AC-DC switch voltage reduction circuit

Abstract

The utility model discloses an AC-DC switch step-down circuit, which comprises a mains supply input source module, a rectifier module, an energy storage capacitor module, a power supply chip, an energy storage transformer and a power supply voltage output module, can generate two power supply voltage outputs 12V and + 5V / 3.3 V, increases the output current of + 5V / 3.3 V, and is simpler in circuit structure and lower in material cost. The non-isolated step-down switching power supply circuit solves the problems that an output circuit of an existing non-isolated step-down switching power supply circuit is small, cost is high when a flyback circuit is used for improving output current, heating of a post-stage circuit is reduced, and circuit cost is high.

Description

Technical Field

[0001] This utility model relates to the field of voltage regulation circuit technology, specifically to an AC-DC switching step-down circuit. Background Technology

[0002] Currently, low-power non-isolated power supply circuits generally use BUCK circuits. The basic structure is shown in the lower left corner: equivalent circuit when the switch is on; lower right corner: equivalent circuit when the switch is off, or a BUCK-BOOST topology. Due to the internal MOS power limitations of the AC-DC power management chip, the output current is currently limited. If a high-power supply is required, a flyback circuit topology is chosen; however, flyback circuits are more expensive. For applications requiring two voltage outputs, a linear step-down converter or BUCK circuit is generally needed to generate a lower voltage for the 5V or 3.3V system. Using current solutions involves more circuit components and is also more expensive.

[0003] Based on this, the applicant proposes an AC-DC switching step-down circuit. Utility Model Content

[0004] To address the aforementioned problems, this application provides an AC-DC switching step-down circuit, employing the following technical solution:

[0005] An AC-DC switching step-down circuit, characterized in that:

[0006] The AC-DC switching buck circuit includes:

[0007] The AC power input module includes L and N interfaces for connecting to a 220V AC power source and outputting high-voltage AC power to the rectifier module.

[0008] The rectifier module, including rectifier diode D2, is used to rectify 220V AC mains power into DC power output to the energy storage capacitor module;

[0009] The energy storage capacitor module includes energy storage capacitor EC1 and energy storage capacitor EC2, which are used to store the DC power rectified by the rectifier module in the capacitors.

[0010] The power management chip, including power chip U1, generates a PWM waveform, detects the output voltage, and adjusts the PWM duty cycle to stabilize the output voltage to the energy storage transformer.

[0011] Energy storage transformer, including transformer T1; used to reduce the output voltage of the secondary side and increase the output current of the secondary side, and can generate two power supply voltage outputs of 12V and 5V / 3.3V;

[0012] The power supply voltage output module includes two sets, which are used to connect and output 12V and 5V / 3.3V DC power respectively;

[0013] The mains input voltage is rectified into a pulsating DC waveform by rectifier diode D2, and then converted into DC by a filter energy storage circuit composed of energy storage capacitor EC1, inductor L1, and energy storage capacitor EC2. The high-voltage PWM waveform generated by power chip U1 then supplies energy to transformer T1. The energy stored in transformer T1 is then used by freewheeling diode D3, energy storage capacitor EC4, rectifier diode D4, and energy storage capacitor EC3 to generate two power supply voltages: 12V and +5V / 3.3V. Power chip U1 can adjust the duty cycle of the high-voltage PWM output to stabilize the +5V / 3.3V power supply voltage by sampling the voltage across voltage divider resistors R1 and R2.

[0014] Furthermore, it also includes a filter circuit, which consists of an inductor L1, an energy storage capacitor EC1, and an energy storage capacitor EC2. The inductor L1, the energy storage capacitor EC1, and the energy storage capacitor EC2 form a CLC-type Π-type filter circuit, which converts pulsating DC into DC.

[0015] Furthermore, it also includes an energy storage capacitor C1 used to power the power chip U1.

[0016] Furthermore, T1, the transformer, transfers the energy stored at pins 6 and 10 to pins 5 and 2 according to the transformer's turns ratio, thereby reducing the secondary side's output voltage and increasing the secondary side's output current.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This invention addresses the problems of small output circuit size in existing non-isolated buck switching power supply circuits and high cost of using flyback circuits to increase output current, thereby reducing heat generation in subsequent circuits and reducing circuit cost. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of an AC-DC switching step-down circuit according to this utility model;

[0021] Figure 2 This is a circuit diagram of an AC-DC switching step-down circuit shown in this utility model. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0023] In this embodiment:

[0024] AC-DC power supplies are devices that convert alternating current (AC) into stable direct current (DC) and are widely used in various products.

[0025] Power management integrated circuits (PICs) are chips in electronic device systems that are responsible for the conversion, distribution, detection, and other management of electrical energy.

[0026] A transformer is a device that uses the principle of electromagnetic induction to change alternating current voltage and current. Its main components are the primary coil, the secondary coil, and the magnetic core.

[0027] Please refer to the details. Figure 1 An AC-DC switching step-down circuit includes:

[0028] The AC power input module includes L and N interfaces for connecting to a 220V AC power source and outputting high-voltage AC power to the rectifier module.

[0029] The rectifier module, including rectifier diode D2, is used to rectify 220V AC mains power into DC power output to the energy storage capacitor module;

[0030] The energy storage capacitor module includes energy storage capacitor EC1 and energy storage capacitor EC2, which are used to store the DC power rectified by the rectifier module in the capacitors.

[0031] The power management chip, including power chip U1, generates a PWM waveform, detects the output voltage, and adjusts the PWM duty cycle to stabilize the output voltage to the energy storage transformer.

[0032] Energy storage transformer, including transformer T1; used to reduce the output voltage of the secondary side and increase the output current of the secondary side, and can generate two power supply voltage outputs of 12V and 5V / 3.3V;

[0033] The power supply voltage output module consists of two sets, which are used to connect and output 12V and 5V / 3.3V DC power respectively.

[0034] In this embodiment, please refer to Figure 2 L and N are the mains power input sources; D2 is a rectifier diode that rectifies the AC mains power into DC power; EC1 and EC2 are energy storage capacitors that store the DC power rectified by diode D2; L1 is an inductor, and L1, EC1, and EC2 form a CLC-type Π-type filter circuit; U1 is a power chip that generates a PWM waveform, detects the output voltage, and adjusts the PWM duty cycle to stabilize the output voltage; C1 is an energy storage capacitor that supplies power to the chip; R1 and R2 are voltage divider resistors that feed back the output 5V / 3.3V voltage to the power chip U1 according to the voltage division ratio (R1 / R2) to detect the output voltage; C2 is a filter capacitor that filters the output voltage; D1 is a feedback diode that filters the output voltage. The voltage feedback is sent to the power supply chip to detect the output voltage; D3 is a freewheeling diode, which, when the MOSFET of the power supply chip is off, freewheels the energy stored in the inductor when the MOSFET is on to capacitor EC4; T1 is a transformer, which transfers the energy stored at pins 6 and 10 to pins 5 and 2 according to the transformer's turns ratio, which can reduce the secondary output voltage and increase the secondary output current; EC4 is an energy storage capacitor, which stores the energy stored in the inductor at pins 6 and 10 of the transformer to achieve a stable 12V output voltage; D4 is a rectifier diode, which rectifies the secondary output of the transformer; EC3 is an energy storage capacitor, which stores the energy transferred from pins 5 and 2 of the transformer to achieve a stable +5V / 3.3V output voltage.

[0035] The mains input voltage is rectified into a pulsating DC waveform by rectifier diode D2, and then converted into DC by a filter energy storage circuit composed of energy storage capacitor EC1, inductor L1, and energy storage capacitor EC2. The high-voltage PWM waveform generated by power chip U1 then supplies energy to transformer T1. The energy stored in transformer T1, through freewheeling diode D3, energy storage capacitor EC4, and rectifier diode D4 and energy storage capacitor EC3, generates two power supply voltages: 12V and +5V / 3.3V. Power chip U1, by sampling the voltage across voltage divider resistors R1 and R2, can adjust the duty cycle of the high-voltage PWM output to stabilize the +5V / 3.3V power supply voltage. In this circuit, both energy storage capacitors EC3 and EC4 have one end grounded.

[0036] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An AC-DC switching step-down circuit, characterized in that: The AC-DC switching step-down circuit comprises: a mains input source module comprising L, N interfaces for connecting to a 220V AC power supply and outputting high-voltage AC power to a rectifier module; the rectifier module comprises a rectifier diode D2 for rectifying the 220V AC mains to DC power and outputting the DC power to an energy storage capacitor module; the energy storage capacitor module comprises energy storage capacitors EC1 and EC2 for storing the rectified DC power from the rectifier module in the capacitors; a power management chip comprising a power chip U1 for generating a PWM waveform, detecting the output voltage, and adjusting the PWM duty cycle to stabilize the output voltage to an energy storage transformer; the energy storage transformer comprises a transformer T1 for reducing the output voltage of the secondary side and increasing the output current of the secondary side, and can generate two power voltage outputs of 12V, 5V / 3.3V; the power voltage output module comprises two groups for connecting to output 12V, 5V / 3.3V DC power, respectively; the mains input voltage is rectified by the rectifier diode D2 into a pulsating DC waveform, and then the pulsating DC is converted into DC power by the filter and energy storage circuit composed of the energy storage capacitors EC1, the inductor L1, and the energy storage capacitors EC2; the high-voltage PWM waveform generated by the power chip U1 is used to store energy in the transformer T1, and the energy stored in the transformer T1 is converted into 12V and +5V / 3.3V two power voltage outputs through the freewheeling diode D3, the energy storage capacitor EC4, and the rectifier diode D4, the energy storage capacitor EC3; the power chip U1 can adjust the output high-voltage PWM duty cycle to stabilize the +5V / 3.3V power voltage by collecting the voltage on the voltage dividing resistors R1 and R2.

2. An AC-DC switching buck circuit according to claim 1, characterized in that, It also includes a filter circuit composed of the inductor L1, the energy storage capacitors EC1 and EC2, and a CLC type Π type filter circuit composed of the inductor L1, the energy storage capacitors EC1 and EC2, which converts the pulsating DC into DC power.

3. An AC-DC switching buck circuit according to claim 1, wherein, It also includes an energy storage capacitor C1 for supplying power to the power chip U1.

4. An AC-DC switching buck circuit according to claim 1, wherein, The transformer T1 stores energy in the 6 and 10 pins and transmits the energy to the 5 and 2 pins according to the transformer ratio, thereby reducing the output voltage of the secondary side and increasing the output current of the secondary side.

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