Wide current range precision CNC DC power supply

Abstract

This utility model discloses a wide-range precision CNC DC power supply, including an input terminal group, a current detection circuit, a sampling circuit, a control circuit, and a filter circuit. The input terminal group includes a first input terminal and a second input terminal. The first input terminal is grounded through the sampling circuit, which is electrically connected to the control circuit and the current detection circuit. The sampling circuit is also electrically connected to the filter circuit. The sampling circuit includes a first sampling resistor and a second sampling resistor. The first input terminal is grounded sequentially through the first and second sampling resistors. In this utility model, by switching between a first field-effect transistor and a second field-effect transistor, the microcontroller enters a microampere sampling mode when the sampled current is less than 2mA, and otherwise samples and controls a large current, thus achieving microampere-level current control. The current detection circuit enables accurate detection of microampere-level current, improving control accuracy.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to a precision numerically controlled DC power supply with a wide current range. Background Technology

[0002] Existing digitally controlled adjustable DC power supplies generally lack a current measurement range of 1mA-5A, which is insufficient for the low-power supply and measurement functions of modern power supply equipment. Power supplies with a current ratio reaching the microamplitude level would cost over 5000 yuan. Some applications require a combination of a standard power supply and a microamplitude-level multimeter to meet low-power measurement needs. Utility Model Content

[0003] To overcome the above-mentioned shortcomings, this utility model provides a precision CNC DC power supply with a wide current range.

[0004] This utility model achieves the above objectives through the following technical solutions:

[0005] A precision numerically controlled DC power supply with a wide current range includes an input terminal group, a current detection circuit, a sampling circuit, a control circuit, and a filter circuit. The input terminal group includes a first input terminal and a second input terminal. The first input terminal is grounded through the sampling circuit. The sampling circuit is electrically connected to the control circuit and is electrically connected to the current detection circuit. The second input terminal is electrically connected to the filter circuit.

[0006] The sampling circuit includes a first sampling resistor and a second sampling resistor, and the first input terminal is grounded through the first sampling resistor and the second sampling resistor in sequence;

[0007] The signal input terminal of the current detection circuit is electrically connected to the first sampling resistor and the second sampling resistor, respectively.

[0008] The control circuit includes a first field-effect transistor, a second field-effect transistor, and a driving circuit. The gates of both the first and second field-effect transistors are electrically connected to a driving circuit. The drains of both the first and second field-effect transistors are grounded. The sources of the first and second field-effect transistors are electrically connected to a first sampling resistor and a second sampling resistor, respectively.

[0009] Preferably, the filter circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a third diode, an inductor, a first indicator light, a second indicator light, and a third indicator light. The second input terminal is electrically connected to the first indicator light, the second indicator light, and the third indicator light through the inductor. The seventh capacitor is connected in parallel between the first indicator light and the second indicator light, and the eighth capacitor is connected in parallel between the second indicator light and the third indicator light. One end of the inductor is grounded through the third capacitor and the fourth capacitor, and the other end of the inductor is grounded through the fifth capacitor, the sixth capacitor, and the third diode. The cathode of the third diode is grounded.

[0010] Preferably, the gate of the first field-effect transistor is electrically connected to a protection circuit, which includes an eighth resistor and a ninth resistor. The gate of the first field-effect transistor is connected to an external 8V DC power supply through the eighth resistor, and the gate of the first field-effect transistor is grounded through the ninth resistor. The protection circuit is a power-on protection circuit, which can protect the first field-effect transistor from power-on and solves the problem of irregular voltage output when the device is uncontrollable at the moment of power-on.

[0011] Preferably, the second sampling resistor is connected in parallel with a first diode and a second diode. The cathodes of the first diode and the second diode are both grounded. The first diode and the second diode serve to protect the second sampling resistor.

[0012] Preferably, the current detection circuit includes a first integrated circuit, a first resistor, a second resistor, a first capacitor, and a second capacitor. The first integrated circuit is model INA199A2DCKR. The first, second, and fifth terminals of the first integrated circuit are all grounded. The third terminal of the first integrated circuit is connected to an external 8V DC power supply. The third terminal of the first integrated circuit is grounded through the second capacitor. The third terminal of the first integrated circuit is connected to the first and second sampling resistors through the second resistor. The fourth terminal of the first integrated circuit is connected to the first and second sampling resistors. The sixth terminal of the first integrated circuit is grounded through the first resistor and the first capacitor. The current in the first sampling circuit, when a 1-2mA current passes through the dedicated current sampling first integrated circuit, is amplified 100 times, and then sampled by a 16-bit ADC, a current of 0.1 microamps can be distinguished.

[0013] Preferably, the driving circuit includes a second integrated circuit, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor. The second integrated circuit is an LMV331. The first terminal of the second integrated circuit is electrically connected to the seventh resistor, the second terminal of the second integrated circuit is grounded, the third terminal of the second integrated circuit is connected to an external 8V DC power supply through the fifth resistor, the third terminal of the second integrated circuit is grounded through the sixth resistor, the fifth terminal of the second integrated circuit is connected to an external 8V DC power supply through the third resistor, and the fourth terminal of the second integrated circuit is grounded through the fourth resistor.

[0014] The beneficial effects of this utility model are as follows: In this wide-range precision numerical control DC power supply, by switching between the first field-effect transistor and the second field-effect transistor, the microcontroller enters the micro-ampere sampling mode when the sampled current is less than 2mA, and otherwise samples and controls the large current, thereby realizing the control of the micro-ampere level current. At the same time, the current detection circuit can realize the accurate detection of the micro-ampere level current, improving the accuracy of control. Attached Figure Description

[0015] This utility model will be described by way of example and with reference to the accompanying drawings, wherein:

[0016] Figure 1 This is the circuit schematic diagram of this utility model;

[0017] Figure 2 This is a circuit diagram of the current detection circuit of this utility model;

[0018] Figure 3 This is a circuit diagram of the driving circuit of this utility model. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0020] like Figures 1-3As shown, a wide-range precision digitally controlled DC power supply includes an input terminal group, a current detection circuit, a sampling circuit, a control circuit, and a filter circuit. The input terminal group includes a first input terminal P1 and a second input terminal P2. The first input terminal P1 is grounded through the sampling circuit, which is electrically connected to the control circuit and the current detection circuit. The second input terminal P2 is electrically connected to the filter circuit. The sampling circuit includes a first sampling resistor RM1 and a second sampling resistor RM2. The first input terminal P1 is grounded through the first sampling resistor RM1 and the second sampling resistor RM2 in sequence. The signal input terminal of the current detection circuit is electrically connected to the first sampling resistor RM1 and the second sampling resistor RM2, respectively. The control circuit includes a first field-effect transistor Q1, a second field-effect transistor Q2 and a driving circuit. The gates of the first field-effect transistor Q1 and the second field-effect transistor Q2 are both electrically connected to a driving circuit. The drains of the first field-effect transistor Q1 and the second field-effect transistor Q2 are both grounded. The sources of the first field-effect transistor Q1 and the second field-effect transistor Q2 are electrically connected to the first sampling resistor RM1 and the second sampling resistor RM2, respectively.

[0021] In this wide-range precision CNC DC power supply, a standard 2mA-5A current sampling resistor (first sampling resistor RM1) and a microamp 1μA-2mA sampling resistor (second sampling resistor RM2) are connected in series. These are switched by a first field-effect transistor (FET) Q1 and a second FET Q2. The microcontroller switches between FETs based on the current sampled: if the current is less than 2mA, it enters microamp sampling mode; otherwise, it performs high-current sampling and control. The circuit uses an 8V power supply, which allows for better low-resistance conduction characteristics of the FETs.

[0022] The first sampling resistor RM1 has a value of 0.1 milliohms and the second sampling resistor RM2 has a value of 12 ohms. The first field-effect transistor Q1 and the second field-effect transistor Q2 with low on-resistance are connected in parallel. Turning on the first sampling resistor RM1 (0.1 milliohms) can minimize the impact of the second sampling resistor RM2 (12 ohms) on the high-current sampling resistor. Compared with ordinary field-effect transistors (100m8), the signal-to-noise ratio is at least 10 times better.

[0023] Specifically, the filter circuit includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a third diode D3, an inductor L1, a first indicator LED1, a second indicator LED2, and a third indicator LED3. The second input terminal P2 is electrically connected to the first indicator LED1, the second indicator LED2, and the third indicator LED3 through the inductor L1. The seventh capacitor C7 is connected in parallel between the first indicator LED1 and the second indicator LED2. The eighth capacitor C8 is connected in parallel between the second indicator LED2 and the third indicator LED3. One end of the inductor L1 is grounded through the third capacitor C3 and the fourth capacitor C4, and the other end of the inductor L1 is grounded through the fifth capacitor C5, the sixth capacitor C6, and the third diode D3. The cathode of the third diode D3 is grounded.

[0024] Specifically, the gate of the first field-effect transistor Q1 is electrically connected to a protection circuit, which includes an eighth resistor R8 and a ninth resistor R9. The gate of the first field-effect transistor Q1 is connected to an external 8V DC power supply through the eighth resistor R8, and the gate of the first field-effect transistor Q1 is grounded through the ninth resistor R9. The protection circuit is a power-on protection circuit, which can protect the first field-effect transistor Q1 from power-on and solve the problem of irregular voltage output when the device is uncontrollable at the moment of power-on.

[0025] Specifically, the second sampling resistor RM2 is connected in parallel with a first diode D1 and a second diode D2. The cathodes of the first diode D1 and the second diode D2 are both grounded. The first diode D1 and the second diode D2 serve to protect the second sampling resistor RM2.

[0026] Specifically, the current detection circuit includes a first integrated circuit U1, a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2. The first integrated circuit U1 is model INA199A2DCKR. The first, second, and fifth terminals of the first integrated circuit U1 are all grounded. The third terminal of the first integrated circuit U1 is connected to an external 8V DC power supply and is grounded through the second capacitor C2. The third terminal of the first integrated circuit U1 is connected to the first sampling resistor RM1 and the second sampling resistor RM2 through the second resistor R2. The fourth terminal of the first integrated circuit U1 is connected to the first sampling resistor RM1 and the second sampling resistor RM2. The sixth terminal of the first integrated circuit U1 is grounded through the first resistor R1 and the first capacitor C1. The current in the first sampling circuit, when a 1-2mA current passes through the dedicated current sampling first integrated circuit U1, is amplified 100 times, and then sampled by a 16-bit ADC, a current of 0.1 microamps can be distinguished.

[0027] Specifically, the driving circuit includes a second integrated circuit U2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The second integrated circuit U2 is an LMV331. The first terminal of the second integrated circuit U2 is electrically connected to the seventh resistor R7, and the second terminal of the second integrated circuit U2 is grounded. The third terminal of the second integrated circuit U2 is connected to an external 8V DC power supply through the fifth resistor R5, and the third terminal of the second integrated circuit U2 is grounded through the sixth resistor R6. The fourth terminal of the second integrated circuit U2 is connected to an external 8V DC power supply through the third resistor R3, and the fourth terminal of the second integrated circuit U2 is grounded through the fourth resistor R4.

[0028] Based on the above description and inspired by this utility model, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A precision CNC DC power supply with a wide current range, characterized in that: It includes an input terminal group, a current detection circuit, a sampling circuit, a control circuit, and a filter circuit. The input terminal group includes a first input terminal and a second input terminal. The first input terminal is grounded through the sampling circuit. The sampling circuit is electrically connected to the control circuit and is electrically connected to the current detection circuit. The second input terminal is electrically connected to the filter circuit. The sampling circuit includes a first sampling resistor and a second sampling resistor, and the first input terminal is grounded through the first sampling resistor and the second sampling resistor in sequence; The signal input terminal of the current detection circuit is electrically connected to the first sampling resistor and the second sampling resistor, respectively. The control circuit includes a first field-effect transistor, a second field-effect transistor, and a driving circuit. The gates of both the first and second field-effect transistors are electrically connected to a driving circuit. The drains of both the first and second field-effect transistors are grounded. The sources of the first and second field-effect transistors are electrically connected to a first sampling resistor and a second sampling resistor, respectively.

2. The wide current range precision numerically controlled DC power supply according to claim 1, characterized in that: The filter circuit includes a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a third diode, an inductor, a first indicator light, a second indicator light, and a third indicator light. The second input terminal is electrically connected to the first, second, and third indicator lights via the inductor. The seventh capacitor is connected in parallel between the first and second indicator lights, and the eighth capacitor is connected in parallel between the second and third indicator lights. One end of the inductor is grounded via the third and fourth capacitors, and the other end of the inductor is grounded via the fifth, sixth, and third diodes. The cathode of the third diode is grounded.

3. The wide current range precision numerically controlled DC power supply according to claim 1, characterized in that: The gate of the first field-effect transistor is electrically connected to a protection circuit, which includes an eighth resistor and a ninth resistor. The gate of the first field-effect transistor is connected to an external 8V DC power supply through the eighth resistor, and the gate of the first field-effect transistor is grounded through the ninth resistor.

4. The wide current range precision numerically controlled DC power supply according to claim 1, characterized in that: The second sampling resistor is connected in parallel with a first diode and a second diode, and the cathodes of the first diode and the second diode are both grounded.

5. The wide current range precision numerically controlled DC power supply according to claim 1, characterized in that: The current detection circuit includes a first integrated circuit, a first resistor, a second resistor, a first capacitor, and a second capacitor. The first integrated circuit is model INA199A2DCKR. The first, second, and fifth terminals of the first integrated circuit are all grounded. The third terminal of the first integrated circuit is connected to an external 8V DC power supply. The third terminal of the first integrated circuit is grounded through the second capacitor. The third terminal of the first integrated circuit is connected to the first sampling resistor and the second sampling resistor through the second resistor. The fourth terminal of the first integrated circuit is connected to the first sampling resistor and the second sampling resistor. The sixth terminal of the first integrated circuit is grounded through the first resistor and the first capacitor.

6. The wide current range precision numerically controlled DC power supply according to claim 1, characterized in that: The driving circuit includes a second integrated circuit, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and a seventh resistor. The second integrated circuit is an LMV331. The first terminal of the second integrated circuit is electrically connected to the seventh resistor, and the second terminal of the second integrated circuit is grounded. The third terminal of the second integrated circuit is connected to an external 8V DC power supply through the fifth resistor, and the third terminal of the second integrated circuit is grounded through the sixth resistor. The fourth terminal of the second integrated circuit is connected to an external 8V DC power supply through the third resistor, and the fourth terminal of the second integrated circuit is grounded through the fourth resistor.

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