CN100428322C - Inverter circuit for suppressing power conduction interference - Google Patents

Abstract

The invention discloses an inverter circuit for inhibiting electric power conduction interference, which receives an electric power signal output by an electric power input loop, outputs a working frequency by a control unit, receives the working frequency cutting electric power signal by a driving unit and outputs a driving signal, receives the driving signal by a voltage transformation unit to carry out electric power conversion so as to drive a first load to act, and is provided with an isolation unit between the driving unit and the control unit.

Description

Inverter circuit for suppressing power conduction disturbance

technical field

The invention relates to an inverter circuit for suppressing electric power conduction interference, in particular to an inverter circuit for converting large and small currents and high and low voltage power at the same time.

Background technique

Please refer to Figure 1, which is a schematic block diagram of the power supply circuit of video products such as traditional LCD screens or LCD TVs. The power signal is converted into a pulsed DC power signal by a rectifier unit composed of a diode group, and then a power factor adjustment unit is used for power correction to become a regulated DC power signal, and the regulated DC power signal is output in parallel to a Inverter (inverter), and through the second drive circuit to a second transformation unit, the second transformation unit is used to step down and output low-voltage power signal to drive the second load, and the inverter is used to boost and output high voltage The power signal is used to drive the first load. The second load here includes video processing circuits, speakers and other devices that need to be driven by low voltage. The first load is the cold cathode lamp that provides the brightness of the display screen.

From the circuit block diagram of traditional video products, it can be seen that since the power source belongs to the same rectifier unit and the same drive circuit, the first load and the second load are in a common ground state, and because the second load is driven by low-voltage power, And it is necessary to maintain a stable DC power signal during the driving process. If the power signal is disturbed and fluctuates, it will affect the effect of the second load action, such as ripples on the display screen, uneven color response, and impure sound quality and noise from the speaker output. Another phenomenon of power interference lies in the inverter circuit, because the inverter circuit includes a control unit that outputs the operating frequency, a drive unit that receives the operating frequency cutting power signal and outputs a drive signal, and a drive unit that receives the operating frequency The drive signal performs power conversion and outputs a high-voltage power signal to drive the first transformer unit of the first load. As shown in Figure 2, when the drive unit cuts the power signal at the working frequency, it adopts the charging and discharging mode, which causes the power signal to fluctuate. The fluctuating signal will also affect the control unit, resulting in unstable operating frequency and flickering of the first load.

The main reason for the interference is that the boosting action of the inverter adopts a oscillating and fluctuating method. The fluctuating electric energy will affect the second load and the control unit from the common ground terminal, so that the second load and the control unit will be disturbed by the power conduction of the inverter. The above-mentioned defects occur, and this phenomenon is especially easy to occur in large-size video products, which greatly affects the normal image and audio performance of video products.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, and provide an inverter circuit that suppresses power conduction interference.

According to the inverter circuit for suppressing power conduction interference of the present invention, a power input circuit outputs a power signal to an inverter circuit, and the inverter circuit outputs an operating frequency from a control unit, and a driving unit Receive the working frequency cutting power signal and output a drive signal, and use a first transformation unit to receive the drive signal to perform power conversion to drive the first load action, wherein:

An isolation unit is arranged between the drive unit and the control unit, and the type of the drive unit and the control unit is separated by the isolation unit and the primary side and the secondary side of the first transformation unit as non-common ground, thereby achieving suppression The effect of electrical conduction disturbances.

The present invention provides a separate grounding method. In addition to using the non-common grounding type of the primary side and the secondary side of the first transformer unit, a device with the same function is also arranged between the drive unit and the control unit of the inverter. The isolation unit on the primary side and the secondary side is used to completely separate the fluctuating power interference effect caused by the power signal cut by the drive unit at the working frequency, so that the working frequency of the control unit can be stabilized, and the flickering of the first load can be avoided, so that the second The second load has the effect of suppressing power interference, so that normal video performance can be maintained.

Description of drawings

FIG. 1 is a schematic block diagram of a power supply circuit of a traditional video product;

Fig. 2 is a timing diagram of the drive unit cutting the power signal at the working frequency;

Fig. 3 is the schematic diagram of the first embodiment of the inverter circuit of the present invention;

Fig. 4 is the schematic diagram of the first embodiment of the overall circuit of the present invention;

Figure 5 is a schematic diagram of a second embodiment of the overall circuit of the present invention; and

FIG. 6 is a schematic diagram of a second embodiment of the inverter circuit of the present invention.

Detailed ways

Relevant detailed description and technical contents of the present invention are as follows now in conjunction with the accompanying drawings:

3 and 4, the present invention outputs a power signal to an inverter circuit 20 from a power input circuit 10, the power input circuit 10 is an alternating current input unit 11, and a rectifying unit that converts alternating current to direct current 12, and the inverter circuit 20 outputs a working frequency from a control unit 21, and receives the working frequency cutting power signal with a driving unit 22a and outputs a driving signal, and receives the driving with a first transforming unit 23 The signal undergoes power conversion to drive the first load 25 to act, and the first load 25 feeds back voltage and current signals to the control unit 21, wherein an isolation unit 24a is arranged between the drive unit 22a and the control unit 21, and through the isolation unit 24a and the primary side and secondary side of the first transformer unit 23 separate the drive unit 22a and the control unit 21, so that the grounding type is non-common. The first transformer unit 23 of the present invention can be a wire-wound transformer Or it is a piezoelectric transformer. If it is a piezoelectric transformer, an inductance 231 is arranged between the first transformer unit 23 and the drive unit 22a. For the convenience of understanding the technical solution of the present invention, the inverter circuit 20 is used as A piezoelectric transformer will be described as an example.

4 shows a schematic diagram of the first embodiment of the overall circuit of the present invention, the power input circuit 10 is connected in series with another drive circuit 14, and a power supply is configured between the drive circuit 14 and the inverter circuit 20 and the rectifier unit 12. The factor adjustment unit 13 performs power correction through the power factor adjustment unit 13. At this time, the output power signal is a regulated DC signal (12DCV-48DCV), and the drive circuit 14 outputs the drive signal to a second transformation unit 15 Perform power conversion to drive the second load 16, and the second transformer unit 15 also outputs power signals to drive the control unit 21. As far as the existing structure is concerned, the inverter circuit 20 and the drive circuit are respectively configured on two circuit boards 14. Please refer to FIG. 3 for matching. Since the present invention separates the drive unit 22a and the control unit 21 with an isolation unit 24a having an optocoupler, a capacitor, or a transformer on the primary side and the secondary side, and cooperates with the existing first transformer The primary side and the secondary side of the voltage unit 23, so that the grounding type of the drive unit 22a is completely non-common with the control unit 21 and the first load 25, and the second transformer unit 15 also has a primary side and a secondary side. Also make the second load 16 and the drive unit 22a non-common ground, so that the fluctuation electric energy of the drive unit 22a due to the cutting power signal of the working frequency is suppressed, and will not be conducted to the control unit 21 and the second load 16 from the ground terminal , so that the operating frequency output by the control unit 21 is relatively stable, thereby maintaining the light effect produced by the first load 25 of the cold cathode lamp tube, and the second load 16 of the video processing circuit and the speaker is due to the connection between the control unit 21 and the first load 25 The grounding type is a common ground and there is no power interference to maintain stable output quality of video products.

FIG. 5 shows a schematic diagram of the second embodiment of the overall circuit of the present invention. The difference between this embodiment and the embodiment shown in FIG. The signal is a pulsed DC signal, and the pulsed DC signal is directly input to the drive unit 22a and then to the first transformation unit 23. Since the input is a medium-voltage power signal (150DCV-300DCV), the power loss of low-voltage power conversion can be avoided. The effect of suppressing power interference is the same as above.

Please refer to FIG. 6, which is a schematic diagram of a second embodiment of the inverter circuit 20 of the present invention. As shown in the figure, the inverter circuit 20 of the present invention simultaneously outputs the same frequency to multiple drive units by a control unit 21. 22a, 22b. At this time, an isolation unit 24a, 24b is provided between the control unit 21 and each drive unit 22a, 22b, which can also achieve the above-mentioned effect of suppressing power interference.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. circuit of inverter that suppresses the electric power Conduction Interference, by an electric power input circuit (10) output one electric power signal to a circuit of inverter (20), described circuit of inverter (20) is by a control module (21) output one frequency of operation, and receive described frequency of operation cutting electric power signal and export a drive signal with a driver element (22a), and carry out power conversions with the described drive signal of first voltage transformation unit (23) reception and move to drive first load (25), it is characterized in that:

Dispose an isolated location (24a) between described driver element (22a) and the control module (21), the ground connection kenel that primary side by described isolated location (24a) and first voltage transformation unit (23) and secondary side are separated described driver element (22a) and control module (21) be non-altogether, thereby suppress the electric power Conduction Interference

Wherein, described electric power input circuit (10) is connected in series, and another drives loop (14), dispose a power factor adjustment unit (13) between described driving loop (14) and the described electric power input circuit (10), and described driving loop (14) output drive signal to one second voltage transformation unit (15) is carried out power conversions to drive second load (16), and described second voltage transformation unit (15) is gone back the output power signal to drive described control module (21).

2. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1, it is characterized in that, described first load (25) feedback voltage and current signal be to control module (21), and the ground connection kenel of described first load (25) and control module (21) is for altogether.

3. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, described electric power signal is voltage stabilizing direct current signal or pulse direct current signal.

4. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, described electric power input circuit (10) comprises that an alternating current input block (11) and is converted to galvanic rectification unit (12) with alternating current.

5. the circuit of inverter of inhibition electric power Conduction Interference according to claim 4 is characterized in that, disposes described power factor adjustment unit (13) between described rectification unit (12) and the driver element (22a).

6. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, the ground connection kenel of described second load (16) and control module (21), first load (25) is for altogether.

7. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, described second load (16) is video signal treatment circuit and loudspeaker.

8. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, described isolated location (24a) is for having photo-coupler, electric capacity or the transformer of primary side and secondary side.

9. the circuit of inverter of inhibition electric power Conduction Interference according to claim 1 is characterized in that, described first load (25) is a cold cathode fluorescent lamp.

Images