CN214626786U - Constant current driving circuit - Google Patents
Constant current driving circuit Download PDFInfo
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- CN214626786U CN214626786U CN202120287971.4U CN202120287971U CN214626786U CN 214626786 U CN214626786 U CN 214626786U CN 202120287971 U CN202120287971 U CN 202120287971U CN 214626786 U CN214626786 U CN 214626786U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model provides a constant current drive circuit, include: the device comprises a negative pressure generating unit, an error integrating unit, a current collecting unit and a field effect tube; the drain electrode of the field effect transistor is connected with the negative electrode terminal; the source electrode of the field effect transistor is connected with the input end of the current acquisition unit; the grid of the field effect transistor is connected with the output end of the error integration unit; the output end of the current acquisition unit is connected with the first input end of the error integration unit; and the output end of the negative pressure generation unit is connected with the second input end of the error integration unit. The utility model provides a constant current drive circuit produces the negative pressure through the negative pressure, enlarges the back with negative pressure and standby voltage stack and integral at error integral unit, can make field effect transistor's grid voltage be less than source voltage to turn-off field effect transistor can block the flow of standby current among the constant current drive circuit, the waste of electric energy when can reducing the standby of constant current drive circuit.
Description
Technical Field
The utility model relates to a power electronics field especially relates to a constant current drive circuit.
Background
The semiconductor laser can generate stimulated emission in a certain excitation mode.
The constant current driving circuit may be classified into a switching power type and a linear power type. The switching power supply type driving circuit has the characteristics of high conversion efficiency, convenience in installation and the like, but can still output standby current of about several hundred milliamperes when the switching power supply type driving circuit is in standby. The linear power supply type driving circuit has the characteristics of quick response and the like, and when the linear power supply type driving circuit is in standby, the output standby current can be generally controlled within one hundred milliamperes. The standby current output by the constant current driving circuit during standby can cause the waste of electric energy.
SUMMERY OF THE UTILITY MODEL
The utility model provides a constant current drive circuit for there is the extravagant problem of electric energy in constant current drive circuit when the standby among the solution prior art, the waste of electric energy when realizing reducing the constant current drive circuit standby.
The utility model provides a constant current drive circuit, include: the device comprises a negative pressure generating unit, an error integrating unit, a current collecting unit and a field effect tube;
the drain electrode of the field effect transistor is connected with the negative electrode terminal; the source electrode of the field effect transistor is connected with the input end of the current acquisition unit; the grid electrode of the field effect tube is connected with the output end of the error integration unit;
the output end of the current acquisition unit is connected with the first input end of the error integration unit;
and the output end of the negative pressure generation unit is connected with the second input end of the error integration unit.
According to the utility model provides a pair of constant current drive circuit, the negative pressure produces the unit, include: a negative pressure generating subunit and a power supply subunit;
the input end of the negative pressure generating subunit is connected with the power supply subunit;
and the output end of the negative pressure generating subunit is connected with the second input end of the error integrating unit.
According to the utility model provides a pair of constant current drive circuit still includes: a voltage dividing unit;
the voltage division unit is connected with the second input end of the error integration unit.
According to the utility model provides a pair of constant current drive circuit, the negative pressure that the negative pressure produced the output of subunit is-3V to-10V.
According to the utility model provides a pair of constant current drive circuit, the negative pressure that the negative pressure produced the output of subunit is-5V.
According to the utility model provides a pair of constant current drive circuit, the output voltage of power subunit is 3V to 10V.
According to the utility model provides a pair of constant current drive circuit, the output voltage of power subunit is 5V.
According to the utility model provides a pair of constant current drive circuit, field effect transistor is N channel metal oxide semiconductor type field effect transistor.
According to the utility model provides a pair of constant current drive circuit, the negative pressure produces the unit, still includes: a switch subunit;
and the output end of the negative pressure generating subunit is connected with the second input end of the error integrating unit through the switch subunit.
The utility model provides a constant current drive circuit produces the negative pressure through the negative pressure, enlarges the back with negative pressure and standby voltage stack and integral at error integral unit, can make field effect transistor's grid voltage be less than source voltage to turn-off field effect transistor can block standby current's among the constant current drive circuit flow, the waste of electric energy, constant current drive circuit's simple structure when can reducing the standby of constant current drive circuit.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the following briefly introduces the drawings required for the embodiments or the prior art descriptions, and obviously, the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is one of schematic structural diagrams of a constant current driving circuit provided by the present invention;
fig. 2 is a second schematic structural diagram of the constant current driving circuit according to the present invention.
Reference numerals:
101: a negative pressure generating unit; 102: an error integration unit;
103: a current collection unit; 104: a field effect transistor;
105: a drain electrode of the field effect transistor; 106: a power supply input terminal;
107: a positive terminal; 108: negative electrode terminal:
109: a source electrode of the field effect transistor; 110: an input end of the current collection unit;
111: an output end of the current collection unit; 112: a gate of the field effect transistor;
113: an output of the error integration unit; 114: a first input of an error integration unit;
115: an output end of the negative pressure generating unit; 116: a second input of the error integration unit;
117: a load; 201: a negative pressure generating subunit;
202: a power supply subunit; 203: a voltage dividing unit;
204: an N-channel MOS tube; 205: a grid electrode of the N-channel MOS tube;
206: and the source electrode of the N-channel MOS tube.
Detailed Description
To make the objects, technical solutions and advantages of the present invention clearer, the drawings of the present invention are combined to clearly and completely describe the technical solutions of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the embodiments of the present invention, it should be noted that unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the embodiments of the present invention can be understood in specific cases by those skilled in the art.
Fig. 1 is one of the schematic structural diagrams of the constant current driving circuit provided by the present invention. The constant current driving circuit of the present invention is described below with reference to fig. 1. As shown in the first figure, the constant current driving circuit includes: the device comprises a negative pressure generating unit 101, an error integrating unit 102, a current collecting unit 103 and a field effect tube 104.
The negative pressure generating unit 101 may generate a first negative pressure.
Specifically, the negative voltage is relative to the reference voltage, and when the actual voltage is lower than the reference voltage, the actual voltage is the negative voltage.
The negative pressure generating unit 101 may generate the first negative pressure in various ways, which will be described below by way of several examples.
The negative voltage generation unit 101 may generate a first negative voltage of a lower power through a built-in charge pump device. The charge pump device built in the negative voltage generating unit 101 may be: TTL level/323 level conversion chip.
The negative pressure generating unit 101 may also generate the first negative pressure through a built-in inverter.
The negative pressure generating unit 101 may also generate a first negative pressure through a built-in negative pressure power converter. The negative voltage power converter built in the negative voltage generating unit 101 may be MAX 749. MAX749 is the stabilized voltage of phase-inverted PFM switch, the input voltage is +2V to +6V, and the output voltage can reach more than-100V.
The negative voltage generating unit 101 may also provide the first negative voltage through a built-in DC/DC voltage inverter. The DC/DC voltage inverter built in the negative voltage generating unit 101 may be ME 7660. ME7660 can convert positive pressure with input range of +1.5V to +10V to corresponding negative pressure of-1.5V to-10V.
The error integration unit 102 comprises two inputs and an output. The two inputs of the error integrating unit 102 are a first input 114 of the error integrating unit and a second input 116 of the error integrating unit, respectively.
The error integration unit 102 may superimpose and integrate and amplify voltages input through two input terminals, and output the result.
The current collection unit 103 may convert the current passing through the current collection unit 103 into a voltage having a voltage magnitude corresponding to the magnitude of the current.
The fet 104 is a voltage control device that can control the output loop current by controlling the electric field effect of the input loop. The fet 104 may include three electrodes, a source 109, a drain 105, and a gate 112.
The fet can work under very little current or very low voltage conditions and voltage control characteristics (drain current can be controlled by controlling gate voltage) because of it, in the embodiment of the present invention the fet 104 acts equivalently to the electronic switch.
A drain 105 of the field effect transistor connected to a negative terminal 108; the source electrode 109 of the field effect transistor is connected with the input end 110 of the current acquisition unit; the gate 112 of the fet is connected to the output 113 of the error integration unit.
The positive terminal 107 and the negative terminal 108 are connected to the positive electrode and the negative electrode of the load 117, respectively, and form a path between the constant current drive circuit and the load 117.
The embodiment of the present invention takes the load 117 connected to the constant current driving module as an example of a semiconductor laser, and describes the constant current driving circuit.
When the semiconductor laser operates normally, an operating voltage can be input to the semiconductor laser through the power input terminal 106. Current can be input to the drain 105 of the fet through the positive terminal 107, the semiconductor laser, and the negative terminal 108.
When the semiconductor laser is in a standby state, the operating current input through the power input terminal 106 is zero. The output 111 of the current collection unit is connected to the second input 114 of the error integration unit.
The output 115 of the negative pressure generating unit is connected to a second input 116 of the error integrating unit.
Specifically, the positive terminal 107, the current collection unit 103, the error integration unit 102, the field effect transistor 104, the negative terminal 108, and the semiconductor laser connected to the positive terminal 107 and the negative terminal 108 form a closed loop.
Conventionally, when a semiconductor laser is in a standby state, a standby current exists in a closed circuit constituted by a constant current drive circuit and a semiconductor device. The magnitude of the standby current ranges from within one hundred milliamperes to several hundred milliamperes.
It should be noted that, in the embodiment of the present invention, the standby current is smaller than the threshold current of the semiconductor laser. The semiconductor laser has less potential safety hazard caused by standby current in a standby state.
The current collection unit 103 may convert the standby current passing through the current collection unit 103 into a standby voltage having a voltage corresponding to the standby current, and input the standby voltage to the error integration unit through the second input terminal 114 of the error integration unit.
It should be noted that, since the standby current is small, the standby voltage converted by the current collection unit 103 according to the standby current is a positive voltage close to zero.
The negative pressure generating unit 101 may input the generated first negative pressure to the error integrating unit 102 through the second input terminal 116 of the error integrating unit.
It should be noted that the absolute value of the first negative voltage generated by the negative voltage generating unit 101 needs to be greater than the standby voltage.
The error integration unit 102 may obtain a second negative voltage after superimposing and integrating the first negative voltage generated by the negative voltage generation unit 101 and the standby voltage.
When the semiconductor laser is in a standby state, the working current input to the constant current driving circuit through the power input terminal 106 is zero. The voltage at the source 109 of the fet is the standby voltage.
The absolute value of the first negative voltage is greater than the standby voltage, and the error integration unit 102 superimposes the first negative voltage on the standby voltage to obtain a negative voltage whose voltage is the algebraic sum of the first negative voltage and the standby voltage. After the negative pressure obtained by the superposition is subjected to integral amplification, a second negative pressure can be obtained. The error integrating unit 102 may output the second negative voltage to the gate 112 of the fet through an output terminal 113 of the error integrating unit, and a voltage at the gate 112 of the fet is the second negative voltage.
The voltage at the source 109 of the fet is a positive voltage, the voltage at the gate 112 of the fet is a negative voltage, and the voltage at the gate 112 of the fet is less than the voltage at the source 109.
The embodiment of the present invention provides an embodiment of the present invention, if the voltage at the gate 112 of the field effect transistor is smaller than the voltage at the source, the field effect transistor 104 cannot be turned on, thereby causing the open circuit of the closed circuit and blocking the flow of the standby current in the closed circuit.
It should be noted that the embodiment of the present invention provides a constant current driving circuit, which can reduce the standby current from within one hundred milliamperes to several hundred milliamperes, and to microamperes.
The embodiment of the utility model provides a produce the unit through the negative pressure and produce the negative pressure, after error integral unit enlargies negative pressure and standby voltage stack and integral, can make field effect transistor's grid voltage be less than source voltage to turn off field effect transistor, can block standby current's among the constant current drive circuit flow, the waste of electric energy when can reducing the standby of constant current drive circuit, constant current drive circuit's simple structure.
Based on the content of the above embodiments, the negative pressure generating unit 101 includes: a negative pressure generating subunit and a power supply subunit.
The input end of the negative pressure generating subunit is connected with the power supply subunit.
The power supply subunit can input positive voltage to the negative voltage generating subunit through the input end of the negative voltage generating subunit.
The negative pressure generating sub-unit may convert the positive pressure input from the power supply sub-unit into a first negative pressure.
The negative voltage generating sub-unit may be a negative voltage power converter, an inverter, or a DC/DC voltage inverter, etc.
The output of the negative voltage generating subunit is connected to a second input 116 of the error integrating unit.
The first negative pressure generated by the negative pressure generating subunit can be input to the error integrating unit via the output of the negative pressure generating subunit and the second input 116 of the error integrating unit.
The embodiment of the utility model provides a positive pressure conversion that produces the subunit through the negative pressure and be first negative pressure with the power subunit input can be simple, the efficient acquires the negative pressure, can make error integral circuit acquire the second negative pressure based on first negative pressure to for the grid of field effect transistor provides a negative pressure, turn-off field effect transistor after making the voltage of field effect transistor's grid electrode position be less than the voltage of source electrode position.
Based on the content of the above embodiments, the method further includes: a voltage dividing unit.
The voltage dividing unit is connected to the second input 116 of the error integrating unit.
Specifically, the input terminal of the voltage dividing unit is connected to the external analog input terminal, and the output terminal of the voltage dividing unit is connected to the second input terminal 116 of the error integrating unit.
The analog quantity of external input can be input to the voltage division unit through the external analog input end, the power of the output laser of the semiconductor laser and the analog quantity of the external input are in a linear relation, and the power of the output laser can be adjusted by changing the analog quantity of the external input according to the requirement of the output laser power.
When the semiconductor laser is in a standby state, the analog quantity input from the outside is zero.
The embodiment of the utility model provides a be connected through the second input of partial pressure unit with error integral unit, can regulate and control the voltage in the constant current drive circuit, can protect the constant current drive circuit.
Based on the content of the above embodiments, the negative pressure output by the negative pressure generating subunit is-3V to-10V.
Specifically, if the first negative voltage output by the negative voltage generation subunit is too small, it cannot be ensured that the second voltage obtained after the error integration circuit 102 superimposes and integrally amplifies the first negative voltage and the standby voltage is less than the standby voltage, that is, the voltage at the gate 112 of the fet is less than the voltage at the source 109, and thus the fet 104 cannot be ensured to be turned off, and the flow of the standby current in the closed loop cannot be effectively blocked.
If the first negative voltage output by the negative voltage generation subunit is too large, the error integration unit 102 may be damaged.
The embodiment of the utility model provides an in, according to semiconductor device under standby state, the range of the stand-by current of closed loop, the first negative pressure that confirms negative pressure production subunit output is minimum 3V. Based on the protection of the error integration unit 102, the first negative pressure output by the negative pressure generation subunit is determined to be 10V at most.
The embodiment of the utility model provides a produce the negative pressure that subunit output voltage scope is-3V to-10V through the negative pressure, can ensure to be less than source voltage based on the grid voltage that the negative pressure produced the subunit output obtained when protecting constant current drive circuit, and then can effectually block the flow of standby current in the constant current drive circuit.
Based on the above embodiments, the negative pressure output by the negative pressure generating subunit is-5V.
Specifically, the first negative pressure output by the negative pressure generating subunit is preferably-5V.
The negative voltage generating subunit outputs negative voltage of-5V, which can ensure that the error integrating circuit superposes and amplifies the voltage of-5V and the standby voltage to obtain negative voltage. The voltage at the gate 112 of the fet can be ensured to be lower than the voltage at the source 109, so that the fet 104 can be ensured to be turned off, and the flow of standby current in the closed loop can be effectively blocked.
The embodiment of the utility model provides a through negative pressure production subunit output-5V's negative pressure, can ensure to be less than source voltage based on the voltage at the grid that power subunit output voltage obtained when protecting constant current drive circuit, and then can effectually block the flow of standby current among the constant current drive circuit.
Based on the content of the above embodiments, the output voltage of the power supply subunit is 3V to 10V.
Specifically, the output voltage of the power supply subunit is equal to the absolute value of the first negative voltage generated by the negative voltage generation subunit.
If the output voltage of the power supply subunit is smaller, the first negative voltage generated by the negative voltage generating subunit according to the output voltage of the power supply subunit is smaller. The first negative voltage generated by the negative voltage generation subunit is small, and it cannot be ensured that after the error integration circuit superimposes and integrates and amplifies the first negative voltage and the standby voltage, the obtained second voltage is smaller than the standby voltage, that is, it cannot be ensured that the voltage at the gate 112 of the field effect transistor is smaller than the voltage at the source 109, so that the field effect transistor 104 cannot be ensured to be turned off, and the flow of the standby current in the closed loop cannot be effectively blocked.
If the output voltage of the power supply subunit is larger, the negative voltage generating subunit may be damaged.
The embodiment of the utility model provides an in, according to semiconductor device under standby state, the output voltage of confirming the power subunit is minimum 3V in the stand-by current's of closed loop scope. Based on the protection of the negative voltage generating subunit, it is determined that the output voltage of the power supply subunit is 10V at the maximum.
The embodiment of the utility model provides a be 3V to 10V's voltage through power subunit output voltage scope, can ensure to be less than source voltage based on the grid voltage that power subunit output voltage obtained when protecting constant current drive circuit, and then can effectually block the flow of standby current in the constant current drive circuit.
Based on the content of the above embodiments, the output voltage of the power supply subunit is 5V.
In particular, the output voltage of the power supply subunit is preferably 5V.
The negative voltage generation subunit can convert the 5V positive voltage input by the power supply subunit into-5V negative voltage, and can ensure that the error integration circuit superposes and amplifies the-5V voltage and the standby voltage to obtain negative voltage. The voltage at the gate 112 of the fet can be ensured to be lower than the voltage at the source 109, so that the fet 104 can be ensured to be turned off, and the flow of standby current in the closed loop can be effectively blocked.
The embodiment of the utility model provides a through the voltage of power subunit output 5V, can ensure to be less than source voltage based on the grid voltage that power subunit output voltage obtained when protecting constant current drive circuit, and then can effectually block the flow of standby current among the constant current drive circuit.
Based on the above embodiments, the fet 104 is an N-channel metal oxide semiconductor type fet.
A Metal Oxide Semiconductor Field Effect Transistor (MOS) belongs to an insulated gate type of a Field Effect Transistor, and the MOS Transistor is also called an insulated gate Field Effect Transistor. MOS transistors have the advantages of high input impedance, low noise, good thermal stability, simple manufacturing process, and strong radiation, and are often used in amplifier circuits or switching circuits.
The MOS transistor can be divided into an N-channel MOS transistor and a P-channel MOS transistor.
The N-channel MOS tube consists of a p-type substrate and two high-concentration N diffusion regions, and can be conducted only when the voltage at the grid source is greater than that at the source electrode. The N-channel MOS tube has small on-resistance under the condition of on-voltage drop, the grid drive does not need current, and the driving circuit is simple and is suitable for high-power parallel connection.
The P-channel MOS transistor refers to an n-type substrate, and a P-channel MOS transistor that carries current by the flow of holes. The P-channel MOS transistor has low hole mobility, and the transconductance of the P-channel MOS transistor is smaller than that of the N-channel MOS transistor under the condition that the geometric dimension of the MOS transistor is equal to the absolute value of the working voltage. In addition, the absolute value of the threshold voltage of the P-channel MOS transistor is high, and a high operating voltage is required. And finally, the voltage and polarity of the power supply of the P-channel MOS transistor are not compatible with the bipolar transistor. Therefore, the P-channel MOS transistor has a limited application range due to the defects of a large logic swing, a long charging and discharging process, a small transconductance of the device, and a low operating speed.
Based on the advantage and the defect of above-mentioned N channel MOS pipe and P channel MOS pipe, the embodiment of the utility model provides a select N channel MOS pipe for use as field effect transistor 104.
It should be noted that, the N-channel MOS transistor may further include a parasitic diode. The parasitic diode can protect the N-channel MOS tube. The embodiment of the utility model provides an in N channel MOS pipe is used as electronic switch, then this parasitic diode's negative pole is connected with power input 106, and this parasitic diode's positive pole is connected with current acquisition circuit's input.
In order to facilitate understanding of the above embodiments of the present invention, the constant current driving circuit of the present invention is described below by way of an example.
Fig. 2 is a second schematic structural diagram of the constant current driving circuit according to the present invention. As shown in fig. 2, the constant current drive circuit includes: the negative voltage generating unit 101, the error integrating unit 102, the current collecting unit 103, the N-channel MOS 204, the voltage dividing unit 203, the power input end 106, the positive terminal 107, the negative terminal 108, the negative voltage generating subunit 201, the power subunit 202, and the like. The constant current drive circuit and the semiconductor laser connected to the positive terminal 107 and the negative terminal 108 form a closed circuit.
C4, C5, and C6 in the negative voltage generating unit 101 are filter capacitors of the negative voltage generating subunit 201. After the power supply subunit 202 outputs +5V to the negative voltage generating subunit 201201, the negative voltage generating subunit 201 can generate a voltage of-5V and output the voltage of-5V to the error integrating unit 102 via the resistor R2.
The output terminal 115 of the negative voltage generating unit, the output terminal of the voltage dividing unit 203 and the second input terminal 116 of the error integrating unit are connected at a connection point VA.
The voltage dividing unit 203 includes R3, R7, and RP 1. The input end of the voltage dividing unit 203 is connected with an external analog input end, D/A is used for representing the analog quantity input from the outside, and the D/A value is 0V when the semiconductor laser is in a standby state. The maximum output power of the semiconductor laser can be modified by adjusting RP 1.
The current collecting unit 103 comprises R6 and R8, wherein R8 is a shunt. When the semiconductor laser is in a standby state, a standby current flows through R8, and R8 and R6 can convert the standby current into a standby voltage having a voltage magnitude corresponding to the magnitude of the standby current. Where Isamp is used to represent the standby voltage.
The error integration unit 102 is composed of C1, R1, and R5, and C2 is a filter capacitor of the error integration unit 102. The error integration unit can output a negative voltage after the negative voltage generated by the negative voltage generation unit and the standby voltage are superposed, integrated and amplified. The negative voltage is output to the gate 205 of the N-channel MOS transistor 204 through the R4, so that the voltage at the gate 205 of the N-channel MOS transistor 204 is a negative voltage. The voltage at the source 206 of the N-channel MOS transistor 204 is a standby voltage, the voltage at the gate 205 of the N-channel MOS transistor 204 is lower than the voltage at the source 206, and the N-channel MOS transistor 204 cannot be turned on.
When N-channel MOS transistor 204 is not turned on, the current flowing through N-channel MOS transistor 204 is caused by the saturation leakage current (I) of N-channel MOS transistor 204DSS) It is related. The saturation leakage current is usually several microamperes, which can reduce the standby current in the closed loop when the semiconductor laser is in standby.
The embodiment of the utility model provides a through chooseing for use N channel MOS pipe as field effect transistor, can be based on the characteristic of N channel MOS pipe, effectual flow of blocking standby current among the constant current drive circuit when semiconductor laser is in standby state.
Based on the content of the above embodiments, the negative pressure generating unit further includes: and a switch subunit.
The output of the negative voltage generating subunit is connected to the second input 116 of the error integrating unit via said switching subunit.
In particular, the switching subunit may be arranged between the output of the negative voltage generating subunit and the second input of the error integrating unit.
The switching sub-unit may be closed or opened depending on the state of the semiconductor laser.
If the semiconductor laser is in a standby state, the switch subunit is closed, at this time, the output end of the negative voltage generation subunit and the second input end 116 of the error integration unit are connected, the negative voltage generation subunit can input a first negative voltage to the error integration unit, so that the error integration unit can obtain a second negative voltage based on the first negative voltage to ensure that the voltage at the gate 112 of the field-effect transistor is smaller than the voltage at the source 109, and the field-effect transistor 104 is turned off to block the flow of standby current in the constant current driving circuit.
If the semiconductor laser is in a normal working state, the switch subunit is closed, and at this time, the output end of the negative pressure generating subunit is disconnected from the second input end 116 of the error integrating unit. The error integration unit 102 may amplify the input voltage such that the voltage at the gate 112 of the fet is greater than the voltage at the source 109 and the fet 104 is turned on.
The embodiment of the utility model provides an in the switch subunit is closed or the disconnection according to semiconductor laser's state, can ensure when semiconductor laser is in standby state that field effect transistor grid voltage is less than source voltage for field effect transistor turn-offs, blocks standby current's among the constant current drive circuit flow, can ensure that field effect transistor grid voltage is greater than source voltage at semiconductor laser normal operating condition, makes field effect transistor switch on, whether can more nimble control export the negative pressure.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (9)
1. A constant current driving circuit, comprising: the device comprises a negative pressure generating unit, an error integrating unit, a current collecting unit and a field effect tube;
the drain electrode of the field effect transistor is connected with the negative electrode terminal; the source electrode of the field effect transistor is connected with the input end of the current acquisition unit; the grid electrode of the field effect tube is connected with the output end of the error integration unit;
the output end of the current acquisition unit is connected with the first input end of the error integration unit;
and the output end of the negative pressure generation unit is connected with the second input end of the error integration unit.
2. The constant current drive circuit according to claim 1, wherein the negative voltage generation unit includes: a negative pressure generating subunit and a power supply subunit;
the input end of the negative pressure generating subunit is connected with the power supply subunit;
and the output end of the negative pressure generating subunit is connected with the second input end of the error integrating unit.
3. The constant current drive circuit according to claim 1, further comprising: a voltage dividing unit;
the voltage division unit is connected with the second input end of the error integration unit.
4. The constant current driving circuit according to claim 2, wherein the negative voltage output by the negative voltage generating subunit is from-3V to-10V.
5. The constant current driving circuit according to claim 4, wherein the negative voltage output by the negative voltage generating subunit is-5V.
6. The constant current driving circuit according to claim 2, wherein the output voltage of the power supply subunit is 3V to 10V.
7. The constant current driving circuit according to claim 6, wherein the output voltage of the power supply subunit is 5V.
8. The constant current driving circuit according to any one of claims 1 to 7, wherein the field effect transistor is an N-channel metal oxide semiconductor type field effect transistor.
9. The constant current drive circuit according to claim 2, 4, 5, 6, or 7, wherein the negative voltage generation unit further includes: a switch subunit;
and the output end of the negative pressure generating subunit is connected with the second input end of the error integrating unit through the switch subunit.
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| CN202120287971.4U CN214626786U (en) | 2021-02-01 | 2021-02-01 | Constant current driving circuit |
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| CN202120287971.4U CN214626786U (en) | 2021-02-01 | 2021-02-01 | Constant current driving circuit |
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