the push-pull isolation circuit, and selecting the working frequency fs of the push-pull isolation circuit according to the voltage required by the voltage output end Vout.

Technical Field

The invention relates to the technical field of electronic circuits, in particular to a wide-range input DC-DC isolation conversion power circuit and a control method thereof.

Background

With the development of power electronic technology, the types of power electronic equipment with direct current output are more and more, and the voltage range is wider and wider; the popularization and application of the direct current output power electronic equipment promote the development of the energy storage industry, effectively meet the mobile flexibility and continuous continuity of energy requirements, and have larger and larger market capacity. The corresponding energy feedback load needs to be compatible with a wider input voltage range, so that the flexibility and the convenience are stronger, the equipment investment of an aging link is reduced, and the customer expenditure is saved.

At present, a Boost circuit with an auxiliary winding is adopted for a common energy feedback load supporting a wide voltage input range, and the Boost circuit can realize small duty ratio change and support large gain change, so that wide voltage range input is realized, but the problem that the stress of a diode D1 is overlarge exists, the Boost circuit can only carry out boosting and can not carry out voltage reduction, and high-voltage devices must be selected for the subsequent DC-DC isolation circuit, so that the cost is very high.

Disclosure of Invention

The present invention aims to overcome the above-mentioned shortcomings and provide a technical solution to solve the above-mentioned problems.

A DC-DC isolation conversion power circuit with wide-range input comprises a coupling inductance Sepic circuit and a push-pull isolation circuit, wherein the coupling inductance Sepic circuit comprises a pair of voltage input ends Vin, a coupling inductance L11-1 and a coupling inductance L11-2 are connected between the pair of voltage input ends, two ends of the coupling inductance L11-2 are connected with a polar capacitor C22 in a cross-connection mode, and two poles of the polar capacitor C22 are connected with a USB power supply terminal Vbus and connected with the push-pull isolation circuit through the USB power supply terminal Vbus;

the push-pull isolation circuit comprises a polar capacitor C1 with two poles connected to a USB power supply terminal Vbus, a transformer T1 is connected to the anode of the polar capacitor C1, the transformer T1 comprises a transformer primary T1-1, a transformer primary T1-2 and a transformer secondary T1-3, the transformer primary T1-1 and the transformer primary T1-2 are connected to the anode of the polar capacitor C1 in parallel, two ends of the transformer secondary T1-3 are respectively connected with a capacitor C3 and a coupling inductor L1-1 to form a resonant network, and the transformer secondary T1-3 is connected with a voltage output end Vout through the resonant network.

Further, a diode D11 is connected between the anode of the polar capacitor C22 and the coupling inductor L11-2, and the cathode of the diode D11 is connected with the anode of the polar capacitor C22.

Further, the turn ratio of the coupling inductor L11-1 to the coupling inductor L11-2 is 1: 1.

Further, a capacitor C33 is connected between the coupling inductor L11-1 and the coupling inductor L11-2, a polar capacitor C11 is connected across two ends of the voltage input end Vin, the anode of the polar capacitor C11 is connected with the coupling inductor L11-1, and a MOS switch Q11 is connected between the capacitor C33 and the cathode of the polar capacitor C11.

Furthermore, a polar capacitor C2 is connected across two ends of a voltage output end in the push-pull isolation circuit, a diode D1 is connected between the anode of the polar capacitor C2 and the coupling inductor L1-1, a diode D3 is connected between the anode of the polar capacitor and the capacitor C3, and the cathodes of the diode D1 and the diode D3 are both connected with the anode of the polar capacitor C3;

a diode D2 is connected between the cathode of the polar capacitor C2 and the coupling inductor L1-1, a diode D4 is connected between the cathode of the polar capacitor and the capacitor C3, and the anodes of the diode D1 and the diode D3 are both connected with the cathode of the polar capacitor C3.

The control method of the wide-range input DC-DC isolation conversion power circuit is applied to the wide-range input DC-DC isolation conversion power circuit and comprises the following steps:

s1: according to the voltage relation between a voltage input end Vin and a USB power supply terminal Vbus in a coupling inductance Sepic circuit:

wherein Vbus is the voltage at the USB power supply terminal Vbus,

vin is the voltage at the voltage input terminal Vin,

d is the duty cycle of the MOS switch-on Q11,

setting a voltage threshold value at a voltage input end Vin;

s2: and establishing a frequency-gain relation chart of the push-pull isolation circuit, and selecting the working frequency fs of the push-pull isolation circuit according to the voltage required by the voltage output end Vout.

Compared with the prior art, the invention has the following beneficial effects: according to the invention, a coupling inductance type Sepic circuit and an improved push-pull isolation circuit are combined, Sepic can realize a voltage boosting and reducing function, a Sepic output voltage Vbus is not required to be set to be larger than a maximum input voltage, a high-voltage device is not required to be adopted, the cost is reduced, meanwhile, a control mode of changing the Sepic output voltage is adopted, the Sepic circuit is prevented from working in a state that the duty ratio is extremely small, good dynamic characteristics and efficiency are realized, and the design difficulty of a driving circuit is reduced. The improved push-pull isolation circuit realizes a soft switching technology by introducing a resonant network, reduces switching loss, improves conversion efficiency, saves original output inductance and controls cost.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic circuit diagram of a coupling inductor Sepic circuit in the present invention.

Fig. 2 is a circuit schematic diagram of a push-pull isolation circuit in the present invention.

Fig. 3 is a frequency-gain relationship diagram of a push-pull isolation circuit in accordance with the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-2, a wide-range input DC-DC isolation conversion power circuit includes a coupling inductance Sepic circuit and a push-pull isolation circuit, the coupling inductance Sepic circuit includes a pair of voltage input ends Vin, a coupling inductance L11-1 and a coupling inductance L11-2 are connected between the pair of voltage input ends, two ends of the coupling inductance L11-2 are connected across a polarity capacitor C22, two poles of the polarity capacitor C22 are connected with a USB power supply terminal Vbus and connected with the push-pull isolation circuit through the USB power supply terminal Vbus;

the push-pull isolation circuit comprises a polar capacitor C1 with two poles connected to a USB power supply terminal Vbus, a transformer T1 is connected to the anode of the polar capacitor C1, the transformer T1 comprises a transformer primary T1-1, a transformer primary T1-2 and a transformer secondary T1-3, the transformer primary T1-1 and the transformer primary T1-2 are connected to the anode of the polar capacitor C1 in parallel, two ends of the transformer secondary T1-3 are respectively connected with a capacitor C3 and a coupling inductor L1-1 to form a resonant network, and the transformer secondary T1-3 is connected with a voltage output end Vout through the resonant network.

Further, a diode D11 is connected between the anode of the polar capacitor C22 and the coupling inductor L11-2, and the cathode of the diode D11 is connected with the anode of the polar capacitor C22.

Further, the turn ratio of the coupling inductor L11-1 to the coupling inductor L11-2 is 1: 1.

Further, a capacitor C33 is connected between the coupling inductor L11-1 and the coupling inductor L11-2, a polar capacitor C11 is connected across two ends of the voltage input end Vin, the anode of the polar capacitor C11 is connected with the coupling inductor L11-1, and a MOS switch Q11 is connected between the capacitor C33 and the cathode of the polar capacitor C11.

Furthermore, a polar capacitor C2 is connected across two ends of a voltage output end in the push-pull isolation circuit, a diode D1 is connected between the anode of the polar capacitor C2 and the coupling inductor L1-1, a diode D3 is connected between the anode of the polar capacitor and the capacitor C3, and the cathodes of the diode D1 and the diode D3 are both connected with the anode of the polar capacitor C3;

a diode D2 is connected between the cathode of the polar capacitor C2 and the coupling inductor L1-1, a diode D4 is connected between the cathode of the polar capacitor and the capacitor C3, and the anodes of the diode D1 and the diode D3 are both connected with the cathode of the polar capacitor C3.

The control method of the wide-range input DC-DC isolation conversion power circuit is applied to the wide-range input DC-DC isolation conversion power circuit and comprises the following steps:

s1: according to the voltage relation between a voltage input end Vin and a USB power supply terminal Vbus in a coupling inductance Sepic circuit:

Vbus＝D/(1-D)Vin

wherein Vbus is the voltage at the USB power supply terminal Vbus,

vin is the voltage at the voltage input terminal Vin,

d is the duty cycle of the MOS switch-on Q11,

setting a voltage threshold value at a voltage input end Vin;

s2: a frequency-gain relation chart (as shown in fig. 3) of the push-pull isolation circuit is established, and the working frequency fs of the push-pull isolation circuit is selected according to the voltage required by the voltage output end Vout.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.