阅读说明：本技术 牙科x射线机用高压驱动电路及牙科x射线机 (High-voltage driving circuit for dental X-ray machine and dental X-ray machine ) 是由 张立宇 孙浩 王宏灿 陶欢 于 2021-10-20 设计创作，主要内容包括：本发明涉及一种牙科X射线机用高压驱动电路及牙科X射线机。高压驱动电路包括驱动芯片,第一、第二MOS管和高频变压器和倍压模块；驱动芯片的第一、第二开关控制输出端分别接第一、第二MOS管的G极,第一、第二MOS管的S极接地,第一、第二MOS管的D极分别接高频变压器的初级绕组的两端,该初级绕组的中间抽头接电池的正极；高频变压器的次级绕组的一端接地,另一端接倍压模块的交流电输入端；倍压模块输出高压直流电。倍压模块输出的高压直流电经分压采样电路后接驱动芯片的采样输入端,驱动芯片的设定电压端接一正电压。倍压模块输出的高压直流电经分压采样电路后接运放的同相端,运放的反相端接过压阈值电压。(The invention relates to a high-voltage driving circuit for a dental X-ray machine and the dental X-ray machine. The high-voltage driving circuit comprises a driving chip, a first MOS tube, a second MOS tube, a high-frequency transformer and a voltage doubling module; the first switch control output end and the second switch control output end of the driving chip are respectively connected with the G poles of the first MOS tube and the second MOS tube, the S poles of the first MOS tube and the second MOS tube are grounded, the D poles of the first MOS tube and the second MOS tube are respectively connected with two ends of a primary winding of the high-frequency transformer, and a middle tap of the primary winding is connected with the anode of the battery; one end of a secondary winding of the high-frequency transformer is grounded, and the other end of the secondary winding of the high-frequency transformer is connected with an alternating current input end of the voltage doubling module; the voltage doubling module outputs high-voltage direct current. The high-voltage direct current output by the voltage doubling module is connected with the sampling input end of the driving chip after passing through the voltage division sampling circuit, and the set voltage end of the driving chip is connected with a positive voltage. The high-voltage direct current output by the voltage doubling module is connected with the non-inverting end of the operational amplifier after passing through the voltage division sampling circuit, and the inverting end of the operational amplifier is connected with the overvoltage threshold voltage.)

1. A high voltage driving circuit for a dental X-ray machine is characterized in that: the circuit comprises a driving chip (IC), a first MOS tube, a second MOS tube (Q1, Q2), a high-frequency transformer and a voltage doubling module;

the first and second switch control output ends of a driving chip (IC) are respectively connected with G poles of the first and second MOS tubes (Q1, Q2), S poles of the first and second MOS tubes (Q1, Q2) are grounded, D poles of the first and second MOS tubes (Q1, Q2) are respectively connected with two ends of a primary winding of the high-frequency transformer, and a middle tap of the primary winding is connected with the positive pole of a battery;

one end of a secondary winding of the high-frequency transformer is grounded, and the other end of the secondary winding of the high-frequency transformer is connected with an alternating current input end of the voltage doubling module;

the voltage doubling module outputs high-voltage direct current.

2. The high voltage driver circuit of claim 1, wherein: the high-voltage direct current output by the voltage doubling module is connected with a sampling input end (+ IN 1) of the driving chip (IC) after passing through the voltage division sampling circuit, and the set voltage end of the driving chip (IC) is connected with a positive voltage (V-set).

3. The high voltage driving circuit according to claim 1 or 2, wherein: the high-voltage direct current output by the voltage doubling module is connected with the non-inverting end of an operational amplifier (COMP) after passing through a voltage division sampling circuit, and the inverting end of the operational amplifier (COMP) is connected with an overvoltage threshold voltage (OV _ value).

4. The high voltage driving circuit according to claim 1 or 2, wherein: the voltage doubling module is the voltage doubling rectifying circuit.

5. A dental X-ray machine, characterized by: the dental X-ray machine employs the high voltage drive circuit according to claim 1 or 2 as a power supply circuit.

6. A dental X-ray machine, characterized by: the dental X-ray machine employs the high voltage drive circuit of claim 3 as a power supply circuit.

7. A dental X-ray machine, characterized by: the dental X-ray machine employs the high voltage drive circuit of claim 4 as a power supply circuit.

Technical Field

The invention relates to a high-voltage driving circuit for a dental X-ray machine and the dental X-ray machine.

Background

When a doctor treats a dental disease for a patient, a dental X-ray machine is usually required to take X-ray pictures to know partial lesions of the tooth, know the situation around the tooth root and also know the degree of the lesions in the tooth. Such as: the extent of caries, the condition around the root, and the fullness of the root canal after filling.

Dental X-ray machines can be divided into stationary, mobile, portable and hand-held types by construction and manner of installation and use. Hand-held dental X-ray machines are typically powered using lithium batteries. High voltage of tens kV is required for generating X-ray, so the stability and reliability of the high voltage driving circuit are important. The traditional power frequency X-ray machine driving mode has low efficiency, low stability of high output voltage and no closed-loop control, and when the machine is used for a long time, the output voltage may deviate, so that the corresponding protection function is not perfect.

Disclosure of Invention

The invention aims to solve the technical problem that a high-voltage driving circuit for a dental X-ray machine and the dental X-ray machine which have good stability of outputting high voltage and can form closed-loop control are adopted.

In order to solve the technical problem, the invention provides a high-voltage driving circuit for a dental X-ray machine, which comprises a driving chip, a first MOS tube, a second MOS tube, a high-frequency transformer and a voltage doubling module, wherein the driving chip is connected with the first MOS tube and the second MOS tube; the first switch control output end and the second switch control output end of the driving chip are respectively connected with the G poles of the first MOS tube and the second MOS tube, the S poles of the first MOS tube and the second MOS tube are grounded, the D poles of the first MOS tube and the second MOS tube are respectively connected with two ends of a primary winding of the high-frequency transformer, and a middle tap of the primary winding is connected with the anode of a battery; one end of a secondary winding of the high-frequency transformer is grounded, and the other end of the secondary winding of the high-frequency transformer is connected with an alternating current input end of the voltage doubling module; the voltage doubling module outputs high-voltage direct current.

The high-voltage direct current output by the voltage doubling module is connected with the sampling input end of the driving chip after passing through the voltage division sampling circuit, and the set voltage end of the driving chip is connected with a positive voltage.

The high-voltage direct current output by the voltage doubling module is connected with the non-inverting end of the operational amplifier after passing through the voltage division sampling circuit, and the inverting end of the operational amplifier is connected with the overvoltage threshold voltage.

The voltage doubling module is the voltage doubling rectifying circuit.

A dental X-ray machine adopts the high-voltage drive circuit as a power supply circuit.

This neotype beneficial effect: the high-voltage driving circuit for the dental X-ray machine adopts a high-frequency inversion mode, has high output efficiency, ensures the stability of high voltage by closed-loop control of the output high voltage, can monitor whether the high voltage is over-voltage or not and perform corresponding protection action, and is safe and reliable.

Drawings

In order to clearly illustrate the innovative principles of the invention and its technical advantages compared to the existing blue-violet curing machines, a possible embodiment is illustrated below by way of non-limiting example applying said principles, with the aid of the accompanying drawings. In the figure:

FIG. 1 is a schematic circuit diagram of a high voltage drive for a dental X-ray machine of the present invention;

FIG. 2 is a schematic diagram of a high frequency transformer in the high voltage driving circuit;

fig. 3 is a schematic circuit diagram of a voltage doubling module in the high voltage driving circuit.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.

All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

Example 1

Referring to fig. 1-3, a high voltage driving circuit for a dental X-ray machine comprises a driving chip IC, first and second MOS transistors Q1, Q2, a high frequency transformer and a voltage doubling module; the first switch control output end and the second switch control output end of the driving chip IC are respectively connected with G poles of the first MOS tube Q1 and the second MOS tube Q2, S poles of the first MOS tube Q1 and the second MOS tube Q2 are grounded, D poles of the first MOS tube Q1 and the second MOS tube Q2 are respectively connected with two ends of a primary winding of the high-frequency transformer, and a middle tap of the primary winding is connected with the anode of a battery; one end of a secondary winding of the high-frequency transformer is grounded, and the other end of the secondary winding of the high-frequency transformer is connected with an alternating current input end of the voltage doubling module; the voltage doubling module outputs high-voltage direct current.

The high-voltage direct current output by the voltage doubling module is connected with a sampling input end + IN1 of the driving chip IC after passing through the voltage division sampling circuit, and the set voltage end of the driving chip IC is connected with a positive voltage V-set.

The high-voltage direct current output by the voltage doubling module is connected with the in-phase end of the operational amplifier COMP after passing through the voltage division sampling circuit, and the reverse end of the operational amplifier COMP is connected with the overvoltage threshold voltage OV _ value. The voltage doubling module is the voltage doubling rectifying circuit.

The driving chip IC is TL594, the output high voltage HV is connected with a voltage KVS obtained through voltage division of resistors R1, R2 and R3 and connected with a pin 1 of the driving chip IC, the resistors R1, R2 and R3 form the voltage division sampling circuit, a pin 2 of the driving chip IC is connected with a set voltage value V-set, a pin 13 of the driving chip IC is in short circuit with a pin 14 of the driving chip IC, the KVS value obtained through voltage division is connected with a non-inverting input end of an operational amplifier COMP, an overvoltage set value OV _ value is connected with an inverting input end of the operational amplifier COMP, the output of the operational amplifier COMP directly drives a pin 4 of the driving chip IC, and the pin 4 of the driving chip IC is grounded through a resistor R5. The pin 5 of the driving chip IC is grounded through a capacitor C1, and the pin 6 of the driving chip IC is grounded through a resistor R4. The pin 7 of the driving chip IC is grounded, and the pins 8, 11 and 12 of the driving chip IC are connected with a power supply VCC. The pin 9 of the driving chip IC is connected to the G pole of the MOS transistor Q1, one end of the resistor R7 is connected to the G pole of the first MOS transistor Q1, and the other end is connected to the S pole of the first MOS transistor Q1. The S pole of the first MOS transistor Q1 is grounded, and the D pole of the first MOS transistor Q1 is connected to the T1 pin of the primary winding of the high-frequency transformer.

The pin 10 of the driving chip IC is connected to the G pole of the second MOS transistor Q2, one end of the resistor R6 is connected to the G pole of the second MOS transistor Q2, the other end of the resistor R6 is connected to the S pole of the second MOS transistor Q2, and the S pole of the MOS transistor Q2 is grounded. The D pole of the second MOS tube Q2 is connected to the T2 pin of the primary winding of the high frequency transformer, and the V _ BAT of the primary winding of the high voltage distribution transformer is connected to the output of the battery.

Driver chip TL594 is a PWM driver circuit with very well-established functionality. Pin 4 of TL594 is the dead band control terminal and the voltage input of 0-4V may cause the duty cycle to go from maximum to off. The duty cycle is maximum if the 4-pin ground is used. The 5 pin and the 6 pin of the TL594 determine the oscillation frequency, and the formula is

The frequencies calculated here are the frequencies for single-ended applications.

The pin 13 of the TL594 determines the operation mode, and the pin 13 is connected to the pin 14 output, and the 5V output indicates a push-pull output. Output frequency of. Pins 8, 9, 10 and 11 of the TL594 are output of an internal triode, and the output current of the TL594 is relatively large and can be directly driven by an external MOS (metal oxide semiconductor) tube.

The voltage stabilization function is implemented with an internal error amplifier of the TL594 chip. The pin 1 outputs a sampled value KVS of the high voltage HV,

is given by the formula

The 2 pin of the TL594 is connected with a set value V-set, so that the voltage of the 1 pin is fixed at the V-set according to the requirement of high-voltage output, and the high voltage HV output is also fixed, so that the stability of the high voltage output is better.

The overvoltage protection function is implemented with the dead time setting of TL 594.

And the high-voltage acquisition value KVS is connected with the non-inverting input end of the operational amplifier chip COMP, the overvoltage threshold value OV _ value is connected with the inverting input end of the COMP, and the output is connected with a pin 4 of the TL 594.

COMP here is used as a comparator and outputs a high voltage when the high voltage pickup KVS is greater than the over-voltage threshold OV _ value, at which time the dead time of TL594 is maximized, thereby turning off the output. And continuously outputting the PWM signal by the chip until the KVS value is smaller than the OV _ value, thereby forming closed-loop control.

Referring to fig. 3, the voltage doubling rectifying circuit is composed of a high-voltage capacitor and a high-voltage resistor, and the alternating current input is a high-frequency low-voltage alternating current signal.

The capacitors C5, C6, C7, C8, C9, C10, C19, C20, D1, D2, D3, D4, D5, D6, D7 and D8 form a forward symmetric voltage-doubling rectifying circuit. The capacitors C11, C12, C13, C14, C15, C16, C17, C18, D9, D10, D11, D12, D13, D14, D15 and D16 form a negative voltage doubling rectifying circuit.

High-voltage direct current is output between the positive output end HV + and the negative output end HV-, and the voltage doubling rectifying circuit mainly utilizes the unidirectional conductivity of the diode and the energy storage function of the capacitor to realize the voltage doubling function.

Assuming that the voltage of the alternating current input is E, when the alternating current is in a negative half cycle, the C6 is charged in the positive voltage doubling rectifying circuit through a rectifying diode D8, the voltage is E, and the direction is up, positive, down and negative. When the alternating current is in a positive half cycle, D7 is conducted, and D8 is cut off. The alternating current signal and the capacitor C6 have the same polarity, which is equivalent to two power supplies connected in series, and the maximum voltage is 2E. At this time, the series power supply charges C10, the voltage of C10 is 2E, and the polarity is positive up and negative down. And during the negative half cycle of the next cycle, the alternating current passes through D6 to charge a capacitor C7, the charging voltage is 2E, the polarity of C7 is positive, negative and positive, and during the positive half cycle of the cycle, the alternating current passes through D5 to charge C8, and according to the subsequent Hough voltage law, the sum of the loop voltages is 0, the voltage at the end of C8 is calculated to be 2E, and the polarity is positive, negative and positive. In this case, the capacitors C10 and C8 are connected in series, so that ideally, C10 and C8 can obtain 4E. By analogy, the capacitors C10, C8, C9 and C19 can obtain a voltage of 8E in total.

Meanwhile, in the negative voltage doubling rectifying circuit, the voltages of-8E can be obtained by C18, C16, C14 and C12 in total. Then a total of 16E for the high voltage dc voltage is available.

A dental X-ray machine adopts the high-voltage drive circuit as a power supply circuit.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.