CN210201738U

CN210201738U - Positive and negative symmetrical stable power supply based on capacitance voltage reduction

Info

Publication number: CN210201738U
Application number: CN201921463276.8U
Authority: CN
Inventors: Jianguo Cui; 崔建国; Yongxiang Ning; 宁永香; Yi Cui; 崔燚
Original assignee: Shanxi Engineering Institute
Current assignee: Shanxi Engineering Institute; Shanxi Institute of Technology
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2020-03-27
Anticipated expiration: 2029-09-04

Abstract

The utility model discloses a technology of positive and negative symmetry stable power supply based on electric capacity step-down, it includes live wire circuit, earth circuit, zero line circuit, fuse circuit, neon lamp circuit, electric capacity step-down circuit, positive half cycle rectifier circuit, positive half cycle voltage stabilizing circuit, positive half cycle filter circuit, negative half cycle rectifier circuit, negative half cycle voltage stabilizing circuit, negative half cycle filter circuit; the zero line is connected to the ground through the fuse in the circuit, so that the step-down capacitor can be connected with the live wire, otherwise, the fuse is blown, and meanwhile, the neon lamp emits light for display.

Description

Positive and negative symmetrical stable power supply based on capacitance voltage reduction

Technical Field

The utility model relates to a section is based on positive and negative symmetry stable power of electric capacity step-down method and is produced the technique of circuit, especially one kind is different from adopting traditional transformer step-down method to produce stable power, is a novel stable power structure, is connected to the zero line through the fuse in the circuit and can guarantees to make step-down electric capacity link to each other with the live wire on the earth, otherwise the fuse will blow, neon lamp luminous demonstration simultaneously.

Background

The dc power supply of many electronic devices is obtained by stepping down the mains voltage, and there are two general ways: the transformer step-down and the capacitor step-down are common, the working principle is well understood, but the portable handheld device has the defects of large size and poor stability, and the transformer falling-off condition is easy to occur in the transformer step-down power supply mode;

the capacitor voltage reduction mode has the characteristics of economy and convenience, and is often adopted in the power supply of low-power devices or handheld equipment such as driving remote control equipment.

Disclosure of Invention

The utility model aims to solve the technical problem that a simple structure, novelty, convenient to use, reliable are different from the conventional equipment that utilizes the transformer to step down and realize stabilizing power output is provided.

In order to achieve the purpose, the utility model provides a positive and negative symmetry stable power supply based on electric capacity step-down, it includes live wire circuit, earth circuit, zero line circuit, fuse circuit, neon lamp circuit, electric capacity step-down circuit, positive half cycle rectifier circuit, positive half cycle voltage stabilizing circuit, positive half cycle filter circuit, negative half cycle rectifier circuit, negative half cycle voltage stabilizing circuit, negative half cycle filter circuit; when the positive half cycle of the commercial power comes, the end of the live wire circuit is positive, and the charge sequentially passes through the capacitor voltage reduction circuit and the diode D of the positive half cycle rectifying circuit₁And the voltage stabilizing diode DW of the positive half-cycle voltage stabilizing circuit₁The earth circuit, the fuse circuit F and the zero line circuit form a power supply loop, and the positive half-cycle voltage stabilizing circuit diode DW₁And the positive half-cycle filter circuit capacitor C₃Connected in parallel and finally connected from the filter circuit capacitor C with the earth as a common terminal₃The two ends output a +14V stable power supply; when the negative half cycle of the commercial power comes, the circuit end of the zero line is positive, and the charge sequentially passes through the fuse circuit F, the ground circuit and the negative half cycle voltage stabilizing circuit diode DW₂The negative half-cycle rectifier circuit diode D₂The capacitor voltage reduction circuit and the live wire circuit form a power supplyA circuit loop, the negative half cycle voltage stabilizing circuit diode DW₂And the negative half-cycle filter circuit capacitor C₄In parallel connection, and finally taking the earth as a common terminal to obtain the capacitance C of the negative half-cycle filter circuit₄The two ends output a-14V stable power supply; the neon lamp and the resistor R1 form the neon lamp circuit, and the fuse circuit F is connected with the neon lamp circuit in parallel.

The capacitance voltage reduction circuit is formed by connecting a capacitor C1 and a resistor R2 in parallel.

Drawings

FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9 are included to provide a further understanding of the present invention, and form a part of the present application, wherein FIG. 1 is a typical capacitor voltage step-down and stabilizing circuit, FIG. 2 is a typical capacitor voltage step-down and stabilizing practical circuit, FIG. 3 is a full-wave rectification capacitor voltage step-down and stabilizing circuit, FIG. 4 is a capacitor voltage step-down and stabilizing circuit based on a zener diode power amplifying circuit implemented by an NPN triode, FIG. 5 is a capacitor voltage step-down and stabilizing circuit based on a zener diode power amplifying circuit implemented by a PNP triode, FIG. 6 is a different connection mode of a half-wave rectification circuit DC power output terminal and a utility power common terminal when a power tube is a one-way thyristor, FIG. 7 is a different connection mode of a, fig. 8 is a circuit diagram of a conventional transformer step-down full-wave rectifier circuit, and fig. 9 is a circuit diagram of a simple positive-negative symmetrical stable power supply obtained by using a capacitance step-down method.

Detailed Description

Working principle of common capacitance voltage reduction voltage stabilizer

In the field of electronic industrial design, the design schemes of voltage regulators with capacitance voltage reduction are different according to different requirements, the design scheme is more complex with higher requirements, the design schemes of a plurality of common voltage regulators with capacitance voltage reduction are described from simple requirements, the last scheme can provide two voltage-stabilized power supply outputs with positive and negative symmetry at the same time, and the voltage regulators with capacitance voltage reduction are very convenient to use in daily circuit design.

Typical capacitive buck voltage regulator circuit

If the low-voltage control circuit has less strict requirements on various constants of the power supply, the capacitor step-down power supply shown in fig. 1 and 2 can be adopted, which is a more typical capacitor step-down voltage stabilizing circuit, and the basic principle of capacitor step-down is as follows: because the capacitor has capacitive reactance in alternating current, the capacitor can be approximately equivalent to a voltage reduction resistor, the impedance of the capacitor is determined by the formula X =1/2 pi fC, and the alternating current frequency f of the commercial power is 50 Hz.

And obtained according to ohm's law I = U/X

I=69080*C

Where C is in units of microfarads (F) and I is in units of amperes (A).

The load current capability of the capacitor voltage reduction is only related to the capacity of the capacitor, which is actually the rectification characteristic of the capacitor, and the voltage reduction capacitor can be selected according to the formula.

The working process of fig. 1 is: negative half cycle C of commercial power input₁Warp D₁Is charged, and makes the positive half cycle of the input commercial power pass through C₁And a rectifier diode D₂To the load and filter capacitor C₂Forward charging, here a simple diode in parallel regulated voltage is employed.

It can be seen that the rectification after the voltage reduction of the capacitor is half-wave rectification, so that the circuit shown in fig. 2 can be changed from the circuit shown in fig. 1, and at this time, the voltage regulator tube DW can provide a voltage pair C₁The charging channel can also realize the purpose of voltage stabilization.

The capacitor step-down circuit shown in fig. 3 adopts bridge rectifier circuits of D1-D4, so that the rectifier efficiency of the circuit is higher than that of fig. 1 and 2, and thus the short-circuit output current of the capacitor step-down circuit is tested when the step-down capacitors with the same capacity are adopted, and the circuit of fig. 3 is twice that of the circuit of fig. 1 and 2.

If the circuits in fig. 1, 2 and 3 are operated under the condition of open load, it is obvious that the stabilizing current of the capacitor will flow through the voltage-regulator tube, so the voltage-regulator tube is often burned out, and when the voltage-regulator tube DW is selected, the dissipated power P of the voltage-regulator tube is greater than I_C*V_Z(wherein I)_CFor rectifying current, V, by capacitors_ZIs the regulated voltage of the regulator tube).

Capacitor voltage reduction and stabilization circuit based on voltage stabilization tube power expansion circuit

Since the voltage regulator tube of the capacitance voltage reduction circuit shown in the circuits of fig. 1, 2 and 3 is easily burned out, the best method is to adopt the capacitance voltage reduction voltage stabilizing circuit based on the voltage regulator tube power expansion circuit shown in fig. 4 and 5, and the working principle is as follows: when the load is disconnected, the current passing through the voltage stabilizing tube is increased, and the sampling resistor R₁The voltage is increased, when the voltage drop is more than 0.65V, the transistor BG is conducted to release the current which is larger than the current flowing through the voltage-stabilizing tube, so that the voltage-stabilizing tube can select the tube with smaller dissipation power, and the voltage-stabilizing value is V_Z+V_BE, R₂Is the protective resistance of the transistor BG.

1.3 different connection modes of half-wave rectification circuit DC power supply output end and commercial power public end

In the half-wave rectifier circuit using the capacitor for voltage reduction, the output terminal of the dc power supply and the common terminal of the utility power supply can adopt different connection modes according to the needs of the load, for example, when the unidirectional silicon controlled ac load is driven in fig. 6, the common terminal of the general dc power supply and the utility power supply takes the negative pole.

However, when the ac load is driven by the triac, the effective voltage for triggering the gate of the triac must be negative, and the common terminal between the output of the dc power supply and the utility power is generally positive, and the circuit thereof is shown in fig. 7.

1.4 obtaining simple positive-negative symmetrical stable power supply by using capacitance step-down method

The transformer voltage reduction method is also the most common design mode for realizing the positive and negative symmetrical stable power supply, and is very simple, and when the transformer is wound, double-wire parallel winding and head-to-tail connection can be realized, so that the positive and negative power supplies have equal direct current resistance and equal voltage.

When the transformer is wound, a single wire can be wound, a middle tap can obtain double power supplies, the winding process needs to be considered in the latter method, generally, the outer ring of the transformer is provided with a plurality of wires and has large direct-current resistance, and the voltage is also equal according to the turn ratio, as shown in figure 8.

However, the power frequency transformer is not suitable for mobile devices or handheld devices, and a simple positive and negative symmetrical stable power supply can be obtained by using a capacitance voltage reduction mode, the circuit of the power frequency transformer is shown in fig. 9, a zero line is connected to the ground through a fuse to ensure that the voltage reduction capacitor is connected with a live wire, otherwise, the fuse is blown, and a neon lamp emits light for display.

As can be seen from the circuit of FIG. 9, the positive and negative symmetrical stable power generating circuit comprises a live wire circuit, a ground circuit, a zero line circuit, a fuse circuit, a neon lamp circuit, a capacitor voltage reducing circuit, a positive half-cycle rectifying circuit, a positive half-cycle voltage stabilizing circuit, a positive half-cycle filter circuit, a negative half-cycle rectifying circuit, a negative half-cycle voltage stabilizing circuit and a negative half-cycle filter circuit.

The principle of operation is simple, the +14V output is well understood, the principle of-14V output is not well understood, and can be understood as follows:

the earth is taken as a public end (namely a 0V end) of the positive and negative symmetrical stable power supply output, and the original commercial power zero line is connected with the earth (namely the public end) through a fuse F (the internal resistance is zero). When the positive half cycle of the commercial power comes, the fire wire end is positive, and the voltage is reduced by the voltage reduction capacitor C₁Rectifier diode D₁Voltage stabilizing diode DW₁Filter capacitor C₃The earth, the fuse F and the zero line (negative) form a power supply loop, and finally the earth is used as a common end (0V) at C₃The two ends output +14V stable power supply.

When the negative half cycle of the commercial power comes, the zero line end is positive, and the charge passes through the fuse F, the earth and the filter capacitor C₄Voltage stabilizing diode DW₂Rectifier diode D₂Voltage reducing capacitor C₁The live wire (negative) forms a power supply loop, and finally the earth is used as a common end (0V) at C₄Two ends output a-14V stable power supply.

Making of

When manufacturing a direct current stabilized power supply with a capacitor voltage reduction function, the following points should be noted:

1) any part of a circuit of the direct current power supply and a load thereof are provided with commercial power, and the direct contact with hands is strictly forbidden during manufacturing and use.

2) The voltage reduction capacitor and the rectifier diode are both required to adopt devices with voltage resistance of more than 400V, and the resistor connected with the voltage reduction capacitor in parallel cannot be omitted, so that after the circuit is separated from mains supply, the charge on the voltage reduction capacitor is released, and the resistor with the voltage of 100K-1M can be generally adopted.

3) The stabilizing current of most voltage-stabilizing tubes is generally required to be more than 5mA, but is less than the maximum stabilizing current; in addition, the reliable connection of the voltage-regulator tube is ensured, and if the voltage-regulator tube is disconnected from a circuit, the high voltage of the circuit is easy to cause the breakdown of a load.

4) The filter capacitor in the filter circuit can be an electrolytic capacitor of 47 uF-220 uF, and the withstand voltage value of the electrolytic capacitor is larger than the stable voltage of the circuit.

Claims

1. The utility model provides a positive negative symmetry stabilized power supply based on electric capacity step-down which characterized in that: the positive and negative symmetrical stable power supply comprises a live wire circuit, a ground circuit, a zero line circuit, a fuse circuit, a neon lamp circuit, a capacitor voltage reduction circuit, a positive half-cycle rectification circuit, a positive half-cycle voltage stabilizing circuit, a positive half-cycle filter circuit, a negative half-cycle rectification circuit, a negative half-cycle voltage stabilizing circuit and a negative half-cycle filter circuit; when the positive half cycle of the commercial power comes, the end of the live wire circuit is positive, and the charge sequentially passes through the capacitor voltage reduction circuit and the diode D of the positive half cycle rectifying circuit₁And the voltage stabilizing diode DW of the positive half-cycle voltage stabilizing circuit₁The earth circuit, the fuse circuit F and the zero line circuit form a power supply loop, and the positive half-cycle voltage stabilizing circuit diode DW₁And the positive half-cycle filter circuit capacitor C₃Connected in parallel and finally connected from the filter circuit capacitor C with the earth as a common terminal₃The two ends output a +14V stable power supply; when the negative half cycle of the commercial power comes, the circuit end of the zero line is positive, and the charge sequentially passes through the fuse circuit F, the ground circuit and the negative half cycle voltage stabilizing circuit diode DW₂The negative half-cycle rectifier circuit diode D₂The capacitor voltage reduction circuit and the live wire circuit form a power supply loop, and the negative half-cycle voltage stabilizing circuit diode DW₂And the negative half-cycle filter circuit capacitor C₄In parallel connection, and finally taking the earth as a common terminal to obtain the capacitance C of the negative half-cycle filter circuit₄The two ends output a-14V stable power supply; the neon lamp and the resistor R1 form the neon lamp circuit, and the fuse circuit F is connected with the neon lamp circuit in parallel.

2. The positive-negative symmetrical stable power supply based on capacitance voltage reduction as claimed in claim 1, wherein: the capacitance voltage reduction circuit is formed by connecting a capacitor C1 and a resistor R2 in parallel.