High-precision constant current source with remote control function

Abstract

The utility model discloses a high-precision constant current source with a remote control function. The high-precision constant current source comprises an alternating current input circuit, a transformer, a rectifying and filtering circuit, a linear adjusting circuit, an output filtering circuit and a constant current output circuit which are connected in sequence, the linear adjustment circuit comprises a constant current power circuit and a constant current control circuit, and the constant current control circuit controls the constant current power circuit to realize constant output current; the output quantity sampling circuit is used for sampling current and voltage values of constant-current output and transmitting sampling information to the MCU control circuit, and the MCU control circuit is used for controlling the constant-current control circuit; and a remote computer realizes data communication with the MCU control circuit through the communication interface circuit. The beneficial effects of the utility model are that the power grid adaptive capacity is strong, the output constant current precision is high, the output ripple voltage is low, the output current is large, the reliability is high, the short-circuit constant current is supported, the computer remote control can be realized, and the power grid adaptive capacity is strong; all-metal sealing and solid potting are achieved, and harsh use environment resistance is achieved.

Description

Technical Field

[0001] This utility model relates to a power supply circuit, specifically, to a high-precision constant current source circuit with remote control function. Background Technology

[0002] A linear constant current power supply is a type of constant output current source. It utilizes the linear amplification principle of a regulating transistor, adjusting the output voltage by regulating the line voltage drop of the transistor, thereby achieving a constant output current. Its constant current accuracy and response speed are far superior to other constant current power supplies. However, traditional linear constant current sources can only achieve relative constant current, meaning that constant current control is lost when the load approaches a short circuit. Traditional constant current power supplies require adjusting the output current limit value during use, or can only achieve local control adjustment through potentiometers or external circuits, but cannot implement remote monitoring of output parameters. Utility Model Content

[0003] This utility model is designed to solve the above-mentioned technical problems by providing a highly reliable, integrated, high-precision constant current source with remote control function and supporting short-circuit constant current.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A high-precision constant current source with remote control capability includes an AC input circuit, a transformer, a rectifier and filter circuit, a linear adjustment circuit, an output filter circuit, and a constant current output circuit connected in sequence. The linear adjustment circuit includes a constant current power circuit and a constant current control circuit. The constant current power circuit is controlled by the constant current control circuit to achieve a constant output current. The output quantity sampling circuit samples the current and voltage values ​​of the constant current output and transmits the sampling information to the MCU control circuit, which then controls the constant current control circuit. A remote computer communicates with the MCU control circuit via a communication interface circuit.

[0006] The high-precision constant current source with remote control function includes a constant current power circuit comprising cascaded transistors Q1 and Q2, diode D11, resistors R* and R20, and capacitors C11, C12, and C13. The collectors of the cascaded transistors Q1 and Q2 are connected to the output of the rectifier and filter circuit. The base of transistor Q1 is connected to the constant current control circuit drive output connection point b. The emitter of transistor Q2, i.e., connection point I, is connected to the positive input terminal of the output filter circuit, i.e., connection point R, through the voltage divider resistor R20. The positive input terminal of the output filter circuit is connected to the negative terminal of diode D11, one end of capacitor C12, and the positive terminal of C13, respectively. The negative input terminal of the output filter circuit is connected to the positive terminal of diode D11, the other end of capacitor C12, and the negative terminal of C13, respectively. One end of the parallel connection of resistor R* and capacitor C11 is connected to the negative input terminal of the output filter circuit, and the other end is connected to the constant current control circuit adjustment output connection point ADJ.

[0007] The high-precision constant current source with remote control function has a constant current control circuit that samples the output voltage through the voltage divider resistor R20 at the constant current output terminal and then feeds it back to the non-inverting input of the operational amplifier IC3-1. That is, connection point I is connected to the non-inverting input of the operational amplifier IC3-1 through capacitor C5. It is compared with the reference voltage of the inverting input. After the output signal is amplified, it controls the base current of the transistor Q3 to adjust the on-resistance of the transistor Q3, thereby adjusting the output voltage and achieving a relatively stable output voltage.

[0008] The constant current control circuit samples the output current through a sampling resistor R20 connected in series on the output line. The current signal is converted into a voltage signal and fed back to the non-inverting input of the operational amplifier IC3-2 through the series resistor R8. The voltage signal is compared with the reference voltage at the inverting input. After the output signal is amplified, it controls the base current of the transistor to adjust the on-resistance of the transistor, thereby adjusting the output voltage and achieving a constant output current. The regulated output is then filtered by a filter capacitor before being supplied to the load.

[0009] The high-precision constant current source with remote control function uses a power frequency transformer to achieve isolation and voltage reduction.

[0010] The high-precision constant current source with remote control function adopts an RS485 / 232 interface for communication interface circuit. The computer can remotely control and read parameters through the RS485 / 232 interface to realize remote control of the MCU control circuit.

[0011] The high-precision constant current source with remote control function adopts an all-metal seal and solid potting structure.

[0012] This invention relates to an online integrated monolithic linear regulated power supply. The input voltage is stepped down using a power frequency transformer, and the DC output voltage is adjusted using an operational amplifier and a regulating transistor to achieve a constant output current. Short-circuit constant current is achieved by utilizing the positive and negative power supplies of the amplifier. It connects to a computer via a 485 / 232 converter interface, and displays and outputs the voltage and current on a monitor. The output voltage and current can be adjusted via commands sent from the computer. The power supply employs solid potting and a fully sealed metal structure to improve environmental adaptability.

[0013] The working process of this utility model is as follows: The 220V AC input is first isolated and stepped down by a power frequency transformer to meet the low voltage drop requirement of the subsequent regulating transistor. It is then converted into pulsating DC by a rectifier and filter circuit. A voltage regulation control circuit composed of operational amplifiers adjusts the base current of the transistor to regulate the output voltage. Output sampling uses a resistor connected in series in the output line. Changes in output current are detected by monitoring the voltage change across the sampling resistor, and this feedback is sent to the adjustment circuit to adjust the output voltage. This allows for adaptive adjustment of the output voltage when the load changes, achieving a constant output current. An A / D conversion unit collects various parameters of the power supply output and sends them to a computer via a 485 / 232 conversion interface. These parameters are then displayed on a monitor. The computer transmits control commands to a D / A conversion unit via the 485 / 232 conversion interface. After conversion by the D / A conversion unit, the output voltage and output current of the power supply are adjusted.

[0014] Compared with traditional constant current sources, this invention has the following advantages:

[0015] 1. Online working mode, directly connected to the municipal power grid.

[0016] 2. Constant current accuracy is higher than 5‰.

[0017] 3. Supports short-circuit constant current mode.

[0018] 4. Remote computer control and reading of output values.

[0019] 5. All-metal seal, solid potting, resistant to harsh operating environments.

[0020] 6. Strong compatibility with power grid.

[0021] The beneficial effects of this utility model are: it has high constant current accuracy, can output constant current at 0V, supports short-circuit constant current, can realize computer remote control, and has strong power grid adaptability. It is fully metal sealed, solidly potted, and resistant to harsh operating environments. Attached Figure Description

[0022] Figure 1 This is a circuit block diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the input power frequency step-down and rectification filter circuit of this utility model;

[0024] Figure 3 This is the schematic diagram of the constant current power circuit of this utility model;

[0025] Figure 4 This is a schematic diagram of the constant current control circuit of this utility model. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 As shown, this utility model discloses a high-precision constant current source with remote control function, comprising an AC input circuit, a transformer, a rectifier and filter circuit, a linear adjustment circuit, an output filter circuit, and a constant current output circuit connected in sequence. The linear adjustment circuit includes a constant current power circuit and a constant current control circuit. The constant current power circuit is controlled by the constant current control circuit to achieve a constant output current. The output quantity sampling circuit samples the current and voltage values ​​of the constant current output and transmits the sampling information to the MCU control circuit, which in turn controls the constant current control circuit. A remote computer communicates with the MCU control circuit via a communication interface circuit.

[0028] The high-precision constant current source with remote control function, such as Figure 3 As shown, the constant current power circuit includes cascaded transistors Q1 and Q2, diode D11, resistors R* and R20, and capacitors C11, C12, and C13. The collectors of the cascaded transistors Q1 and Q2 are connected to the output of the rectifier and filter circuit. The base of transistor Q1 is connected to the output connection point b of the constant current control circuit. The emitter of transistor Q2, i.e., connection point I, is connected to the positive input terminal of the output filter circuit, i.e., connection point R, through the voltage divider resistor R20. The positive input terminal of the output filter circuit is connected to the negative terminal of diode D11, one end of capacitor C12, and the positive terminal of C13, respectively. The negative input terminal of the output filter circuit is connected to the positive terminal of diode D11, the other end of capacitor C12, and the negative terminal of C13, respectively. One end of the parallel connection of resistor R* and capacitor C11 is connected to the negative input terminal of the output filter circuit, and the other end is connected to the constant current control circuit to adjust the output connection point ADJ.

[0029] The high-precision constant current source with remote control function, such as Figure 4 As shown, the constant current control circuit samples the output voltage through the voltage divider resistor R20 at the constant current output terminal, and then feeds it back to the non-inverting input of the operational amplifier IC3-1. That is, connection point I is connected to the non-inverting input of the operational amplifier IC3-1 through capacitor C5. It is compared with the reference voltage of the inverting input. After the output signal is amplified, it controls the base current of transistor Q3 to adjust the on-resistance of transistor Q3, thereby adjusting the output voltage and achieving a relatively stable output voltage.

[0030] The constant current control circuit samples the output current through a sampling resistor R20 connected in series on the output line. The current signal is converted into a voltage signal and fed back to the non-inverting input of the operational amplifier IC3-2 through the series resistor R8. The voltage signal is compared with the reference voltage at the inverting input. After the output signal is amplified, it controls the base current of the transistor to adjust the on-resistance of the transistor, thereby adjusting the output voltage and achieving a constant output current. The regulated output is then filtered by a filter capacitor before being supplied to the load.

[0031] The high-precision constant current source with remote control function uses a power frequency transformer to achieve isolation and voltage reduction.

[0032] The high-precision constant current source with remote control function adopts an RS485 / 232 interface for communication interface circuit. The computer can remotely control and read parameters through the RS485 / 232 interface to realize remote control of the MCU control circuit.

[0033] The high-precision constant current source with remote control function adopts an all-metal seal and solid potting structure.

[0034] The working process and specific connection method of the high-precision constant current source with remote control function: The AC input voltage of the high-precision constant current source with remote control function first enters the power frequency transformer. The power frequency transformer adopts the grid compatibility design and has strong overload capacity, which greatly improves the grid adaptability of the power supply.

[0035] The power frequency AC voltage, stepped down by the power frequency transformer, is rectified by the rectifier bridge to become pulsating DC. After being filtered by the filter capacitor bank, it enters the voltage regulation circuit, such as... Figure 2 As shown.

[0036] The constant current control circuit consists of an operational amplifier, transistors, etc. It samples the output voltage through a voltage divider resistor at the output terminal, then feeds it back to the non-inverting input of operational amplifier 1. This sampled voltage is compared with the reference voltage at the inverting input. The amplified output signal controls the base current of the transistor, adjusting its on-resistance and thus the output voltage, achieving relative stability. Similarly, it samples the output current through a sampling resistor connected in series on the output line, then feeds it back to the non-inverting input of operational amplifier 2. This sampled current is compared with the reference voltage at the inverting input. The amplified output signal controls the base current of the transistor, adjusting its on-resistance and thus the output voltage, achieving a constant output current. The regulated output is then filtered by a filter capacitor before being supplied to the load.

[0037] like Figure 4 As shown, the constant current control circuit is connected as follows: the positive terminal of rectifier bridge B1 is connected to the Vin terminal of IC1 and the positive terminal of C1, and the negative terminal is connected to the ground of IC1, the negative terminal of C1, the negative terminal of C2, the Vout terminal of IC2, the anode of D1, the cathode of D2, R12, the positive terminal of C5, R5 and contact I; the Vout terminal of IC1 is connected to the positive terminal of C2, R1 and pin 8 of operational amplifier; one end of R3 is connected to R2 and the non-inverting input of operational amplifier 1, and the other end is connected in series with R13 and then connected to contact ADJ; the inverting input of operational amplifier 1 is connected between R4 and R5, and the output terminal is connected in series with R6 and then connected to contact b.

[0038] The positive terminal of rectifier bridge B2 is connected to the Vin terminal of IC2 and the positive terminal of C3. The negative terminal is connected to the ground of IC2, the negative terminal of C3, the negative terminal of C4, R11, pin 4 of operational amplifier, and the emitter of Q3. The Vout terminal of IC2 is connected to the positive terminal of C4, the cathode of D2, R12, and the positive terminal of C5. The non-inverting terminal of operational amplifier 2 is connected to the negative terminal of C5, the other end of R12, and R10. The other end of R10 is connected between the anode of D2 and R11. The inverting terminal of operational amplifier is connected to contact R after being connected in series with R8. A decoupling capacitor C6 is connected between the inverting terminal and the output terminal. The output terminal is connected to the base of Q3 after being connected in series with R9. The collector of Q3 is connected to contact b.

[0039] This utility model is not limited to the above-described preferred embodiments. Any other products that are the same as or similar to this utility model and derived by anyone under the guidance of this utility model shall fall within the protection scope of this utility model.

Claims

1. A high-precision constant current source with remote control function, comprising an AC input circuit, a transformer, a rectifier and filter circuit, a linear adjustment circuit, an output filter circuit, and a constant current output circuit connected in sequence; characterized in that: The linear adjustment circuit includes a constant current power circuit and a constant current control circuit. The constant current control circuit controls the constant current power circuit to achieve a constant output current. The output sampling circuit samples the current and voltage values ​​of the constant current output and transmits the sampling information to the MCU control circuit, which in turn controls the constant current control circuit. A remote computer communicates with the MCU control circuit via a communication interface circuit.

2. The high-precision constant current source with remote control function according to claim 1, characterized in that: The constant current power circuit includes cascaded transistors Q1 and Q2, diode D11, resistors R* and R20, and capacitors C11, C12, and C13. The collectors of the cascaded transistors Q1 and Q2 are connected to the output of the rectifier and filter circuit. The base of transistor Q1 is connected to the constant current control circuit drive output connection point b. The emitter of transistor Q2, i.e., connection point I, is connected to the positive input terminal of the output filter circuit, i.e., connection point R, through the voltage divider resistor R20. The positive input terminal of the output filter circuit is connected to the negative terminal of diode D11, one end of capacitor C12, and the positive terminal of C13, respectively. The negative input terminal of the output filter circuit is connected to the positive terminal of diode D11, the other end of capacitor C12, and the negative terminal of C13, respectively. One end of the parallel connection of resistor R* and capacitor C11 is connected to the negative input terminal of the output filter circuit, and the other end is connected to the constant current control circuit to adjust the output connection point ADJ.

3. The high-precision constant current source with remote control function according to claim 1, characterized in that: The constant current control circuit samples the output voltage through the voltage divider resistor R20 at the constant current output terminal, and then feeds it back to the non-inverting input of the operational amplifier IC3-1. That is, connection point I is connected to the non-inverting input of the operational amplifier IC3-1 through capacitor C5. It is compared with the reference voltage of the inverting input. After the output signal is amplified, it controls the base current of transistor Q3 to adjust the on-resistance of transistor Q3, thereby adjusting the output voltage and achieving a relatively stable output voltage. The constant current control circuit samples the output current through a sampling resistor R20 connected in series on the output line. The current signal is converted into a voltage signal and fed back to the non-inverting input of the operational amplifier IC3-2 through the series resistor R8. The voltage signal is compared with the reference voltage at the inverting input. After the output signal is amplified, it controls the base current of the transistor to adjust the on-resistance of the transistor, thereby adjusting the output voltage and achieving a constant output current. The regulated output is then filtered by a filter capacitor before being supplied to the load.

4. The high-precision constant current source with remote control function according to claim 1, characterized in that: The transformer is a power frequency transformer, which achieves isolation and voltage reduction.

5. The high-precision constant current source with remote control function according to claim 1, characterized in that: The communication interface circuit adopts an RS485 / 232 interface. The computer can remotely control and read parameters through the RS485 / 232 interface to realize remote control of the MCU control circuit.

6. The high-precision constant current source with remote control function according to claim 1, characterized in that: The high-precision constant current source adopts an all-metal seal and a solid potting structure.

Images