Linear starting circuit

Abstract

The utility model provides a linear starting circuit which comprises a power supply, a voltage regulating unit, an output sampling unit, a reference unit and an error amplification compensation unit, the output end of the power supply is connected to the input end of the voltage regulating unit, and the output end of the voltage regulating unit is connected with the input end of the output sampling unit. The output end of the output sampling unit is connected to the input end of the error amplification compensation unit, the input end of the error amplification compensation unit is further connected with a reference unit, and the output end of the error amplification compensation unit is connected to the voltage regulating unit; and a feed-forward network unit is further arranged, the feed-forward network unit is used for feeding an output voltage signal forward to the reference unit, the input end of the feed-forward network unit is connected to the output end of the voltage regulating unit, and the output end of the feed-forward network unit is connected to the input end of the reference unit. The starting circuit provided by the utility model can restrain input surge current under the condition of not changing the establishment time of the output voltage.

Description

Technical Field

[0001] The utility model mainly relates to the technical field of direct current voltage-stabilized power supply, in particular to a linear starting circuit. Background Art

[0002] The power supply is the power source of all electronic equipment. The quality of its performance directly affects the safety and reliability of electronic equipment. In the power conversion system, DC regulated power supplies are widely used in communications, computers, military equipment and other fields. A DC regulated power supply (referred to as a regulated power supply) is an electronic device that can provide a stable DC power supply to the load. Its power supply is mostly an AC power supply. When the voltage of the AC power supply or the load resistance changes, the DC output voltage of the regulator will remain stable. As electronic equipment develops towards high precision, high stability and high reliability, regulated power supplies have put forward high requirements for the power supply of electronic equipment.

[0003] According to the control method, the voltage-stabilized power supply is divided into two categories: linear power supply and switching power supply. The linear power supply means that the voltage regulating unit always works in the linear amplification area, and the switching power supply means that the voltage regulating unit always works in the high-frequency switching state. They both convert the power supply into the required stable output voltage. In recent years, with the diversification of the types of voltage-stabilized power supplies for electrical equipment, the power of the equipment has increased day by day. At the same time, the equipment also requires power-off retention, so the energy storage capacitor capacity must be increased. These requirements jointly aggravate the increase in the input surge current of the system. As we all know, the current capacity provided by the power supply is limited. When the current exceeds the power supply's bearing current, it may trigger the power supply to trip and cannot start normally. In severe cases, it may damage the power supply equipment. In order to ensure the reliable and stable operation of the power supply, the input surge current index requirements for each type of voltage-stabilized power supply are becoming more and more stringent.

[0004] In order to meet the input surge current requirements, the traditional approach is to extend the reference base to increase the output voltage build-up time. Although this can improve the input surge current, it sacrifices the startup time and is difficult to adapt to systems with timing control requirements. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a linear starting circuit which can suppress input surge current without changing the output voltage establishment time.

[0006] In order to solve the above technical problems, the utility model provides a linear starting circuit, comprising: a power supply, a voltage regulating unit, an output sampling unit, a reference base unit and an error amplification and compensation unit, wherein the output end of the power supply is connected to the input end of the voltage regulating unit, the output end of the voltage regulating unit is connected to the input end of the output sampling unit, the output end of the output sampling unit is connected to the input end of the error amplification and compensation unit, the input end of the error amplification and compensation unit is also connected to the reference base unit, the output end of the error amplification and compensation unit is connected to the voltage regulating unit, and a feedforward network unit is also provided, the feedforward network unit is used to feedforward the output voltage signal to the reference base unit, the input end of the feedforward network unit is connected to the output end of the voltage regulating unit, and the output end of the feedforward network unit is connected to the input end of the reference base unit.

[0007] Furthermore, the feedforward network unit includes a resistor R1, and two ends of the resistor R1 are respectively connected to the output end of the voltage regulating unit and the input end of the reference standard unit.

[0008] Furthermore, the feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the input end of the reference unit, and the anode of the diode D1 is connected to the output end of the voltage regulating unit.

[0009] Furthermore, the feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the output end of the voltage regulating unit, and the cathode of the diode D1 is connected to the input end of the reference unit.

[0010] Furthermore, the resistor R1 is an adjustable resistor.

[0011] Compared with the prior art, the utility model has the following beneficial effects: a feedforward network unit is provided, the input end of the feedforward network unit is connected to the output end of the voltage regulating unit, and the output end of the feedforward network unit is connected to the input end of the reference reference unit, for feeding forward the output voltage signal to the reference reference unit, so that the startup circuit can suppress the input surge current without changing the output voltage establishment time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are included to provide a further understanding of the present invention. They are included and constitute a part of the present invention. The accompanying drawings illustrate embodiments of the present invention and together with the specification serve to explain the principles of the present invention. In the accompanying drawings:

[0013] Figure 1 This is the schematic diagram of the traditional nonlinear starting circuit;

[0014] Figure 2 It is a structural diagram of a traditional nonlinear starting circuit;

[0015] Figure 3 This is a schematic diagram of a linear starting circuit according to an embodiment of the utility model;

[0016] Figure 4 This is a structural diagram of a linear starting circuit of an embodiment of the utility model;

[0017] Figure 5 It is a schematic diagram of a simulation curve of a reference charging current and a feedforward current in an embodiment of the utility model;

[0018] Figure 6 It is a schematic diagram of a reference benchmark simulation curve in an embodiment of the utility model;

[0019] Figure 7 It is a schematic diagram of output voltage and input surge current simulation curves in one embodiment of the utility model. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present utility model. For ordinary technicians in this field, the present utility model can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0021] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0022] Figure 1 This is the schematic diagram of the traditional nonlinear starting circuit, refer to Figure 1As shown, after the power supply (providing energy) is turned on, the output voltage is obtained after being processed by the voltage regulating unit. The output sampling unit sends the signal of the output voltage after resistor voltage division to the error amplification and compensation unit, and compares it with the reference reference signal in the error amplification and compensation unit. The obtained signal controls the operation of the voltage regulating unit to stabilize the output voltage at the set value.

[0023] During the output voltage startup process, the output sampling unit constantly monitors and follows the reference signal. When the output sampling signal is equal to the reference setting value, the output voltage is established. Since the output voltage is established by following the reference, extending the reference establishment time is equivalent to extending the output startup time, thereby achieving the purpose of reducing the input surge current. The traditional reference delay is formed by the RC charging circuit, and the establishment process is a nonlinear curve. For specific circuits, please refer to Figure 2 As shown, Figure 2 This is a structural diagram of a traditional nonlinear starting circuit, in which:

[0024] Power supply: V1;

[0025] Voltage regulating unit: Q1;

[0026] Output sampling unit: upper voltage divider resistor R4, lower voltage divider resistor R5;

[0027] Reference unit: reference source U2, reference delay capacitor C2, reference charging resistor R2,

[0028] Reference power supply V2, reference discharge resistor R3;

[0029] Error amplification and compensation unit: error amplifier U1, compensation capacitor C1;

[0030] In addition, REF1 represents the traditional nonlinear startup reference voltage, Ic1 represents the traditional nonlinear startup input surge current, VO1 represents the traditional nonlinear startup output voltage, Ir1 represents the traditional nonlinear startup reference charging current, and C3 is the output energy storage capacitor.

[0031] Figure 3 This is a schematic diagram of a linear startup circuit according to an embodiment of the utility model. Figure 3As shown, the linear starting circuit provided in this embodiment includes a power supply, a voltage regulating unit, an output sampling unit, a reference base unit and an error amplification and compensation unit; the output end of the power supply is connected to the input end of the voltage regulating unit, the output end of the voltage regulating unit is connected to the input end of the output sampling unit, the output end of the output sampling unit is connected to the input end of the error amplification and compensation unit, the input end of the error amplification and compensation unit is also connected to the reference base unit, the output end of the error amplification and compensation unit is connected to the voltage regulating unit, and a feedforward network unit is also provided. The feedforward network unit is used to feedforward the output voltage signal to the reference base unit, the input end of the feedforward network unit is connected to the output end of the voltage regulating unit, and the output end of the feedforward network unit is connected to the input end of the reference base unit.

[0032] The circuit of this embodiment adds a feedforward network unit, which directly feeds the output voltage signal forward to the reference unit. During the output voltage establishment process, the output voltage gradually increases, and the feedforward amount (i.e., charging current) also gradually increases. The charging current of the RC charging circuit gradually decreases as the reference voltage is established. Therefore, the feedforward network unit can effectively compensate the RC charging circuit, thereby achieving the purpose of linear establishment of the reference signal, and finally realizing linear startup of the output voltage, which can further reduce the input surge current. For specific circuits, please refer to Figure 4 As shown, where:

[0033] Power supply: V1;

[0034] Voltage regulating unit: Q1;

[0035] Output sampling unit: upper voltage divider resistor R4, lower voltage divider resistor R5;

[0036] Reference unit: reference source U2, reference delay capacitor C2, reference charging resistor R2,

[0037] Reference power supply V2, reference discharge resistor R3;

[0038] Error amplification and compensation unit: error amplifier U1, compensation capacitor C1;

[0039] Feedforward network unit: feedforward resistor R1 (to set feedforward compensation current), feedforward diode D1 (to eliminate the influence of output voltage drop);

[0040] In addition, REF2 represents the linear startup reference voltage, Ic2 represents the linear startup input surge current, VO2 represents the linear startup output voltage, Ir1 represents the traditional nonlinear startup reference charging current, Ir2 represents the linear startup newly added feedforward current, and C3 is the output energy storage capacitor.

[0041] In some implementations, the feedforward network unit includes a resistor R1 , and two ends of the resistor R1 are respectively connected to an output end of the voltage regulating unit and an input end of the reference standard unit.

[0042] In some implementations, the feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the input end of the reference unit, and the anode of the diode D1 is connected to the output end of the voltage regulating unit.

[0043] In some implementations, the feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the output end of the voltage regulating unit, and the cathode of the diode D1 is connected to the input end of the reference unit.

[0044] In some implementations, the resistor R1 is an adjustable resistor.

[0045] Figure 5 It is a schematic diagram of a simulation curve of a reference charging current and a feedforward current in an embodiment of the utility model. Figure 6 This is a schematic diagram of a reference benchmark simulation curve in an embodiment of the utility model. Figure 7 This is a schematic diagram of the output voltage and input surge current simulation curve in one embodiment of the utility model, refer to Figure 5~Figure 7 It can be seen that by building a circuit simulation, it is proved that under the same output startup time, the input surge current of the linear startup circuit provided by this embodiment is only half of the input surge current of the traditional nonlinear startup circuit, that is, under the conditions of the same input surge current and output startup time, the linear startup circuit has an energy storage capacitor capacity that is nearly doubled. In short, the linear startup circuit of this embodiment can suppress the input surge current without changing the output voltage build-up time.

[0046] For those skilled in the art, the above utility model disclosure is only used as an example and does not constitute a limitation of the utility model. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the utility model. Such modifications, improvements and amendments are suggested in the utility model, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the utility model.

[0047] Although the present invention has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present invention, they will fall within the scope of the claims of the present invention.

Claims

1. A linear starting circuit, comprising: A power supply, a voltage regulating unit, an output sampling unit, a reference base unit and an error amplification and compensation unit, wherein the output end of the power supply is connected to the input end of the voltage regulating unit, the output end of the voltage regulating unit is connected to the input end of the output sampling unit, the output end of the output sampling unit is connected to the input end of the error amplification and compensation unit, the input end of the error amplification and compensation unit is also connected to a reference base unit, the output end of the error amplification and compensation unit is connected to the voltage regulating unit, and a feedforward network unit is also provided, the feedforward network unit is used to feedforward the output voltage signal to the reference base unit, the input end of the feedforward network unit is connected to the output end of the voltage regulating unit, and the output end of the feedforward network unit is connected to the input end of the reference base unit.

2. The linear starting circuit according to claim 1, characterized in that: The feedforward network unit includes a resistor R1 , and two ends of the resistor R1 are respectively connected to the output end of the voltage regulating unit and the input end of the reference standard unit.

3. The linear startup circuit according to claim 1, characterized in that: The feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the input end of the reference unit, and the anode of the diode D1 is connected to the output end of the voltage regulating unit.

4. The linear starting circuit according to claim 1, characterized in that: The feedforward network unit includes a series branch consisting of a resistor R1 and a diode D1, wherein one end of the resistor R1 is connected to the output end of the voltage regulating unit, and the cathode of the diode D1 is connected to the input end of the reference unit.

5. The linear starting circuit according to any one of claims 2 to 4, characterized in that: The resistor R1 is an adjustable resistor.

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