Power supply circuit for measuring wide voltage input while drilling

Abstract

The utility model relates to the technical field of power supply circuit design, in particular to a power supply circuit for measuring wide voltage input while drilling, which comprises a power supply filtering unit, a pulse width control unit, a transformer, a rectification filtering unit, a pulse width control unit, a switch tube and a current and voltage sampling unit, the transformer converts AC input power output by the power supply filtering unit into AC power output by the secondary side of the transformer. The rectifying and filtering unit is used for converting an alternating current power supply output by the secondary side of the transformer into a pulsating direct current signal for supplying power to the measurement-while-drilling equipment, and the input end of the pulse width control unit is connected with the output end of the power supply filtering unit and the output end of the current and voltage sampling unit and used for controlling the switch-on and switch-off of a switch tube; a drain electrode of the switching tube is connected with a primary side of the transformer and is used for controlling storage and release of energy of the transformer; the input end of the current and voltage sampling unit is connected with the output end of the rectifying and filtering unit and used for feeding back output current and voltage signals to the pulse width control unit, and the circuit provides a wide-range direct-current voltage source for measurement while drilling equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power circuit design, and particularly relates to a power circuit for wide voltage input in measurement while drilling. Background Art

[0002] Measurement while drilling technology plays a crucial role in oilfield exploration and construction. Due to its complex working environment, it needs to work under extreme conditions such as high temperature, high pressure, and vibration. Traditional power supply methods are difficult to meet the power requirements of measurement while drilling equipment. Therefore, a new type of power module with wide voltage input is required to ensure the stable operation of the equipment in the extreme downhole environment. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiency that the power supply working range of measurement while drilling equipment in the prior art is narrow, and to provide a power circuit for wide voltage input in measurement while drilling.

[0004] In a first aspect, the present invention provides a power circuit for wide voltage input in measurement while drilling, including a power filter unit, a pulse width control unit, a transformer, a rectifier filter unit, a switching tube, and a current and voltage sampling unit.

[0005] The power filter unit is used to convert the input DC power supply into an AC input power supply.

[0006] The transformer converts the AC input power supply into an AC power supply output from the secondary side of the transformer, and outputs the AC power supply output from the secondary side of the transformer to the rectifier filter unit.

[0007] The rectifier filter unit is used to convert the AC power supply output from the secondary side of the transformer into a pulsating DC signal, and the pulsating DC signal is used to supply power to the measurement while drilling equipment.

[0008] The input end of the pulse width control unit is respectively connected to the output end of the power filter unit and the output end of the current and voltage sampling unit, and the output end of the pulse width control unit is connected to the gate of the switching tube, and is used to control the conduction and closing of the switching tube.

[0009] The drain of the switching tube is connected to the primary side of the transformer, and is used to control the storage and release of the energy of the transformer.

[0010] The input end of the current and voltage sampling unit is connected to the output end of the rectifier filter unit, and is used to feedback the output current and voltage signals of the rectifier filter unit to the pulse width control unit.

[0011] As a preferred solution, the pulse width control unit is constructed based on the TPS4000 chip. The VDD terminal of the TPS4000 chip is connected to the output terminal of the power supply filtering unit, and DIS_EN_N is used to input an enable input signal; the COMP terminal is used to connect to the output terminal of the current and voltage sampling unit. The GDRV terminal of the TPS4000 chip is used to output a switching signal to the gate of the switching transistor. The ISNS terminal is connected to the source of the switching transistor through a resistor R9, and the SS terminal, RC terminal, GND terminal, and BP terminal are all grounded through capacitors.

[0012] As a preferred solution, the current and voltage sampling unit includes a capacitor and a resistor.

[0013] One end of resistor R1 is connected to the output terminal of the rectifying and filtering unit, and the other end of resistor R1 is connected to an RC parallel circuit. The RC parallel circuit includes capacitor C1, capacitor C7, and resistor R5. Capacitor C1 and resistor R5 are connected in series and then in parallel with capacitor C7. One end of the parallel connection of capacitor C1 and capacitor C7 serves as the output terminal of the current and voltage sampling unit and is connected to the COMP terminal of the TPS4000 chip;

[0014] Resistors R2 and R3 are connected in series, one end is connected to the connection point of resistor R1 and resistor R5, and the other end is grounded.

[0015] As a preferred solution, the rectifying and filtering unit includes a first rectifying and filtering unit. The first rectifying and filtering unit includes a capacitor, a resistor, and a diode.

[0016] The anode of diode D1 is connected to one end of the secondary side of the transformer. The cathode of diode D1 and the other end of the secondary side of the transformer are in parallel with capacitors C2 and C4. A resistor R4 is connected between one end of capacitor C4 and capacitor C3. The other end of capacitor C3 is connected to the other end of the secondary side of the transformer. Capacitors C22, C23, C24, C5, and C6 are also in parallel across the two ends of capacitor C3. One end of capacitor C3 is grounded, and the other end outputs a negative pulsating DC signal VOUT-. Capacitors C29, C30, and C31 are also in parallel between the negative pulsating DC signal VOUT- and ground.

[0017] As a preferred solution, it further includes a second rectifying and filtering unit.

[0018] The second rectifying and filtering unit includes a capacitor, a resistor, and a diode.

[0019] The anode of diode D2 is connected to one end of the secondary side of the transformer. The cathode of diode D2 and the other end of the secondary side of the transformer are connected in parallel with capacitors C9 and C11. A resistor R6 is connected between one end of capacitor C11 and one end of capacitor C10. The other end of capacitor C10 is connected to the other end of the secondary side of the transformer. Capacitors C25, C18, C19, C12, and C13 are also connected in parallel across both ends of capacitor C10. One end of capacitor C10 is grounded, and the other end of capacitor C10 outputs a positive pulsating DC signal VOUT+. Capacitors C32, C33, and C34 are also connected in parallel between the positive pulsating DC signal VOUT+ and ground.

[0020] As a preferred solution, for the power supply filtering unit, the negative input terminal V- is grounded, the positive input terminal V+ is connected to the anode of diode D3. A first branch, a second branch, and a capacitor C15 are connected in parallel between the cathode of diode D3 and ground. The first branch includes resistors R12 and R13 connected in series. The second branch includes capacitors C20 and C21 connected in series. The connection point between resistors R12 and R13 is connected to the VCC-CE signal. The connection point between capacitors C20 and C21 is connected to the VCC-CE signal. The cathode of diode D3 is also connected to one end of the primary side of the transformer. Capacitors C26, C27, and C28 are connected in parallel between the cathode of diode D3 and VCC-CE. Capacitors C35, C36, and C37 are connected in parallel between VCC-CE and ground.

[0021] As a preferred solution, the input voltage of the power supply filtering unit is a DC voltage of 5 to 50V, and the output voltage of the rectification and filtering unit is DC +12V or -12V.

[0022] As a preferred solution, an enable circuit is further included. The enable circuit includes transistors Q1, Q2, Q3, Q4 and resistors R15, R17, R18, R19. The input terminal EN of the enable signal is connected to the emitter of transistor Q1. The collector of transistor Q1 is connected to the emitter of transistor Q2. The collector of transistor Q2 is connected to the emitter of transistor Q3. The bases of transistors Q2, Q3, and Q4 are respectively shorted to their emitters. The emitter of transistor Q3 is connected to the base of transistor Q4 through resistor R16. The collector of transistor Q4 is connected to the working power supply VIN+ through resistor R18. The emitter of transistor Q4 is grounded. A resistor R19 is connected in parallel between the collector and emitter of transistor Q4. A resistor R17 is connected in parallel between the base and emitter of transistor Q4. The input terminal EN of the enable signal is grounded through resistor R15.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The utility model innovatively designs a power supply circuit with a wide voltage range for measurement-while-drilling technology. It has the ability to input wide voltage, ensuring the stability and reliability of the power supply module in complex downhole environments. The utility model is applicable to the field of measurement-while-drilling technology. Through the wide voltage input high-temperature power supply module of the utility model, the problem of power supply for measurement-while-drilling equipment in complex underground environments can be effectively solved, providing strong support for the technological development in fields such as oilfield exploration. It is widely used in underground environments such as oilfield exploration and geological exploration, providing stable and reliable power support for measurement-while-drilling equipment, and promoting the application and development of measurement-while-drilling technology in oilfield exploration and construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. is a structural block diagram of a power supply circuit with wide voltage input for measurement-while-drilling in Embodiment 1 of the present invention;

[0026] Figure 2 FIG. is a schematic circuit diagram of a power supply circuit with a wide voltage range for measurement-while-drilling technology in Embodiment 2 of the present invention;

[0027] Figure 3 FIG. is a circuit diagram for generating an enable signal of the TPS4000 chip in Embodiment 3 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described in detail below in combination with test examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0029] In the description of the specific embodiments of the present invention, without special instructions, the expression terms of orientation or positional relationships such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationships shown in the drawings, or the orientation or positional relationships when the invention product / device / equipment is usually used and placed. These terms of orientation or positional relationships are only for the convenience of describing the solution of the present invention or simplifying the description in the specific embodiments, facilitating technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, it cannot be understood as a limitation to the present invention.

[0030] In addition, when terms such as "horizontal", "vertical", "hanging", "parallel" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel, but it can be slightly inclined or have a deviation. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and it does not mean that the structure must be completely horizontal, but it can be slightly inclined. Or, it can be simply understood that the corresponding device / component / element is arranged in directions such as "horizontal", "vertical", "hanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still perform its function in the solution of the present invention.

[0031] In addition, when expressions such as "first", "second", "third", etc. appear in the terms, they are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0032] In addition, in the description of the embodiments of the present invention, "several", "multiple", "a plurality of" represent at least 2. It can be any situation such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and can even be a situation of more than 9.

[0033] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / limited, when terms such as "set", "installed", "connected", "connected", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, threaded connection, etc. This connection can be a mechanical connection, an electrical connection or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0034] Embodiment 1

[0035] A power supply circuit for measuring while drilling with wide voltage input, the structural block diagram is as Figure 1 shown, including a power filter unit 1, a pulse width control unit 2, a transformer 6, a rectifier filter unit, a switching tube 7 (MOS tube) and a current and voltage sampling unit 3,

[0036] The power supply filtering unit 1 is used to convert the input DC power supply into an AC input power supply and output the AC input power supply to the primary side of the transformer 6. The power supply filtering unit 1 also has two functions. One is to filter the background harmonics in the input power supply to solve problems such as false alarms and false operations caused by power supply harmonics. The other is to filter the harmonics generated by non-linear electrical equipment to solve the problem of non-linear electrical equipment polluting the power supply.

[0037] The transformer converts the AC input power supply into an AC power supply output from the secondary side of the transformer and outputs the AC power supply output from the secondary side of the transformer to the rectifying and filtering unit. The main function of the transformer is to convert electrical energy into magnetic energy for storage and release the stored energy at an appropriate time.

[0038] The rectifying and filtering unit is used to convert the AC power supply output from the secondary side of the transformer into a pulsating DC signal, and the pulsating DC signal is used to supply power to the measurement-while-drilling equipment. The main function of this circuit is to convert the AC signal into a pulsating DC signal, and then reduce the pulsation and noise in the signal through filtering to provide a high-quality power supply for the subsequent equipment.

[0039] As a preferred solution, the rectifying and filtering unit includes a first rectifying and filtering unit and a second rectifying and filtering unit.

[0040] The first rectifying and filtering unit includes a capacitor, a resistor, and a diode. The anode of the diode D1 is connected to one end of the secondary side of the transformer. The cathode of the diode D1 and the other end of the secondary side of the transformer are connected in parallel with capacitors C2 and C4. A resistor R4 is connected between one end of the capacitor C4 and one end of the capacitor C3. The other end of the capacitor C3 is connected to the other end of the secondary side of the transformer. Capacitors C22, C23, C24, C5, and C6 are also connected in parallel across the two ends of the capacitor C3. One end of the capacitor C3 is grounded, and the other end of the capacitor C3 outputs a negative pulsating DC signal VOUT-. Capacitors C29, C30, and C31 are also connected in parallel between the negative pulsating DC signal VOUT- and the ground.

[0041] The second rectifying and filtering unit includes a capacitor, a resistor, and a diode. The anode of the diode D2 is connected to one end of the secondary side of the transformer. The cathode of the diode D2 and the other end of the secondary side of the transformer are connected in parallel with capacitors C9 and C11. A resistor R6 is connected between one end of the capacitor C11 and one end of the capacitor C10. The other end of the capacitor C10 is connected to the other end of the secondary side of the transformer. Capacitors C25, C18, C19, C12, and C13 are also connected in parallel across the two ends of the capacitor C10. One end of the capacitor C10 is grounded, and the other end of the capacitor C10 outputs a positive pulsating DC signal VOUT+. Capacitors C32, C33, and C34 are also connected in parallel between the positive pulsating DC signal VOUT+ and the ground.

[0042] The input ends of the pulse width control unit are respectively connected to the output end of the power supply filtering unit and the output end of the current and voltage sampling unit. The output end of the pulse width control unit is connected to the gate of the switching tube, and is used to control the conduction and cut-off of the switching tube.

[0043] The main function of the pulse width control unit is to control the on and off time of the switching tube 7 (MOS tube). The on and off of the switching tube 7 adjusts the energy storage of the transformer 6, thereby realizing the control and regulation of the output voltage. The general control principle is that when the output voltage is lower than the set value, the pulse width control unit increases the conduction time of the MOS tube, so that the energy stored in the transformer increases, realizing the increase of the output voltage. When the output voltage is higher than the set value, the pulse width control unit reduces the conduction time of the MOS tube, so that the energy stored in the transformer decreases, reducing the output voltage. In addition, when the feedback output current reaches the preset turn-off threshold, the pulse width control unit will turn off the MOS tube, so that the transformer no longer performs energy conversion to realize short-circuit, overload and other protections.

[0044] The input end of the current and voltage sampling unit is connected to the output end of the rectification and filtering unit, and is used to feedback the output current and voltage signals of the rectification and filtering unit to the pulse width control unit. The main function of this unit is to feedback the output current and voltage signals to the pulse width control unit 2 to form a closed loop.

[0045] All units use high-temperature-resistant components to ensure long-term stable operation in high-temperature environments.

[0046] The switching tube 7 is preferably a MOS tube. The drain of the switching tube is connected to the primary side of the transformer, the gate is connected to the pulse width control unit 2, and the drain is grounded through the resistor R10. The main function of this device is to act as a switch for the energy storage and release of the transformer. When it conducts, the transformer stores energy, and when it turns off, the transformer releases energy.

[0047] Embodiment 2

[0048] A schematic diagram of a power supply circuit for a wide voltage range applied to measurement-while-drilling technology is as Figure 2 shown. The pulse width control unit is the main component of this circuit. When designing, a Texas Instruments TPS4000 series chip is selected. This chip is a switching power supply controller chip with constant frequency and current mode control. It is applicable to various DC / DC converter topologies, such as buck, boost, flyback, etc. Its ultra-wide voltage input range enables the module to have a very wide input voltage.

[0049] The pulse width control unit is constructed based on the TPS4000 chip. The VDD terminal of the TPS4000 chip is connected to the output terminal of the power supply filtering unit, and DIS_EN_N is used to input an enable input signal; the COMP terminal is used to connect to the output terminal of the current-voltage sampling unit. The GDRV terminal of the TPS4000 chip is used to output a switching signal to the gate of the switching transistor. The ISNS terminal is connected to the source of the switching transistor through the resistor R9. The SS terminal, RC terminal, GND terminal, and BP terminal are all grounded through capacitors.

[0050] In addition, the current-voltage sampling unit includes a capacitor and a resistor.

[0051] One end of the resistor R1 is connected to the output terminal of the rectification and filtering unit, and the other end of the resistor R1 is connected to the RC parallel circuit. The RC parallel circuit includes the capacitor C1, capacitor C7, and resistor R5. After the capacitor C1 and the resistor R5 are connected in series, they are connected in parallel with the capacitor C7. One end of the parallel connection of the capacitor C1 and the capacitor C7 serves as the output terminal of the current-voltage sampling unit and is connected to the COMP terminal of the TPS4000 chip; after the resistors R2 and R3 are connected in series, one end is connected to the connection point of the resistor R1 and the resistor R5, and the other end is grounded.

[0052] Furthermore, for the power supply filtering unit, the negative input terminal V- is grounded, the positive input terminal V+ is connected to the anode of the diode D3. A first branch, a second branch, and the capacitor C15 are connected in parallel between the cathode of the diode D3 and the ground. The first branch includes the resistors R12 and R13 connected in series, and the second branch includes the capacitors C20 and C21 connected in series. The connection point between the resistors R12 and R13 is connected to the VCC-CE signal, and the connection point between the capacitors C20 and C21 is connected to the VCC-CE signal. The cathode of the diode D3 is also connected to one end of the primary side of the transformer; capacitors C26, C27, and C28 are connected in parallel between the cathode of the diode D3 and VCC-CE, and capacitors C35, C36, and C37 are connected in parallel between VCC-CE and the ground. The role of the VCC-CE network is to connect one end of the capacitor in parallel with the resistor to achieve voltage balance and prevent the situation that a single capacitor is overcharged due to factors such as capacitor aging, resulting in capacitor damage.

[0053] The input voltage of the power supply filtering unit is a DC voltage of 5 to 50V, and the output voltage of the rectification and filtering unit is DC +12V or -12V. In actual applications, the output voltage of the rectification and filtering unit is DC ±13.5V.

[0054] As a preferred solution, an enable circuit is further included. The circuit diagram for generating the enable signal of the TPS4000 chip is as shown in Figure 3As shown, the enabling circuit includes transistors Q1, Q2, Q3, Q4 and resistors R15, R17, R18, R19. The input terminal EN of the enabling signal is connected to the emitter of transistor Q1. The collector of transistor Q1 is connected to the emitter of transistor Q2. The collector of transistor Q2 is connected to the emitter of transistor Q3. The bases of transistors Q2, Q3, Q4 are respectively shorted to their emitters. The emitter of transistor Q3 is connected to the base of transistor Q4 through resistor R16. The collector of transistor Q4 is connected to the working power supply VIN+ through resistor R18. The emitter of transistor Q4 is grounded. A resistor R19 is connected in parallel between the collector and emitter of transistor Q4. A resistor R17 is connected in parallel between the base and emitter of transistor Q4. The input terminal EN of the enabling signal is grounded through resistor R15. PW-EN is the enabling signal of the TPS4000 chip. When the upper-level device believes that the lower-level device can be shut down, this signal is set to a low level to turn off the power supply of this unit circuit, so as to save the battery power and extend the working time of the device underground.

[0055] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A power supply circuit with wide voltage input for measurement while drilling, characterized in that: It includes power filter unit, pulse width control unit, transformer, rectifier filter unit, switch tube and current and voltage sampling unit. The power filter unit is used to convert the input DC power into AC input power; The transformer converts the AC input power into an AC power output by the secondary side of the transformer, and outputs the AC power output by the secondary side of the transformer to a rectifier and filter unit; The rectifier and filter unit is used to convert the AC power outputted by the secondary side of the transformer into a pulsating DC signal, and the pulsating DC signal is used to power the measurement while drilling equipment; The input end of the pulse width control unit is connected to the output end of the power filter unit and the output end of the current and voltage sampling unit respectively, and the output end of the pulse width control unit is connected to the gate of the switch tube to control the switch tube to be turned on and off; The drain of the switch tube is connected to the primary side of the transformer, and is used to control the storage and release of energy of the transformer; The input end of the current and voltage sampling unit is connected to the output end of the rectifying and filtering unit, and is used to feed back the output current and voltage signals of the rectifying and filtering unit to the pulse width control unit.

2. A power supply circuit with wide voltage input for measurement while drilling as claimed in claim 1, characterized in that: The pulse width control unit is constructed based on the TPS4000 chip. The VDD terminal of the TPS4000 chip is connected to the output terminal of the power filter unit, and DIS_EN_N is used to input the enable input signal; the COMP terminal is used to connect to the output terminal of the current and voltage sampling unit, and the GDRV terminal of the TPS4000 chip is used to output the switching signal to the gate of the switching tube. The ISNS terminal is connected to the source of the switching tube through the resistor R9, and the SS terminal, RC terminal, GND terminal, and BP terminal are all grounded.

3. A power supply circuit for wide voltage input for measurement while drilling as claimed in claim 1, characterized in that: The current and voltage sampling unit includes a capacitor and a resistor. One end of the resistor R1 is connected to the output end of the rectifier and filter unit, and the other end of the resistor R1 is connected to the RC parallel circuit, wherein the RC parallel circuit includes a capacitor C1, a capacitor C7 and a resistor R5. The capacitor C1 and the resistor R5 are connected in series and then connected in parallel with the capacitor C7. One end of the capacitor C1 and the capacitor C7 connected in parallel is connected to the COMP end of the TPS4000 chip as the output end of the current and voltage sampling unit; The resistors R2 and R3 are connected in series, one end of which is connected to the connection point between the resistors R1 and R5, and the other end is grounded.

4. A power supply circuit for wide voltage input for measurement while drilling as claimed in claim 1, characterized in that: The rectification and filtering unit comprises a first rectification and filtering unit, wherein the first rectification and filtering unit comprises a capacitor, a resistor and a diode. The anode of the diode D1 is connected to one end of the secondary side of the transformer, the cathode of the diode D1 and the other end of the secondary side of the transformer are connected in parallel with capacitors C2 and C4, a resistor R4 is connected between capacitor C4 and one end of capacitor C3, the other end of capacitor C3 is connected to the other end of the secondary side of the transformer, both ends of capacitor C3 are also connected in parallel with capacitors C22, C23, C24, C5 and C6, one end of capacitor C3 is grounded, the other end of capacitor C3 outputs a negative pulsating DC signal VOUT-, and capacitors C29, C30, C31 are also connected in parallel between the negative pulsating DC signal VOUT- and the ground.

5. A power supply circuit with wide voltage input for measurement while drilling as claimed in claim 4, characterized in that: It also includes a second rectifying and filtering unit, The second rectifying and filtering unit includes a capacitor, a resistor and a diode. The anode of the diode D2 is connected to one end of the secondary side of the transformer, the cathode of the diode D2 and the other end of the secondary side of the transformer are connected in parallel with capacitors C9 and C11, a resistor R6 is connected between capacitor C11 and one end of capacitor C10, the other end of capacitor C10 is connected to the other end of the secondary side of the transformer, capacitors C25, C18, C19, C12 and C13 are also connected in parallel across capacitor C10, one end of capacitor C10 is grounded, the other end of capacitor C10 outputs a positive pulsating DC signal VOUT+, and capacitors C32, C33 and C34 are also connected in parallel between the positive pulsating DC signal VOUT+ and the ground.

6. A power supply circuit with wide voltage input for measurement while drilling as claimed in claim 1, characterized in that: The power filter unit, wherein the negative input terminal V- is grounded, the positive input terminal V+ is connected to the anode of the diode D3, the first branch, the second branch and the capacitor C15 are connected in parallel between the cathode of the diode D3 and the ground, the first branch includes resistors R12 and R13 connected in series, the second branch includes capacitors C20 and C21 connected in series, the connection point between the resistors R12 and R13 is connected to the VCC-CE signal, the capacitors C20 and C21 are connected to the VCC-CE signal, the cathode of the diode D3 is also connected to one end of the primary side of the transformer; capacitors C26, C27, and C28 are connected in parallel between the cathode of the diode D3 and VCC-CE, and capacitors C35, C36, and C37 are also connected in parallel between VCC-CE and the ground.

7. A power supply circuit with wide voltage input for measurement while drilling as claimed in claim 1, characterized in that: The input voltage of the power filter unit is a DC voltage of 5 to 50V, and the output voltage of the rectifier filter unit is DC +12V or -12V.

8. A power supply circuit for measurement while drilling with wide voltage input as claimed in any one of claims 2 to 7, characterized in that: It also includes an enabling circuit, which includes transistors Q1, Q2, Q3, Q4 and resistors R15, R17, R18, and R19. The input end EN of the enabling signal is connected to the emitter of the transistor Q1, the collector of the transistor Q1 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is connected to the emitter of the transistor Q3, the bases of the transistors Q2, Q3, and Q4 are short-circuited with their emitters respectively, the emitter of the transistor Q3 is connected to the base of the transistor Q4 through the resistor R16, the collector of the transistor Q4 is connected to the working power supply VIN+ through the resistor R18, the emitter of the transistor Q4 is grounded, the resistor R19 is connected in parallel between the collector and the emitter of the transistor Q4, the resistor R17 is connected in parallel between the base and the emitter of the transistor Q4, and the input end EN of the enabling signal is grounded through the resistor R15.

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