High-voltage precision adjustable analog linear DC voltage stabilizing power supply

Abstract

The utility model provides a kind of high pressure precision adjustable analog linear DC regulated power supply, including signal processing unit, rectification filter unit, control unit and stabilizing unit, wherein: signal processing unit, the voltage amplification of received external signal is output to control unit;Rectification filter unit, the rectification and filtering of input ac power are carried out, obtain direct current, power supply to control unit;Control unit, power output voltage is sampled, and output voltage is adjusted based on sampling signal and external signal, to control the output value of stabilizing unit;Stabilizing unit, the step-by-step amplification of current based on received output voltage, to adjust self output voltage, and filter and finally output to output voltage.The utility model solves the problem that the existing foreign imported linear adjustable power supply procurement and maintenance cost is high, the common linear regulated DC power supply and switching power supply ripple on market are big, stability is poor, voltage drift is obvious and the problem that the range of voltage regulation is limited.

Description

Technical Field

[0001] This utility model relates to the field of DC regulated power supply technology, and in particular to a high-voltage precision adjustable analog linear DC regulated power supply. Background Technology

[0002] In the instrumentation industry, pressure transmitters are critical products. For pressure transmitter manufacturers, ensuring high performance and high quality requires a clean, smooth DC power supply with high stability, high reliability, precise voltage regulation, and extremely low ripple. Since the power supply range of pressure transmitters is between DC 10.5V and 42V, under this power supply condition, factories need to perform precise calibration and correction on the pressure transmitters to meet the testing accuracy and various experimental requirements during the manufacturing process.

[0003] At present, there are the following problems with the power supply of pressure transmitters: (1) Some factories use imported linear adjustable power supplies to power pressure transmitters, which have high procurement and maintenance costs, thus increasing the production costs of the factories; (2) The ripple of the commonly used linear regulated DC power supplies on the market is large and unstable. During long-term use, the voltage drift phenomenon is serious and the adjustable range is narrow, which cannot meet the power supply requirements in the manufacturing process of pressure transmitters; (3) Although switching power supplies are also a power supply option, they have extremely large ripple and cannot adjust the voltage over a wide range, making them unsuitable for use in the production and manufacturing process of pressure transmitters. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a high-voltage precision adjustable analog linear DC regulated power supply, which solves the problems of high procurement and maintenance costs of imported linear adjustable power supplies, large ripple, instability, severe voltage drift and narrow adjustable range of common linear regulated DC power supplies on the market, and large ripple and inability to adjust voltage over a wide range of switching power supplies.

[0005] According to an embodiment of this utility model, a high-voltage precision adjustable analog linear DC regulated power supply includes a signal processing unit, a rectification and filtering unit, a control unit, and a voltage regulation unit, wherein: The signal processing unit is used to receive external signal input, amplify the voltage based on the received external signal, and output it to the control unit; The rectifier and filter unit is used to rectify and filter the input AC power to obtain DC power to supply power to the control unit. The control unit includes a sampling circuit and a first operational amplifier. The sampling circuit is used to sample the power supply output voltage and output a sampling signal to the first operational amplifier. The first operational amplifier is used to receive the sampling signal and the amplified external signal, and to adjust its own output voltage based on the received sampling signal and the external signal to control the output value of the voltage regulator unit. The voltage regulator unit includes an adjustment circuit and a first filter circuit. The adjustment circuit is used to receive the output voltage of the first operational amplifier and to amplify the current step by step based on the received output voltage to adjust its final output voltage. The first filter circuit is used to filter the output voltage of the adjustment circuit and output it.

[0006] Compared with the prior art, the present invention has the following beneficial effects: The rectifier and filter unit rectifies and filters the input AC power to obtain the DC power required to power the control unit. After the control unit is powered on, the sampling circuit of the control unit samples the power output voltage and outputs the sampling signal to the first operational amplifier. The signal processing unit amplifies the received external signal and outputs it to the first operational amplifier, so that the first operational amplifier adjusts its own output voltage based on the received sampling signal and the amplified external signal. Then, the adjustment circuit of the voltage regulator unit amplifies the current step by step based on the output voltage of the first operational amplifier to adjust its own final output voltage. The first filter circuit filters the output voltage, so that the power supply can provide the transmitter with a clean and smooth DC power supply with a power supply range of 0-90V to meet the production and manufacturing requirements of the transmitter and high-precision electrical experiments. This solves the problems of high procurement and maintenance costs of existing imported linear adjustable power supplies, and large ripple, poor stability, obvious voltage drift and limited voltage adjustment range of common linear regulated DC power supplies and switching power supplies on the market. It can reduce the procurement and maintenance costs of power supplies, while having small and stable output voltage ripple, low voltage drift and wide adjustable range. Attached Figure Description

[0007] Figure 1 This is a control principle diagram of a high-voltage precision adjustable analog linear DC regulated power supply according to an embodiment of the present invention.

[0008] Figure 2 This is a circuit diagram of a high-voltage precision adjustable analog linear DC regulated power supply according to an embodiment of the present invention.

[0009] Figure 3 This is a control principle diagram of a high-voltage precision adjustable analog linear DC regulated power supply according to another embodiment of the present invention.

[0010] Figure 4 This is a circuit diagram of a high-voltage precision adjustable analog linear DC regulated power supply according to another embodiment of the present invention.

[0011] Figure 5 This is a circuit diagram of an external component for a wiring terminal according to another embodiment of the present invention. Detailed Implementation

[0012] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0013] Example 1 like Figure 1 and Figure 2 As shown ( Figure 2 The OPA454 operational amplifier in this embodiment (i.e., the first pin of the first operational amplifier and the second operational amplifier is the common enable / disable terminal, the second pin is the inverting input terminal, the third pin is the non-inverting input terminal, the fourth pin is the negative power supply terminal, the sixth pin is the output terminal, the seventh pin is the positive power supply terminal, and the eighth pin is the enable / disable control terminal) proposes a high-voltage precision adjustable analog linear DC regulated power supply, including a signal processing unit, a rectification and filtering unit, a control unit, and a voltage regulation unit, wherein: The signal processing unit is used to receive external signal input, amplify the voltage based on the received external signal, and output it to the control unit; The rectifier and filter unit is used to rectify and filter the input AC power to obtain DC power to supply power to the control unit. The control unit includes a sampling circuit and a first operational amplifier. The sampling circuit is used to sample the power supply output voltage and output a sampling signal to the first operational amplifier. The first operational amplifier is used to receive the sampling signal and the amplified external signal, and to adjust its own output voltage based on the received sampling signal and the external signal to control the output value of the voltage regulator unit. The voltage regulator unit includes an adjustment circuit and a first filter circuit. The adjustment circuit is used to receive the output voltage of the first operational amplifier and to amplify the current step by step based on the received output voltage to adjust its final output voltage. The first filter circuit is used to filter the output voltage of the adjustment circuit and output it.

[0014] Specifically, the first operational amplifier is preferably a Texas Instruments OPA454 operational amplifier (Alternatively, Analog Devices' ADHV4702-1 operational amplifier can be used, with a supply voltage of 220V. This operational amplifier can also be adjusted from 0-90V, but the price of ADHV4702-1 is around 65 yuan, while the price of OPA454 is around 2 yuan. To reduce costs, it is recommended to use OPA454). As can be seen from the introduction of the Texas Instruments OPA454 operational amplifier, it is powered by DC100V in single power supply mode, and the minimum output is 2.5V when powered by single power supply. There is a dead zone below 2.5V that is not adjustable. By connecting 4 diodes in series after the output pin (pin 6) of this operational amplifier, it can meet the maximum DC 0-100V voltage output. However, considering the limitation of ripple, it is only necessary to control the maximum output of 90V. Therefore, the output voltage of this operational amplifier can achieve linear adjustment from 2.5V to 90V (without affecting linearity).

[0015] However, considering that the OPA454's excessive output current is prone to overheating and temperature drift, leading to system instability, the output ripple voltage calculation formula is used as follows: ,in, Indicates ripple voltage. Indicates the load current. Indicates the capacitance value. Indicates time, Indicates the resistance value. This represents the base of the natural logarithm. As shown in the above formula, the larger the load, the greater the power supply ripple voltage, posing a significant challenge to transmitter testing. Therefore, to reduce the output ripple value, this application designs the output current to be amplified, specifically a rated maximum continuous output current of 1A, linearly adjustable from DC 2.5 to 80V. This power supply operates at currents below 100mA, with extremely low ripple voltage at a load operating current of 20mA, providing the transmitter with a clean and smooth DC power supply to meet the manufacturing requirements and high-precision electrical testing needs of the transmitter.

[0016] In this embodiment, the input AC power is first rectified and filtered by the rectifier and filter unit to obtain the DC power required to power the control unit. After the control unit is powered on, the power supply output voltage is sampled by the sampling circuit of the control unit, and the power supply output voltage is converted into a sampling signal proportional to the output voltage. The sampling signal is then output to the first operational amplifier. The signal processing unit amplifies the received external signal and outputs it to the first operational amplifier. The first operational amplifier performs calculations and comparisons on the received sampling signal and the external input signal, and adjusts its own output voltage according to the calculation and comparison results. Then, the adjustment circuit of the voltage regulator unit amplifies the current step by step based on the output voltage of the first operational amplifier. The output voltage is then filtered by the first filter circuit to convert the pulsating DC into smooth DC, so that the power supply can provide the transmitter with a clean and smooth DC power supply with a power supply range of 0 to 90V to meet the manufacturing requirements of the transmitter and high-precision electrical experiments. At the same time, the filtered output voltage change is fed back to the first operational amplifier through the sampling circuit to form a negative feedback closed loop to adjust the final output voltage of the adjustment circuit, achieving the purpose of voltage regulation with minimal output ripple.

[0017] Preferably, the signal processing unit includes a terminal block U13 and a second operational amplifier U16; The first pin of the terminal U13 is connected to the third pin of the second operational amplifier U16 via resistor R9, and the second pin of the terminal U13 is grounded; the end of resistor R9 away from the terminal U13 is connected to one end of resistor R10, the other end of resistor R10 is grounded, and capacitor C14 is connected in parallel with resistor R10. The second pin of the second operational amplifier U16 is grounded via resistor R17. The sixth pin of the second operational amplifier U16 is connected to the third pin of the first operational amplifier U15 via resistor R14. The sixth pin of the second operational amplifier U16 is grounded sequentially via resistors R15, R16, and R17, and the center tap of resistor R16 is connected to the end of resistor R16 closest to resistor R15. The end of resistor R14 furthest from the second operational amplifier U16 is connected to one end of resistor R13, and the other end of resistor R13 is grounded. Capacitor C15 is connected in parallel with resistor R13. The fourth pin of the second operational amplifier U16 is grounded. The seventh pin of the second operational amplifier U16 is connected to the seventh pin of the first operational amplifier U15. The first and eighth pins of the second operational amplifier U16 are connected via capacitor C32, and the first pin of the second operational amplifier U16 is grounded.

[0018] Specifically, such as Figure 2As shown, the external signal input from the terminal U13 is transmitted to the non-inverting input of the second operational amplifier U16 through the RC circuit consisting of resistor R9, resistor R10, and capacitor C14. During the transmission process, resistor R9 can limit the current input from the terminal U13 to the inverting input of the second operational amplifier U16 to prevent excessive current from damaging the second operational amplifier U16. The RC circuit consisting of resistor R10 and capacitor C14 can filter the input signal, making the signal input to the non-inverting input of the second operational amplifier U16 more stable.

[0019] After the second operational amplifier U16 receives an external signal, it can amplify the voltage of the received signal. At this time, the amplification factor of the second operational amplifier U16 can be adjusted by adjusting the resistance value of resistor R16. After amplification, the voltage-amplified signal will be transmitted to the non-inverting input terminal of the first operational amplifier U15 through the RC circuit composed of resistor R14, resistor R13, and capacitor C15. During the transmission process, resistor R14 can limit the current input from the second operational amplifier U16 to the first operational amplifier U15 to prevent excessive current from damaging the first operational amplifier U15. The RC circuit composed of resistor R13 and capacitor C15 can filter the signal input to the first operational amplifier U15, making the signal input to the non-inverting input terminal of the first operational amplifier U15 more stable.

[0020] Preferably, the rectifier-filter unit includes a rectifier circuit and a second filter circuit, wherein: The rectifier circuit includes a terminal block U8, diodes D1, D2, D3, and D4. Terminal block U8 is connected to the secondary winding of the transformer to input alternating current. The anode of diode D1 is connected to the first pin of terminal block U8 and the cathode of diode D4. The cathode of diode D1 is connected to the cathode of diode D2. The anode of diode D2 is connected to the second pin of terminal block U8 and the cathode of diode D3. The anode of diode D3 is connected to the anode of diode D4, and the anode of diode D4 is grounded. The second filter circuit includes capacitors C1 and C2. One end of capacitor C1 is connected to the negative terminal of diode D1, and the other end of capacitor C1 is grounded. Capacitor C2 is connected in parallel with capacitor C1.

[0021] Specifically, diodes D1, D2, D3, and D4 form a full-wave bridge rectifier circuit, and capacitors C1 and C2 form a capacitor filter circuit. The AC power input from the transformer is introduced into the full-wave bridge rectifier circuit composed of diodes D1, D2, D3, and D4 through the terminal U8. The full-wave bridge rectifier circuit composed of diodes D1, D2, D3, and D4 converts the input AC power into pulsating DC power. Then, the capacitor filter circuit composed of capacitors C1 and C2 smooths the voltage fluctuations, and finally outputs stable DC power, providing the main input power of the power supply circuit and the power supply of the first operational amplifier U15.

[0022] Preferably, the sampling circuit includes resistors R11 and R12. One end of resistor R11 is connected to the power supply output voltage, and the other end of resistor R11 is connected to one end of resistor R12 and the second pin of the first operational amplifier U15. The other end of resistor R12 is grounded. The second pin of the first operational amplifier U15 is connected to the sixth pin of the first operational amplifier U15 through an RC circuit, which consists of resistor R21 and capacitor C36 in parallel. The sixth pin of the first operational amplifier U15 is grounded through resistor R8, the fourth pin of the first operational amplifier U15 is grounded, and the first and eighth pins of the first operational amplifier U15 are connected through capacitor C33, with the first pin of the first operational amplifier U15 also grounded.

[0023] The adjustment circuit includes at least two transistors; the at least two transistors include transistors Q1 and Q2, the base of transistor Q1 is connected to the sixth pin of the first operational amplifier U15 via resistor R7, the collector of transistor Q1 is connected to the seventh pin of the first operational amplifier U15 and the cathode of diode D1, the emitter of transistor Q1 is connected to the base of transistor Q2, the collector of transistor Q2 is connected to the collector of transistor Q1, and the emitter of transistor Q2 outputs the adjusted voltage.

[0024] Specifically, resistors R11 and R12 form a voltage divider network. The power supply output voltage is divided by the voltage divider network formed by resistors R11 and R12 to obtain a sampling voltage proportional to the power supply output voltage. After voltage division, the divided voltage value is sent to the inverting input terminal of the first operational amplifier U15. Combined with the voltage value amplified by the second operational amplifier U16 and sent to the non-inverting input terminal of the first operational amplifier U15, the first operational amplifier U15 can quickly perform linear calculations on the two voltage values ​​and adjust its own output voltage according to the calculation comparison result. Then, the output terminal of the first operational amplifier U15 drives the transistor Q1 (the transistor Q1 is preferably a 2N5551). When the output terminal of the first operational amplifier U15 outputs voltage, the integrating circuit formed by capacitor C36 and resistor R21 can eliminate self-oscillation and make the output of the first operational amplifier U15 smoother. Resistor R7 can limit the current output from the first operational amplifier U15 to prevent excessive current from damaging the transistors Q1 and Q2.

[0025] After transistor Q1 is driven, its base-emitter junction is turned on, causing the emitter voltage of transistor Q1 to rise (approximately close to the base voltage minus about 0.7V). Since the emitter of transistor Q1 is directly connected to the base of transistor Q2, the base voltage of transistor Q2 rises synchronously, causing transistor Q2 to also turn on. When transistor Q2 is turned on, its emitter output voltage (i.e., the adjusted voltage) will be close to the base voltage of transistor Q2 minus 0.7V. Since the base voltage of transistor Q2 is determined by the emitter of transistor Q1, the final output voltage of transistor Q2 is clamped at the voltage of the seventh pin of the first operational amplifier U15 minus 1.4V (considering the dual voltage drops of Q1 and Q2). Therefore, the output voltage of transistor Q2 can be adjusted according to the output voltage of the first operational amplifier U15 to achieve voltage regulation.

[0026] Preferably, the first filter circuit includes capacitors U1, U2, U23, C6 and C9. One end of capacitors U1, U23 and C6 is connected to the emitter of transistor Q2, the other end of capacitor U1 is connected to one end of capacitor U2, the other end of capacitor C6 is connected to one end of capacitor C9, and the other ends of capacitors U2, U23 and C9 are grounded.

[0027] Specifically, capacitors U1, U2, U23, C6, and C9 constitute a capacitor filter circuit, and the emitter of transistor Q2 is the input of the capacitor filter circuit. Through the energy storage and charging / discharging characteristics of the capacitors in the capacitor filter circuit composed of capacitors U1, U2, U23, C6, and C9, the voltage output from the emitter of transistor Q2 is smoothed, high-frequency noise or ripple is filtered out, thereby outputting a more stable DC voltage as the power supply output voltage.

[0028] The detailed working process of this embodiment is as follows: The terminal U8 is connected to the secondary winding of the transformer. The AC power input from the secondary winding of the transformer is introduced into the full-wave bridge rectifier circuit composed of diodes D1, D2, D3 and D4 through the terminal U8. The full-wave bridge rectifier circuit composed of diodes D1, D2, D3 and D4 converts the input AC power into pulsating DC power. Then, the voltage fluctuation is smoothed by the capacitor filter circuit composed of capacitors C1 and C2, and finally a stable DC power is output, providing the main input power of the power supply circuit and the power supply of the first operational amplifier U15.

[0029] Subsequently, the power supply output voltage is divided by the voltage divider network composed of resistors R11 and R12 to obtain a sampling voltage proportional to the power supply output voltage. After voltage division, the divided voltage value is sent to the inverting input terminal of the first operational amplifier U15. At the same time, the second operational amplifier U16 receives the external signal and amplifies the received external signal. After amplification, the signal is filtered by the RC circuit composed of resistor R13 and capacitor C15 and then input to the non-inverting input terminal of the first operational amplifier U15. At this time, the potentiometer connected to the terminal U13 is not adjusted and is in a fixed state, so that the non-inverting input terminal of the first operational amplifier U15 serves as a stable and adjustable reference voltage value. This allows the first operational amplifier U15 to perform fast linear calculations on the two voltage values ​​and adjust its output voltage according to the calculation comparison result.

[0030] Then, the output of the first operational amplifier U15 drives the transistor Q1. After the transistor Q1 is driven, the base-emitter junction of the transistor Q1 is turned on, causing the emitter voltage of the transistor Q1 to be pulled high. Since the emitter of the transistor Q1 is directly connected to the base of the transistor Q2, the base voltage of the transistor Q2 rises synchronously, causing the transistor Q2 to also enter the conducting state. When the transistor Q2 is turned on, the emitter output voltage of the transistor Q2 (i.e., the adjusted voltage) will be close to the base voltage of the transistor Q2 minus 0.7V. Since the base voltage of the transistor Q2 is determined by the emitter of the transistor Q1, and the emitter of the transistor Q1 is controlled by its base voltage, and the base voltage of the transistor Q1 is determined by the output voltage of the first operational amplifier U15, the final output voltage of the transistor Q2 can be adjusted by the output voltage of the first operational amplifier U15.

[0031] Finally, by utilizing the energy storage and charging / discharging characteristics of the capacitors in the capacitor filter circuit composed of capacitors U1, U2, U23, C6, and C9, the voltage output from the emitter of transistor Q2 is smoothed, filtering out high-frequency noise or ripple, thereby outputting a more stable DC voltage as the power supply output voltage. This power supply can provide the transmitter with a clean and smooth DC power supply, with a power supply range of 0–90V, to meet the manufacturing requirements of the transmitter and high-precision electrical experiments. At the same time, the filtered output voltage change is fed back to the first operational amplifier U15, forming a negative feedback closed loop, so as to adjust the output voltage of transistor Q2 according to the output voltage of the first operational amplifier U15, achieving the purpose of voltage stabilization and minimal output ripple.

[0032] Example 2 like Figures 3-5 As shown ( Figure 4 In the LM358 operational amplifier, the first pin is the output terminal, the second pin is the inverting input terminal, the third pin is the non-inverting input terminal, the fourth pin is the negative power supply terminal, and the eighth pin is the positive power supply terminal. According to another embodiment of this utility model, the high-voltage precision adjustable analog linear DC regulated power supply further includes an overcurrent protection unit, a low-temperature drift precision voltage regulation unit, and a power supply unit, wherein: The overcurrent protection unit is used to cut off the output of the adjustment circuit when the power output is short-circuited or overloaded, so as to achieve overcurrent or short-circuit protection. The low-temperature drift precision voltage regulator unit is used to provide the signal processing unit with a high-precision, low-temperature drift stable reference voltage output, and to manually adjust the output voltage based on actual needs; The power supply unit is used to rectify, filter, and regulate the input AC power before supplying power to the overcurrent protection unit and the low-temperature drift precision voltage regulator unit.

[0033] Specifically, the power supply unit rectifies, filters, and regulates the input AC power to obtain 15V DC power, which is simultaneously supplied to the overcurrent protection unit and the low-temperature drift precision voltage regulator unit. The overcurrent protection unit provides drive power, and the low-temperature drift precision voltage regulator unit provides auxiliary power. The overcurrent protection unit monitors the current at the power output terminal in real time. When a short-circuit fault or overload condition (current exceeding a threshold) is detected, the protection circuit is automatically triggered. At this time, the output path of the adjustment circuit is quickly disconnected to block the propagation of the fault current, preventing equipment damage due to overcurrent or short circuit, thus achieving overcurrent or short-circuit protection. The low-temperature drift precision voltage regulator unit uses a potentiometer to manually adjust the output voltage, achieving adjustable output voltage.

[0034] Preferably, the overcurrent protection unit includes a terminal block U10 and a third operational amplifier U6; The first pin of the terminal U10 is connected to the third pin of the third operational amplifier U6 via resistor R3, and the first pin of the terminal U10 is grounded via resistor U14; the second pin of the terminal U10 is connected to the power supply output voltage; one end of the capacitor C10 is connected to the end of resistor R3 away from resistor U14, and the other end of the capacitor C10 is grounded. The second pin of the third operational amplifier U6 is grounded via resistor R2, the center tap of resistor R2 is grounded, capacitor C12 is connected in parallel with resistor R2, and the second pin of the third operational amplifier U6 is connected to the eighth pin of the third operational amplifier U6 via resistor R1; the fourth pin of the third operational amplifier U6 is grounded, the first pin of the third operational amplifier U6 is connected to the third pin of the third operational amplifier U6 via resistor R4, and the first pin of the third operational amplifier U6 is connected to the base of transistor Q3 via resistor R6; the collector of transistor Q3 is connected to the cathode of diode D9, the anode of diode D9 is connected to the base of transistor Q1, and the emitter of transistor Q3 is grounded.

[0035] Specifically, the first and second pins of the terminal U10 are connected to an external load, and the second pin of the terminal U10 is connected to the power supply output voltage. The resistor U14 converts the load current introduced by the terminal U10 into a voltage signal, samples the voltage signal and the power supply output voltage, and then sends the sampled voltage signal to the filter circuit composed of the resistor R3 and the capacitor C10. After filtering and voltage division, the signal is output to the non-inverting input of the third operational amplifier U6. Resistor R2 and capacitor C12 together form a filter circuit, providing a stable reference voltage after filtering to the inverting input of the third operational amplifier U6 (the reference voltage can be adjusted by adjusting the center tap of resistor R2). This allows the third operational amplifier U6 (which is a voltage comparator, preferably LM358) to compare the input sampling voltage with the reference voltage and determine whether the power output is short-circuited or overloaded based on the comparison result. (Under normal operating conditions, the voltage at the non-inverting input of the third operational amplifier U6 is lower than the reference voltage at the inverting input; under short-circuit or overload conditions, the voltage at the non-inverting input of the third operational amplifier U6 exceeds the reference voltage at the inverting input). If the power output is short-circuited or overloaded, the output of the third operational amplifier U6 drives transistor Q3 to conduct, causing diode D9 to conduct momentarily, clamping the base voltage of transistor Q1, and causing transistors Q1 and Q2 to be cut off with no output, thus providing overcurrent or short-circuit protection for the power output.

[0036] In addition, multiple interlocking protection measures can be implemented by connecting a fuse or relay outside the terminal U10. When a fuse is connected outside the terminal U10, if the power output is short-circuited or overloaded, the fuse will blow and the power output will be cut off. When a relay is connected outside the terminal U10, if the power output is short-circuited or overloaded, the relay will disconnect and the power output will be cut off.

[0037] Preferably, the overcurrent protection unit further includes a terminal U11, the first and second pins of which are respectively connected to the two ends of the resistor R5, and the capacitor C13 is connected in parallel with the resistor R5; the first pin of the terminal U11 is grounded, and the second pin of the terminal U11 is connected to the non-inverting input of the third operational amplifier U6.

[0038] Specifically, the first and second pins of the terminal U11 are connected to an external reset switch. When the load returns to normal, the reset switch is manually pressed. At this time, the first and second pins of the terminal U11 are turned on through the external reset switch, providing a reset signal to the circuit. When the reset signal is detected, the protection lockout state inside the circuit is released. The transistors Q1 and Q2, which were originally in the cutoff state due to overcurrent protection, will turn on again according to normal operating conditions, restoring the power supply to the load. At the same time, the comparison state of the third operational amplifier U6 will also return to the normal operating state, and the sampled voltage and the reference voltage will be compared again to continuously monitor whether the circuit will experience overcurrent or short circuit again.

[0039] Preferably, the low-temperature drift precision voltage regulator unit includes a terminal block U17 and a three-terminal adjustable reference source U18; The first pin of the terminal U17 is connected to the third pin of the three-terminal adjustable reference source U18 and one end of the capacitor C34. The other end of the capacitor C34 is grounded. The capacitor C35 is connected in parallel with the capacitor C34. The second pin of the terminal U17 is grounded. The first and second pins of the three-terminal adjustable reference source U18 are respectively connected to the two ends of the resistor R20, and the center tap of the resistor R20 is connected to the first pin of the three-terminal adjustable reference source U18. The capacitor C30 is connected in parallel with the resistor R20. The first pin of the three-terminal adjustable reference source U18 is connected to the third pin of the three-terminal adjustable reference source U18 via the resistor R19, and the third pin of the three-terminal adjustable reference source U18 is connected to the eighth pin of the third operational amplifier U6 via the resistor R18.

[0040] Specifically, the first pin of terminal U17 serves as the manual adjustment reference voltage output terminal, connected to one end of an external precision potentiometer. The other end of the external precision potentiometer is connected to the second pin of terminal U13, and the adjustment terminal of the external precision potentiometer is connected to the first pin of terminal U13 as input. (It is worth noting that the first pin of terminal U13 can be connected to an external D / A output control signal, allowing direct control of terminal U13 via the PLC's D / A output to achieve automatic control; or the first pin of terminal U13 can be connected to a potentiometer, allowing manual control via manual adjustment.) Taking manual adjustment with a potentiometer as an example, the two ends of the potentiometer are connected to terminal U17 and terminal U13 respectively, providing a voltage... The potentiometer provides a precise and stable voltage. The center tap of the potentiometer is connected to the first pin of the terminal U13. When the power is on, adjusting the potentiometer increases the voltage at the first pin of the terminal U13, which is then fed to the third pin of the second operational amplifier U16, increasing the voltage at the sixth pin of the second operational amplifier U16. This voltage is then fed to the third pin of the first operational amplifier U15, increasing the voltage at the sixth pin of the first operational amplifier U15, and finally fed to the base of the transistor Q1. Since transistors Q1 and Q2 form a series-connected composite transistor, the emitter voltage of transistor Q2 increases. This voltage then flows through the external load connected to the terminal U10, forming a loop from the resistor U14 connected to the second pin of the terminal U10 to ground.

[0041] The power supply is input to the three-terminal adjustable reference source U18 via resistors R18 and R19. Resistor R18 is a current-limiting resistor, which limits the current flowing into the three-terminal adjustable reference source U18. Resistors R19 and R20 together form a voltage divider circuit. By adjusting the ratio of resistors R19 and R20, the reference voltage input to the input terminal of the three-terminal adjustable reference source U18 can be changed, thereby adjusting the output voltage of the three-terminal adjustable reference source U18. Then, through the cooperation of capacitors C34 and C35, the fluctuation of the output voltage is filtered out, the power supply ripple is reduced, and a regulated reference source is provided for the second operational amplifier U16. This reference source is transmitted to the terminal U13 via the terminal U17.

[0042] The three-terminal adjustable reference source U18 is preferably a TL431 manufactured by Texas Instruments. The TL431 uses a TO-92 package and features excellent voltage regulation characteristics and a flexible voltage setting range. According to the calculation formula for the TL431... The formula for calculating the reference source output from terminal U17 to terminal U13 can be derived as follows: ,because The value is very small, so the above calculation formula can be simplified to: Since the TL431 has a built-in 2.495V precision voltage regulator, when the input reference voltage is higher than 2.5V, the TL431 will immediately turn on to regulate the output voltage. Therefore, the regulated output value of the TL431 is determined by the voltage division value of R19 and R20. The output value of the TL431 can be changed by adjusting the ratio of resistors R19 and R20, that is, by changing the voltage value of the voltage regulator input from the terminal U13 to the second operational amplifier U16.

[0043] Preferably, the power supply unit includes a terminal block U9, diodes D5, D6, D7, D8, and a voltage regulator U7; The terminal U9 is connected to the secondary winding of the transformer to input AC power; the anode of diode D5 is connected to the first pin of terminal U9 and the cathode of diode D8, the cathode of diode D5 is connected to the cathode of diode D6, the anode of diode D6 is connected to the second pin of terminal U9 and the cathode of diode D7, the anode of diode D7 is connected to the anode of diode D8, and the anode of diode D8 is grounded; The first pin of the voltage regulator U7 is connected to the negative terminal of the diode D5 and one end of the capacitor U3. The other end of the capacitor U3 is grounded, and the capacitor C7 is connected in parallel with the capacitor U3. The second pin of the voltage regulator U7 is grounded. The third pin of the voltage regulator U7 is connected to one end of the capacitor C4 and the eighth pin of the third operational amplifier U6. The other end of the capacitor C4 is grounded, and the capacitors C8 and C11 are both connected in parallel with the capacitor C4.

[0044] Specifically, diodes D5, D6, D7, and D8 form a full-wave bridge rectifier circuit, and capacitors U3 and C7, as well as capacitors C4, C8, and C11, form different capacitor filter circuits. The AC input from the transformer is introduced into the full-wave bridge rectifier circuit formed by diodes D5, D6, D7, and D8 through terminal U9. The full-wave bridge rectifier circuit forms the input AC input and converts it into pulsating DC. Then, the capacitor filter circuit formed by capacitors U3 and C7 smooths the voltage fluctuations and finally outputs a stable DC to the voltage regulator U7. The voltage regulator U7 then regulates the filtered DC and outputs a stable DC voltage. Subsequently, capacitors C4, C8, and C11 further filter the output voltage to remove high-frequency noise, providing a clean and stable power supply for the third operational amplifier U6 and the three-terminal adjustable reference source U18.

[0045] The detailed working process of this embodiment is as follows: The terminal U9 is connected to the secondary winding of the transformer. The AC power input from the secondary winding of the transformer is introduced through the terminal U9 to the full-wave bridge rectifier circuit composed of diodes D5, D6, D7, and D8. The full-wave bridge rectifier circuit converts the input AC power into pulsating DC power. Then, the voltage fluctuation is smoothed by the capacitor filter circuit composed of capacitors U3 and C7, and finally a stable DC power is output to the voltage regulator U7. The voltage regulator U7 regulates the filtered DC power and outputs a stable DC voltage. Subsequently, the output voltage is further filtered by capacitors C4, C8, and C11 to remove high-frequency noise, providing a clean and stable power supply for the third operational amplifier U6 and the three-terminal adjustable reference source U18.

[0046] Next, connect the first and second pins of terminal U10 to an external load, and connect the first and second pins of terminal U11 to an external reset switch. This causes resistor U14 to convert the load current introduced by terminal U10 into a voltage signal, which is then sampled along with the power supply output voltage. The sampled voltage signal is then fed into a filter circuit composed of resistor R3 and capacitor C10. After filtering and voltage division, the signal is output to the non-inverting input of the third operational amplifier U6. The third operational amplifier U6 compares the sampled input voltage with the reference voltage and determines whether the power supply output is short-circuited or overloaded based on the comparison result. If the power supply output is short-circuited or overloaded, the output of the third operational amplifier U6 drives transistor Q3 to conduct, causing diode D9 to conduct momentarily, clamping the... The base voltage of transistor Q1 causes transistors Q1 and Q2 to be cut off, thus providing overcurrent or short-circuit protection for the power output. When the load returns to normal, manually pressing the reset switch will connect the first and second pins of terminal U11 through the external reset switch, providing a reset signal to the circuit. Upon detecting the reset signal, the internal protection lockout is released, and transistors Q1 and Q2, which were originally cut off due to overcurrent protection, will turn on again under normal operating conditions, restoring normal power supply to the load. Simultaneously, the comparison state of the third operational amplifier U6 will return to its normal operating state, re-comparing the sampled voltage and the reference voltage to continuously monitor whether the circuit experiences overcurrent or short-circuit conditions again.

[0047] Simultaneously, the first pin of the terminal U17 is used as the manual adjustment reference voltage output terminal, connected to one end of an external precision potentiometer. The other end of the external precision potentiometer is connected to the second pin of the terminal U13, and the adjustment terminal of the external precision potentiometer is connected to the first pin of the terminal U13. After the power supply is input to the three-terminal adjustable reference source U18 through resistors R18 and R19, the three-terminal adjustable reference source U18 can generate a stable and adjustable reference voltage based on the input voltage and its own adjustment characteristics. This reference voltage is then provided to the second operational amplifier U16 as the voltage reference source of the second operational amplifier U16, providing an accurate voltage reference for the normal operation of the second operational amplifier U16, ensuring that it can perform accurate signal comparison, amplification and other operations based on this reference.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A high-voltage precision adjustable analog linear DC regulated power supply, characterized in that, It includes a signal processing unit, a rectification and filtering unit, a control unit, and a voltage regulation unit, wherein: The signal processing unit is used to receive external signal input, amplify the voltage based on the received external signal, and output it to the control unit; The rectifier and filter unit is used to rectify and filter the input AC power to obtain DC power to supply power to the control unit. The control unit includes a sampling circuit and a first operational amplifier. The sampling circuit is used to sample the power supply output voltage and output a sampling signal to the first operational amplifier. The first operational amplifier is used to receive the sampling signal and the amplified external signal, and to adjust its own output voltage based on the received sampling signal and the external signal to control the output value of the voltage regulator unit. The voltage regulator unit includes an adjustment circuit and a first filter circuit. The adjustment circuit is used to receive the output voltage of the first operational amplifier and to amplify the current step by step based on the received output voltage to adjust its final output voltage. The first filter circuit is used to filter the output voltage of the adjustment circuit and output it.

2. The high-voltage precision adjustable analog linear DC regulated power supply according to claim 1, characterized in that, The signal processing unit includes a terminal block U13 and a second operational amplifier U16; The first pin of the terminal U13 is connected to the third pin of the second operational amplifier U16 via resistor R9, and the second pin of the terminal U13 is grounded; the end of resistor R9 away from the terminal U13 is connected to one end of resistor R10, the other end of resistor R10 is grounded, and capacitor C14 is connected in parallel with resistor R10. The second pin of the second operational amplifier U16 is grounded via resistor R17. The sixth pin of the second operational amplifier U16 is connected to the third pin of the first operational amplifier U15 via resistor R14. The sixth pin of the second operational amplifier U16 is grounded sequentially via resistors R15, R16, and R17, and the center tap of resistor R16 is connected to the end of resistor R16 closest to resistor R15. The end of resistor R14 furthest from the second operational amplifier U16 is connected to one end of resistor R13, and the other end of resistor R13 is grounded. Capacitor C15 is connected in parallel with resistor R13. The fourth pin of the second operational amplifier U16 is grounded. The seventh pin of the second operational amplifier U16 is connected to the seventh pin of the first operational amplifier U15. The first and eighth pins of the second operational amplifier U16 are connected via capacitor C32, and the first pin of the second operational amplifier U16 is grounded.

3. The high-voltage precision adjustable analog linear DC regulated power supply according to claim 1, characterized in that, The rectifier and filter unit includes a rectifier circuit and a second filter circuit, wherein: The rectifier circuit includes a terminal block U8, diodes D1, D2, D3, and D4. Terminal block U8 is connected to the secondary winding of the transformer to input alternating current. The anode of diode D1 is connected to the first pin of terminal block U8 and the cathode of diode D4. The cathode of diode D1 is connected to the cathode of diode D2. The anode of diode D2 is connected to the second pin of terminal block U8 and the cathode of diode D3. The anode of diode D3 is connected to the anode of diode D4, and the anode of diode D4 is grounded. The second filter circuit includes capacitors C1 and C2. One end of capacitor C1 is connected to the negative terminal of diode D1, and the other end of capacitor C1 is grounded. Capacitor C2 is connected in parallel with capacitor C1.

4. The high-voltage precision adjustable analog linear DC regulated power supply according to claim 1, characterized in that, The sampling circuit includes resistors R11 and R12. One end of resistor R11 is connected to the power supply output voltage, and the other end of resistor R11 is connected to one end of resistor R12 and the second pin of the first operational amplifier U15. The other end of resistor R12 is grounded. The second pin of the first operational amplifier U15 is connected to the sixth pin of the first operational amplifier U15 through an RC circuit, which consists of resistor R21 and capacitor C36 in parallel. The sixth pin of the first operational amplifier U15 is grounded through resistor R8, the fourth pin of the first operational amplifier U15 is grounded, and the first and eighth pins of the first operational amplifier U15 are connected through capacitor C33, with the first pin of the first operational amplifier U15 also grounded.

5. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 3, characterized in that, The adjustment circuit includes at least two transistors; The at least two transistors include transistors Q1 and Q2. The base of transistor Q1 is connected to the sixth pin of the first operational amplifier U15 via resistor R7. The collector of transistor Q1 is connected to the seventh pin of the first operational amplifier U15 and the cathode of diode D1. The emitter of transistor Q1 is connected to the base of transistor Q2. The collector of transistor Q2 is connected to the collector of transistor Q1. The emitter of transistor Q2 outputs a regulated voltage.

6. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 5, characterized in that, The first filter circuit includes capacitors U1, U2, U23, C6 and C9. One end of capacitors U1, U23 and C6 is connected to the emitter of transistor Q2, the other end of capacitor U1 is connected to one end of capacitor U2, the other end of capacitor C6 is connected to one end of capacitor C9, and the other end of capacitors U2, U23 and C9 is grounded.

7. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 5, characterized in that, It also includes an overcurrent protection unit, a low-temperature drift precision voltage regulator unit, and a power supply unit, among which: The overcurrent protection unit is used to cut off the output of the adjustment circuit when the power output is short-circuited or overloaded, so as to achieve overcurrent or short-circuit protection. The low-temperature drift precision voltage regulator unit is used to provide the signal processing unit with a high-precision, low-temperature drift stable reference voltage output, and to manually adjust the output voltage according to actual needs. The power supply unit is used to rectify, filter, and regulate the input AC power before supplying power to the overcurrent protection unit and the low-temperature drift precision voltage regulator unit.

8. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 7, characterized in that, The overcurrent protection unit includes a terminal block U10 and a third operational amplifier U6; The first pin of the terminal U10 is connected to the third pin of the third operational amplifier U6 via resistor R3, and the first pin of the terminal U10 is grounded via resistor U14; the second pin of the terminal U10 is connected to the power supply output voltage; one end of the capacitor C10 is connected to the end of resistor R3 away from resistor U14, and the other end of the capacitor C10 is grounded. The second pin of the third operational amplifier U6 is grounded via resistor R2, the center tap of resistor R2 is grounded, capacitor C12 is connected in parallel with resistor R2, and the second pin of the third operational amplifier U6 is connected to the eighth pin of the third operational amplifier U6 via resistor R1; the fourth pin of the third operational amplifier U6 is grounded, the first pin of the third operational amplifier U6 is connected to the third pin of the third operational amplifier U6 via resistor R4, and the first pin of the third operational amplifier U6 is connected to the base of transistor Q3 via resistor R6; the collector of transistor Q3 is connected to the cathode of diode D9, the anode of diode D9 is connected to the base of transistor Q1, and the emitter of transistor Q3 is grounded.

9. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 8, characterized in that, The low-temperature drift precision voltage regulator unit includes a terminal block U17 and a three-terminal adjustable reference source U18; The first pin of the terminal U17 is connected to the third pin of the three-terminal adjustable reference source U18 and one end of the capacitor C34. The other end of the capacitor C34 is grounded. The capacitor C35 is connected in parallel with the capacitor C34. The second pin of the terminal U17 is grounded. The first and second pins of the three-terminal adjustable reference source U18 are respectively connected to the two ends of the resistor R20, and the center tap of the resistor R20 is connected to the first pin of the three-terminal adjustable reference source U18. The capacitor C30 is connected in parallel with the resistor R20. The first pin of the three-terminal adjustable reference source U18 is connected to the third pin of the three-terminal adjustable reference source U18 via the resistor R19, and the third pin of the three-terminal adjustable reference source U18 is connected to the eighth pin of the third operational amplifier U6 via the resistor R18.

10. A high-voltage precision adjustable analog linear DC regulated power supply according to claim 9, characterized in that, The power supply unit includes terminal block U9, diodes D5, D6, D7, D8 and voltage regulator U7; The terminal U9 is connected to the secondary winding of the transformer to input AC power; the anode of diode D5 is connected to the first pin of terminal U9 and the cathode of diode D8, the cathode of diode D5 is connected to the cathode of diode D6, the anode of diode D6 is connected to the second pin of terminal U9 and the cathode of diode D7, the anode of diode D7 is connected to the anode of diode D8, and the anode of diode D8 is grounded; The first pin of the voltage regulator U7 is connected to the negative terminal of the diode D5 and one end of the capacitor U3. The other end of the capacitor U3 is grounded, and the capacitor C7 is connected in parallel with the capacitor U3. The second pin of the voltage regulator U7 is grounded. The third pin of the voltage regulator U7 is connected to one end of the capacitor C4 and the eighth pin of the third operational amplifier U6. The other end of the capacitor C4 is grounded, and the capacitors C8 and C11 are both connected in parallel with the capacitor C4.

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