High-power flyback power supply chip and controller

Abstract

The invention discloses a high-power flyback power supply chip and a controller. The high-power flyback power supply chip comprises a packaging shell, and a flyback control chip, wherein the flyback control chip is packaged in the packaging shell. The power switch tube and the diode are packaged in the packaging shell, a grid electrode of the power switch tube is connected to the flyback control chip, and a source electrode of the power switch tube is connected to the flyback control chip and a power switch tube current detection pin of the packaging shell; the positive electrode of the diode is connected to the drain electrode of the power switch tube and the drain electrode pin of the packaging shell, and the negative electrode of the diode is connected to the RCD pin and used for protecting the power switch tube. The flyback power supply device can be highly integrated, the packaging size of the flyback power supply chip is reduced, the heat dissipation effect can be improved, meanwhile, the number of discrete devices can be reduced, and the production cost and the failure rate are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to a high-power flyback power supply chip and a controller. Background Art

[0002] Flyback switching power supplies have the advantages of simple topology and easy implementation, and are widely used in various electronic products and equipment, such as notebook adapters, mobile phone chargers, LCD monitors, power tools, electric bicycle chargers, and TV standby power supplies.

[0003] Currently, there are no products with built-in MOS for flyback switching power supply chips above 100W, and the devices are connected through external MOS, while flyback switching power supply chips within 100W do not have leakage inductance absorption diodes.

[0004] As a result, there are many discrete components in flyback switching power supply chips of different powers, which not only increases the failure rate of the product, but also greatly increases the production cost and material cost; at the same time, if these chips are installed in one package in traditional small packages such as DIP, TO220, etc., the heat dissipation problem cannot be solved, shortening the service life of the product. Summary of the invention

[0005] The purpose of the present invention is to provide a technical solution of a high-power flyback power supply chip and a controller to address the deficiencies in the prior art, which can not only make the flyback power supply device highly integrated and reduce the volume of the flyback power supply chip package, but also improve the heat dissipation effect, while reducing the number of discrete devices, reducing production costs and failure rates.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A high-power flyback power supply chip, comprising

[0008] Encapsulation shell;

[0009] and a flyback control chip, wherein the flyback control chip is packaged in a packaging shell;

[0010] It is characterized by:

[0011] It also includes a power switch tube and a diode packaged in a package shell, wherein the gate of the power switch tube is connected to a flyback control chip, and the source of the power switch tube is connected to the flyback control chip and a current detection pin of the power switch tube of the package shell;

[0012] The positive electrode of the diode is connected to the drain of the power switch tube and the drain pin of the package shell, and the negative electrode of the diode is connected to the RCD pin, which is used to protect the power switch tube.

[0013] Through the design of the above structure, not only can the flyback power supply device be highly integrated and the package volume of the flyback power supply chip be reduced, but also the heat dissipation effect can be improved, while the number of discrete devices can be reduced, and the production cost and failure rate can be reduced.

[0014] Furthermore, the flyback control chip is connected to a power supply voltage input pin of the package shell.

[0015] Furthermore, the flyback control chip is connected to the output voltage feedback pin of the package shell.

[0016] Furthermore, the flyback control chip is connected to a function selection pin of the package shell for selecting an output mode.

[0017] Furthermore, the flyback control chip is connected to a ground pin of the package casing.

[0018] A controller, characterized in that it includes the high-power flyback power supply chip, resistor R1 and capacitor C2 as described above, wherein the diode of the high-power flyback power supply chip, resistor R1 and capacitor C2 form an RCD absorption circuit.

[0019] Furthermore, the power switch tube current detection pin of the high-power flyback power supply chip is connected to the resistor R2 and the capacitor C1.

[0020] Furthermore, the drain pin of the high-power flyback power supply chip is connected to the transformer.

[0021] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0022] The present invention can not only make the flyback power supply device highly integrated and reduce the package volume of the flyback power supply chip, but also improve the heat dissipation effect, and at the same time can reduce the number of discrete devices, reduce production costs and failure rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings:

[0024] Figure 1 A circuit diagram of a high-power flyback power supply chip and a flyback power supply chip in a controller of the present invention;

[0025] Figure 2 It is a circuit diagram of the controller in the present invention.

[0026] In the figure: 1-flyback control chip; 2-power switch tube; 3-diode; 4-package shell. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0030] like Figure 1 As shown, a high-power flyback power supply chip of the present invention comprises a packaging shell 4 and a flyback control chip 1 , wherein the flyback control chip 1 is packaged in the packaging shell 4 .

[0031] It also includes a power switch tube 2 and a diode 3 packaged in a package shell 4, the gate of the power switch tube 2 is connected to the flyback control chip 1, and the source of the power switch tube 2 is connected to the flyback control chip 1 and the current detection pin CS of the power switch tube 2 of the package shell 4;

[0032] The anode of the diode 3 is connected to the drain of the power switch tube 2 and the drain pin D of the package shell 4 , and the cathode of the diode 3 is connected to the RCD pin, so as to protect the power switch tube 2 .

[0033] The flyback control chip 1 is connected to a power supply voltage input pin VCC of the package housing 4 .

[0034] The flyback control chip 1 is connected to an output voltage feedback pin FB of the package housing 4 .

[0035] The flyback control chip 1 is connected to the function selection pin DEM of the package shell 4 for selecting the output mode. Connecting to ground is a constant voltage output mode, and connecting to a capacitive constant voltage and constant current output mode.

[0036] The flyback control chip 1 is connected to a ground pin GND of the package housing 4 .

[0037] The package shell in this application can adopt GBU-7 package, and the pin sequence can be selected according to actual use requirements.

[0038] Through the design of the above structure, not only can the flyback power supply device be highly integrated and the package volume of the flyback power supply chip be reduced, but also the heat dissipation effect can be improved, while the number of discrete devices can be reduced, and the production cost and failure rate can be reduced.

[0039] like Figure 2 As shown, a controller of the present invention includes the high-power flyback power chip, resistor R1 and capacitor C2 as mentioned above, and the diode 3 of the high-power flyback power chip, the resistor R1 and the capacitor C2 form an RCD absorption circuit.

[0040] The current detection pin CS of the power switch tube 2 of the high-power flyback power supply chip is connected to the resistor R2 and the capacitor C1.

[0041] The drain pin D of the high-power flyback power supply chip is connected to the transformer.

[0042] When the present invention is actually working, the flyback control chip 1 controls the power switch tube 2 to turn on. At this time, the current flows in from the drain pin D of the package shell 4 and flows out from the current detection pin CS of the power switch tube 2 of the package shell 4. The current detection pin CS of the power switch tube 2 is connected to an external resistor R2 to sample the current flowing through the power switch tube 2. When the flyback control chip 1 collects the current flowing through the power switch tube 2 and reaches the threshold, the power switch tube 2 is turned off. At this time, the drain pin D resonates with the equivalent capacitor here due to the leakage inductance of the transformer, so that the pin generates a peak voltage greater than the withstand voltage value of the power switch tube 2. The RCD absorption circuit is formed by the diode 3, the peripheral resistor R1 and the capacitor C2 to absorb the peak voltage of the drain pin D, thereby protecting the power switch tube 2. After the flyback control chip 1 waits for a certain period of time to allow the transformer to demagnetize and output energy, it controls the power switch tube 2 to turn on again, and repeats the above steps.

[0043] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A high-power flyback power supply chip, comprising Encapsulation shell; and a flyback control chip, wherein the flyback control chip is packaged in the packaging shell; Features ； It also includes a power switch tube and a diode packaged in the package shell, the gate of the power switch tube is connected to the flyback control chip, and the source of the power switch tube is connected to the flyback control chip and the power switch tube current detection pin of the package shell; The anode of the diode is connected to the drain of the power switch tube and the drain pin of the package shell, and the cathode of the diode is connected to the RCD pin, so as to protect the power switch tube.

2. A high-power flyback power supply chip according to claim 1, characterized in that: The flyback control chip is connected to the power supply voltage input pin of the packaging shell.

3. The high-power flyback power supply chip according to claim 1, characterized in that: The flyback control chip is connected to the output voltage feedback pin of the packaging shell.

4. The high-power flyback power supply chip according to claim 1, characterized in that: The flyback control chip is connected to the function selection pin of the package shell and is used for selecting an output mode.

5. The high-power flyback power supply chip according to claim 1, characterized in that: The flyback control chip is connected to the ground pin of the packaging shell.

6. A controller, characterized in that: The invention comprises a high-power flyback power supply chip, a resistor R1 and a capacitor C2 as claimed in any one of claims 1 to 5, wherein the diode of the high-power flyback power supply chip, the resistor R1 and the capacitor C2 form an RCD absorption circuit.

7. A controller according to claim 6, characterized in that: The power switch tube current detection pin of the high-power flyback power supply chip is connected to the resistor R2 and the capacitor C1.

8. A controller according to claim 6, characterized in that: The drain pin of the high-power flyback power supply chip is connected to the transformer.

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