Laser pumping drive circuit

Abstract

The utility model provides a laser pumping drive circuit, and relates to the technical field of drive circuits. The output end of a voltage-controlled constant current source unit is connected with a pumping laser; the output end of the dual-mode current setting unit is connected with the reference input end of the voltage-controlled constant current source unit; the output end of the temperature control driving unit is connected with the thermoelectric refrigerating unit, and the feedback input end of the temperature control driving unit is used for receiving a temperature sensing signal; the analog input end of the multi-channel signal acquisition unit is respectively connected with a current sampling point of the voltage-controlled constant current source unit, the output end of the monitoring photodiode and a temperature sensing signal node; the positive power supply output end and the negative power supply output end of the power supply management unit are respectively connected with the power supply ends of the voltage-controlled constant current source unit and the multi-channel signal acquisition unit, and the enabling control end of the power supply management unit is connected with an external interface and is used for receiving a digital enabling signal and guaranteeing the temperature stability and reliability of the laser pumping drive circuit.

Description

Technical Field

[0001] This utility model relates to the field of driving circuit technology, and more specifically, to a laser pump driving circuit. Background Technology

[0002] In fiber optic communication systems, semiconductor-pumped lasers are widely used as excitation sources for optical amplifiers. These lasers have extremely high requirements for the stability of the driving current, the accuracy of temperature control, and the real-time monitoring of their operating status. Current fluctuations can lead to unstable output optical power, which in turn can cause increased signal noise or even communication interruption; while wavelength drift is mainly affected by temperature, especially in multi-band multiplexing scenarios, where even a small temperature control deviation can cause channel crosstalk.

[0003] In related technologies, laser pump drive circuits mostly adopt a single-mode current setting method, which cannot suppress current and temperature fluctuations under dynamic operating conditions, thus affecting the stability of the laser junction temperature. Utility Model Content

[0004] The problem this invention addresses is how to ensure the stability and reliability of laser pump drive circuits.

[0005] To solve the above problems, this utility model provides a laser pump drive circuit.

[0006] In the first aspect, this utility model provides a laser pump drive circuit, including a voltage-controlled constant current source unit, a dual-mode current setting unit, a temperature-controlled drive unit, a multi-channel signal acquisition unit, and a power management unit.

[0007] The output terminal of the voltage-controlled constant current source unit is connected to the pump laser;

[0008] The output terminal of the dual-mode current setting unit is connected to the reference input terminal of the voltage-controlled constant current source unit;

[0009] The output terminal of the temperature control drive unit is connected to the thermoelectric cooler, and the feedback input terminal of the temperature control drive unit is used to receive temperature sensing signals.

[0010] The analog input terminal of the multi-channel signal acquisition unit is connected to the current sampling point, the monitoring photodiode output terminal, and the temperature sensing signal node of the voltage-controlled constant current source unit, respectively.

[0011] The power output terminal of the power management unit is connected to the power supply terminals of the voltage-controlled constant current source unit and the multi-channel signal acquisition unit, respectively. The enable control terminal of the power management unit is connected to an external interface to receive digital enable signals.

[0012] Optionally, the dual-mode current setting unit includes a double-pole double-throw switch, an adjustable potentiometer group, and a digital-to-analog converter interface. The common terminal of the double-pole double-throw switch is connected to the reference input terminal of the voltage-controlled constant current source unit, and the two input terminals of the double-pole double-throw switch are respectively connected to the sliding terminal of the adjustable potentiometer group and the digital-to-analog converter interface.

[0013] Optionally, the adjustable potentiometer group includes two first potentiometers, the first fixed terminal of each first potentiometer is connected to the output node of the voltage reference source after voltage division, and the second fixed terminal of each first potentiometer is grounded;

[0014] The third and fourth terminals of the double-pole double-throw switch are respectively connected to the sliding terminals of the two first potentiometers, and the first and second terminals of the double-pole double-throw switch are respectively connected to the first fixed terminals of the two first potentiometers.

[0015] Optionally, the voltage-controlled constant current source unit includes a first constant current branch and a second constant current branch arranged symmetrically;

[0016] The first constant current branch includes a first operational amplifier, a first MOS transistor, and a first sampling resistor. The non-inverting input of the first operational amplifier receives a reference voltage. The inverting input of the first operational amplifier is connected to the first terminal of the first sampling resistor. The output of the first operational amplifier is connected to the gate of the first MOS transistor. The source of the first MOS transistor is connected to the first terminal of the first sampling resistor. The second terminal of the first sampling resistor is grounded. The drain of the first MOS transistor is connected to the positive terminal of the pump laser.

[0017] The second constant current branch includes a second operational amplifier, a second MOS transistor, and a second sampling resistor. The non-inverting input of the second operational amplifier receives a reference voltage, the inverting input of the second operational amplifier is connected to the first end of the second sampling resistor, the output of the second operational amplifier is connected to the gate of the second MOS transistor, the source of the second MOS transistor is connected to the first end of the second sampling resistor, the second end of the second sampling resistor is connected to the negative power supply, and the drain of the second MOS transistor is connected to the negative terminal of the pump laser.

[0018] Optionally, the temperature control drive unit includes a second control chip, an LC filter network, and a thermoelectric cooler interface;

[0019] The positive and negative output pins of the second control chip are connected to the input terminal of the LC filter network;

[0020] The LC filter network includes a first inductor, a second inductor, a first electrolytic capacitor, and a second electrolytic capacitor.

[0021] The first end of the first inductor is connected to the positive output pin of the second control chip, and the second end is connected to the positive terminal of the thermoelectric cooler interface;

[0022] The first end of the second inductor is connected to the negative output pin of the second control chip, and the second end is connected to the negative terminal of the thermoelectric cooler interface;

[0023] The first electrolytic capacitor is connected between the positive terminal of the thermoelectric cooler interface and ground;

[0024] The second electrolytic capacitor is connected between the negative terminal of the thermoelectric cooler interface and ground.

[0025] Optionally, the second control chip further includes a positive feedback input pin and a negative feedback input pin;

[0026] The positive feedback input pin is connected to the temperature sensing signal node through a second resistor, and the positive feedback input pin is grounded through a second capacitor;

[0027] The negative feedback input pin is connected to the positive power supply through a voltage divider network composed of the third and fourth resistors.

[0028] Optionally, the multi-channel signal acquisition unit includes at least three analog-to-digital converters, which are used to acquire LD drive current, photodiode current and temperature signals, respectively.

[0029] Optionally, the analog input terminal of the first analog-to-digital converter is connected to both ends of the LD drive current sampling resistor;

[0030] The analog input terminal of the second analog-to-digital converter is connected to the output terminal of the transimpedance amplifier monitoring the photodiode;

[0031] The analog input of the third analog-to-digital converter is connected to the temperature sensing signal node.

[0032] Optionally, the power management unit includes a positive power control subunit, a negative power control subunit, and a digital enable control subunit;

[0033] The digital enable control subunit includes a first NPN transistor, the base of which serves as the digital enable input terminal to receive the digital enable signal, the emitter of which is grounded, and the collector of which serves as the output terminal of the digital enable control subunit.

[0034] The positive power supply control subunit includes a second NPN transistor and a third MOS transistor. The base of the second NPN transistor is connected to the collector of the first NPN transistor. The collector of the second NPN transistor is grounded. The emitter of the second NPN transistor is connected to the gate of the third MOS transistor. The source of the third MOS transistor is grounded. The drain of the third MOS transistor is connected to the positive power supply output terminal.

[0035] The negative power supply control subunit includes a third NPN transistor and a fourth MOS transistor. The base of the third NPN transistor is connected to the collector of the first NPN transistor. The collector of the third NPN transistor is grounded. The emitter of the third NPN transistor is connected to the source of the fourth MOS transistor. The drain and gate of the fourth MOS transistor are connected to the negative power supply output terminal.

[0036] Optionally, the positive power supply control subunit further includes a delayed start circuit, which includes a first resistor, a first capacitor, and a fourth NPN transistor.

[0037] The first end of the first resistor is connected to a positive power supply, and the second end of the first resistor is connected to the base of the fourth NPN transistor.

[0038] The first terminal of the first capacitor is connected to the base of the fourth NPN transistor, and the second terminal of the first capacitor is grounded.

[0039] The collector of the fourth NPN transistor is grounded, and the emitter of the fourth NPN transistor is connected to the gate of the first MOS transistor of the positive power control subunit.

[0040] The beneficial effects of the laser pump drive circuit of this invention are:

[0041] The output of the voltage-controlled constant current source unit is connected to the pump laser. Voltage control ensures a stable output of the laser's drive current, preventing optical power drift or device damage caused by current fluctuations and providing stable operating conditions for the laser. The output of the dual-mode current setting unit is connected to the reference input of the voltage-controlled constant current source unit, supporting both manual and digital adjustment. This balances debugging flexibility with automated operation, allowing the current setpoint to quickly adapt to different working scenarios, improving operational adaptability and control response. The output of the temperature-controlled drive unit is connected to a thermoelectric cooler, and its feedback input receives temperature sensing signals, forming a closed-loop temperature control circuit. Based on real-time temperature feedback, the cooling or heating power of the thermoelectric cooler is dynamically adjusted to maintain the laser's operating temperature within the set range, suppressing wavelength drift and efficiency degradation. The analog input of the multi-channel signal acquisition unit is connected to the pump laser's current sampling point, the monitoring photodiode output, and the temperature sensing signal node, simultaneously acquiring drive current, output optical power, and temperature signals. The positive and negative power outputs of the power management unit supply power to the voltage-controlled constant current source unit and the multi-channel signal acquisition unit, respectively. The enable control terminal receives external digital enable signals. Independent positive and negative power rails meet the bipolar power supply requirements of the voltage-controlled constant current source. Digital enable control enables controlled start and stop of the power supply, avoiding power-on surges and reducing the risk of false triggering. All units work together to form an integrated drive architecture that combines current control, temperature regulation, status monitoring, and power management, ensuring the temperature stability and long-term operational reliability of the laser pump drive circuit. Attached Figure Description

[0042] Figure 1 This is a system block diagram of the laser pump drive circuit according to an embodiment of the present invention;

[0043] Figure 2 This is a topology diagram of the dual-mode current setting unit according to an embodiment of the present invention;

[0044] Figure 3 This is a topology diagram of the voltage-controlled constant current source unit according to an embodiment of the present invention;

[0045] Figure 4 This is a topology diagram of the temperature control drive unit according to an embodiment of the present invention;

[0046] Figure 5 This is a topology diagram of the power management unit according to an embodiment of the present invention. Detailed Implementation

[0047] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Although some embodiments of this utility model are shown in the drawings, it should be understood that this utility model can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this utility model. It should be understood that the drawings and embodiments of this utility model are for illustrative purposes only and are not intended to limit the scope of protection of this utility model.

[0048] It should be understood that the steps described in the method embodiments of this utility model may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this utility model is not limited in this respect.

[0049] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this utility model are only used to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0050] It should be noted that the terms "one" and "multiple" used in this utility model are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0051] The names of the messages or information exchanged between the multiple devices in this embodiment of the invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0052] like Figure 1 As shown in the figure, a laser pump drive circuit provided by this utility model includes a voltage-controlled constant current source unit, a dual-mode current setting unit, a temperature-controlled drive unit, a multi-channel signal acquisition unit, and a power management unit.

[0053] The output of the voltage-controlled constant current source unit is connected to the pump laser.

[0054] The voltage-controlled constant current source unit is used to provide a controlled drive current to the pump laser. The output is directly connected to the pump laser, and the output current can be linearly adjusted by regulating the internal reference voltage. This unit uses voltage as the control input, featuring fast response and low ripple, which helps maintain stable laser output power.

[0055] The output terminal of the dual-mode current setting unit is connected to the reference input terminal of the voltage-controlled constant current source unit.

[0056] The output of the dual-mode current setting unit is connected to the reference input of the voltage-controlled constant current source unit to provide the setting voltage. This unit is suitable for two independent setting modes: a local manual adjustment mode, suitable for on-site commissioning or scenarios without a host computer; and a remote digital control mode, facilitating integration into automated management environments. The two modes can be switched without interference, enhancing the device's adaptability to different application scenarios.

[0057] The output terminal of the temperature control drive unit is connected to the thermoelectric cooler, and the feedback input terminal of the temperature control drive unit is used to receive temperature sensing signals.

[0058] The output of the temperature control drive unit is connected to a thermoelectric cooler (TEC) for active temperature regulation of the pump laser. Its feedback input receives an electrical signal from a temperature sensing node, reflecting the current temperature state of the laser. Based on this feedback, the temperature control drive unit dynamically adjusts the driving direction and intensity of the TEC, thereby maintaining the laser's operating temperature within the target range and effectively suppressing wavelength drift.

[0059] The analog input terminal of the multi-channel signal acquisition unit is connected to the current sampling point, the monitoring photodiode output terminal, and the temperature sensing signal node of the voltage-controlled constant current source unit, respectively.

[0060] The multi-channel signal acquisition unit has multiple analog input terminals, which are respectively connected to the current sampling point of the voltage-controlled constant current source unit, the output terminal of the monitoring photodiode, and the temperature sensing signal node. By synchronously acquiring the drive current, output optical power indication signal, and temperature information, it provides comprehensive status data to the external main controller, facilitating fault diagnosis, performance evaluation, or closed-loop regulation.

[0061] The positive and negative power output terminals of the power management unit are connected to the power supply terminals of the voltage-controlled constant current source unit and the multi-channel signal acquisition unit, respectively. The enable control terminal of the power management unit is connected to an external interface to receive digital enable signals.

[0062] The power management unit is responsible for providing operating power to analog circuits that require controlled power-up. Its positive and negative power outputs are connected to the power supply terminals of the voltage-controlled constant current source unit and the temperature-controlled drive unit, respectively, meeting their bipolar power requirements. This unit also has an enable control terminal, which connects to an external interface to receive digital enable signals. These signals allow for unified control of the opening and closing of each power rail, preventing power-up surges and improving the laser's operational safety.

[0063] Optionally, such as Figure 2 As shown, the dual-mode current setting unit includes a double-pole double-throw switch, an adjustable potentiometer group, and a digital-to-analog converter interface. The common terminal of the double-pole double-throw switch is connected to the reference input terminal of the voltage-controlled constant current source unit, and the two input terminals of the double-pole double-throw switch are respectively connected to the sliding terminal of the adjustable potentiometer group and the digital-to-analog converter interface.

[0064] Optionally, the adjustable potentiometer group includes two first potentiometers, the first fixed terminal of each first potentiometer is connected to the output node of the voltage reference source after voltage division, and the second fixed terminal of each first potentiometer is grounded;

[0065] The third and fourth terminals of the double-pole double-throw switch are respectively connected to the sliding terminals of the two first potentiometers, and the first and second terminals of the double-pole double-throw switch are respectively connected to the first fixed terminals of the two first potentiometers.

[0066] The dual-mode current setting unit is used to provide a switchable reference voltage to the voltage-controlled constant current source unit, so as to achieve flexible setting of the pump laser drive current. This unit includes a double-pole double-throw switch SW1 and a fixed reference voltage branch consisting of a high-precision voltage reference source U20 and its voltage divider resistors.

[0067] The double-pole double-throw switch SW1 serves as a mode selection device. Pin 4 is connected to the reference input terminal C_Vref of the voltage-controlled constant current source unit; pins 1 and 2 are respectively connected to the first fixed terminals of two first potentiometers. One potentiometer and the voltage divider resistor R119 form the first branch, and its sliding terminal is connected through the fourth terminal pin 4 of SW1; the other potentiometer and the voltage divider resistor R120 form the second branch, and its sliding terminal is connected through the third terminal pin 3 of SW1.

[0068] By toggling the double-pole double-throw switch SW1, a physical switch can be made between two setting modes: when SW1 is in the ON position, the voltage of the sliding terminal of the local potentiometer is connected to C_Vref for manual adjustment; when SW1 is in the OFF position, the output of another potentiometer or DAC is connected to C_Vref for digital setting.

[0069] Optionally, the voltage-controlled constant current source unit includes a first constant current branch and a second constant current branch arranged symmetrically;

[0070] The first constant current branch includes a first operational amplifier, a first MOS transistor, and a first sampling resistor. The non-inverting input of the first operational amplifier receives a reference voltage. The inverting input of the first operational amplifier is connected to the first terminal of the first sampling resistor. The output of the first operational amplifier is connected to the gate of the first MOS transistor. The source of the first MOS transistor is connected to the first terminal of the first sampling resistor. The second terminal of the first sampling resistor is grounded. The drain of the first MOS transistor is connected to the positive terminal of the pump laser.

[0071] The second constant current branch includes a second operational amplifier, a second MOS transistor, and a second sampling resistor. The non-inverting input of the second operational amplifier receives a reference voltage, the inverting input of the second operational amplifier is connected to the first end of the second sampling resistor, the output of the second operational amplifier is connected to the gate of the second MOS transistor, the source of the second MOS transistor is connected to the first end of the second sampling resistor, the second end of the second sampling resistor is connected to the negative power supply, and the drain of the second MOS transistor is connected to the negative terminal of the pump laser.

[0072] The positive terminal of the pump laser is also connected to the positive power supply output terminal +5V_1, and the negative terminal of the pump laser is also connected to the negative power supply output terminal -5V_1.

[0073] like Figure 3 As shown, the voltage-controlled constant current source unit includes a symmetrically arranged first constant current branch and a second constant current branch, used to provide a stable current for the pump laser. The first constant current branch consists of an operational amplifier U23, a MOSFET AO3400A, and a sampling resistor R121. The non-inverting input of the operational amplifier is connected to a reference voltage V_ref, the inverting input is connected to the first terminal of the sampling resistor, the output is connected to the gate of the MOSFET, the source of the MOSFET is connected to the first terminal of the sampling resistor and grounded through the sampling resistor, and the drain is connected to the positive terminal of the pump laser. The second constant current branch consists of an operational amplifier U24, a MOSFET AO3400A, and a sampling resistor R122, with the same structure as the first branch, but the drain of its MOSFET is connected to the negative terminal of the pump laser. The two branches obtain power from the positive and negative power rails respectively, and achieve dynamic control of the voltage across the laser through feedback adjustment, thereby maintaining the set current value. This implementation utilizes a symmetrical topology to reduce noise impact and improve current stability, making it suitable for laser driving scenarios requiring high dynamic response.

[0074] Optionally, the temperature control drive unit includes a second control chip, an LC filter network, and a thermoelectric cooler interface;

[0075] The positive and negative output pins of the second control chip are connected to the input terminal of the LC filter network;

[0076] The LC filter network includes a first inductor, a second inductor, a first electrolytic capacitor, and a second electrolytic capacitor.

[0077] The first end of the first inductor is connected to the positive output pin of the second control chip, and the second end is connected to the positive terminal of the thermoelectric cooler interface;

[0078] The first end of the second inductor is connected to the negative output pin of the second control chip, and the second end is connected to the negative terminal of the thermoelectric cooler interface;

[0079] The first electrolytic capacitor is connected between the positive terminal of the thermoelectric cooler interface and ground;

[0080] The second electrolytic capacitor is connected between the negative terminal of the thermoelectric cooler interface and ground.

[0081] like Figure 4 As shown, the temperature control drive unit includes a second control chip MAX1978, an LC filter network, and a thermoelectric cooler interface. The positive and negative output pins of the second control chip are respectively connected to the input terminals of the LC filter network. This LC filter network consists of inductors L4 and L5, electrolytic capacitors C41 and C45. One end of inductor L4 is connected to the positive output pin of the second control chip, and the other end is connected to the positive terminal of the thermoelectric cooler interface. Electrolytic capacitor C41 is connected in parallel between the positive terminal of the thermoelectric cooler interface and ground. One end of inductor L5 is connected to the negative output pin of the second control chip, and the other end is connected to the negative terminal of the thermoelectric cooler interface. Electrolytic capacitor C45 is connected in parallel between the negative terminal of the thermoelectric cooler interface and ground. The second control chip generates a drive signal through its internal H-bridge circuit, which is smoothed by the LC filter network and then sent to the thermoelectric cooler to dynamically adjust the voltage across the cooler, thereby controlling its operating state. This embodiment utilizes the combination of inductors and capacitors to suppress current ripple, reduce electromagnetic interference, and improve temperature control stability.

[0082] Optionally, the second control chip further includes a positive feedback input pin and a negative feedback input pin;

[0083] The positive feedback input pin is connected to the temperature sensing signal node through a second resistor, and the positive feedback input pin is grounded through a second capacitor;

[0084] The negative feedback input pin is connected to the positive power supply through a voltage divider network composed of the third and fourth resistors.

[0085] The second control chip, MAX1978, has a positive feedback input pin CS+ and a negative feedback input pin CS. The positive feedback input pin CS+ is connected to the temperature sensing signal node via a resistor. This node is connected to the output of a voltage divider circuit consisting of a thermistor and a pull-up resistor, and is grounded via a capacitor to form a low-pass filter to suppress high-frequency noise. The negative feedback input pin CS... A voltage divider network composed of resistors is connected to the main positive power supply +5V_1 to provide a stable common-mode reference voltage. Two feedback pins together form a differential input structure, comparing the temperature sensing signal with the reference voltage. This allows the second control chip to dynamically adjust the direction and amplitude of the thermoelectric cooler's drive current based on the temperature difference, achieving closed-loop control of the laser temperature.

[0086] Optionally, the multi-channel signal acquisition unit includes at least three analog-to-digital converters, which are used to acquire LD drive current, photodiode current and temperature signals, respectively.

[0087] Optionally, the analog input terminal of the first analog-to-digital converter is connected to both ends of the LD drive current sampling resistor;

[0088] The analog input terminal of the second analog-to-digital converter is connected to the output terminal of the transimpedance amplifier monitoring the photodiode;

[0089] The analog input of the third analog-to-digital converter is connected to the temperature sensing signal node.

[0090] The multi-channel signal acquisition unit includes three analog-to-digital converters (ADCs) for acquiring the laser drive current, monitoring the photodiode output current, and sensing the temperature voltage, respectively. The first ADC is connected to the temperature sensing signal node, with its analog input connected to a thermistor voltage divider output, converting the temperature voltage signal into a digital value via an SPI interface. The second ADC is connected to the output of the photodiode transimpedance amplifier, acquiring the voltage signal corresponding to the current generated by the optical power, enabling real-time monitoring of the laser output intensity. The third ADC is connected to the LD load current sampling point, with its input connected to the differential voltage across the current sampling resistor, used to acquire the actual value of the constant current source output current. All three ADCs employ independent power supplies and reference voltage configurations, communicating with the main control chip through different SPI channels to complete the synchronous digitization processing of multiple analog signals. This implementation utilizes a high-resolution ADC to achieve independent acquisition of key parameters, improving control response capability and data reliability.

[0091] Optionally, the power management unit includes a positive power control subunit, a negative power control subunit, and a digital enable control subunit;

[0092] The digital enable control subunit includes a first NPN transistor, the base of which serves as the digital enable input terminal to receive the digital enable signal, the emitter of which is grounded, and the collector of which serves as the output terminal of the digital enable control subunit.

[0093] The positive power supply control subunit includes a second NPN transistor and a third MOS transistor. The base of the second NPN transistor is connected to the collector of the first NPN transistor. The collector of the second NPN transistor is grounded. The emitter of the second NPN transistor is connected to the gate of the third MOS transistor. The source of the third MOS transistor is grounded. The drain of the third MOS transistor is connected to the positive power supply output terminal.

[0094] The negative power supply control subunit includes a third NPN transistor and a fourth MOS transistor. The base of the third NPN transistor is connected to the collector of the first NPN transistor. The collector of the third NPN transistor is grounded. The emitter of the third NPN transistor is connected to the source of the fourth MOS transistor. The drain and gate of the fourth MOS transistor are connected to the negative power supply output terminal.

[0095] like Figure 5 As shown, the power management unit includes a positive power control subunit, a negative power control subunit, and a digital enable control subunit.

[0096] The positive power supply control subunit includes an NPN transistor Q6 and a P-channel MOSFET Q1. The collector of Q6 is connected to the base of Q1. The collector of Q1 is grounded, the emitter is connected to the gate of the first MOSFET, the source of the third MOSFET is grounded, and the drain is connected to the positive power supply output terminal 5V_1.

[0097] The negative power supply control subunit includes a third NPN transistor Q8 and a fourth MOSFET Q2. The base of the third NPN transistor Q8 is connected to the collector of the first NPN transistor, and the collector of the third NPN transistor Q8 is grounded. The emitter of the third NPN transistor Q8 is connected to the source of the fourth MOSFET Q2, and the drain and gate of the fourth MOSFET Q2 are connected to the negative power supply output terminal -5V_1. This embodiment achieves synchronous controlled start and stop of the positive and negative power supplies through a three-stage transistor cascade structure and provides a basic driving node for the subsequent delayed start function.

[0098] Optionally, the positive power supply control subunit further includes a delayed start circuit, which includes a first resistor, a first capacitor, and a fourth NPN transistor.

[0099] The first end of the first resistor is connected to a positive power supply, and the second end of the first resistor is connected to the base of the fourth NPN transistor.

[0100] The first terminal of the first capacitor is connected to the base of the fourth NPN transistor, and the second terminal of the first capacitor is grounded.

[0101] The collector of the fourth NPN transistor is grounded, and the emitter of the fourth NPN transistor is connected to the gate of the first MOS transistor of the positive power supply control subunit.

[0102] The positive power supply control subunit includes a delayed start-up circuit, which consists of a resistor R84, a capacitor, and an NPN transistor Q6. This implementation utilizes the RC time constant to achieve a power-on delay, preventing the laser from operating when the power supply is unstable, and works in conjunction with digital enable control to complete the controlled power-on process. Specifically, the NPN transistor Q6 serves as both the second NPN transistor in the positive power supply control subunit and the fourth NPN transistor in the delayed start-up circuit, combining logic driving and delay functions.

[0103] Although the present invention has been disclosed above, its protection scope is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the protection scope of the present invention.

Claims

1. A laser pump drive circuit, characterized in that, It includes a voltage-controlled constant current source unit, a dual-mode current setting unit, a temperature control drive unit, a multi-channel signal acquisition unit, and a power management unit; The output terminal of the voltage-controlled constant current source unit is connected to the pump laser; The output terminal of the dual-mode current setting unit is connected to the reference input terminal of the voltage-controlled constant current source unit; The output terminal of the temperature control drive unit is connected to the thermoelectric cooler, and the feedback input terminal of the temperature control drive unit is used to receive temperature sensing signals. The analog input terminal of the multi-channel signal acquisition unit is connected to the current sampling point, the monitoring photodiode output terminal, and the temperature sensing signal node of the voltage-controlled constant current source unit, respectively. The power output terminal of the power management unit is connected to the power supply terminals of the voltage-controlled constant current source unit and the multi-channel signal acquisition unit, respectively. The enable control terminal of the power management unit is connected to an external interface to receive digital enable signals.

2. The laser pump drive circuit as described in claim 1, characterized in that, The dual-mode current setting unit includes a double-pole double-throw switch, an adjustable potentiometer group, and a digital-to-analog converter interface. The common terminal of the double-pole double-throw switch is connected to the reference input terminal of the voltage-controlled constant current source unit, and the two input terminals of the double-pole double-throw switch are respectively connected to the sliding terminal of the adjustable potentiometer group and the digital-to-analog converter interface.

3. The laser pump drive circuit as described in claim 2, characterized in that, The adjustable potentiometer group includes two first potentiometers, the first fixed terminal of each first potentiometer is connected to the output node of the voltage reference source after voltage division, and the second fixed terminal of each first potentiometer is grounded; The third and fourth terminals of the double-pole double-throw switch are respectively connected to the sliding terminals of the two first potentiometers, and the first and second terminals of the double-pole double-throw switch are respectively connected to the first fixed terminals of the two first potentiometers.

4. The laser pump drive circuit as described in claim 1, characterized in that, The voltage-controlled constant current source unit includes a first constant current branch and a second constant current branch arranged symmetrically. The first constant current branch includes a first operational amplifier, a first MOS transistor, and a first sampling resistor. The non-inverting input of the first operational amplifier receives a reference voltage. The inverting input of the first operational amplifier is connected to the first terminal of the first sampling resistor. The output of the first operational amplifier is connected to the gate of the first MOS transistor. The source of the first MOS transistor is connected to the first terminal of the first sampling resistor. The second terminal of the first sampling resistor is grounded. The drain of the first MOS transistor is connected to the positive terminal of the pump laser. The second constant current branch includes a second operational amplifier, a second MOS transistor, and a second sampling resistor. The non-inverting input of the second operational amplifier receives a reference voltage, the inverting input of the second operational amplifier is connected to the first end of the second sampling resistor, the output of the second operational amplifier is connected to the gate of the second MOS transistor, the source of the second MOS transistor is connected to the first end of the second sampling resistor, the second end of the second sampling resistor is connected to the negative power supply, and the drain of the second MOS transistor is connected to the negative terminal of the pump laser.

5. The laser pump drive circuit as described in claim 1, characterized in that, The temperature control drive unit includes a second control chip, an LC filter network, and a thermoelectric cooler interface; The positive and negative output pins of the second control chip are connected to the input terminal of the LC filter network; The LC filter network includes a first inductor, a second inductor, a first electrolytic capacitor, and a second electrolytic capacitor. The first end of the first inductor is connected to the positive output pin of the second control chip, and the second end is connected to the positive terminal of the thermoelectric cooler interface; The first end of the second inductor is connected to the negative output pin of the second control chip, and the second end is connected to the negative terminal of the thermoelectric cooler interface; The first electrolytic capacitor is connected between the positive terminal of the thermoelectric cooler interface and ground; The second electrolytic capacitor is connected between the negative terminal of the thermoelectric cooler interface and ground.

6. The laser pump drive circuit as described in claim 5, characterized in that, The second control chip also includes a positive feedback input pin and a negative feedback input pin; The positive feedback input pin is connected to the temperature sensing signal node through a second resistor, and the positive feedback input pin is grounded through a second capacitor; The negative feedback input pin is connected to the positive power supply through a voltage divider network composed of the third and fourth resistors.

7. The laser pump drive circuit as described in claim 1, characterized in that, The multi-channel signal acquisition unit includes at least three analog-to-digital converters, which are used to acquire LD drive current, photodiode current and temperature signals, respectively.

8. The laser pump drive circuit as described in claim 7, characterized in that, The analog input terminal of the first analog-to-digital converter is connected to both ends of the LD drive current sampling resistor; The analog input terminal of the second analog-to-digital converter is connected to the output terminal of the transimpedance amplifier monitoring the photodiode; The analog input of the third analog-to-digital converter is connected to the temperature sensing signal node.

9. The laser pump drive circuit as described in claim 1, characterized in that, The power management unit includes a positive power control subunit, a negative power control subunit, and a digital enable control subunit. The digital enable control subunit includes a first NPN transistor, the base of which serves as the digital enable input terminal to receive the digital enable signal, the emitter of which is grounded, and the collector of which serves as the output terminal of the digital enable control subunit. The positive power supply control subunit includes a second NPN transistor and a third MOS transistor. The base of the second NPN transistor is connected to the collector of the first NPN transistor. The collector of the second NPN transistor is grounded. The emitter of the second NPN transistor is connected to the gate of the third MOS transistor. The source of the third MOS transistor is grounded. The drain of the third MOS transistor is connected to the positive power supply output terminal. The negative power supply control subunit includes a third NPN transistor and a fourth MOS transistor. The base of the third NPN transistor is connected to the collector of the first NPN transistor. The collector of the third NPN transistor is grounded. The emitter of the third NPN transistor is connected to the source of the fourth MOS transistor. The drain and gate of the fourth MOS transistor are connected to the negative power supply output terminal.

10. The laser pump drive circuit as described in claim 9, characterized in that, The positive power supply control subunit also includes a delayed start circuit, which includes a first resistor, a first capacitor, and a fourth NPN transistor. The first end of the first resistor is connected to a positive power supply, and the second end of the first resistor is connected to the base of the fourth NPN transistor. The first terminal of the first capacitor is connected to the base of the fourth NPN transistor, and the second terminal of the first capacitor is grounded. The collector of the fourth NPN transistor is grounded, and the emitter of the fourth NPN transistor is connected to the gate of the first MOS transistor of the positive power supply control subunit.

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