High-temperature-resistant, high-vibration-resistant and high-voltage power supply circuit adapted to downhole gamma detection

Abstract

The application relates to the field of high-voltage direct-current power supply and downhole extreme environment detection, and provides a high-temperature-resistant and high-shock-resistant high-voltage power supply circuit suitable for downhole gamma detection, which comprises a linear voltage reduction circuit, an auxiliary circuit, a controller chip, a high-frequency power conversion circuit, a tripler voltage boosting circuit, a feedback circuit, a current limiting circuit, a compensation circuit and power consumption management logic; through the cooperative design of wide-voltage input voltage stabilization, multi-stage voltage multiplication rectification, closed-loop feedback voltage stabilization, a high-temperature-resistant component system, integrated shock resistance reinforcement and double-mode power consumption management, wide-range continuous adjustable high-voltage output, super-high-temperature multi-channel load carrying, reliable operation under strong impact vibration and low-power consumption long service life are realized.

Description

Technical Field

[0001] This invention relates to the field of high-voltage DC power supply and downhole extreme environment detection technology, and in particular to a high-temperature resistant and shock-resistant high-voltage power supply circuit adapted for downhole gamma detection. Background Technology

[0002] Gamma-ray logging while drilling (GLOBAL) and engineering explosive cutting detection equipment are trending towards miniaturization and deeper well applications. Downhole tools have narrow inner diameters, and their power supply voltage is greatly affected by battery discharge and load fluctuations (12V~60V). Deep wells and geothermal environments often reach temperatures of 175℃~205℃, and the drilling and explosive processes subject the equipment to continuous high-intensity impact and vibration. Under these harsh conditions, gamma-ray detection relies on photomultiplier tubes to convert and amplify photon signals. A stable, wide-range high voltage is required to establish an internal electron multiplication electric field, and the stability of the high-voltage power supply directly determines the gamma-ray energy resolution and count rate accuracy.

[0003] Traditional commercial high-voltage power supplies are mostly designed for normal temperature laboratory environments. A small number of downhole high-voltage boards can only meet the requirements of ≤150℃, ≤30G shock resistance, fixed input of 24V, and maximum output of 1500V. They have weak high-temperature load capacity, high power consumption, and short lifespan, and cannot meet the long-term operation needs of deep high-temperature wells and strong impact engineering explosion scenarios.

[0004] The typical topology of a traditional well logging high-voltage board is as follows: a fixed 24V input linear step-down circuit, a pre-made epoxy-encapsulated high-frequency transformer, a single-stage voltage multiplier rectifier circuit, general-purpose industrial capacitors, and commercial high-voltage MOSFETs. The PCB uses conventional soldering processes and has not undergone special anti-vibration reinforcement. This solution only supports driving 1-2 photomultiplier tubes, uses segmented voltage regulation for the output, has a maximum output of 1500V, a rated temperature resistance of 125℃~150℃, and an anti-vibration rating of 20G~30G.

[0005] The aforementioned traditional solutions have the following significant technical drawbacks: (1) Input voltage adaptability and bottleneck of high transformation ratio topology Traditional solutions employ a fixed 24V input design, which cannot accommodate battery voltage fluctuations ranging from 12V to 60V. When the downhole battery pack deviates from 24V due to deep discharge or temperature drift, the voltage regulator circuit enters an abnormal operating range, causing the output high voltage to drop or oscillate. The upper limit of the output voltage is only 1500V, and it uses segmented step-by-step adjustment, which cannot cover the continuous voltage regulation requirements of 300V to 3200V. Multiple photomultiplier tubes cannot be interchanged, requiring multiple circuit boards, increasing the size of downhole tools and the cost of spare parts. Limited by the fixed turns ratio transformer and single-stage voltage multiplier structure, traditional solutions cannot achieve wide-range continuous voltage regulation while maintaining high integration.

[0006] (2) Limits of material physical properties on high-temperature service The upper temperature limit for general-purpose industrial capacitors and commercial high-voltage MOSFETs is 150℃. At 205℃, the accelerated evaporation of the capacitor electrolyte leads to capacitance decay, a surge in equivalent series resistance, and a dramatic increase in leakage current. The operating temperature limit for commercial silicon-based MOSFETs is typically no more than 150℃; at high temperatures, the on-resistance increases significantly, increasing the risk of thermal breakdown. More critically, finished transformers use epoxy potting, and ordinary epoxy resin undergoes thermal degradation and carbonization above 200℃, resulting in a sharp decline in insulation performance and causing inter-turn short circuits. These material characteristics constitute a high-temperature service bottleneck that traditional solutions cannot overcome.

[0007] (3) Mismatch between multi-path detection carrying capacity and thermal stress Traditional solutions can only stably drive 1-2 photomultiplier tubes at high temperatures. When multiple tubes are connected in parallel, the output voltages of each tube drift due to differences in load characteristics and uneven leakage current at high temperatures, resulting in distortion of the gamma detection signal and failing to meet the signal accuracy requirements of high-temperature multi-channel detection.

[0008] (4) Failure cumulative effect under mechanical vibration The PCB uses a conventional FR-4 substrate without reinforcement, with components directly soldered and the transformer windings unencapsulated. Under drilling vibration and engineering explosion impacts (above 30G), the solder joints of the heavy-duty transformer and capacitors are subjected to cyclic mechanical stress, resulting in fatigue cracks and eventual fracture. At the same time, the internal windings of the unencapsulated transformer experience relative displacement, and the enameled wire insulation wears down. This is one of the core reasons for sudden failures during deep well drilling.

[0009] (5) Lack of power management and transient protection for critical sensors The static current of the entire unit is 20mA~50mA, and the standby current exceeds 10mA, significantly shortening the battery life in the well. More seriously, the traditional solution lacks soft-start and surge current limiting design. At the moment of power-on, the transformer core saturation and output capacitor charging generate a surge current of up to 2A, which directly breaks down the delicate electrode structure inside the photomultiplier tube, causing irreversible damage. Summary of the Invention

[0010] The purpose of this invention is to solve at least one technical problem in the background art and to provide a high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection.

[0011] To achieve the above objectives, the present invention provides a high-temperature, high-vibration, and high-voltage power supply circuit adapted for downhole gamma detection, comprising: A linear step-down circuit is used to accept a wide range of DC input voltages and adjust the input voltage to the power supply voltage required by each functional module; An auxiliary circuit, connected to the output of the linear buck circuit, is used to provide auxiliary working signals to the controller chip and is connected to the feedback circuit. The controller chip receives external control signals and feedback signals, and is used to output pulse width modulation drive signals with a specific frequency. A high-frequency power conversion circuit includes a power switching element and an energy storage inductor. The power switching element is controlled by the pulse width modulation drive signal to charge and discharge the energy storage inductor to store energy. The triple voltage boosting circuit, connected to the output terminal of the energy storage inductor, includes a cascaded voltage boosting topology composed of a high-temperature capacitor and a high-temperature high-voltage rectifier diode, used to perform multi-stage voltage boosting and rectification of the energy on the energy storage inductor to output continuously adjustable high-voltage DC power. The feedback circuit collects the output voltage of the triple boost circuit and feeds the collected voltage signal back to the controller chip. A current limiting circuit is installed in the high-voltage output circuit of the triple boost circuit to limit instantaneous inrush current. A compensation circuit, connected between the controller chip and the triple boost circuit and connected to ground, is used to filter or compensate for high-frequency noise in order to suppress self-oscillation of the power supply circuit. The controller chip is also equipped with power management logic to control the circuit to switch between working mode and standby mode. In standby mode, the power supply to the triple boost circuit is cut off or reduced.

[0012] According to one aspect of the present invention, the wide-range DC input voltage is 12V~60V; the continuously adjustable high-voltage DC voltage range is 300V~3200V; the current limiting circuit limits the instantaneous inrush current to within 0.5A; the static current consumption of the whole machine in the working mode is ≤10mA, and the standby current in the standby mode is ≤0.5mA.

[0013] According to one aspect of the present invention, the linear step-down circuit includes a bidirectional reverse connection protection unit, a two-stage LC filter unit, and a transient surge absorption circuit connected in sequence.

[0014] According to one aspect of the present invention, the output terminal of the triple boost circuit is divided into multiple independent high-voltage channels, and each high-voltage channel is provided with an independent current limiting protection circuit.

[0015] According to one aspect of the present invention, the multiple independent high-voltage channels are four independent high-voltage channels.

[0016] According to one aspect of the present invention, the triple boost circuit is provided with a voltage divider sampling network, the feedback circuit obtains the feedback voltage through the voltage divider sampling network, and connects the sampling signal to the error amplification input terminal of the controller chip via the compensation circuit.

[0017] According to one aspect of the present invention, the energy storage inductor and the high-temperature capacitor and high-temperature high-voltage rectifier diode in the tripler circuit all adopt a high-temperature resistant component system: the high-temperature capacitor adopts a high-temperature solid capacitor with a temperature resistance of ≥220℃, the power switching element adopts a silicon carbide high-temperature high-voltage diode, and the high-temperature high-voltage rectifier diode has a temperature resistance of ≥220℃; the high-temperature capacitor in the tripler circuit has a voltage resistance of ≥5kV.

[0018] According to one aspect of the present invention, the energy storage inductor is a self-wound high-temperature transformer, which is wound with a high-temperature insulating frame and polyimide high-temperature enameled wire, and the winding is vacuum high-temperature impregnation and sealing treatment after winding is completed, and the magnetic core is made of high-temperature low-loss ferrite.

[0019] According to one aspect of the present invention, the high-voltage power supply circuit is mounted on a rigid substrate, the substrate being provided with reinforcing ribs and thickened copper foil; the components in the triple boost circuit, the power switching element and the energy storage inductor are fixed to the substrate by full-coverage dispensing of high-temperature thermally conductive potting compound, and the pins of the high-temperature capacitor and the high-temperature high-voltage rectifier diode in the triple boost circuit are soldered to the substrate using a flexible buffer extended pad process.

[0020] According to one aspect of the present invention, the controller chip further includes a mode control terminal; when the circuit is in standby mode, the controller chip stops outputting pulse width modulation drive signals or cuts off the power supply circuit of the triple boost circuit; the circuit further includes a full-loop temperature sampling module, used to feed back a signal to the controller chip when the ambient temperature exceeds a set threshold, so as to perform a power reduction protection action.

[0021] According to the present invention, a high-temperature, high-vibration, and high-voltage power supply circuit adapted for downhole gamma detection is provided. Through the coordinated design of a linear step-down circuit, auxiliary circuit, controller chip, high-frequency power conversion circuit, triple boost circuit, feedback circuit, current limiting circuit, compensation circuit, and power management logic, it achieves wide voltage input adaptation, wide-range continuously adjustable high-voltage output, synchronous drive of multiple photomultiplier tubes under ultra-high temperature conditions, reliable operation under strong impact and vibration conditions, low power consumption control, and impact-resistant current limiting protection, significantly extending the service life under extreme environments. Attached Figure Description

[0022] Figure 1 This schematic diagram illustrates the principle block diagram of a high-temperature, high-vibration, and high-voltage power supply circuit adapted for downhole gamma detection according to one embodiment of the present invention. Figure 2 This schematic diagram illustrates a PCB layout of a high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to an embodiment of the present invention. Detailed Implementation

[0023] The invention will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0024] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0025] Figure 1 This schematic diagram illustrates the principle block diagram of a high-temperature, high-vibration, and high-voltage power supply circuit adapted for downhole gamma detection according to one embodiment of the present invention. Figure 1 As shown, the high-temperature, high-vibration, and high-voltage power supply circuit adapted for downhole gamma detection consists of a linear step-down circuit, an auxiliary circuit, a controller chip, a high-frequency power conversion circuit, a triple boost circuit, a feedback circuit, a current limiting circuit, a compensation circuit, and power management logic.

[0026] In this embodiment, the linear step-down circuit is used to accept a wide range of DC input voltages (preferably 12V~60V from the downhole battery pack voltage) and adjusts the input wide-voltage DC voltage to the power supply voltage required by each functional module. Its input terminal is equipped with a bidirectional reverse connection protection circuit to prevent damage to the circuit from reverse battery connection; it also features a two-stage LC high-temperature filter circuit to filter out high-frequency conducted interference from the downhole drill or motor, and is equipped with a transient surge absorption circuit to suppress instantaneous high-voltage spikes during power-on or voltage changes.

[0027] The auxiliary circuit is connected to the output of the linear buck circuit to provide a stable bias signal and auxiliary drive conditions for the controller chip. Simultaneously, the auxiliary circuit maintains a signal connection with the feedback circuit to coordinate the operating states. The controller chip is the core control unit of this circuit module. It can receive external CTL control signals, auxiliary operating signals, and voltage sampling signals from the feedback circuit, and output pulse width modulation (PWM) drive signals with a specific frequency according to the set closed-loop logic. Through the fixed proportional relationship between the CTL control signal and the target high-voltage output value (HV), the controller chip can achieve voltage control amplification of hundreds of times.

[0028] The high-frequency power conversion circuit mainly consists of power switching elements and an energy storage inductor. The PWM drive signal output by the controller chip controls the high-speed switching of the power switching elements, thereby periodically charging and discharging the energy storage inductor to store energy. Due to the confined space downhole and the extremely high reliability requirements of components, the energy storage inductor in this invention is a high-temperature inductor specially customized to match the current operating frequency and power level, and is the core component for energy conversion and power control.

[0029] The high-frequency AC energy output from the energy storage inductor is fed to a tripler circuit. This circuit employs a multi-stage Cockcroft-Walton cascaded voltage multiplier topology, consisting of high-temperature resistant high-frequency capacitors and high-temperature, high-voltage rectifier diodes. This topology performs multi-stage voltage multiplication and rectification on the AC high voltage output from the energy storage inductor, ultimately outputting a continuously adjustable DC high voltage (300V~3200V). The capacitors and diodes in the tripler circuit are all custom-designed for operation at 205℃, achieving extremely low leakage current and significantly reducing power consumption compared to traditional solutions.

[0030] To cope with drastic fluctuations in downhole load, the feedback circuit acquires the final output voltage of the tripler circuit in real time, obtains the feedback signal through a voltage divider sampling network, and sends it back to the controller chip in a closed loop, achieving millisecond-level rapid voltage regulation. A current-limiting circuit is installed on the high-voltage output loop of the tripler circuit, performing soft-start delay limiting during power-on or sudden load changes to strictly limit the instantaneous inrush current within a preset threshold. To prevent system self-oscillation caused by high voltage, high current, and parasitic parameters, this invention also introduces a compensation circuit. The compensation circuit is connected between the controller chip and the tripler circuit and to ground. It uses an RC network to filter or compensate for high-frequency high-voltage noise in the feedback loop, effectively purifying the control signal and suppressing power supply self-oscillation.

[0031] In addition, the controller chip is equipped with a power management logic module, which controls the circuit to switch between operating mode and standby mode. In normal operating detection mode, the power management logic allows the whole machine to operate efficiently; in standby mode, it directly cuts off or reduces the high voltage power supply to the triple boost circuit, significantly reducing the standby power consumption of the whole machine.

[0032] In this embodiment, the high-voltage power supply circuit architecture achieves compatible input voltage of 12V~60V and continuous stepless voltage regulation of 300V~3200V under extreme environments. Through the dual closed loop of compensation circuit and feedback circuit, the industry problem of easy self-oscillation in traditional circuits is solved, and the foundation is laid for subsequent long-life and low-power operation.

[0033] Furthermore, according to one embodiment of the present invention, the aforementioned wide-range DC input voltage is preferably 12V~60V, which adapts to the wide range of voltage fluctuations caused by deep discharge or temperature drift in downhole battery packs. The aforementioned high-voltage output range is set to 300V~3200V, covering the driving requirements of the entire series of photomultiplier tubes.

[0034] Regarding current limiting protection, this invention limits the maximum output surge current of the current limiting circuit to within 0.5A. This mechanism effectively suppresses the surge caused by transformer core saturation and output capacitor charging at power-on (conventional solutions can reach 2A), playing a crucial role in protecting the delicate electrode structure inside the photomultiplier tube.

[0035] In terms of power consumption management, when the system is in normal working detection state, the maximum static current consumption of the whole machine is controlled within 10mA; when the controller chip receives an external command to enter the sleep standby state, the high voltage multiplier circuit is cut off, and the standby current of the whole machine is as low as 0.5mA.

[0036] In this embodiment, compared to the static current of 20mA~50mA and the standby current of over 10mA of traditional products, the power consumption of this invention is reduced by more than 70% in high-temperature standby mode. This extremely low power consumption characteristic greatly extends the battery's operating time per operation and reduces the frequency of battery replacements during tripping up and down the drilling site due to rapid power depletion.

[0037] Furthermore, according to one embodiment of the present invention, the linear buck circuit integrates multiple protection and filtering structures. Specifically, a bidirectional reverse connection protection unit, a two-stage LC high-temperature filter unit, and a transient surge absorption circuit are connected in series at the input terminal.

[0038] In this embodiment, the bidirectional reverse connection protection unit can effectively prevent circuit burnout in case of wiring operation errors downhole; the two-stage LC high-temperature filter circuit can completely filter out high-intensity electromagnetic interference (such as drilling rig motors and blasting electromagnetic pulses) downhole; the transient surge absorption circuit can absorb high-voltage surges caused by drastic load changes or external lightning strikes downhole, ensuring that the downstream low-voltage control circuit and controller chip are not damaged in extremely harsh electrical environments.

[0039] Furthermore, according to one embodiment of the present invention, the output terminal of the triple boost circuit is divided into multiple independent high-voltage channels, each of which is equipped with an independent current-limiting protection circuit. In practical applications, this structure ensures that even in the event of a load short circuit or abnormal overcurrent, the normal power supply to other channels will not be affected by the output of each channel.

[0040] In this embodiment, the multi-channel independent current limiting design enables the device to drive multiple photomultiplier tubes synchronously, stably, and in isolation in an ultra-high temperature environment of 205℃, solving the problem of voltage drift and signal distortion caused by uneven leakage current in traditional high temperature detection devices.

[0041] Furthermore, according to one embodiment of the present invention, the multiple independent high-voltage channels are specifically configured as four independent high-voltage channels.

[0042] In this embodiment, the four-channel parallel high-voltage output architecture can be perfectly adapted to the high-precision downhole gamma logging system or array photomultiplier tube detection requirements that require multi-probe collaborative detection. It not only saves space inside the small downhole tool, but also significantly reduces spare parts costs.

[0043] Furthermore, according to one embodiment of the present invention, to ensure ultra-high accuracy of the high-voltage output, a precision high-voltage divider sampling network is provided inside the triple-boost circuit. The feedback circuit obtains the true output voltage ratio signal through this voltage divider sampling network and inputs the sampling signal to the controller chip via the compensation circuit.

[0044] In this embodiment, the numerically controlled voltage divider closed-loop feedback loop achieves stepless continuous linear voltage regulation from 300V to 3200V. Under conditions of drastic temperature fluctuations and frequent load changes in the downhole environment, the feedback circuit, in conjunction with the compensation circuit, can achieve rapid output voltage correction and stabilization at the millisecond level, greatly reducing the impact of high-voltage drift on gamma-ray energy resolution and count rate accuracy.

[0045] Furthermore, according to one embodiment of the present invention, in order to achieve an ultra-high temperature limit service life of 205°C, the present invention establishes a complete system of high-temperature resistant components. Specifically, the energy storage inductor, as well as the high-temperature capacitor and high-temperature high-voltage rectifier diode in the tripler circuit, all adopt this system.

[0046] In terms of specific material selection, the high-temperature capacitors abandon traditional industrial electrolytic capacitors and adopt high-temperature solid-state capacitors with a temperature resistance rating of no less than 220℃, fundamentally eliminating the problem of leakage current surge caused by electrolyte vaporization in traditional capacitors at 205℃. The power switching components abandon traditional silicon-based MOSFETs and adopt silicon carbide (SiC) high-temperature and high-voltage transistors, ensuring no significant increase in conduction losses at 205℃. The high-temperature and high-voltage rectifier diodes are custom-designed high-temperature resistant diodes. Furthermore, the high-temperature capacitors in the triple-boost circuit are all preferably high-voltage rated with a voltage resistance of no less than 5kV, which, together with the custom diodes, forms a high-frequency boost circuit with extremely low leakage current at 205℃.

[0047] In this embodiment, the high-temperature resistant component system enables the entire machine to operate at a rated long-term temperature of up to 205°C, with key components having a temperature redundancy of over 220°C. Based on this system, the leakage current of the triple-boost circuit is significantly reduced at high temperatures, resulting in a power consumption reduction of over 40% compared to mainstream international high-voltage modules.

[0048] It is worth noting that in practical applications, if the size of the circuit components needs to be adapted to specific micro downhole tools, the cascaded voltage multiplier unit of the triple voltage booster in the circuit can be reduced by 1 to 2 stages according to the voltage requirements. Combined with the secondary output voltage of the energy storage inductor (or transformer), it can still fully cover the high voltage regulation range of 300V to 3200V, and the power consumption, temperature resistance, and shock resistance remain unchanged.

[0049] Furthermore, according to one embodiment of the present invention, the high-temperature reliability of the energy storage inductor relies on its specific material selection and winding process. The energy storage inductor is a self-wound high-temperature transformer, rather than a commercially available transformer with ordinary epoxy encapsulation. It uses a special insulation frame resistant to 230°C and is wound with polyimide high-temperature enameled wire resistant to 220°C. After the winding is completed, it must undergo a rigorous vacuum high-temperature impregnation and sealing process to remove air from the winding gaps and solidify into a whole. The magnetic core uses high-temperature, low-loss ferrite, ensuring that its permeability decay is less than 5% at 205°C.

[0050] In this embodiment, traditional epoxy-encapsulated transformers experience epoxy resin carbonization and insulation failure at temperatures above 200°C. This invention completely eliminates the high-temperature carbonization problem by abandoning epoxy resin, employing high-temperature resistant polyimide enameled wire, and using a vacuum high-temperature impregnation process. This self-wound high-temperature transformer maintains extremely low magnetic loss and extremely high insulation strength even at 205°C.

[0051] The self-winding high-temperature transformer of the present invention can also be replaced with a high-temperature resistant planar transformer of the same specifications. Its skeleton, insulating varnish and vacuum impregnation process remain unchanged, and it can still achieve a temperature resistance of 205℃ and a shock resistance of 100G. Only the magnetic core structure is flattened, which can be adapted to micro downhole tools with smaller outer diameters.

[0052] Furthermore, according to one embodiment of the present invention, in order to adapt to extreme high-impact conditions such as downhole directional drilling and engineering explosive cutting, the present invention has made a revolutionary design in terms of physical and mechanical structure. For example... Figure 2 As shown in the PCB layout diagram, the entire circuit is physically laid out using a reasonably rigid substrate. The left side of the diagram contains the input terminals and filter circuit area (containing input interfaces J2 and J3, a linear step-down circuit and filter inductor L1, auxiliary circuit components C6, C9, R8-R11, etc.). The middle section contains the controller chip U1 and the control circuit area (containing the controller chip, power switch component Q1 and its driving resistors and capacitors R4-R7, etc.). The right side contains the tripler circuit and high-voltage output area (containing high-temperature capacitors C2-C4, high-temperature and high-voltage rectifier diodes D1 and D3, voltage divider sampling resistors R1-R3, high-voltage output terminal HV, and ground terminal GND). The energy storage inductor (high-temperature transformer), as the core component of the high-frequency power conversion circuit, is located on the power transmission path between the controller chip U1 and the tripler circuit.

[0053] In the specific physical manufacturing and structural reinforcement, the overall high-voltage power supply circuit is mounted on a rigid substrate, which is preferably a high-rigidity metal-ceramic substrate, but a thickened high-TG high-temperature resistant FR-4 substrate can also be used. The substrate is reinforced with full-board stiffeners and thickened copper foil, greatly improving the PCB board's bending and vibration resistance. Circular mounting holes are provided at the four corners and center of the substrate for overall machine fixation and stress distribution.

[0054] Regarding the component mounting method, the high-voltage components in the tripler circuit (especially high-temperature capacitors C2-C4 and high-temperature high-voltage rectifier diodes D1 and D3), power switch element Q1, and energy storage inductor are all fully covered and fixed with high-temperature thermally conductive potting compound to prevent displacement during severe vibration. Simultaneously, to address the issue of pin stress concentration, this invention introduces a flexible buffer extended pad process. The pins of the high-voltage components are soldered to the substrate through specific flexible pads, utilizing the special physical shape of the pads to absorb and release mechanical vibration stress. As an overall vibration-resistant measure of this invention, the energy storage inductor (high-temperature transformer) is also integrally potted, eliminating relative displacement friction of the internal windings under high-acceleration vibration.

[0055] In this embodiment, through the synergistic effect of the aforementioned substrate reinforcement, full-coverage adhesive application, and integrated flexible pad reinforcement structure, the entire machine passed the 100G random vibration and shock test, far exceeding the 20G~30G performance of existing products. Under drilling and engineering blasting impacts, it completely eliminates faults such as coil desoldering, high-voltage pin breakage, component detachment, and insulation breakdown.

[0056] Furthermore, according to one embodiment of the present invention, in terms of standby power consumption control, the controller chip has a dedicated integrated or designed mode control terminal. When the controller chip receives an externally set standby command, it immediately stops outputting the PWM modulation drive signal (causing the power switching element to stop working), or directly cuts off the main power supply circuit of the triple boost circuit, thereby achieving extremely low power consumption in standby mode.

[0057] In terms of thermal management, the high-voltage power supply circuit of this invention is also equipped with a real-time full-loop temperature sampling module. This module monitors the operating temperature of the circuit board in real time through a temperature sensor that is closely attached to the core heat-generating element and the substrate. When the ambient temperature or its own operating temperature exceeds the set safety threshold, the module feeds back an overheating signal to the controller chip, and the controller chip then performs a power reduction protection action (e.g., reducing the PWM duty cycle or reducing the output current).

[0058] In this embodiment, this intelligent automatic power reduction mechanism effectively prevents thermal runaway of the circuit under extreme high-temperature environments. Combined with the aforementioned high-temperature resistant component system and low-loss circuit topology, the entire device possesses exceptionally long lifespan characteristics. Actual measurements show that it operates continuously and stably for over 1000 hours at an ambient temperature of 205°C; over 2000 hours at an ambient temperature of 175°C; and over 5000 hours at an ambient temperature of 150°C. Under the same conditions, its service life is 3-5 times that of existing commercial downhole high-pressure boards, significantly reducing the construction and on-site maintenance costs associated with replacing circuit boards during drilling and tripping.

[0059] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

[0060] It should be understood that the sequence number of each step in the invention and its embodiments does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Claims

1. A high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection, characterized in that: include: A linear step-down circuit is used to accept a wide range of DC input voltages and adjust the input voltage to the power supply voltage required by each functional module; An auxiliary circuit, connected to the output of the linear buck circuit, is used to provide auxiliary working signals to the controller chip and is connected to the feedback circuit. The controller chip receives external control signals and feedback signals, and is used to output pulse width modulation drive signals with a specific frequency. A high-frequency power conversion circuit includes a power switching element and an energy storage inductor. The power switching element is controlled by the pulse width modulation drive signal to charge and discharge the energy storage inductor to store energy. The triple voltage boosting circuit, connected to the output terminal of the energy storage inductor, includes a cascaded voltage boosting topology composed of a high-temperature capacitor and a high-temperature high-voltage rectifier diode, used to perform multi-stage voltage boosting and rectification of the energy on the energy storage inductor to output continuously adjustable high-voltage DC power. The feedback circuit collects the output voltage of the triple boost circuit and feeds the collected voltage signal back to the controller chip. A current limiting circuit is installed in the high-voltage output circuit of the triple boost circuit to limit instantaneous inrush current. A compensation circuit, connected between the controller chip and the triple boost circuit and connected to ground, is used to filter or compensate for high-frequency noise in order to suppress self-oscillation of the power supply circuit. The controller chip is also equipped with power management logic to control the circuit to switch between working mode and standby mode. In standby mode, the power supply to the triple boost circuit is cut off or reduced.

2. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The wide-range DC input voltage is 12V~60V; the continuously adjustable high-voltage DC voltage range is 300V~3200V; the current limiting circuit limits the instantaneous inrush current to within 0.5A; the static current consumption of the whole machine in the working mode is ≤10mA, and the standby current in the standby mode is ≤0.5mA.

3. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The linear step-down circuit includes a bidirectional reverse connection protection unit, a two-stage LC filter unit, and a transient surge absorption circuit connected in sequence.

4. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The output of the triple boost circuit is divided into multiple independent high-voltage channels, and each high-voltage channel is equipped with an independent current-limiting protection circuit.

5. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 4, characterized in that, The multiple independent high-voltage channels consist of four independent high-voltage channels.

6. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The triple boost circuit is equipped with a voltage divider sampling network. The feedback circuit obtains the feedback voltage through the voltage divider sampling network and connects the sampled signal to the error amplification input terminal of the controller chip via the compensation circuit.

7. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The energy storage inductor, the high-temperature capacitor, and the high-temperature high-voltage rectifier diode in the tripler circuit all adopt a high-temperature resistant component system: the high-temperature capacitor adopts a high-temperature solid capacitor with a temperature resistance of ≥220℃, the power switching element adopts a silicon carbide high-temperature high-voltage diode, and the high-temperature high-voltage rectifier diode has a temperature resistance of ≥220℃; the high-temperature capacitor in the tripler circuit has a voltage resistance of ≥5kV.

8. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The energy storage inductor is a self-wound high-temperature transformer, which is wound with a high-temperature insulating frame and polyimide high-temperature enameled wire. After the winding is completed, the winding is vacuum high-temperature impregnation and sealing treatment, and the magnetic core is made of high-temperature low-loss ferrite.

9. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The high-voltage power supply circuit is mounted on a rigid substrate, which is provided with reinforcing ribs and thickened copper foil. The components in the triple boost circuit, the power switching element and the energy storage inductor are fixed to the substrate by full coverage dispensing of high-temperature thermally conductive potting compound. The pins of the high-temperature capacitor and the high-temperature high-voltage rectifier diode in the triple boost circuit are soldered to the substrate using a flexible buffer extended pad process.

10. The high-temperature, high-vibration, high-voltage power supply circuit adapted for downhole gamma detection according to claim 1, characterized in that, The controller chip also has a mode control terminal; when the circuit is in standby mode, the controller chip stops outputting pulse width modulation drive signals or cuts off the power supply circuit of the triple boost circuit; the circuit also has a full-loop temperature sampling module, which is used to feed back a signal to the controller chip when the ambient temperature exceeds a set threshold, so as to perform power reduction protection action.

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