A current source with high-precision pulse output

Abstract

The present invention relates to the technical field of constant current sources, and discloses a current source with high-precision pulse output, comprising: a feedback unit, a driving unit and an adjusting unit, wherein a control signal is input to a first input end of the feedback unit, an output end of the feedback unit is connected to a control end of the driving unit, and the feedback unit is used to follow and amplify the control signal and then output a driving signal; the output end of the driving unit is connected to a control end of the adjusting unit, and the driving unit is used to output an adjusting signal after switching a switch state based on the driving signal; the first output end of the adjusting unit is connected to a second input end of the feedback unit, and the adjusting unit is connected in series with a load, and the adjusting unit is used to adjust an internal voltage division based on the adjusting signal, and output the current flowing through the load and the voltage at both ends of the load as a feedback signal; the feedback unit adjusts the driving signal based on the feedback signal. The current source of the present invention can dynamically adjust the current flowing through the load and the voltage at both ends of the load according to the feedback signal, thereby improving the accuracy of the current source.

Description

Technical Field

[0001] The present invention relates to the technical field of constant current sources, and particularly relates to a current source with high-precision pulse output. Background Art

[0002] In the detection stage of communication chip R & D and post-processing, various specifications of power supplies are required as driving sources for chip testing. Communication chips are generally LD laser chips, which emit light based on stimulated emission. The characteristic of this light-emitting principle is that current driving directly generates laser. Therefore, the optical output power is linearly related to the current. Thus, a constant current source is generally selected as the driving source for communication chips. However, due to different manufacturing processes and application scenarios of different communication chips, there are differences in the magnitude of the driving current, the total power, and the chip heat generation, and the accuracy is mostly one-thousandth, resulting in inaccurate test results. Therefore, when testing communication chips, a constant current source with high precision, high power, and narrow pulses is required. Summary of the Invention

[0003] In view of this, the present invention provides a current source with high-precision pulse output to solve the problem of low accuracy of existing current sources.

[0004] The present invention provides a current source with high-precision pulse output, including: a feedback unit, a driving unit, and an adjusting unit. Among them, a control signal is input to the first input end of the feedback unit, and the output end of the feedback unit is connected to the control end of the driving unit. The feedback unit is used to follow and amplify the control signal and then output a driving signal; the output end of the driving unit is connected to the control end of the adjusting unit. The driving unit is used to switch the switch state based on the driving signal and then output an adjusting signal; the first output end of the adjusting unit is connected to the second input end of the feedback unit. The adjusting unit is connected in series with the load. The adjusting unit is used to adjust the internal voltage division based on the adjusting signal and output the current flowing through the load and the voltage across the load as a feedback signal, where the voltage division is used to adjust the magnitude of the current flowing through the load; the feedback unit adjusts the driving signal based on the feedback signal.

[0005] For the current source with high-precision pulse output provided by the present invention, the feedback unit can adjust the driving signal according to the feedback signal output by the adjusting unit, so that the adjusting signal output by the driving unit changes, and then the voltage division in the adjusting unit is adjusted, so that the voltage across the load and the current flowing through the load change, and the feedback signal changes, thereby forming an automatic closed-loop adjustment, and the load current can be accurately controlled.

[0006] In an alternative embodiment, the feedback unit includes: a first follower unit and a feedback amplification unit. Wherein, a control signal is input to the input end of the first follower unit, the output end of the first follower unit is connected to the first input end of the feedback amplification unit, and the first follower unit is used to follow the control signal; the second input end of the feedback amplification unit is connected to the first output end of the adjustment unit, and the feedback amplification unit is used to adjust and output a drive signal based on the deviation between the feedback signal and the control signal.

[0007] In an alternative embodiment, the drive unit includes: a first resistor, a second resistor, a first diode, a second diode, a first controllable switch, a second controllable switch, a third controllable switch, and a fourth controllable switch. Wherein, the first end of the first controllable switch is connected to the first end of the second controllable switch, the first end of the first resistor, and an external power supply, the control end of the first controllable switch is connected to the control end of the second controllable switch, the second end of the first resistor, and the anode of the first diode, and the second end of the first controllable switch is connected to the second end of the second controllable switch, the first end of the third controllable switch, the first end of the fourth controllable switch, and the control end of the adjustment unit; the control end of the third controllable switch is connected to the control end of the fourth controllable switch, the cathode of the second diode, and the first end of the second resistor, and the second end of the third controllable switch is connected to the second end of the fourth controllable switch and the second end of the second resistor and is grounded; the cathode of the first diode is connected to the anode of the second diode and the output end of the feedback unit.

[0008] In an alternative embodiment, the feedback signal includes a feedback current and a feedback voltage, and the adjustment unit includes: a sampling unit, a current output unit, and a voltage output unit. Wherein, the input end of the sampling unit is connected to the output end of the drive unit, the first end of the sampling unit is connected to the first input end of the current output unit, the output end of the sampling unit is connected to the second input end of the current output unit and the first end of the load, and the sampling unit is used to divide the voltage of the adjustment signal by adjusting the internal resistance to obtain a divided voltage with a corresponding amplitude; the output end of the current output unit is connected to the output end of the voltage output unit and the second input end of the feedback unit, and the current output unit is used to output the current flowing through the load as the feedback current; the input end of the voltage output unit is connected to the second end of the load, and the voltage output unit is used to output the voltage across the load as the feedback voltage.

[0009] In an alternative embodiment, the sampling unit includes: a sampling circuit and a plurality of adjustable resistor circuits connected in parallel with the sampling circuit.

[0010] The current source provided by the present invention can control the sampling unit to achieve different degrees of voltage division by controlling the input of adjustable resistor circuits in different paths or adjusting the resistance values of the adjustable resistor circuits, thereby changing the current flowing through the load, switching different ranges of the current source, and expanding the applicable range.

[0011] In an alternative embodiment, the current output unit includes: a second follower unit and a first amplification unit. Among them, the first input end of the second follower unit is connected to the input end of the sampling unit, the second input end of the second follower unit is connected to the output end of the sampling unit, the first output end of the second follower unit is connected to the first input end of the first amplification unit, the second output end of the second follower unit is connected to the second input end of the first amplification unit, and the second follower unit is used to follow and amplify the voltages at the input end and the output end of the sampling unit; the output end of the first amplification unit is connected to the second input end of the feedback unit, and the first amplification unit is used to amplify the voltage difference between the input end and the output end of the sampling unit and then output a feedback signal.

[0012] In an alternative embodiment, the second follower unit includes: a second amplification unit and a third amplification unit. Among them, the input end of the second amplification unit is connected to the input end of the sampling unit, the output end of the second amplification unit is connected to the first input end of the first amplification unit, and the second amplification unit is used to increase the input impedance of the first input end of the first amplification unit; the input end of the third amplification unit is connected to the output end of the sampling unit, the output end of the third amplification unit is connected to the second input end of the first amplification unit, and the third amplification unit is used to increase the input impedance of the second input end of the first amplification unit.

[0013] In an alternative embodiment, the feedback signal includes: a feedback voltage, and the current source further includes: a current limiting unit. Among them, the first input end of the current limiting unit is connected to the second output end of the regulation unit, the output end of the current limiting unit is connected to the control end of the driving unit, and the current limiting unit is used to compare the magnitudes of the feedback voltage and the internal reference voltage, and limit the current magnitude of the driving signal when the feedback voltage is greater than the reference voltage.

[0014] In an alternative embodiment, the reference voltage includes: a positive reference voltage and a negative reference voltage, and the current limiting unit includes: a positive current limiting circuit and a negative current limiting circuit. Among them, the first input end of the positive current limiting circuit inputs the positive reference voltage, the second input end of the positive current limiting circuit is connected to the second input end of the negative current limiting circuit and the second output end of the regulation unit, the output end of the positive current limiting circuit is connected to the output end of the negative current limiting circuit and the control end of the driving unit, and the positive current limiting circuit is used to limit the current magnitude of the driving signal when the feedback voltage is greater than zero and the feedback voltage is greater than the positive reference voltage; the first input end of the negative current limiting circuit inputs the negative reference voltage, and the negative current limiting circuit is used to limit the current magnitude of the driving signal when the feedback voltage is less than zero and the feedback voltage is less than the negative reference voltage.

[0015] For the current source provided by the present invention, when the feedback voltage is relatively large, the current limiting unit adjusts the voltage division within the adjustment unit by limiting the current magnitude of the drive signal, so as to reduce the current flowing through the load and the voltage across the load. The current limiting unit of the present invention can limit the voltages in both positive and negative directions respectively, improve the accuracy and reliability of the current source, and expand the applicable range of the current source.

[0016] In an optional embodiment, the forward current limiting circuit includes: a fourth amplification unit and a comparison unit. Among them, the forward reference voltage is input to the input terminal of the fourth amplification unit, and the output terminal of the fourth amplification unit is connected to the first input terminal of the comparison unit. The fourth amplification unit is used to amplify the forward reference voltage; the feedback signal is input to the second input terminal of the comparison unit, and the output terminal of the comparison unit is connected to the control terminal of the drive unit. The comparison unit is used to limit the current magnitude of the drive signal when the feedback voltage is greater than zero and the feedback voltage is greater than the forward reference voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 is a component diagram of a current source according to an embodiment of the present invention;

[0019] Figure 2 is a specific circuit structure diagram of a feedback unit according to an embodiment of the present invention;

[0020] Figure 3 is a specific circuit structure diagram of a drive unit according to an embodiment of the present invention;

[0021] Figure 4 is another component diagram of a current source according to an embodiment of the present invention;

[0022] Figure 5 is a specific circuit structure diagram of an adjustment unit according to an embodiment of the present invention;

[0023] Figure 6 is another component diagram of a current source according to an embodiment of the present invention;

[0024] Figure 7 is a specific circuit structure diagram of a current limiting unit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can also be the communication inside two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] This embodiment provides a current source with high-precision pulse output, as Figure 1 shown, including: a feedback unit 1, a driving unit 2, and an adjusting unit 3.

[0030] As Figure 1 shown, a control signal is input to the first input end of the feedback unit 1, and the output end of the feedback unit 1 is connected to the control end of the driving unit 2; the output end of the driving unit 2 is connected to the control end of the adjusting unit 3; the first output end of the adjusting unit 3 is connected to the second input end of the feedback unit 1, and the adjusting unit 3 is connected in series with the load.

[0031] Figure 1Among them, the feedback unit 1 is used to follow and amplify the control signal and then output a drive signal. The drive unit 2 is used to output an adjustment signal after switching the switch state based on the drive signal. The adjustment unit 3 is used to adjust the internal voltage division based on the adjustment signal, and output the current flowing through the load and the voltage across the load as a feedback signal. Among them, the voltage division is used to adjust the magnitude of the current flowing through the load.

[0032] Specifically, Figure 1 Among them, the feedback unit 1 adjusts the drive signal based on the feedback signal. When the control signal and the feedback signal are respectively input to the voltage of the first input terminal and the second input terminal of the feedback unit 1, and the voltages of the first input terminal and the second input terminal are different, the feedback unit 1 adjusts the magnitude of the current and voltage of the drive signal, so that the current of the adjustment signal output by the drive unit changes.

[0033] Specifically, Figure 1 Among them, since the load is connected in series with the adjustment unit, according to the principle that the current is the same everywhere in a series circuit, the magnitude of the current flowing through the load is adjusted by adjusting the voltage division of the adjustment unit 3, thereby changing the voltage across the load until the voltage across the load changes to the same as the voltage of the control signal, and the voltages of the first input terminal and the second input terminal of the feedback unit 1 also tend to be the same. When the voltages of the first input terminal and the second input terminal of the feedback unit 1 are the same, at this time, the entire current source circuit returns to the stable state at the initial time, and the current flowing through the load can be obtained by calculating the voltage of the control signal and the equivalent resistance of the part connected in series with the load. The current source can switch the switch through the host computer program to control the output of direct current or pulse.

[0034] For the current source with high-precision pulse output provided in this embodiment, the feedback unit can adjust the drive signal according to the feedback signal output by the adjustment unit, so that the adjustment signal output by the drive unit changes, and then adjust the voltage division in the adjustment unit, so that the voltage across the load and the current flowing through the load change, and the feedback signal changes, thereby forming an automatic closed-loop adjustment, and the current on the load can be accurately controlled.

[0035] In some alternative embodiments, such as Figure 2 shown, the feedback unit 1 includes: a first follower unit 11 and a feedback amplifier unit 12. Among them, the input terminal of the first follower unit 11 inputs the control signal, and the output terminal of the first follower unit 11 is connected to the first input terminal of the feedback amplifier unit 12; the second input terminal of the feedback amplifier unit 12 (i.e., the end for inputting the feedback signal) is connected to the first output terminal of the adjustment unit 3.

[0036] Specifically, Figure 2 Among them, the first follower unit 11 is used to follow the control signal and amplify the control signal synchronously; the feedback amplifier unit 12 is used to amplify the deviation between the feedback signal and the control signal, and adjust and output the drive signal.

[0037] Specifically, Figure 2 in [the circuit], the first following unit 11 includes: an RC filter circuit composed of a resistor R42, a resistor R40, and a capacitor C14 for current limiting, and an operational amplifier IOP8; the feedback amplification unit 12 includes: an RC filter circuit composed of a resistor R38, a resistor R39, capacitors C12 and C13, and a resistor R37 for current limiting, an operational amplifier IOP1, and a variable resistor P4. The positive input terminal of IOP1 inputs a control signal, the negative input terminal inputs a feedback signal, and the output terminal outputs a driving signal with adjustable current magnitude through the variable resistor P4. The switching state of the switch K can be switched through a host computer program, such that the non-inverting input terminal of IOP1 is grounded, or such that the non-inverting input terminal of IOP1 is connected to the output terminal of IOP8, thereby controlling IOP1 to output a direct current or a pulse.

[0038] In some alternative embodiments, such as Figure 3 shown, the driving unit 2 includes: a first resistor R2, a second resistor R18, a first diode D1, a second diode D2, a first controllable switch T1, a second controllable switch T2, a third controllable switch T3, and a fourth controllable switch T4. Among them, the first end of the first controllable switch T1 is connected to the first end of the second controllable switch T2, the first end of the first resistor R2, and an external power supply; the control end of the first controllable switch T1 is connected to the control end of the second controllable switch T2, the second end of the first resistor R2, and the anode of the first diode D1; the second end of the first controllable switch T1 is connected to the second end of the second controllable switch T2, the first end of the third controllable switch T3 (i.e., the end for outputting an adjustment signal), the first end of the fourth controllable switch T4, and the control end of the adjustment unit; the control end of the third controllable switch T3 is connected to the control end of the fourth controllable switch T4, the cathode of the second diode D2, and the first end of the second resistor R18; the second end of the third controllable switch T3 is connected to the second end of the fourth controllable switch T4 and the second end of the second resistor R18 and is grounded; the cathode of the first diode D1 is connected to the anode of the second diode D2 and the output terminal of the feedback unit 1 (i.e., the end for receiving the driving signal).

[0039] Specifically, Figure 3 in [the circuit], the driving signal is a direct current signal or a pulse signal. By controlling the first controllable switch T1, the second controllable switch T2, the third controllable switch T3, and the fourth controllable switch T4 to alternately switch between on and off states, an adjustment signal is output, and the current magnitude of the adjustment signal changes with the current of the driving signal.

[0040] Optionally, Figure 3Among them, the first controllable switch T1, the second controllable switch T2, the third controllable switch T3, and the fourth controllable switch T4 are all MOS transistors, and the drains of the MOS transistors are connected to the power supply. Multiple MOS transistors in the driving unit 2 are connected in parallel, which can disperse heat and achieve better heat dissipation. The driving unit 2 uses MOS transistors as switches, which has the advantages of fast driving speed and large generated current. MOS transistors can drive a large current and have a very fast startup time, and can output pulsed current with a narrower pulse width. The rising edge of the current pulse can be controlled within 50 μs, and the current magnitude can reach twelve amperes.

[0041] In some alternative embodiments, such as Figure 4 shown, the feedback signal includes a feedback current and a feedback voltage. The adjustment unit 3 includes: a sampling unit 31, a current output unit 32, and a voltage output unit 33. Among them, the input end of the sampling unit 31 is connected to the output end of the driving unit 2. The first end of the sampling unit 31 is connected to the first input end of the current output unit 32. The output end of the sampling unit 31 is connected to the second input end of the current output unit 32 and the first end of the load. The output end of the current output unit 32 is connected to the output end of the voltage output unit 33 and the second input end of the feedback unit 1. The input end of the voltage output unit 33 is connected to the second end of the load.

[0042] Optionally, Figure 4 in, the sampling unit 31 may include a plurality of adjustable resistors. By adjusting the resistance value of the adjustable resistors, the magnitude of the current flowing through the sampling unit 31 and the load is adjusted. The load is connected in series with the sampling unit 31. According to the principle that the current is the same everywhere in a series circuit, the current and voltage on the load are controlled and fed back by controlling the voltage across the adjustable resistors.

[0043] Specifically, Figure 4 in, the sampling unit 31 is used to divide the voltage of the adjustment signal by adjusting the internal resistance to obtain a divided voltage with a corresponding amplitude. Since the sampling unit 31 is connected in series with the load, the current output unit 32 is used to equalize the current flowing through the sampling unit 31 as the current flowing through the load and output it as the feedback current. The voltage output unit 33 is used to output the voltage across the load as the feedback voltage. Then, the feedback unit 1 adjusts the driving signal according to the difference between the feedback voltage and the voltage of the control signal, or the difference between the feedback current and the current of the control signal, and further adjusts the signal until the feedback unit 1 determines that the feedback signal is consistent with the control signal, indicating that the entire current source circuit returns to the stable state at the initial time, and the dynamic adjustability of the current source accuracy is realized by means of closed-loop regulation.

[0044] In some alternative embodiments, such as Figure 5As shown, the current output unit includes: a second follower unit 321 and a first amplifier unit 322. Among them, the first input terminal of the second follower unit 321 (i.e., the terminal for inputting the adjustment signal) is connected to the input terminal of the sampling unit 31, the second input terminal of the second follower unit 321 is connected to the output terminal of the sampling unit 31, the first output terminal of the second follower unit 321 is connected to the first input terminal of the first amplifier unit 322, and the second output terminal of the second follower unit 321 is connected to the second input terminal of the first amplifier unit 322; the output terminal of the first amplifier unit 322 (i.e., the terminal for outputting the feedback current) is connected to the second input terminal of the feedback unit 1.

[0045] Specifically, Figure 5 In it, the second follower unit 321 is used to follow and amplify the voltages at the input terminal and the output terminal of the sampling unit 31, and the first amplifier unit 322 is used to amplify the voltage difference between the input terminal and the output terminal of the sampling unit 31 and then output the feedback current.

[0046] Specifically, Figure 5 In it, the second follower unit 321 includes: a second amplifier unit 3211 and a third amplifier unit 3212. Among them, the input terminal of the second amplifier unit 3211 (i.e., the terminal for inputting the adjustment signal) is connected to the input terminal of the sampling unit 31, and the output terminal of the second amplifier unit 3211 is connected to the first input terminal of the first amplifier unit 322; the input terminal of the third amplifier unit 3212 is connected to the output terminal of the sampling unit 31, and the output terminal of the third amplifier unit 3212 is connected to the second input terminal of the first amplifier unit 322.

[0047] Specifically, Figure 5 In it, the second amplifier unit 3211 is used to increase the input impedance of the first input terminal of the first amplifier unit 322, and the third amplifier unit 3212 is used to increase the input impedance of the second input terminal of the first amplifier unit 322.

[0048] Optionally, Figure 5 In it, the sampling unit includes: a sampling circuit and a plurality of adjustable resistance circuits connected in parallel with the sampling circuit. The sampling circuit includes a sampling resistor R1, and each adjustable resistance circuit respectively includes a sampling resistor (R21, R22, R23, R24) and an adjustable resistor (R36, R37, R38, R39) connected in series. The on / off of the switches (K5B, K6B, K7B, K8B) respectively connected in series with each adjustable resistance circuit can be controlled to control the corresponding adjustable resistance circuit to be put into or withdrawn. The adjustable resistance circuits with different resistance values are connected in parallel with the sampling resistor R1 and then connected in series with the load DUT, that is, the current on the load DUT is controlled by adjusting the voltage across the sampling resistor R1. By controlling the resistance value of each adjustable resistance circuit, the ammeter can switch different current ranges, thereby improving the accuracy of the ammeter, which is about one-thousandth to five-ten-thousandths.

[0049] Specifically, Figure 5 In , the first amplification unit 322 includes resistors R6, R7, R8, and R9, operational amplifier IOP5, and capacitor C2. The second amplification unit 3211 includes resistors R3, R4, and R5, operational amplifier IOP3, and capacitor C1. The third amplification unit 3212 includes resistors R10, R11, and R12, operational amplifier IOP4, and capacitor C3. The voltage output unit includes resistors R13, R14, and R15, operational amplifier IOP2, and capacitor C4. IOP3, IOP4, and IOP5 are current feedback devices, and IOP2 is a voltage feedback device. All of them pass through switch SW-SPDT1 to input the feedback signal to feedback unit 1. IOP3 and IOP4 are voltage followers, which can increase the input impedance of the subtractor. IOP5 is a subtractor. IOP3 and IOP4 can increase the input impedance of IOP5. The voltage across sampling resistor R1 is fed back to IOP5 and then output as the feedback signal of load DUT, reducing shunt and ensuring the accuracy of the current value of load DUT.

[0050] In some alternative embodiments, the feedback signal includes: a feedback voltage, such as Figure 6 shown, the current source further includes: a current limiting unit 4, wherein the first input end of the current limiting unit 4 is connected to the second output end of the regulating unit 3, the output end of the current limiting unit 4 is connected to the control end of the driving unit 2, and the current limiting unit 4 is used to compare the magnitudes of the feedback voltage and the internal reference voltage, and limit the current magnitude of the driving signal when the feedback voltage is greater than the reference voltage.

[0051] Specifically, the reference voltage includes: a forward reference voltage and a reverse reference voltage, such as Figure 7 shown, the current limiting unit 4 includes: a forward current limiting circuit 41 and a reverse current limiting circuit 42, wherein the first input end of the forward current limiting circuit 41 inputs the forward reference voltage, the second input end of the forward current limiting circuit 41 (i.e., the end for inputting the feedback signal) is connected to the second input end of the reverse current limiting circuit 42 and the second output end of the regulating unit 3 (i.e., Figure 5 the stationary contact of KA in ), the output end of the forward current limiting circuit 41 is connected to the output end of the reverse current limiting circuit 42 and the control end of the driving unit 2; the first input end of the reverse current limiting circuit 42 inputs the reverse reference voltage.

[0052] Specifically, Figure 7 in, the forward current limiting circuit 41 is used to limit the current magnitude of the driving signal when the feedback voltage is greater than zero and the feedback voltage is greater than the forward reference voltage, and the reverse current limiting circuit is used to limit the current magnitude of the driving signal when the feedback voltage is less than zero and the feedback voltage is less than the reverse reference voltage.

[0053] Specifically, Figure 7In the figure, the forward current limiting circuit 41 includes: a fourth amplification unit 411 and a comparison unit 412. Among them, the input terminal of the fourth amplification unit 411 inputs a forward reference voltage, and the output terminal of the fourth amplification unit 411 is connected to the first input terminal of the comparison unit 412; the second input terminal of the comparison unit 412 inputs a feedback signal, and the output terminal of the comparison unit 412 is connected to the control terminal of the driving unit 2.

[0054] Specifically, Figure 7 In the figure, the fourth amplification unit 411 includes an operational amplifier IOP9, and the fourth amplification unit 411 is used to amplify the forward reference voltage; the comparison unit 412 includes an operational amplifier IOP6, and the comparison unit 412 is used to limit the current magnitude of the current limiting drive signal when the feedback voltage is greater than zero and the feedback voltage is greater than the forward reference voltage. The forward feedback voltage or forward feedback current is input to the inverting input terminal of IOP6, and the forward reference voltage is input to the non-inverting input terminal of IOP6 after being reversely amplified by IOP9. The forward reference voltage is the maximum voltage limit value of the current source. When the feedback voltage is positive and greater than the forward reference voltage, the current source outputs an overlimit value, and IOP6 outputs a level signal to limit the current magnitude in the drive signal, so that the regulated current output by the driving unit is reduced, thereby adjusting the gate voltage of the MOS transistor, controlling the current flowing through the load, and further controlling the voltage value across the sampling resistor to below the limit, achieving the purpose of limiting the load current and the voltage across the load. When the feedback voltage is positive and less than or equal to the forward reference voltage, the current source output is within the normal range, and IOP6 does not adjust the drive signal.

[0055] Specifically, Figure 7 In the figure, the reverse current limiting circuit 42 includes operational amplifiers IOP7 and IOP10. The reverse feedback voltage or reverse feedback current is input to the inverting input terminal of IOP7, and the reverse reference voltage is input to the non-inverting input terminal of IOP7 after being non-reversely amplified by IOP10. The reverse reference voltage is the minimum voltage limit value of the current source. When the feedback voltage is negative and less than the reverse reference voltage, the current source outputs an overlimit value, and IOP7 outputs a level signal to limit the current magnitude in the drive signal, so that the regulated current output by the driving unit is reduced, thereby adjusting the gate voltage of the MOS transistor, controlling the current flowing through the load, and further controlling the voltage value across the sampling resistor to below the limit, achieving the purpose of limiting the load current and the voltage across the load. When the feedback voltage is negative and less than or equal to the reverse reference voltage, the current source output is within the normal range, and IOP7 does not adjust the drive signal.

[0056] Optionally, the operator can freely set the magnitudes of the forward reference voltage and the reverse reference voltage according to the limit value of the ammeter.

[0057] It should be noted that the method of using the feedback unit to control the current in the sampling unit in this embodiment can accurately control the current on the load, and the accuracy of the current can reach five-thousandths. The requirements for the operational amplifier are more lenient, and the above functions can also be achieved without using a rail-to-rail operational amplifier.

[0058] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A current source with high-precision pulse output, characterized in that: include: Feedback unit, drive unit and adjustment unit, wherein: The first input terminal of the feedback unit inputs a control signal, the output terminal of the feedback unit is connected to the control terminal of the driving unit, and the feedback unit is used to follow and amplify the control signal and then output a driving signal; The output end of the driving unit is connected to the control end of the regulating unit, and the driving unit is used to output a regulating signal after switching a switch state based on the driving signal; The first output end of the regulating unit is connected to the second input end of the feedback unit, the regulating unit is connected in series with the load, the regulating unit is used to adjust the internal voltage division based on the regulating signal, and output the current flowing through the load and the voltage across the load as the feedback signal, wherein the voltage division is used to adjust the magnitude of the current flowing through the load; The feedback unit adjusts the drive signal based on the feedback signal; The feedback unit includes: a first follower unit and a feedback amplifier unit, wherein: The input end of the first follower unit inputs a control signal, the output end of the first follower unit is connected to the first input end of the feedback amplification unit, and the first follower unit is used to follow the control signal; The second input end of the feedback amplifying unit is connected to the first output end of the regulating unit, and the feedback amplifying unit is used to adjust and output the driving signal based on the deviation between the feedback signal and the control signal; The driving unit includes: a first resistor, a second resistor, a first diode, a second diode, a first controllable switch, a second controllable switch, a third controllable switch and a fourth controllable switch, wherein: The first end of the first controllable switch is connected to the first end of the second controllable switch, the first end of the first resistor and an external power supply, the control end of the first controllable switch is connected to the control end of the second controllable switch, the second end of the first resistor and the anode of the first diode, and the second end of the first controllable switch is connected to the second end of the second controllable switch, the first end of the third controllable switch, the first end of the fourth controllable switch and the control end of the regulating unit; The control end of the third controllable switch is connected to the control end of the fourth controllable switch, the cathode of the second diode and the first end of the second resistor, and the second end of the third controllable switch is connected to the second end of the fourth controllable switch and the second end of the second resistor and is grounded; The cathode of the first diode is connected to the anode of the second diode and the output end of the feedback unit; The feedback signal includes a feedback current and a feedback voltage, and the regulating unit includes: a sampling unit, a current output unit and a voltage output unit, wherein: The input end of the sampling unit is connected to the output end of the driving unit, the first end of the sampling unit is connected to the first input end of the current output unit, the output end of the sampling unit is connected to the second input end of the current output unit and the first end of the load, and the sampling unit is used to divide the voltage of the adjustment signal by adjusting the internal resistance to obtain the divided voltage of the corresponding amplitude; The output end of the current output unit is connected to the output end of the voltage output unit and the second input end of the feedback unit, and the current output unit is used to output the current flowing through the load as the feedback current; The input end of the voltage output unit is connected to the second end of the load, and the voltage output unit is used to output the voltage across the load as a feedback voltage.

2. The current source according to claim 1, characterized in that The sampling unit includes: a sampling circuit and a plurality of adjustable resistance circuits connected in parallel with the sampling circuit.

3. The current source according to claim 1, characterized in that The current output unit includes: a second follower unit and a first amplification unit, wherein: The first input end of the second follower unit is connected to the input end of the sampling unit, the second input end of the second follower unit is connected to the output end of the sampling unit, the first output end of the second follower unit is connected to the first input end of the first amplifying unit, the second output end of the second follower unit is connected to the second input end of the first amplifying unit, and the second follower unit is used to follow and amplify the voltages of the input end and the output end of the sampling unit; The output end of the first amplifying unit is connected to the second input end of the feedback unit, and the first amplifying unit is used to amplify the voltage difference between the input end and the output end of the sampling unit and then output the feedback signal.

4. The current source according to claim 3, characterized in that The second following unit includes: a second amplifying unit and a third amplifying unit, wherein: The input end of the second amplifying unit is connected to the input end of the sampling unit, the output end of the second amplifying unit is connected to the first input end of the first amplifying unit, and the second amplifying unit is used to increase the input impedance of the first input end of the first amplifying unit; The input end of the third amplifying unit is connected to the output end of the sampling unit, the output end of the third amplifying unit is connected to the second input end of the first amplifying unit, and the third amplifying unit is used to increase the input impedance of the second input end of the first amplifying unit.

5. The current source according to claim 1, characterized in that The feedback signal includes: a feedback voltage, and the current source further includes: a current limiting unit, wherein: The first input end of the current limiting unit is connected to the second output end of the regulating unit, and the output end of the current limiting unit is connected to the control end of the driving unit. The current limiting unit is used to compare the feedback voltage with the internal reference voltage, and limit the current of the driving signal when the feedback voltage is greater than the reference voltage.

6. The current source according to claim 5, characterized in that The reference voltage includes: a forward reference voltage and a reverse reference voltage, and the current limiting unit includes: a forward current limiting circuit and a reverse current limiting circuit, wherein: The first input end of the forward current limiting circuit inputs a forward reference voltage, the second input end of the forward current limiting circuit is connected to the second input end of the reverse current limiting circuit and the second output end of the regulating unit, the output end of the forward current limiting circuit is connected to the output end of the reverse current limiting circuit and the control end of the driving unit, and the forward current limiting circuit is used to limit the current of the driving signal when the feedback voltage is greater than zero and the feedback voltage is greater than the forward reference voltage; A reverse reference voltage is input to the first input terminal of the reverse current limiting circuit, and the reverse current limiting circuit is used to limit the current of the driving signal when the feedback voltage is less than zero and the feedback voltage is less than the reverse reference voltage.

7. The current source according to claim 6, characterized in that The forward current limiting circuit comprises: a fourth amplifying unit and a comparing unit, wherein: The input end of the fourth amplifying unit inputs a positive reference voltage, the output end of the fourth amplifying unit is connected to the first input end of the comparing unit, and the fourth amplifying unit is used to amplify the positive reference voltage; The feedback signal is input to the second input terminal of the comparison unit, and the output terminal of the comparison unit is connected to the control terminal of the drive unit. The comparison unit is used to limit the current of the drive signal when the feedback voltage is greater than zero and the feedback voltage is greater than the forward reference voltage.

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