CN2779716Y - Adjustable constant-current output transformer with side voltage input - Google Patents

Abstract

The utility model discloses a wide voltage input transformer capable of regulating constant current output. The utility model comprises an input circuit (01), a rectifying filtering circuit, a voltage transformation IC control chip (U2) and an output circuit (03), wherein the rectifying filtering circuit is connected with the input circuit (01), the voltage transformation IC control chip (U2) is connected with the rectifying filtering circuit, and the output circuit (03) is connected with the voltage transformation IC control chip (U2). A needed output voltage and current can be obtained by regulating the voltage transformation IC control chip (U2) and elements in the circuit, such as an energy exchange inductor (L2), an oscillation resistor (R1), a current regulating resistor (R4), etc. The transformer can be connected with an AC power supply and a DC power supply, and has the advantages of wide input voltage, loaded operation and adjustable output voltage and current; besides, the utility model can be output as a constant current source.

Description

Wide voltage input adjustable constant-flow output transformer

Technical field

The utility model relates to transformer, relates in particular to wide, the adjustable constant current output transformer of a kind of input voltage.

Background technology

The generation of transformer greatly facilitates the application of all kinds of electrical appliances.Existing transformer is made up of members such as former limit winding, secondary winding, magnetic conduction sheets.This small product size is big, weight is big, easily heating, magnetic loss are big.Again because Transformer Winding tap trouble can't realize stepless output voltage.Simultaneously also can't on a transformer, realize to regulate output voltage, can do constant-current source again.Because existing transformer uses alternating magnetic field to come transfer electrical energy, thus can't make energy source with DC power supply, thus limited the selection of transformer to energy source.

The utility model content

The purpose of this utility model be to solve that existing transformer input voltage is narrower, output voltage and electric current can not electrodeless adjustings and technical problem that can not constant current output, propose wide, the adjustable constant current output transformer of a kind of input voltage.

For addressing the above problem, the technical solution of the utility model is a kind of wide voltage input of structure adjustable constant-flow output transformer, and it comprises input circuit, the current rectifying and wave filtering circuit that is connected with this input circuit, the transformation IC control chip that is connected with this current rectifying and wave filtering circuit, the output circuit that is connected with this transformation IC control chip.

In the utility model preferred embodiment, the power input of described input circuit links to each other through the first input end of a protective tube with a safety inductance, described current rectifying and wave filtering circuit is a bridge rectifier, first output of described safety inductance is connected with the input of described bridge rectifier, another power input of described input circuit links to each other with second input of described safety inductance, and second output of this safety inductance is connected with another input of described bridge rectifier; "+" end of first output of "+" utmost point output of described bridge rectifier and the voltage of described transformation IC control chip input (VIN) end, described output circuit and a diode of this output circuit is connected, and vibration pin (ROSC) end of described transformation IC control chip passes through an oscillation resistance ground connection; "-" end of described diode is connected with second output of described output circuit by an energy exchange inductance, "-" end of this diode also is connected with " d " end of an output field effect transistor, " g " end of this output field effect transistor is connected with access input (GATE) end of described transformation IC control chip by a resistance, and " s " end of this output field effect transistor is by a current regulating resistance ground connection.

Wherein, analog current debugging input (LD) end of described transformation IC control chip can also be connected by " VR+ " interface that a resistance and a foreign current are regulated the variable resistor interface, and another interface " VR-" that this foreign current is regulated the variable resistor interface is connected with reference voltage output (VDD) end of described transformation IC control chip by another resistance.By regulating the resistance of non-essential resistance VR, change size of current input analog current debugging input (LD) end, realize the change of the electric current of supply load.

The pulsewidth debugging input (PWM) of described transformation IC control chip also can be connected with a foreign current variable impulse width interface.

But input circuit incoming transport electricity of the present utility model also can insert direct current, is suitable for global input voltage range: i.e. 90VAC～265VAC, 8VDC～450VDC input service voltage.Bringing onto load work, the output voltage electric current is adjustable, voltage V more than the 2V to 100, electric current is adjustable to several A from several mA.Adopt novel elementary IC time variant voltage mode, the cost performance height.Be suitable for doing the power supply in wide voltage input area, high power load (as the LED lamp).Circuit of the present utility model adopts the elementary change pressure type of inductance, volume little (when input voltage was 220Vac, area can arrive 10CMxCM), and the circuit simple and flexible can have different output voltages according to different loads.Both when load variations, output voltage also can respective change, to guarantee constant current output; Because it is the peripheral cell that adopts is few, low with the transformation mode of the existing transformer cost of comparing.Operating voltage wide (8Vdc～450Vdc or 10Vac～265Vac).

Description of drawings

Below in conjunction with the drawings and specific embodiments the utility model is elaborated, wherein:

Fig. 1 is the circuit theory diagrams of the utility model preferred embodiment;

Fig. 2 is the local circuit schematic diagram of energy exchange inductance accumulation of energy among Fig. 1;

Fig. 3 is the local circuit schematic diagram of energy exchange inductance exoergic among Fig. 1.

Embodiment

Fig. 1 shows the circuit structure of the utility model preferred embodiment, described wide voltage input adjustable constant-flow output transformer comprises input circuit 01, the current rectifying and wave filtering circuit that is connected with this input circuit, the transformation IC control chip U2 (can adopt the HV9910 chip in the present embodiment) that is connected with this current rectifying and wave filtering circuit, the output circuit 03 that is connected with this transformation IC control chip.

The power input VIM+ of described input circuit 01 links to each other with the first input end 1 of a safety inductance L 1 through a protective tube F1, the first input end 1 of this safety inductance L 1 is also with an end of a safety capacitor C 4 and connect, described current rectifying and wave filtering circuit is a bridge rectifier U1, first output 3 of described safety inductance is connected with the input of described bridge rectifier U1, another power input VIM-of described input circuit 01 links to each other with second input 2 of described safety inductance L 1, second input 2 of this safety inductance L 1 is also with the other end of described safety capacitor C 4 and connect, and second output 4 of this safety inductance is connected with another input of described bridge rectifier U1; "+" end of first an output VO+ of "+" utmost point output of described bridge rectifier U1 and the voltage of described transformation IC control chip U2 input (VIN) end a, described output circuit 03 and a diode D1 of this output circuit is connected, "-" utmost point output head grounding of described bridge rectifier U1, vibration pin (ROSC) the end b of described transformation IC control chip U2 is by an oscillation resistance R1 ground connection; "-" end of described diode D1 is connected with the second output VO-of described output circuit 03 by an energy exchange inductance L 2, "-" end of this diode D1 also is connected with " d " end of an output field effect transistor Q1 (can adopt 2SK2865 output field effect transistor in the present embodiment), " g " end of this output field effect transistor Q1 is connected with access input (GATE) the end c of described transformation IC control chip U2 by a resistance R 2, and " s " end of this output field effect transistor Q1 is by a current regulating resistance R4 ground connection.

" VR+ " interface that analog current debugging input (LD) the end e of described transformation IC control chip U2 regulates variable resistor interface 04 by a resistance R 5 and a foreign current is connected, and another interface " VR-" that this foreign current is regulated variable resistor interface 04 is connected with reference voltage output (VDD) the end f of described transformation IC control chip U2 by another resistance R 6.Pulsewidth debugging input (PWM) the end h of described transformation IC control chip U2 is connected with a foreign current variable impulse width interface.

The operation principle of the utility model preferred embodiment is as follows:

The alternating current of input becomes direct current and operating voltage is provided for transformation IC control chip U2 through the safety inductance L 1 of input circuit 01 and the rectification of bridge rectifier U1, provides electric energy for output circuit 03 simultaneously.The operation principle of output circuit 03, as shown in Figure 2, transformation IC control chip U2 output high level signal is to the g end of field effect transistor Q1, this field effect transistor Q1 conducting.Electric current flows to the power supply first output port VO+ by "+" end of bridge rectifier U1, electric current is got back to the power supply second output port VO-through overload, "-" that extremely arrives bridge rectifier U1 through energy exchange inductance L 2, field effect transistor Q1, current regulating resistance R4 is extreme, thereby forms a closed-loop path.In this process, energy exchange inductance L 2 is in energy accumulating state.

As shown in Figure 3, transformation IC control chip U2 output low level signal is to the g end of field effect transistor Q1, and this field effect transistor Q1 ends.Energy stored is held its "+" end through diode D1 "-" on the energy exchange inductance L 2, pass through the power supply first output port VO+ again to outer linear load, get back on the energy exchange inductance L 2 by the power supply second output port VO-then, thereby form a closed-loop path.When input dc power, operation principle is identical with the input AC electricity, and the voltage of input is VAC*1.4=VIN when just exchanging, and the input voltage direct current time the and be input value=VIN itself.In this process, energy exchange inductance L 2 is in the exoergic state.In said process,, can obtain the output voltage and the electric current that need by regulating energy exchange inductance L 2, oscillation resistance R1, current regulating resistance R4.

The sensibility reciprocal value L of described energy exchange inductance L 2 is:

$L=\mathrm{Vin}\×\frac{\mathrm{Vled}}{(\mathrm{Vin}+\mathrm{Vled})\×0.3\×\mathrm{Iled}\×\mathrm{Fosc}}$

Wherein: Vin is an input voltage value, and Vled is the pressure drop of the needs of institute's bringing onto load (as LED), and Fosc is the IC frequency of oscillation, and Iled is the electric current of load.

Frequency of oscillation Fosc is in the following formula:

$\mathrm{Fosc}=\frac{25000}{(22+\mathrm{Rosc})\mathrm{KOHM}}\mathrm{kHz}$

Wherein Rosc is the resistance of R1, and unit is KOHM.

In order to regulate output current, can be between VR+ and VR-an external variable resistor, resistance can be 5KOHM.By regulating this variable-resistance resistance, reach the adjusting output current, and the purpose of the brightness of lamp; Also can hold the square wave of an external variable duty ratio, the voltage swing of this point of size adjustment by regulating this duty ratio at PWM.Reach and regulate the output current size, and the purpose of the brightness of lamp!

In order to realize adjustable constant current output,, reach the purpose of adjustable constant current by the electric current variation of current regulating resistance R4 feedback output.When output current became big, the voltage of current regulating resistance R4 feedback raise, and the duty ratio of GATE output diminishes, and genuine output current diminishes, the output current balance! When the electrorheological hour of output, the voltage decreases of current regulating resistance R4 feedback, the duty ratio of GATE output becomes big, makes the electrorheological of output big, reaches the balance of output current.

Claims (4)

1, a kind of wide voltage input adjustable constant-flow output transformer, it is characterized in that, comprise input circuit (O1), the current rectifying and wave filtering circuit that is connected with this input circuit, the transformation IC control chip (U2) that is connected with this current rectifying and wave filtering circuit, the output circuit (O3) that is connected with this transformation IC control chip.

2, transformer as claimed in claim 1, it is characterized in that, the power input (VIM+) of described input circuit (O1) links to each other through the first input end (1) of a protective tube (F1) with a safety inductance (L1), described current rectifying and wave filtering circuit is a bridge rectifier (U1), first output (3) of described safety inductance is connected with the input of described bridge rectifier (U1), another power input (VIM-) of described input circuit (O1) links to each other with second input (2) of described safety inductance (L1), and second output (4) of this safety inductance is connected with another input of described bridge rectifier (U1); "+" utmost point output of described bridge rectifier (U1) and the VIN of described transformation IC control chip (U2) end (a) is connected, "+" end of a diode (D1) of first output (VO+) of described output circuit (03) and this output circuit connects, and the ROSC end (b) of described transformation IC control chip (U2) passes through an oscillation resistance (R1) ground connection; "-" end of described diode (D1) is connected with second output (VO-) of described output circuit (O3) by an energy exchange inductance (L2), "-" end of this diode (D1) also is connected with " d " end of an output field effect transistor (Q1), " g " end of this output field effect transistor (Q1) is connected with the GATE end (c) of described transformation IC control chip (U2) by a resistance (R2), and " s " end of this output field effect transistor (Q1) is by a current regulating resistance (R4) ground connection.

3, transformer as claimed in claim 2, it is characterized in that, " VR+ " interface that the LD end (e) of described transformation IC control chip (U2) is regulated variable resistor interface (04) by a resistance (R5) and a foreign current is connected, another interface " VR-" that this foreign current is regulated variable resistor interface (04) is connected with the vdd terminal (f) of described transformation IC control chip (U2) by another resistance (R6), by regulating the size that changes resistance, change the output of electric current.

4, transformer as claimed in claim 3 is characterized in that, the PWM end (h) of described transformation IC control chip (U2) is connected with a foreign current variable impulse width interface.

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