CN204068714U - A high voltage generating circuit - Google Patents

Abstract

The utility model provides a kind of high-pressure generating circuit, comprising: DC power supply, the self-maintained circuit be connected with described DC power supply, the output circuit be connected with described self-maintained circuit, error increasing circuitry and the feedback circuit be connected with the output of described output circuit; Wherein said self-maintained circuit comprises the primary coil of transistor and high-tension transformer, and described output circuit comprises the secondary coil of rectification circuit and described high-tension transformer; Described error increasing circuitry is used for the voltage that fed back by described feedback circuit and reference voltage compares rear output to control the base voltage of the transistor of described self-maintained circuit.The utility model, by the feedback circuit of step-up error increasing circuitry, controls the base voltage of the transistor of self-maintained circuit, improves the stability of output voltage.

Description

A high voltage generating circuit

technical field

The utility model belongs to the technical field of DC power supplies, in particular to a high-voltage generating circuit with a feedback circuit.

Background technique

The previous high-voltage generating circuit is shown in Figure 1, including a DC power supply providing a DC voltage Ve, a self-excited oscillation circuit 11 connected to the DC power supply, an output circuit connected to the self-excited oscillation circuit 11, and an error amplifier circuit 13. In order to make the output The voltage is stable, and the high-voltage generating circuit is also provided with a first rectifying circuit 14 connected to the error amplifier circuit 13; wherein the first rectifying circuit 14 is composed of the first primary coil n4 of the high-voltage transformer T1, a rectifying diode Di5 and a capacitor C3; self-excited The oscillating circuit 11 includes transistor Tr1 and the second primary coils n1 and n2 of the high-voltage transformer T1, and the output circuit includes the second rectifier circuit 12 and the secondary coil n3 of the high-voltage transformer T1; the error amplification circuit 13 is used to use the first rectifier circuit 14 The rectified voltage is compared with the reference voltage Vref and then output to control the base voltage of the transistor Tr1 of the self-excited oscillation circuit 11 .

With the above circuit, the output voltage on the secondary side is extremely unstable with respect to load fluctuations and temperature, and it is difficult to obtain a stable output voltage. In particular, when the output load is no-load, the output voltage tends to become high, which may cause abnormal discharge or damage the insulation of the transformer.

Contents of the invention

In view of this, the purpose of the present utility model is to provide a high-voltage generating circuit, which can improve the stability of the output voltage.

In order to achieve the above purpose, an embodiment of the present invention provides a high-voltage generating circuit, including:

A DC power supply, a self-excited oscillation circuit connected to the DC power supply, an output circuit connected to the self-excited oscillation circuit, an error amplification circuit, and a feedback circuit connected to the output end of the output circuit;

Wherein the self-excited oscillation circuit includes a transistor and a primary coil of a high-voltage transformer, and the output circuit includes a rectifier circuit and a secondary coil of the high-voltage transformer;

The error amplification circuit is used for comparing the voltage fed back by the feedback circuit with a reference voltage and outputting it to control the base voltage of the transistor of the self-excited oscillation circuit.

Preferably, the feedback circuit is a voltage series negative feedback circuit.

Preferably, the voltage series negative feedback circuit includes a resistor Rf1 and a resistor Rf2 connected in series, the error amplifier circuit is an error amplifier, and the inverting input terminal of the error amplifier is connected between the resistors Rf1 and Rf2.

Preferably, the self-excited oscillation circuit includes a resistor Rb1 with one end connected to the output end of the error amplification circuit, one end connected with the resistor Rb2 connected in series with the resistor Rb1, and the base connected with the other end of the resistor Rb2. A transistor, a resistor Re1 with one end connected to the ground and the other end connected to the emitter of the transistor, a coil n1 connected to the DC power supply and the other end connected to the collector of the transistor, connected between the emitter and the collector A diode Di2 between the electrodes, a diode Di1 with one end connected between the resistor Rb1 and the resistor Rb2 and the other end connected to one end of the coil n2, the other end of the coil n2 is grounded;

The coil n1 and the coil n2 constitute the primary coil of the transformer.

Preferably, the output circuit includes a secondary coil n3 and a double voltage rectifier circuit connected to the coil.

Preferably, the transistor is a PMOS transistor or an NMOS transistor.

Preferably, the primary coils are located on both sides of the secondary coils, and the primary coils are arranged in parallel and/or in series.

The beneficial effects of the utility model:

The utility model controls the base voltage of the transistor of the self-excited oscillating circuit through the feedback circuit, and improves the stability of the output voltage.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present utility model. Those skilled in the art can also obtain other drawings based on these drawings without any creative work.

FIG. 1 is a structural diagram of a high voltage generating circuit in the prior art;

Fig. 2 is the structural diagram of the high voltage generating circuit provided by the utility model;

Fig. 3 is a structural diagram of a high voltage transformer coil in the prior art;

Fig. 4 is the high-voltage transformer coil structural diagram in the utility model;

Fig. 5 is another coil structure diagram of the high voltage transformer in the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in Figure 2, it is a diagram of a high-voltage generating circuit device provided by Embodiment 1 of the present utility model, which includes:

A DC power supply for providing DC voltage Ve, a self-excited oscillation circuit 21 connected to the DC power supply, an output circuit connected to the self-excited oscillation circuit 21, an error amplification circuit 23 and a feedback circuit 24 connected to the output end of the output circuit.

The self-excited oscillation circuit 21 includes a transistor Tr1 and a primary coil of a high voltage transformer T1, and the output circuit includes a rectifier circuit 22 and a secondary coil n3 of a high voltage transformer T1.

The error amplifier circuit 23 is an error amplifier Op1 for comparing the voltage fed back by the feedback circuit 24 with the reference voltage Vref and then amplifying it to output a control signal to control the base voltage of the transistor Tr1 of the self-oscillating oscillator circuit 21 .

In Embodiment 2 of the present utility model, the above-mentioned feedback circuit 24 is a voltage series negative feedback circuit, specifically including two resistors Rf1 and Rf2 connected in series, and the inverting input terminal of the error amplifier Op1 is connected in the middle of the resistors Rf1 and Rf2 . Therefore, the error amplifier compares the midpoint voltage of the resistors Rf1 and Rf2 with the reference voltage Vref, amplifies the difference, and outputs a control signal. That is, the midpoint voltage of the error amplifier feedback resistors Rf1 and Rf2 controls the base voltage of the transistor Tr1 of the self-oscillating oscillation circuit 21 .

In Embodiment 3 of the present utility model, the self-excited oscillation circuit 21 includes a resistor Rb1 with one end connected to the output end of the error amplifier circuit 23, a resistor Rb2 connected in series with the resistor Rb1 at one end, and a transistor Tr1 whose base is connected with the other end of the resistor Rb2. , one end is grounded and the other end is connected to the resistor Re1 of the emitter of the transistor Tr1, one end is connected to the DC power supply and the other end is connected to the coil n1 of the transistor Tr1 collector, the diode Di2 connected between the emitter and the collector, one end is connected to The diode Di1 is between the resistors Rb1 and Rb2 and the other end is connected to one end of the coil n2, and the other end of the coil n2 is grounded, wherein the coil n1 and the coil n2 constitute the primary coil of the high voltage transformer T1.

In Embodiment 4 of the present utility model, the output circuit includes the secondary coil n3 of the high-voltage transformer T1 and a voltage doubler rectifier circuit connected to the secondary coil n3, which may specifically be a double voltage rectifier circuit.

It should be noted that the above-mentioned transistors may also be PMOS transistors or NMOS transistors. The utility model does not specifically limit this.

The invention improves the stability of the output voltage by setting a feedback circuit between the output end of the high voltage generating circuit and the error amplification circuit to control the transistor.

Taking the second embodiment as an example, the midpoint voltage of the resistors Rf1 and Rf2 is adjusted to be consistent with the reference voltage Vref, and the currents of the resistors Rf1 and Rf2 are equal. So the output voltage Eout=Vref*(1+Rf1/Rf2). It can be seen that the final output voltage is related to the ratio of the resistors Rf1 to Rf2.

The utility model relates to a high-voltage transformer. The winding method of the existing high-voltage transformer is as shown in Figure 3. On the skeleton 31, the primary coil and the secondary coil are wound, and the gap between the primary coil 32 and the secondary coil 33 is relatively small. Large, the combination is not good, and the leakage inductance is also large. For this reason, Embodiment 5 of the present utility model provides a kind of high-voltage transformer, as shown in Figure 4, refers to primary coil and secondary coil on skeleton 41, and the turn ratio of its primary coil 42 and secondary coil 43 increases, In the high-voltage transformer with multiple split windings of the secondary coil, the primary coil 42 of the transformer is distributed on both sides of the secondary coil 43, and the primary coils 42 are wound in parallel, so that the combination of the primary coil 42 and the secondary coil 43 While getting better, the leakage inductance also becomes smaller.

Embodiment 6 of the present utility model provides a high-voltage transformer. As shown in FIG. 5 , the primary coil and the secondary coil are wound on the frame 51, and the turn ratio of the primary coil 52 and the secondary coil 53 increases, and the secondary In the high-voltage transformer in which the coil 53 is divided into multiple windings, the primary coil 52 of the transformer is distributed on both sides of the secondary coil 53, and the primary coils 52 are wound in series, so that the combination of the primary coil 52 and the secondary coil 53 becomes better. At the same time, the leakage inductance is also reduced.

Of course, those skilled in the art can imagine that based on the above-mentioned transformer, the primary coil of the transformer can also be arranged on both sides of the secondary coil, and some of the primary coils are wound in series and some of them are wound in parallel, which can also make the primary coil and The bonding of the secondary coil is improved, and the leakage inductance is also reduced.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made, these improvements and Retouching should also be regarded as the scope of protection of the present utility model.

Claims (7)

1. A high-voltage generating circuit, characterized in that the circuit comprises: A DC power supply, a self-excited oscillation circuit connected to the DC power supply, an output circuit connected to the self-excited oscillation circuit, an error amplification circuit, and a feedback circuit connected to the output end of the output circuit; Wherein the self-excited oscillation circuit includes a transistor and a primary coil of a high-voltage transformer, and the output circuit includes a rectifier circuit and a secondary coil of the high-voltage transformer; The error amplification circuit is used for comparing the voltage fed back by the feedback circuit with a reference voltage and outputting it to control the base voltage of the transistor of the self-excited oscillation circuit. 2. The high voltage generating circuit according to claim 1, wherein the feedback circuit is a voltage series negative feedback circuit. 3. The high-voltage generating circuit as claimed in claim 2, wherein the voltage series negative feedback circuit includes a resistor Rf1 and a resistor Rf2 connected in series, the error amplifier circuit is an error amplifier, and the reverse phase of the error amplifier The input terminal is connected in the middle of the resistors Rf1 and Rf2. 4. The high voltage generating circuit according to any one of claims 1 to 3, wherein the self-excited oscillation circuit comprises a resistor Rb1 with one end connected to the output of the error amplification circuit, one end connected to the resistor Rb1 The resistor Rb2 connected in series, the transistor whose base is connected to the other end of the resistor Rb2, one end connected to the ground and the other end connected to the resistor Re1 of the emitter of the transistor, one end connected to the DC power supply and the other end connected to A coil n1 of the collector of the transistor, a diode Di2 connected between the emitter and the collector, a diode having one end connected between the resistor Rb1 and the resistor Rb2 and the other end connected to one end of the coil n2 Di1, the other end of the coil n2 is grounded; The coil n1 and the coil n2 constitute the primary coil of the transformer. 5. The high voltage generating circuit according to claim 4, wherein the output circuit comprises a secondary coil n3 and a double voltage rectification circuit connected to the coil. 6. The high voltage generating circuit according to claim 1, wherein the transistor is a PMOS transistor or an NMOS transistor. 7. The high voltage generating circuit according to claim 1, wherein the primary coil is located on both sides of the secondary coil, and the primary coils are arranged in parallel or in series.