Voltage reduction circuit based on discrete component

Abstract

The utility model provides a step-down circuit based on discrete components, and relates to the technical field of circuit step-down, the step-down circuit comprises a step-down control circuit and a step-down voltage stabilizing circuit, the step-down control circuit comprises a self-locking button H1, an MOS tube U3 and an MOS tube U2, the self-locking button H1 controls the conduction states of the MOS tube U3 and the MOS tube U2 so as to switch the circuit to be in a step-down mode or a non-step-down mode, and the self-locking button H1 controls the conduction states of the MOS tube U3 and the MOS tube U2. The voltage reducing and stabilizing circuit comprises a voltage stabilizing diode ZD1, a voltage stabilizing diode ZD3, a triode Q1 and a triode Q2, and the voltage stabilizing diode ZD1 and the voltage stabilizing diode ZD3 jointly form a clamping device; the technical key points are as follows: switching of voltage reduction modes is realized by ingeniously utilizing a self-locking key, multiple functions of surge resistance, secondary protection, voltage stabilization, overvoltage protection, filtering, outage detection and the like are combined, the stability and the safety of the circuit are ensured, and the voltage reduction circuit is simple, easy to realize, relatively low in cost and relatively high in reliability. And the method can be applied to various electronic devices requiring flexible voltage regulation.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit voltage reduction, in particular to a voltage reduction circuit based on discrete components. Background Art

[0002] In the design of modern electronic equipment, in order to adapt to the power supply voltage required by various loads, it is often necessary to step down the input voltage. The general ways to step down the input voltage include transformer step-down, capacitor step-down and inductor step-down. This function can also be achieved based on switching power supplies or linear regulators.

[0003] However, the use of traditional switching power supplies, linear regulators, transformers, capacitors, and inductors to step down the input voltage is easily limited by its high cost and low conversion efficiency, especially in applications that are cost-sensitive and require simple design. Utility Model Content

[0004] In order to overcome the existing way of stepping down the input voltage, which is easily limited by its high cost and low conversion efficiency, especially in cost-sensitive applications that require simple design, the limitations are particularly obvious. The embodiment of the present application provides a step-down circuit based on discrete components, which cleverly uses a self-locking button to switch the voltage step-down mode, combines surge protection, secondary protection, voltage stabilization, overvoltage protection, filtering, and power failure detection, etc., to ensure the stability and safety of the circuit. At the same time, due to the simple structure, low cost and easy implementation of the voltage step-down circuit, it becomes an ideal low-cost, high-efficiency step-down solution, suitable for various electronic devices that require flexible voltage adjustment.

[0005] The technical solution adopted by the embodiment of the present application to solve the technical problem is:

[0006] A step-down circuit based on discrete components includes a step-down control circuit and a step-down voltage stabilizing circuit, wherein the step-down voltage stabilizing circuit is connected to the step-down control circuit;

[0007] Among them, the buck control circuit includes a self-locking button H1, a MOS tube U3 and a MOS tube U2. The self-locking button H1 controls the conduction state of the MOS tube U3 and the MOS tube U2 respectively to switch the circuit in a buck mode or a non-buck mode. The buck voltage stabilizing circuit includes a zener diode ZD1, a zener diode ZD3, a transistor Q1 and a transistor Q2. The zener diode ZD1 and the zener diode ZD3 together constitute a clamper. The transistor Q1 and the transistor Q2 constitute a voltage follower, and receive the voltage that has undergone preliminary bucking, and use its base-emitter voltage as a reference, and adjust the collector-emitter voltage to follow the input to keep the output end (DC12V) voltage constant at 12V.

[0008] In a possible implementation, the output end of the step-down control circuit is connected to a power protection circuit, and the power protection circuit includes a power supply DC1 and a gas discharge tube U1 , and the gas discharge tube U1 is connected to the input end of the power supply DC1 .

[0009] In a possible implementation, an output end of the step-down control circuit is connected to an anti-surge circuit, and the anti-surge circuit includes a capacitor C1, a capacitor C2, a transient diode D5, and a resistor R5.

[0010] In a possible implementation, the output end of the surge protection circuit is connected to a secondary protection circuit, and the secondary protection circuit includes a diode D1 and a transient diode D6.

[0011] In a possible implementation, an overvoltage protection circuit is further provided between the step-down control circuit and the step-down voltage stabilization circuit. The overvoltage protection circuit includes a diode D7, a voltage regulator ZD2, a capacitor C3 and a capacitor C4. The capacitor C3 and the capacitor C4 constitute a filter circuit.

[0012] In a possible implementation, one end of the step-down control circuit is connected to a M_ACT_DET pin, and one end of the M_ACT_DET pin forms a power-off detection circuit through a resistor R21, a resistor R20 and a diode D9.

[0013] In a possible implementation, the step-down voltage stabilization circuit is connected to a resistor R6 and a resistor R9, and the overvoltage protection circuit is connected to a resistor R4 and a resistor R8.

[0014] In summary, the present invention includes at least one of the following beneficial technical effects:

[0015] In this solution, the voltage step-down mode is switched by cleverly using the self-locking button, combined with multiple functions such as surge protection, secondary protection, voltage stabilization, overvoltage protection, filtering, and power failure detection, to ensure the stability and safety of the circuit. At the same time, due to the simple structure, low cost and easy implementation of the voltage step-down circuit, it becomes an ideal low-cost, high-efficiency step-down solution, suitable for all kinds of electronic equipment that need to flexibly adjust the voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the circuit structure of the utility model;

[0017] Figure 2 This is a flow diagram of current in the circuit during voltage reduction control of the utility model;

[0018] Figure 3 This is a flow diagram of current in the circuit when the utility model is in the step-down and voltage-stabilizing state. DETAILED DESCRIPTION

[0019] The technical solution in the embodiment of the present application is to solve the problems of the above-mentioned background technology, and the overall idea is as follows:

[0020] Embodiment 1:

[0021] This embodiment introduces a specific structure of a step-down circuit based on discrete components. Figure 1-Figure 3 As shown, it includes a step-down control circuit and a step-down voltage stabilizing circuit. The step-down control circuit includes a self-locking button H1, a MOS tube U3 and a MOS tube U2. The step-down voltage stabilizing circuit includes a voltage stabilizing diode ZD1, a voltage stabilizing diode ZD3, a transistor Q1 and a transistor Q2. The transistor Q1 and the transistor Q2 form a voltage follower.

[0022] Among them, the buck stabilizing circuit is connected to the buck control circuit, and the self-locking button H1 is used as a user operation interface. By controlling the pressing state of the self-locking button, the conduction state of the MOS tube U3 and the MOS tube U2 can be controlled respectively to switch the circuit to the buck mode or the non-buck mode;

[0023] At the same time, if Figure 2 As shown, when the self-locking button H1 is not pressed, the MOS tube U3 is in the on state, and the voltage at the DC12V terminal is pulled down, so that the circuit is in the non-step-down mode or the default voltage output state;

[0024] When the self-locking button H1 is in the pressed state, the MOS tube U2 is triggered to conduct, and the MOS tube U3 is turned off, activating the step-down function. This operation changes the current path inside the circuit, so that the subsequent voltage stabilizing elements start to work and step down the input voltage.

[0025] Secondly, if Figure 3 As shown, by making the voltage-stabilizing diode ZD1 and the voltage-stabilizing diode ZD3 together form a clamper, when the self-locking button H1 is pressed, the MOS tube U3 is in the off state, and the MOS tube U2 is turned on, the clamper can be used to limit the voltage amplitude, and then, the voltage follower composed of the transistors Q1 and Q2 receives the voltage that has undergone preliminary voltage reduction, and uses its base-emitter voltage as a reference, and adjusts the collector-emitter voltage to follow the input, so as to keep the output terminal (DC12V) voltage constant at 12V, thereby completing the precise voltage reduction and voltage regulation process;

[0026] like Figure 1-3 As shown, the output end of the step-down control circuit is connected to a power protection circuit, which includes a power supply DC1 and a gas discharge tube U1;

[0027] Among them, the power supply DC1 is used as the positive electrode of the energy storage power supply to provide the initial working voltage for the entire step-down circuit, and the gas discharge tube U1 is connected to the input end of the power supply DC1 to absorb and suppress the instantaneous high-voltage impact and protect the subsequent circuit from overvoltage damage;

[0028] like Figure 1-Figure 3 As shown, the output end of the step-down control circuit is connected to an anti-surge circuit, the anti-surge circuit includes a capacitor C1, a capacitor C2, a transient diode D5 and a resistor R5, and the output end of the anti-surge circuit is connected to a secondary protection circuit, the secondary protection circuit includes a diode D1 and a transient diode D6;

[0029] The anti-surge circuit composed of capacitors C1, C2, transient diode D5 and resistor R5 can effectively suppress the voltage spike generated when the power is turned on, ensuring stable startup of the circuit, while diode D1 and transient diode D6 form a secondary protection link, further enhancing the circuit's protection against abnormal voltage fluctuations;

[0030] like Figure 1-Figure 3 As shown, an overvoltage protection circuit is also provided between the step-down control circuit and the step-down voltage stabilizing circuit. The overvoltage protection circuit includes a diode D7, a voltage stabilizing tube ZD2, a capacitor C3 and a capacitor C4. The capacitor C3 and the capacitor C4 form a filter circuit.

[0031] Among them, when the diode D7 and the voltage regulator ZD2 flow through the circuit, they can prevent the output voltage from being too high during the voltage reduction process, provide overvoltage protection function, and ensure the safety of the load;

[0032] The filter circuit composed of capacitors C3 and C4 can filter out noise and ripples in the output voltage, improve the power quality, and ensure that the load is supplied with a smooth and stable voltage.

[0033] Secondly, one end of the step-down control circuit is connected to the M_ACT_DET pin, and a resistor R21, a resistor R20 and a diode D9 are connected to one end of the M_ACT_DET pin to finally form a power-off detection circuit, while the step-down voltage stabilization circuit is connected to resistors R6 and R9, and the overvoltage protection circuit is connected to resistors R4 and R8;

[0034] At the same time, because resistors R6, R9, R4 and R8 are used as voltage-dividing and current-limiting components, they can reasonably distribute the voltage and limit the current, ensuring that each part of the circuit works within a safe range and avoids overload;

[0035] In addition, with the help of the M_ACT_DET pin, when the main power is interrupted, the power-off detection circuit connected through the M_ACT_DET pin can detect the power-off signal in time, which may be used to trigger the system to enter the corresponding protection state or notify the user of the power failure.

[0036] The above design uses the self-locking button H1 to control the conduction state of the MOS tube U3 and the MOS tube U2 respectively, so as to switch the circuit to the buck mode or the non-buck mode. The anti-surge circuit composed of the capacitor C1, the capacitor C2, the transient diode D5 and the resistor R5, and the secondary protection circuit composed of the diode D1 and the transient diode D6 are combined to ensure the stable startup of the circuit and enhance the protection capability of the circuit against abnormal voltage fluctuations.

[0037] At the same time, the step-down voltage stabilization circuit formed by the voltage stabilization diode ZD1, the voltage stabilization diode ZD3, the transistor Q1 and the transistor Q2 receives the voltage after the preliminary step-down, and uses its base-emitter voltage as a reference, and adjusts the collector-emitter voltage to follow the input, so as to keep the output terminal (DC12V) voltage constant at 12V, thus completing the precise step-down.

[0038] The overvoltage protection circuit composed of diode D7, voltage regulator ZD2, capacitor C3 and capacitor C4 can prevent the output voltage from being too high during the voltage reduction process when the current flows through the circuit, provide overvoltage protection function, and ensure the stability and safety of the circuit.

[0039] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A step-down circuit based on discrete components, characterized in that: include: Buck control circuit; A step-down voltage stabilizing circuit connected to the step-down control circuit; The buck control circuit includes a self-locking button H1, a MOS tube U3 and a MOS tube U2. The self-locking button H1 controls the conduction state of the MOS tube U3 and the MOS tube U2 respectively to switch the circuit to a buck mode or a non-buck mode. The step-down voltage stabilizing circuit includes a voltage stabilizing diode ZD1, a voltage stabilizing diode ZD3, a transistor Q1 and a transistor Q2. The voltage stabilizing diode ZD1 and the voltage stabilizing diode ZD3 together constitute a clamp. The transistor Q1 and the transistor Q2 constitute a voltage follower, and receive the voltage that has undergone preliminary voltage reduction, and use its base-emitter voltage as a reference, and adjust the collector-emitter voltage to follow the input to keep the output end (DC12V) voltage constant at 12V.

2. A step-down circuit based on discrete components as claimed in claim 1, characterized in that: The output end of the step-down control circuit is connected to a power protection circuit. The power protection circuit includes a power supply DC1 and a gas discharge tube U1. The gas discharge tube U1 is connected to the input end of the power supply DC1.

3. A step-down circuit based on discrete components as claimed in claim 1, characterized in that: The output end of the step-down control circuit is connected to an anti-surge circuit, and the anti-surge circuit includes a capacitor C1, a capacitor C2, a transient diode D5 and a resistor R5.

4. A step-down circuit based on discrete components as claimed in claim 3, characterized in that: The output end of the anti-surge circuit is connected to a secondary protection circuit, and the secondary protection circuit includes a diode D1 and a transient diode D6.

5. A step-down circuit based on discrete components as claimed in claim 1, characterized in that: An overvoltage protection circuit is also provided between the step-down control circuit and the step-down voltage stabilizing circuit. The overvoltage protection circuit includes a diode D7, a voltage stabilizing tube ZD2, a capacitor C3 and a capacitor C4. The capacitor C3 and the capacitor C4 form a filter circuit.

6. A step-down circuit based on discrete components as claimed in claim 1, characterized in that: One end of the step-down control circuit is connected to the M_ACT_DET pin, and one end of the M_ACT_DET pin forms a power-off detection circuit through a resistor R21, a resistor R20 and a diode D9.

7. A step-down circuit based on discrete components as claimed in claim 5, characterized in that: The step-down voltage stabilization circuit is connected to a resistor R6 and a resistor R9, and the overvoltage protection circuit is connected to a resistor R4 and a resistor R8.

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