TWM617448U - Switching power supply circuit and control chip thereof - Google Patents

Abstract

A switching power supply circuit and its control chip are provided. The control chip used for the switching power supply circuit includes a power supply voltage input pin, an internal power supply pin of the chip, and a linear voltage regulator-boost conversion circuit connected between the power supply voltage input pin and the internal power supply pin of the chip, of which: the power supply voltage input pin is used In order to receive the chip power supply voltage from the outside of the control chip, the internal power supply pin of the chip is used to provide the internal power supply voltage inside the control chip. The linear voltage-boost conversion circuit generates the internal power supply voltage by stepping down or boosting the chip power supply voltage. And output the internal power supply voltage to the internal power supply pin of the chip. The control chip for the switching power supply circuit according to this creative embodiment can meet the needs of a wide range of output voltage applications, has the characteristics of high efficiency, anti-interference and voltage stability, and can effectively improve the efficiency and reliability of the circuit system .

Description

Switching power supply circuit and its control chip

This creation relates to the field of circuits, in particular to a switching power supply circuit and its control chip.

With the continuous development of electronic technology, the third-generation power switch has begun to be widely used. Due to the characteristics of the power switch itself, the gate drive voltage used for the power switch is required to be low, and the stability and anti-interference ability strong. However, in wide-range output voltage applications, due to the wide output voltage range, the power supply voltage range of the control chip used to provide the gate drive voltage to the power switch is also very wide. Under the condition of safe driving voltage, the power supply voltage can be reduced in order to provide the power switch with the gate driving voltage that meets the requirements. At present, the voltage reduction structure inside the control chip has large losses, weak anti-interference and noise filtering capabilities, and these deficiencies become more obvious when the power supply voltage of the control chip is higher. How to improve the power supply efficiency of the control chip, improve the stability of the gate driving voltage provided by the control chip to the power device, and improve the anti-interference ability of the control chip are problems that need to be solved urgently.

In view of one or more of the above-mentioned problems, this creation provides a switching power supply circuit and its control chip.

The control chip for the switching power supply circuit according to this creative embodiment includes a power supply voltage input pin, an internal power supply pin of the chip, and a linear voltage regulator-boost conversion circuit connected between the power supply voltage input pin and the internal power supply pin of the chip, Among them: the power supply voltage input pin is used to receive the chip power supply voltage from the outside of the control chip, and the internal power supply pin of the chip is used to supply the power inside the control chip. For the internal power supply voltage, the linear regulator-boost conversion circuit generates the internal power supply voltage by stepping down or boosting the chip power supply voltage, and outputs the internal power supply voltage to the internal power supply pin of the chip.

The control chip according to this creative embodiment can meet the needs of a wide range of output voltage applications, has the characteristics of high efficiency, good anti-interference and voltage stability, and can effectively improve the efficiency and reliability of the circuit system.

The switching power supply circuit according to this creative embodiment includes the above-mentioned control chip for the switching power supply circuit.

The switching power supply circuit according to this creative embodiment can provide a wide range of output voltage, and its system efficiency and reliability are high.

100: control chip

VDD: supply voltage input pin

AVDD: chip internal power supply pin

102: Buck-boost conversion circuit

SW1: Output pin of voltage stabilizing circuit

SW2: Boost switch input pin

GATE: drive voltage output pin

CS: Primary side current sensing foot

FB: Output voltage feedback pin

200: Switching power supply circuit

L: External inductor

C: Capacitance

GND: ground pin

This creation can be better understood from the following description of the specific implementation of this creation in conjunction with the accompanying drawings, in which:

Fig. 1 shows a schematic diagram of an exemplary pin arrangement of a control chip for a switching power supply circuit according to an embodiment of the present creation;

FIG. 2 shows an exemplary circuit diagram of a switching power supply circuit using the control chip shown in FIG. 1.

The features and exemplary embodiments of various aspects of the present creation will be described in detail below. In the following detailed description, many specific details are proposed in order to provide a comprehensive understanding of this creation. However, it is obvious to those skilled in the art that this creation can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present creation by showing an example of the present creation. This creation is by no means limited to any specific configuration proposed below, but covers any modification, replacement and improvement of elements and components without departing from the spirit of this creation. In the drawings and the following description, well-known structures and technologies are not shown in order to avoid unnecessary obscurity of the present creation. In addition, it should be noted that the term "A and B are connected" used here can mean "A and B are directly connected" It can also mean that "A and B are indirectly connected via one or more other elements."

In view of one or more problems of current control chips used for switching power supply circuits, the present invention provides a control chip for switching power supply circuits.

Fig. 1 shows an exemplary pin layout diagram of a control chip 100 for a switching power supply circuit according to an embodiment of the present creation. As shown in FIG. 1, the control chip 100 includes a power supply voltage input pin VDD, an internal power supply pin AVDD of the chip, and a linear voltage regulator-boost conversion circuit 102 connected between the power supply voltage input pin VDD and the internal power supply pin AVDD of the chip. The power supply voltage input pin VDD is used to receive the chip power supply input pin VDD voltage from outside the control chip 100. The internal power supply pin AVDD of the chip is used to provide the internal power supply pin AVDD voltage inside the control chip 100. The chip power supply voltage VDD is stepped down or boosted to generate an internal power supply voltage, and the internal power supply voltage is output to the internal power supply pin of the chip.

In some embodiments, as shown in FIG. 1, the control chip 100 may further include a voltage stabilizing circuit output pin SW1 and a boost switch input pin SW2, wherein the voltage stabilizing circuit output pin SW1 is used as a linear voltage regulator-boost converter The output terminal of the linear regulator circuit part in the circuit 102, and the boost switch input pin SW2 is used as the input terminal of the boost switch for controlling the on and off of the boost converter circuit part of the linear regulator-boost converter circuit 102 .

In some embodiments, as shown in FIG. 1, the control chip 100 may further include a driving voltage output pin GATE, which is used to transfer the power between the primary winding of the transformer connected in the switching power supply circuit and the ground. The switch provides the gate drive voltage.

In some embodiments, as shown in FIG. 1, the control chip 100 may further include a primary side current sensing pin CS, which is used to receive from outside the control chip 100 that characterizes the transformer flowing through the switching power supply circuit. The primary current sensing signal of the primary winding current.

In some embodiments, as shown in FIG. 1, the control chip 100 may further include an output voltage feedback pin FB for receiving an output voltage feedback signal representing the output voltage of the switching power supply circuit from outside the control chip.

In some embodiments, as shown in FIG. 1, the control chip 100 may further include a ground pin GND, which is used to provide a reference ground inside the control chip 100.

In some embodiments, the linear voltage regulator-boost converter circuit 102 has a voltage at the chip power supply input pin VDD higher than a first threshold (for example, the voltage regulator threshold of the linear voltage regulator circuit part of the linear voltage regulator-boost converter circuit 102). ), the internal power supply pin AVDD voltage is generated by stepping down the chip power supply input pin VDD voltage, and when the chip power supply input pin VDD voltage is lower than the second threshold (for example, the boost conversion in the linear regulator-boost conversion circuit 102 The boosting threshold of the circuit part is used to boost and rectify the voltage of the chip power supply input pin VDD to generate the internal power supply pin AVDD voltage. In addition, the linear voltage regulator-boost converter circuit 102 directly uses the chip power supply input pin VDD voltage as the internal power supply pin AVDD voltage when the chip power supply input pin VDD voltage is not higher than the first threshold and not lower than the second threshold value. Here, due to the step-down and step-up rectification of the power supply voltage of the chip by the linear regulator-boost conversion circuit 102, the internal power supply voltage of the control chip 100 is lower and more stable, which is suitable for a wide range of output voltage applications. At the same time, the power supply efficiency of the control chip can be improved, and the stability and anti-interference ability of the gate driving voltage provided by the control chip to the power switch can be improved.

FIG. 2 shows an exemplary circuit diagram of a switching power supply circuit 200 to which the control chip 100 shown in FIG. 1 is applied. Here, taking the flyback application as an example, each pin of the control chip 100 and related parts in the switching power supply circuit 200 are described. It should be noted that although FIG. 1 and FIG. 2 both show 8 pins of the control chip 100, the control chip 100 may include more than 8 pins. As shown in FIG. 2, the connection relationship between each pin of the control chip 100 and related parts in the switching power supply circuit 200 is as follows:

The supply voltage input pin VDD is connected to the auxiliary winding of the transformer in the switching power supply circuit 200, as shown by the dotted line ①. The voltage Vaux on the auxiliary winding of the transformer is rectified and filtered by a diode and a capacitor to obtain a stable DC voltage (ie, the chip supply voltage VDD).

The output pin SW1 of the voltage stabilizing circuit is connected to one end of the external inductor L, as shown by the dotted line ②. The chip supply voltage VDD is output to the outside of the control chip 100 through the linear voltage regulator circuit part of the linear voltage regulator-boost converter circuit 102 through the voltage regulator circuit output pin SW1.

The boost switch input pin SW2 is connected to the other end of the external inductor L, as shown by the dotted line ③. After the voltage output by the output pin SW1 of the voltage stabilizing circuit passes through the external inductor L, it is connected to the booster The switch input pin SW2 is thus connected to a boost switch for controlling the opening and closing of the boost conversion circuit part of the linear regulator-boost conversion circuit 102.

The internal power supply pin AVDD of the chip is connected to the external bypass capacitor C, as shown by the dotted line ④. The final output voltage (ie, the internal power supply voltage AVDD) of the linear regulator-boost conversion circuit 102 is internally rectified and then output to the internal power supply pin AVDD of the chip. The external bypass capacitor C plays a role of voltage stabilization and filtering.

The driving voltage output pin GATE is connected to the gate of the power switch (for example, MOS transistor) connected between the primary winding of the transformer in the switching power supply circuit 100 and the ground, as shown by the dotted line ⑤.

The primary current sensing pin CS is connected to the source of a power switch (for example, a MOS tube) connected between the primary winding of the transformer in the switching power supply circuit 100 and the ground, as shown by the dashed line ⑥.

The output voltage feedback pin FB is connected to the optocoupler, as shown by the dotted line ⑦, and receives an output voltage feedback signal representing the output voltage of the secondary winding of the transformer in the switching power supply circuit 100 (ie, the output voltage of the switching power supply circuit 100).

The ground pin GND is connected to the system ground, as shown by the dotted line ⑧, as the reference ground inside the control chip 100.

The switching power supply circuit 200 according to this creative embodiment can provide a wide range of output voltage, and its system efficiency and reliability are high.

This creation can be realized in other concrete forms without departing from its spirit and essential characteristics. The current embodiment is regarded as illustrative rather than restrictive in all aspects, and the scope of this creation is defined by the appended claims rather than the foregoing description, and falls within the meaning of the claims and the scope of equivalents. All changes are included in the scope of this creation.

100: control chip

VDD: supply voltage input pin

AVDD: chip internal power supply pin

102: Buck-boost conversion circuit

SW1: Output pin of voltage stabilizing circuit

SW2: Boost switch input pin

GATE: drive voltage output pin

CS: Primary side current sensing foot

FB: Output voltage feedback pin

GND: ground pin

Claims (10)

A control chip for a switching power supply circuit, which is characterized by comprising a power supply voltage input pin, an internal power supply pin of the chip, and a linear voltage regulator-boosting pin connected between the power supply voltage input pin and the internal power supply pin of the chip Conversion circuit, where: The power supply voltage input pin is used to receive chip power supply voltage from outside the control chip, The internal power supply pin of the chip is used to provide an internal power supply voltage inside the control chip, The linear voltage stabilizing-boosting conversion circuit generates the internal power supply voltage by step-down or step-up rectification of the chip power supply voltage, and outputs the internal power supply voltage to the internal power supply pin of the chip. The control chip according to claim 1, which is characterized in that it further includes a voltage stabilizing circuit output pin and a boost switch input pin, and the voltage stabilizing circuit output pin is used as a linear regulator in the linear voltage stabilizing-boosting conversion circuit. The output terminal of the voltage stabilization circuit part, the boost switch input pin is used as the input end of the boost switch for controlling the on and off of the boost conversion circuit part in the linear voltage stabilization-boost conversion circuit. The control chip according to claim 1 or 2, characterized in that it further comprises a drive voltage output pin, the drive voltage output pin is used to connect between the primary winding of the transformer in the switching power supply circuit and the ground. The power switch provides gate drive voltage. The control chip according to claim 1 or 2, characterized in that it further comprises a primary side current sensing pin, the primary side current sensing pin is used to receive from the outside of the control chip the characteristic flow through the switching power supply circuit The primary current sensing signal of the current in the primary winding of the transformer. The control chip according to claim 1 or 2, further comprising an output voltage feedback pin, the output voltage feedback pin being used to receive an output voltage representing the output voltage of the switching power supply circuit from outside the control chip Feedback signal. The control chip according to claim 1 or 2, further comprising a ground pin, the ground pin being used to provide a reference ground inside the control chip. The control chip according to claim 1 or 2, wherein the linear regulator-boost The conversion circuit generates the internal power supply voltage by stepping down the wafer power supply voltage when the wafer power supply voltage is higher than a first threshold, and supplies power to the wafer when the wafer power supply voltage is lower than a second threshold. The voltage is boosted and rectified to generate the internal power supply voltage. The control chip according to claim 1 or 2, wherein the linear regulator-boost conversion circuit is not higher than the first threshold and not lower than the second threshold when the power supply voltage of the chip is not higher than the second threshold. , Directly use the chip power supply voltage as the internal power supply voltage. A switching power supply circuit, characterized by comprising the control chip according to any one of claims 1 to 8. The switching power supply circuit according to claim 9, further comprising an external inductor connected between the output pin of the voltage stabilizing circuit and the input pin of the boost switch.

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