CN102611338A

CN102611338A - Wide voltage impedance step-down circuit

Info

Publication number: CN102611338A
Application number: CN201110023674XA
Authority: CN
Inventors: 汤乃申; 汤征宁
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-01-21
Filing date: 2011-01-21
Publication date: 2012-07-25

Abstract

The invention relates to a wide voltage impedance step-down circuit. An alternating-current power supply impedance step-down circuit, and a known capacitance step-down circuit and a known inductance step-down circuit are all used under fixed voltages in general; therefore, input voltages of the step-down circuits are only allowed to change in a small range; and when the input voltages change in a wide range, both the voltage and the current of load change in a wide range correspondingly, so that the step-down impedance has to be changed when the wide input voltage is changed, and then the circuit can work when the input voltages change in a wide range. According to the wide voltage impedance step-down circuit, an impedance step-down main loop (1) is used for stepping down the input alternating-current power supply; the step-down input alternating-current power supply is fed to load (8) after passing through an impedance step-down auxiliary loop (2) and a rectifier filter (7); if the voltage changes in a wide range, a voltage sampler (3) acquires a signal, and the signal is amplified by a control circuit (4); a switching circuit (5) is driven to change the impedance of the impedance step-down auxiliary loop and stabilize the voltage and the current of the load (8); and an auxiliary circuit (6) is used for supplying power to the control circuit (4) and the switching circuit (5).

Description

A kind of wide voltage impedance reduction voltage circuit

Technical field

The present invention relates to the technical field of the wide voltage step-down of AC power, particularly relate to a kind of wide voltage impedance reduction voltage circuit.

Background technology

AC power impedance drop volt circuit, known have capacitance decompression, an inductance step-down; Generally all under the fixed voltage situation, use, only allow its input voltage that change is among a small circle arranged, when input voltage when wide region changes; The load voltage electric current all can have corresponding cataclysm; So during wide change in voltage, the impedance of step-down is changed in input thereupon, the present invention is based on this principle.

Summary of the invention

In order to solve the application when the wide change in voltage of input of AC power impedance drop volt circuit in the prior art, the invention provides a kind of efficient, energy-conservation, reliable wide voltage step-down circuit.The present invention proposes following technical scheme:

1, a kind of wide voltage impedance reduction voltage circuit comprises: impedance step-down major loop (1), impedance step-down subsidiary loop (2); Voltage sample (3), control circuit (4), commutation circuit (5), auxiliary circuit (6); Rectifying and wave-filtering (7), load (8), the AC power first via connects impedance step-down major loop (1); Impedance step-down major loop (1) connects impedance step-down subsidiary loop (2), and impedance step-down subsidiary loop (2) output connects rectifying and wave-filtering (7), and rectifying and wave-filtering (7) output connects load (8); AC power the second tunnel connects voltage sample (3), voltage sample (3) output connection control circuit (4), and control circuit (4) output connects commutation circuit (5); Commutation circuit (5) output connects impedance step-down subsidiary loop (2), and the AC power Third Road connects accessory power supply (6), and accessory power supply (6) output is connection control circuit (4) and commutation circuit (5) respectively.

2, described impedance step-down major loop (1) is buck inductor (L), and after AC power one end connect buck inductor (L) as the power supply first via, another termination of buck inductor (L) was by an end of the normally-closed contact (Ja) of auxiliary induction (La), relay (J), bleeder resistance (RL), the impedance step-down subsidiary loop (2) that composes in parallel; The other end of the impedance step-down subsidiary loop (2) that composes in parallel connects the end that the bridge rectifier be made up of diode (D1), (D2), (D3), (D4) exchanges input, and this end is that the positive pole the negative pole of diode (D1) and diode (D2) is formed by connecting, and the AC power other end is as common port; Connect the other end that bridge rectifier exchanges input, this end is that the positive pole the negative pole of diode (D3) and diode (D4) is formed by connecting, and the anodal output of bridge rectifier is to be formed by connecting at the negative pole of diode (D2) and the negative pole of diode (D4), and it is to be formed by connecting at the positive pole of diode (D1) and the positive pole of diode (D3) that the bridge rectifier negative pole is exported; The both positive and negative polarity of bridge rectifier output also connects filter capacitor (C1) two ends composition rectifying and wave-filtering (7), and its both positive and negative polarity output connects the load (8) that the LED lamp is formed, and described voltage sample (3) is by sampling diode (D5); Dropping resistor (R1), sampling filter (C2), sampling resistor (R2), straight tube coupling (ZD); Decoupling capacitor (C3) is formed, and AC power one end connects sampling diode (D5) positive pole as power supply the second tunnel, and sampling diode (D5) negative pole connects dropping resistor (R1) end; The positive pole that the straight tube coupling (ZD) of stabilized voltage characteristic is arranged, serial connection decoupling capacitor (C3) end, the negative pole of straight tube coupling (ZD) connects an end of sampling filter (C2) and an end of sampling resistor (R2), receives the other end of dropping resistor (R1) after three ends connect again; One end of decoupling capacitor (C3) other end, sampling filter (C2) and an end of sampling resistor (R2), three ends connect common port after connecting again, and described control circuit (4) is by triode (BG1); (BG2). (BG3), resistance (R3), (R4), (R5); (R6), electric capacity (C4) (C5) is formed, and the base stage of triode (BG1) connects the positive pole of straight tube coupling (ZD); The collector electrode that the emitter of triode (BG1) connects common port, triode (BG1) connects electric capacity (C4) end, another termination common port of electric capacity (C4), and the collector electrode of triode (BG1) also connects the base stage of triode (BG2), and the emitter of triode (BG2) connects common port; Connect the base stage of triode (BG3) behind the collector series connection resistance (R5) of triode (BG2), behind the base stage series resistor (R4) of triode (BG3), connect the emitter of triode (BG3), after this emitter crosstalk resistance (R6); Connect an end of electric capacity (C5), this end is also received the end as the relay of commutation circuit (5) (J), and the other end of the collector electrode of triode (BG3), electric capacity (C5), the other end of relay (J), three ends connect together and connect common port; Described accessory power supply (6) is by electric capacity (C6), (C7) and diode (D6); (D7), (D8), (D9) form; AC power one end connects electric capacity (C6) respectively as the power supply Third Road, (C7) each end, anodal and diode (D9) negative pole of another terminating diode of electric capacity (C6) (D6); Diode (D6) negative pole series resistor (R3) end, another termination triode (BG1) collector electrode of resistance (R3), diode (D9) positive pole connects common port; Anodal and diode (D8) negative pole of another terminating diode of electric capacity (C7) (D7), diode (D7) negative pole is succeeded an end of electrical equipment (J), and diode (D8) positive pole connects common port.

3, described impedance step-down major loop (1) and impedance step-down subsidiary loop (2); By electric capacity (C), (Ca), resistance (R); (Ra); The circuit that the normally-closed contact (Ja) of relay (J) is formed substitutes, and AC power one end is as power supply first via connection electric capacity (C), resistance (R), the normally-closed contact (Ja) of relay (J), each end, after the other end series resistor (Rc) of the normally-closed contact (Ja) of relay (J) is connected in series electric capacity (Ca) again; Be connected on the other end of electric capacity (C), resistance (R), three ends connect the output as impedance step-down subsidiary loop (2).

4, the normally-closed contact (Ja) of described impedance step-down major loop (1) relay (J) wherein substitutes described control circuit (4) by the normally opened contact (Jb) of relay (J); And auxiliary circuit (6), by triode (BG4), (BG5); Electric capacity (C8), (C9), diode (D10); There is the semiconductor device (ZD1) of stabilized voltage characteristic to substitute; The base stage of triode (BG4) connects the collector electrode of triode (BG1), and the emitter of triode (BG4) connects the base stage of triode (BG5), and the emitter of triode (BG5) connects public pole; The collector electrode of the collector connecting transistor (BG5) of triode (BG4) is received an end of relay (J) again; Electric capacity (C5) and relay (J) also connect, and the other end of electric capacity (C5) and relay (J) and an end of electric capacity (C9) and the negative pole of diode (D10) all connect together, and the positive pole of diode (D10) connects together with the negative pole of the semiconductor device (ZD1) that stabilized voltage characteristic is arranged and an end of electric capacity (C8); The other end of electric capacity (C9) with have the positive pole of the semiconductor device (ZD1) of stabilized voltage characteristic to connect common port, an end of another termination AC power of electric capacity (C8) is as the power supply Third Road.

5, the normally-closed contact (Ja) of described impedance step-down major loop (1) relay (J) wherein substitutes described auxiliary circuit (6) by the normally opened contact (Jb) of relay (J); By transformer (T), diode (D11) (D12) substitutes; One end of the elementary winding one termination AC power of transformer (T) is as the power supply Third Road, another termination common port, and transformer (T) secondary winding two ends connect diode (D11) respectively; (D12) positive pole; Diode (D11), negative pole (D12) connect together and connect an end of electric capacity (C9), and transformer (T) secondary winding centre cap connects common port.

Beneficial effect of the present invention

When the present invention uses in the wide change in voltage of input, because of change in voltage, by voltage sample adopt signal; Make control circuit drive commutation circuit; Change the impedance of impedance step-down subsidiary loop, thereby reach the function of steady load electric current and voltage, the impedance drop volt circuit can be used in wide-voltage range.

Description of drawings

Fig. 1 is an electric functional-block diagram of the present invention

Fig. 2 is one of electrical schematic diagram of wide voltage inductance reduction voltage circuit

Fig. 3 is one of electrical schematic diagram of wide voltage capacitor reduction voltage circuit

Fig. 4 be wide voltage inductance reduction voltage circuit electrical schematic diagram two

Fig. 5 be wide voltage capacitor reduction voltage circuit electrical schematic diagram two

Fig. 6 be wide voltage inductance reduction voltage circuit electrical schematic diagram three

Fig. 7 be wide voltage capacitor reduction voltage circuit electrical schematic diagram three

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is elaborated.

At first combine Fig. 1 that overall technological scheme of the present invention is laid down a definition.

A kind of wide voltage impedance reduction voltage circuit of the present invention comprises: impedance step-down major loop (1), impedance step-down subsidiary loop (2), voltage sample (3); Control circuit (4), commutation circuit (5), auxiliary circuit (6); Rectifying and wave-filtering (7), load (8), the AC power first via connects impedance step-down major loop (1); Impedance step-down major loop (1) connects impedance step-down subsidiary loop (2), and impedance step-down subsidiary loop (2) output connects rectifying and wave-filtering (7), and rectifying and wave-filtering (7) output connects load (8); AC power the second tunnel connects voltage sample (3), voltage sample (3) output connection control circuit (4), and control circuit (4) output connects commutation circuit (5); Commutation circuit (5) output connects impedance step-down subsidiary loop (2), and the AC power Third Road connects accessory power supply (6), and accessory power supply (6) output is connection control circuit (4) and commutation circuit (5) respectively.

Impedance step-down major loop (1) to the input ac power step-down, arrives load (8) through impedance step-down subsidiary loop (2), rectifying and wave-filtering (7); Like the voltage wide variety; By voltage sample (3) adopt signal, amplify through control circuit (4), drive commutation circuit (5); Change the impedance of impedance step-down subsidiary loop (2), stablized the electric current and voltage of load (8).

Again further technical scheme is laid down a definition.

Among the figure: impedance step-down major loop (1) is buck inductor (L), and after AC power one end connect buck inductor (L) as the power supply first via, another termination of buck inductor (L) was by an end of the normally-closed contact (Ja) of auxiliary induction (La), relay (J), bleeder resistance (RL) (can omit when the auxiliary induction inductance value is not very big), the impedance step-down subsidiary loop (2) that composes in parallel, and the bridge rectifier that another termination of the impedance step-down subsidiary loop (2) that composes in parallel is made up of diode (D1), (D2), (D3), (D4) exchanges an end of input; (also available half-wave voltage multiplying rectifier replace bridge rectifier), this end are that the positive pole the negative pole of diode (D1) and diode (D2) is formed by connecting, and the AC power other end exchanges the other end of importing as public termination bridge rectifier, and this end is that the positive pole the negative pole of diode (D3) and diode (D4) is formed by connecting; The anodal output of bridge rectifier is to be formed by connecting at the negative pole of diode (D2) and the negative pole of diode (D4), and the output of bridge rectifier negative pole is to be formed by connecting at the positive pole of diode (D1) and the positive pole of diode (D3), and the both positive and negative polarity of bridge rectifier output also connects filter capacitor (C1) two ends composition rectifying and wave-filtering (7), and its both positive and negative polarity output connects the load (8) that the LED lamp is formed; Described voltage sample (3) is by sampling diode (D5), dropping resistor (R1), sampling filter (C2); Sampling resistor (R2), straight tube coupling (ZD), decoupling capacitor (C3) is formed, and AC power one end is as power supply the second tunnel; Connect sampling diode (D5) positive pole, sampling diode (D5) negative pole connects dropping resistor (R1) end, and the positive pole of the straight tube coupling (ZD) of stabilized voltage characteristic is arranged, serial connection decoupling capacitor (C3) end; The negative pole of straight tube coupling (ZD) connects an end of sampling filter (C2) and an end of sampling resistor (R2), receives the other end of dropping resistor (R1) after the connection again, connects common port again, described control circuit (4) after an end three ends of an end of decoupling capacitor (C3) other end, sampling filter (C2) and sampling resistor (R2) are connected; By triode (BG1), (BG2). (BG3), resistance (R3), (R4); (R5), (R6), electric capacity (C4); (C5) form (also available corresponding amplifier substitutes, as general integrated operational amplifier etc.), the base stage of triode (BG1) connects the positive pole of straight tube coupling (ZD); The collector electrode that the emitter of triode (BG1) connects common port, triode (BG1) connects electric capacity (C4) end, another termination common port of electric capacity (C4), and the collector electrode of triode (BG1) also connects the base stage of triode (BG2); The emitter of triode (BG2) connects common port, connects the base stage of triode (BG3) behind the collector series connection resistance (R5) of triode (BG2), connects the emitter of triode (BG3) behind the base stage series resistor (R4) of triode (BG3); Connect an end of electric capacity (C5) after this emitter crosstalk resistance (R6) when little (like emitter current R6 can omit), this end is also received the end as the relay of commutation circuit (5) (J), and the other end of the collector electrode of triode (BG3), electric capacity (C5), the other end of relay (J), three ends connect together and connect common port; Described accessory power supply (6) is by electric capacity (C6), (C7) and diode (D6); (D7), (D8), (D9) form; AC power one end connects electric capacity (C6) respectively as the power supply Third Road, (C7) each end, anodal and diode (D9) negative pole of another terminating diode of electric capacity (C6) (D6); Diode (D6) negative pole series resistor (R3) end, another termination triode (BG1) collector electrode of resistance (R3), diode (D9) positive pole connects common port; Anodal and diode (D8) negative pole of another terminating diode of electric capacity (C7) (D7), an end of diode (D7) negative pole serial connection relay (J), diode (D8) positive pole connects common port.

La is by the Ja short circuit when normality voltage is imported, during the high voltage input by voltage sample adopt signal, amplify to control circuit through ZD, drive relay J and make Ja contact open circuit, insert La and reduce high voltage.

Impedance step-down subsidiary loop (2), voltage sample (3), control circuit (4), commutation circuit (5) can have many covers, can control in a plurality of voltage sections.

Impedance step-down major loop (1), impedance step-down subsidiary loop (2), rectifying and wave-filtering (7), load (8) also can have many covers, with a plurality of relays polyphones or and connect, perhaps multichannel control is carried out to certain voltage section in a plurality of contacts of relay.

Among the figure: impedance step-down major loop (1) and impedance step-down subsidiary loop (2), by electric capacity (C); (Ca), resistance (R), (Rc) (resistance R can be omitted when capacitor C had leakage current; Resistance R c can omit when capacitor C a was not very big); The circuit that the normally-closed contact (Ja) of relay (J) is formed substitutes, and AC power one end is as power supply first via connection electric capacity (C), resistance (R), the normally-closed contact (Ja) of relay (J), each end, after the other end series resistor (Rc) of the normally-closed contact (Ja) of relay (J) is connected in series electric capacity (Ca) again; Be connected on the other end of electric capacity (C), resistance (R), as the output of impedance step-down subsidiary loop (2).

Ca is connected by Ja when normality voltage is imported, high voltage when input by voltage sample adopt signal, amplify to control circuit through ZD, drive relay J and make Ja contact open circuit, break off Ca and reduce high voltage.

All the other structures, principle are all identical with Fig. 2

Among the figure: the normally-closed contact (Ja) of impedance step-down major loop (1) relay (J) wherein substitutes control circuit (4), and accessory power supply (6) by the normally opened contact (Jb) of relay (J); By triode (BG4), (BG5), electric capacity (C8); (C9); Diode (D10) and have the semiconductor device (ZD1) of stabilized voltage characteristic to substitute, the base stage of triode (BG4) connects the collector electrode of triode (BG1); The emitter of triode (BG4) connects the base stage of triode (BG5); The emitter of triode (BG5) connects public pole, and the collector electrode of the collector connecting transistor (BG5) of triode (BG4) is received an end of relay (J) again, and electric capacity (C5) and relay (J) also connect; The other end of electric capacity (C5) and relay (J) and an end of electric capacity (C9) and the negative pole of diode (D10) all connect together; The positive pole of diode (D10) connects together with negative pole and an end of electric capacity (C8) of the semiconductor device (ZD1) that stabilized voltage characteristic is arranged, the other end of electric capacity (C9) and have the positive pole of the semiconductor device (ZD1) of stabilized voltage characteristic to connect common port, and an end of another termination AC power of electric capacity (C8) is as the power supply Third Road.

This is that two groups of voltage multiplying rectifiers with accessory power supply among Fig. 2 (6) change one group into, the relay (J) of corresponding control circuit (4) and and the electric capacity (C5) that connects to be serially connected in the amplifying circuit.

All the other structures, principle are all identical with Fig. 2

Among the figure: make the inductance step-down of Fig. 4 into capacitance decompression, all the other structures, principle are all identical with Fig. 4.

Among the figure: accessory power supply (6), by transformer (T), diode (D11); (D12) substitute, an end of the elementary winding one termination AC power of transformer (T) is as the power supply Third Road, another termination common port; Transformer (T) secondary winding two ends connect diode (D11) respectively, positive pole (D12), diode (D11); (D12) negative pole connects together and connects an end of electric capacity (C9), and transformer (T) secondary winding centre cap connects common port.

This is that one group of voltage multiplying rectifier with accessory power supply among Fig. 4 (6) changes transformer full-wave rectification (also can connect and be bridge rectifier, halfwave rectifier etc.) into, and all the other structures, principle are all identical with Fig. 4.

Among the figure: make the inductance step-down of Fig. 6 into capacitance decompression, all the other structures, principle are all identical with Fig. 6.

A kind of wide voltage impedance reduction voltage circuit of the present invention can be used in wide-voltage range in sum, and is reliable, energy-conservation because of it is simple, the long-life, will be widely used.

Claims

1. one kind wide voltage impedance reduction voltage circuit is characterized in that comprising impedance step-down major loop (1), impedance step-down subsidiary loop (2), voltage sample (3); Control circuit (4), commutation circuit (5), accessory power supply (6); Rectifying and wave-filtering (7), load (8), the AC power first via connects impedance step-down major loop (1); Impedance step-down major loop (1) connects impedance step-down subsidiary loop (2), and impedance step-down subsidiary loop (2) output connects rectifying and wave-filtering (7), and rectifying and wave-filtering (7) output connects load (8); AC power the second tunnel connects voltage sample (3), voltage sample (3) output connection control circuit (4), and control circuit (4) output connects commutation circuit (5); Commutation circuit (5) output connects impedance step-down subsidiary loop (2), and the AC power Third Road connects accessory power supply (6), and accessory power supply (6) output is connection control circuit (4) and commutation circuit (5) respectively.

2. a kind of wide voltage impedance reduction voltage circuit according to claim 1 is characterized in that described impedance step-down major loop (1) is buck inductor (L), and after AC power one end connect buck inductor (L) as the power supply first via, another termination of buck inductor (L) was by an end of the normally-closed contact (Ja) of auxiliary induction (La), relay (J), bleeder resistance (RL), the impedance step-down subsidiary loop (2) that composes in parallel; The other end of the impedance step-down subsidiary loop (2) that composes in parallel connects the end that the bridge rectifier be made up of diode (D1), (D2), (D3), (D4) exchanges input, and this end is that the positive pole the negative pole of diode (D1) and diode (D2) is formed by connecting, and the AC power other end is as common port; Connect the other end that bridge rectifier exchanges input, this end is that the positive pole the negative pole of diode (D3) and diode (D4) is formed by connecting, and the anodal output of bridge rectifier is to be formed by connecting at the negative pole of diode (D2) and the negative pole of diode (D4), and it is to be formed by connecting at the positive pole of diode (D1) and the positive pole of diode (D3) that the bridge rectifier negative pole is exported; The both positive and negative polarity of bridge rectifier output also connects filter capacitor (C1) two ends composition rectifying and wave-filtering (7), and its both positive and negative polarity output connects the load (8) that the LED lamp is formed, and described voltage sample (3) is by sampling diode (D5); Dropping resistor (R1), sampling filter (C2), sampling resistor (R2), straight tube coupling (ZD); Decoupling capacitor (C3) is formed, and AC power one end connects sampling diode (D5) positive pole as power supply the second tunnel, and sampling diode (D5) negative pole connects dropping resistor (R1) end; The positive pole that the straight tube coupling (ZD) of stabilized voltage characteristic is arranged, serial connection decoupling capacitor (C3) end, the negative pole of straight tube coupling (ZD) connects an end of sampling filter (C2) and an end of sampling resistor (R2), receives the other end of dropping resistor (R1) after three ends connect again; One end of decoupling capacitor (C3) other end, sampling filter (C2) and an end of sampling resistor (R2), three ends connect common port after connecting again, and described control circuit (4) is by triode (BG1); (BG2). (BG3), resistance (R3), (R4), (R5); (R6), electric capacity (C4) (C5) is formed, and the base stage of triode (BG1) connects the positive pole of straight tube coupling (ZD); The collector electrode that the emitter of triode (BG1) connects common port, triode (BG1) connects electric capacity (C4) end, another termination common port of electric capacity (C4), and the collector electrode of triode (BG1) also connects the base stage of triode (BG2); The emitter of triode (BG2) connects common port, connects the base stage of triode (BG3) behind the collector series connection resistance (R5) of triode (BG2), connects the emitter of triode (BG3) behind the base stage series resistor (R4) of triode (BG3); Connect an end of electric capacity (C5) after this emitter crosstalk resistance (R6), this end is also received the end as the relay of commutation circuit (5) (J), and the other end of the collector electrode of triode (BG3), electric capacity (C5), the other end of relay (J), three ends connect together and connect common port; Described accessory power supply (6) is by electric capacity (C6), (C7) and diode (D6); (D7), (D8), (D9) form; AC power one end connects electric capacity (C6) respectively as the power supply Third Road, (C7) each end, anodal and diode (D9) negative pole of another terminating diode of electric capacity (C6) (D6); Diode (D6) negative pole series resistor (R3) end, another termination triode (BG1) collector electrode of resistance (R3), diode (D9) positive pole connects common port; Anodal and diode (D8) negative pole of another terminating diode of electric capacity (C7) (D7), diode (D7) negative pole is succeeded an end of electrical equipment (J), and diode (D8) positive pole connects common port.

3. a kind of wide voltage impedance reduction voltage circuit according to claim 1 is characterized in that described impedance step-down major loop (1) and impedance step-down subsidiary loop (2); By electric capacity (C), (Ca), resistance (R); (Rc); The circuit that the normally-closed contact (Ja) of relay (J) is formed substitutes, and AC power one end is as power supply first via connection electric capacity (C), resistance (R), the normally-closed contact (Ja) of relay (J), each end, after the other end series resistor (Rc) of the normally-closed contact (Ja) of relay (J) is connected in series electric capacity (Ca) again; Be connected on the other end of electric capacity (C), resistance (R), three ends connect the output as impedance step-down subsidiary loop (2).

4. a kind of wide voltage impedance reduction voltage circuit according to claim 1 is characterized in that the normally-closed contact (Ja) of described impedance step-down major loop (1) relay (J) wherein is alternative by the normally opened contact (Jb) of relay (J), described control circuit (4); And accessory power supply (6); By triode (BG4), (BG5), electric capacity (C8); (C9); Diode (D10) and have the semiconductor device (ZD1) of stabilized voltage characteristic to substitute, the base stage of triode (BG4) connects the collector electrode of triode (BG1); The emitter of triode (BG4) connects the base stage of triode (BG5); The emitter of triode (BG5) connects public pole, and the collector electrode of the collector connecting transistor (BG5) of triode (BG4) is received an end of relay (J) again, and electric capacity (C5) and relay (J) also connect; The other end of electric capacity (C5) and relay (J) and an end of electric capacity (C9) and the negative pole of diode (D10) all connect together; The positive pole of diode (D10) connects together with negative pole and an end of electric capacity (C8) of the semiconductor device (ZD1) that stabilized voltage characteristic is arranged, the other end of electric capacity (C9) and have the positive pole of the semiconductor device (ZD1) of stabilized voltage characteristic to connect common port, and an end of another termination AC power of electric capacity (C8) is as the power supply Third Road.

5. a kind of wide voltage impedance reduction voltage circuit according to claim 1 is characterized in that the normally-closed contact (Ja) of described impedance step-down major loop (1) relay (J) wherein is alternative by the normally opened contact (Jb) of relay (J), described accessory power supply (6); By transformer (T), diode (D11) (D12) substitutes; One end of the elementary winding one termination AC power of transformer (T) is as the power supply Third Road, another termination common port, and transformer (T) secondary winding two ends connect diode (D11) respectively; (D12) positive pole; Diode (D11), negative pole (D12) connect together and connect an end of electric capacity (C9), and transformer (T) secondary winding centre cap connects common port.

6. a kind of wide voltage impedance reduction voltage circuit according to claim 1 is characterized in that described load (8), can be the LED lamp.