High-speed constant-current control circuit and power supply

Abstract

The utility model discloses a high-speed constant-current control circuit and a power supply. The high-speed constant-current control circuit comprises an operational amplifier U1, an MOS tube Q1, a triode Q2, a diode D1, and resistors R1 to R6. One end of the resistor R1 and one end of the resistor R2 are connected with a constant current control signal, the other end of the resistor R1 is connected with a pin 1 of the U1, the other end of the resistor R2 is connected with a pin 2 of the U1, one end of the R3 and one end of the R4, a pin 3 of the U1 is connected with a base electrode of the Q2 and a cathode of the D1, a collector electrode of the Q2 is connected with a power supply, an emitting electrode of the Q2 is connected with one end of the R5, an anode of the D1 and the other end of the R5 are connected with a grid electrode of the Q1, a source electrode of the tube Q1 is connected with the other end of the R6 and the other end of the R3, and a drain electrode of the Q1 is connected with a tested product. And the other end of the R4 is connected with the other end of the R6 and a tested product. According to the utility model, the constant-current high-speed change can be realized, and the constant-current high precision can be ensured.

Description

Technical Field

[0001] This utility model relates to the field of DC power supply electronic load technology, and in particular to a high-speed constant current control circuit and power supply. Background Technology

[0002] In existing technologies, methods for achieving high-precision control generally have low control speeds, and high-speed control schemes generally cannot meet the requirements of high precision. Achieving both high speed and high control accuracy with a constant current output control slope is a problem that current solutions cannot solve.

[0003] Therefore, there is an urgent need for a solution that is simple in structure, low in cost, and can achieve high-speed constant current control without sacrificing control accuracy. Utility Model Content

[0004] The main purpose of this invention is to propose a high-speed constant current control circuit and power supply, which aims to achieve both high-speed constant current variation and high-precision constant current control.

[0005] To achieve the above objectives, this utility model provides a high-speed constant current control circuit, including: an operational amplifier U1, a MOSFET Q1, a transistor Q2, a diode D1, a current sampling resistor R6, and resistors R1, R2, R3, R4, and R5.

[0006] In this configuration, one end of resistor R1 is connected to a constant current control signal, and the other end is connected to pin 1 of operational amplifier U1. One end of resistor R2 is connected to a constant current control signal, and the other end is connected to pin 2 of operational amplifier U1, one end of resistor R3, and one end of resistor R4. Pin 3 of operational amplifier U1 is connected to the base of transistor Q2 and the cathode of diode D1. The collector of transistor Q2 is connected to the power supply. The emitter of transistor Q2 is connected to one end of resistor R5 and the anode of diode D1. The other end of resistor R5 is connected to the gate of MOSFET Q1. The source of MOSFET Q1 is connected to one end of resistor R6 and the other end of resistor R3. The drain of MOSFET Q1 is connected to the product under test. The other end of resistor R4 is connected to the other end of resistor R6 and the product under test.

[0007] A further technical solution of this utility model is that it also includes a capacitor C1, one end of which is connected to the other end of the resistor R1 and pin 1 of the operational amplifier U1, and the other end of which is connected to pin 3 of the operational amplifier U1.

[0008] To achieve the above objectives, this utility model also proposes a power supply, which includes the high-speed constant current control circuit described above.

[0009] The high-speed constant current control circuit and power supply of this utility model, through the above technical solution, can achieve both high-speed constant current change and high-precision constant current. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the circuit structure of a preferred embodiment of the high-speed constant current control circuit of this utility model.

[0012] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0014] This utility model proposes a high-speed constant current control circuit, such as... Figure 1 As shown, a preferred embodiment of the high-speed constant current control circuit of this utility model includes: operational amplifier U1, MOSFET Q1, transistor Q2, diode D1, current sampling resistor R6, and resistors R1, R2, R3, R4 and R5.

[0015] In this configuration, one end of resistor R1 is connected to a constant current control signal, and the other end is connected to pin 1 of operational amplifier U1. One end of resistor R2 is connected to a constant current control signal, and the other end is connected to pin 2 of operational amplifier U1, one end of resistor R3, and one end of resistor R4. Pin 3 of operational amplifier U1 is connected to the base of transistor Q2 and the cathode of diode D1. The collector of transistor Q2 is connected to the power supply. The emitter of transistor Q2 is connected to one end of resistor R5 and the anode of diode D1. The other end of resistor R5 is connected to the gate of MOSFET Q1. The source of MOSFET Q1 is connected to one end of resistor R6 and the other end of resistor R3. The drain of MOSFET Q1 is connected to the product under test. The other end of resistor R4 is connected to the other end of resistor R6 and the product under test.

[0016] As one implementation scheme, in this embodiment, the high-speed constant current control circuit further includes a capacitor C1, one end of which is connected to the other end of the resistor R1 and pin 1 of the operational amplifier U1, and the other end of which is connected to pin 3 of the operational amplifier U1.

[0017] The structure and working principle of the high-speed constant current control circuit of this utility model will be further explained below.

[0018] In this embodiment, the operational amplifier U1, MOSFET Q1, resistors R1, R2, R3, R4, R5, and R6 together form a constant current control circuit. The operational amplifier U1 acts as an error amplifier, comparing the signal collected by resistor R6 with the control signal and controlling the output, thereby affecting the conduction level of MOSFET Q1 to achieve a constant current effect. The control ratio is determined by the resistance ratios of R1, R2, R3, and R4. The control accuracy is determined by the accuracy of R1, R2, R3, R4, R6, and the operational amplifier U1. However, when the constant current control signal changes, the output of the operational amplifier U1 will also change.

[0019] When the output of the operational amplifier U1 goes high, the transistor Q2 will turn on more strongly, which will cause the gate capacitance of the MOS transistor Q1 to be quickly filled and the gate voltage to rise rapidly, thereby enabling the MOS transistor Q1 to rapidly increase its conduction level.

[0020] When the output of the operational amplifier U1 goes low, the diode D1 will turn on, which will cause the gate capacitance of the MOS transistor Q1 to discharge rapidly, and the gate voltage can be pulled down very quickly, thereby realizing that the conduction level of the MOS transistor Q1 is reduced very quickly.

[0021] The presence of resistors R1, R2, R3, R4, R6, capacitor C1, and operational amplifier U1 ensures the accuracy of constant current control. Furthermore, the presence of transistor Q2 and diode D1 significantly enhances the output capability of the operational amplifier, thereby achieving high-speed control.

[0022] In summary, the high-speed constant current control circuit of this utility model, through the above technical solution, can achieve high-speed constant current change, high slope of constant current control, and high precision of constant current.

[0023] To achieve the above objectives, this utility model also proposes a power supply, which includes the high-speed constant current control circuit described in the above embodiment. The structure and working principle of the high-speed constant current control circuit have been described in detail above and will not be repeated here.

[0024] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the concept of the present utility model and using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A high-speed constant current control circuit, characterized in that, include: Operational amplifier U1, MOSFET Q1, transistor Q2, diode D1, current sampling resistor R6, and resistors R1, R2, R3, R4 and R5; In this configuration, one end of resistor R1 is connected to a constant current control signal, and the other end is connected to pin 1 of operational amplifier U1. One end of resistor R2 is connected to a constant current control signal, and the other end is connected to pin 2 of operational amplifier U1, one end of resistor R3, and one end of resistor R4. Pin 3 of operational amplifier U1 is connected to the base of transistor Q2 and the cathode of diode D1. The collector of transistor Q2 is connected to the power supply. The emitter of transistor Q2 is connected to one end of resistor R5 and the anode of diode D1. The other end of resistor R5 is connected to the gate of MOSFET Q1. The source of MOSFET Q1 is connected to one end of resistor R6 and the other end of resistor R3. The drain of MOSFET Q1 is connected to the product under test. The other end of resistor R4 is connected to the other end of resistor R6 and the product under test.

2. The high-speed constant current control circuit according to claim 1, characterized in that, It also includes a capacitor C1, one end of which is connected to the other end of the resistor R1 and pin 1 of the operational amplifier U1, and the other end of which is connected to pin 3 of the operational amplifier U1.

3. A power supply, characterized in that, The power supply includes a high-speed constant current control circuit as described in any one of claims 1 to 2.

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