Pulse constant current power supply circuit for camera intermittent trigger LED constant current control

Abstract

The invention relates to the technical field of power supply circuits, in particular to a pulse constant-current power supply circuit for camera intermittent trigger LED constant-current control, a voltage-adjustable Boost power supply module of the pulse constant-current power supply circuit comprises an oscillator, a power supply management chip U1, a first path error amplifier and a second path error amplifier, and the first path error amplifier is used for adjusting the duty ratio of a PWM signal; the second path error amplifier is used for limiting the maximum current; the pulse constant current module supplies power through an internal BOOST boost power supply or an external constant voltage source; and a processor module. The oscillator is matched with the power management chip U1 to generate a sawtooth wave oscillation signal, the two error amplifiers are used for jointly controlling output, the two error amplifiers are responsible for voltage feedback and current limitation respectively to ensure the stability and safety of the system, the first error amplifier is adjusted through a voltage signal output by the MCU DAC, and the second error amplifier is used for adjusting the voltage signal output by the MCU DAC. And the second error amplifier is used for current detection to prevent an overcurrent condition.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply circuits, and in particular to a pulsed constant current power supply circuit for intermittent triggering of LED constant current control in cameras. Background Art

[0002] In the prior art, traditional pulsed power supply designs often struggle to meet the requirements of high-frequency and high-precision control. Especially in application scenarios that require precise current control, such as camera flash control, laser driving, and LED lighting, the limitations of traditional pulsed power supplies are more evident. These application scenarios typically demand that the power supply has high efficiency, fast response time, stable output, and multi-channel synchronous or asynchronous control capabilities. Specifically, traditional pulsed power supplies have the following main problems: Insufficient frequency response: Traditional designs usually cannot provide a high enough frequency response to meet high-speed control requirements. Low current control accuracy: Due to the lack of precise feedback mechanisms and control algorithms, it is difficult to ensure the accuracy and stability of current control. Difficulty in multi-channel synchronization: When multiple loads need to be controlled simultaneously, ensuring the synchronization and independent adjustment capabilities between all channels is a challenge. Summary of the Invention

[0003] The present invention provides a pulsed constant current power supply circuit for intermittent triggering of LED constant current control in cameras. A sawtooth oscillation signal is generated by the cooperation of an oscillator and the power management chip U1, and the output is controlled jointly by two error amplifiers. The two error amplifiers are respectively responsible for voltage feedback and current limiting to ensure the stability and safety of the system. The first error amplifier is finely adjusted by the voltage signal output by the MCU DAC, and the second error amplifier is used for current detection to prevent overcurrent situations.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a pulsed constant current power supply circuit for intermittent triggering of LED constant current control in cameras, which includes:

[0006] An adjustable voltage Boost power supply module, the adjustable voltage Boost power supply module includes an oscillator, a power management chip U1, a first error amplifier, and a second error amplifier. The oscillator and the power management chip U1 cooperate to generate a sawtooth oscillation signal. The first error amplifier is used to receive the voltage signal from an external MCU and input it to the inverting input terminal of a comparator to adjust the duty cycle of the PWM signal. The second error amplifier is used to limit the maximum current.

[0007] A pulsed constant current module, powered by an internal BOOST boost power supply or an external constant voltage source;

[0008] A processor module for controlling the pulse width and detecting pulse input;

[0009] The adjustable - voltage Boost power module and the pulse constant - current module are respectively connected to the processor module.

[0010] Among them, the oscillator includes a resistor R10 and a capacitor C8. The model of the power management chip U1 is TL494. One end of the resistor R10 is connected to the RT pin of the power management chip U1, one end of the capacitor C8 is connected to the CT pin of the power management chip U1, and the other ends of the resistor R10 and the capacitor C8 are connected and then grounded.

[0011] Among them, the adjustable - voltage Boost power module further includes a half - bridge gate driver chip U2 and a resistor R4. The half - bridge gate driver chip U2 is used to receive the PWM output of the power management chip U1 and provide built - in dead - time protection. The HIN pin and the LIN# pin of the half - bridge gate driver chip U2 are connected and then connected to the E2 pin of the power management chip U1 and one end of the resistor R4. The other end of the resistor R4 is grounded, and the E2 pin of the power management chip U1 is connected to the E1 pin of the power management chip U1.

[0012] Among them, the adjustable - voltage Boost power module further includes an MOS transistor Q3, a capacitor C7, a resistor R9, a resistor R12, and a resistor R13. The DTC pin of the power management chip U1 is connected to one end of the resistor R9, the other end of the resistor R9 is grounded, the gate of the MOS transistor Q3 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to the processor module, the source and drain of the MOS transistor Q3 are connected in parallel with the resistor R13, the capacitor C7 is connected in parallel with the resistor R13, and the source of the MOS transistor Q3 is connected to the DTC pin of the power management chip U1.

[0013] Among them, the processor module includes a central processor AX58200, and the central processor AX58200 is communicatively connected to an external host computer through an EtherCAT interface.

[0014] Among them, the processor module further includes a BUCK step - down chip U4, a transient voltage suppression diode D5, a resistor R19, and a resistor R20. The BUCK step - down chip U4 is used to step down the 24V input voltage to 6.8V. The twelfth pin of the central processor AX58200 is connected to one end of the resistor R20, the other end of the resistor R20 is respectively connected to one end of the resistor R19 and the cathode of the transient voltage suppression diode D5, the anode of the transient voltage suppression diode D5 is grounded, and the other end of the resistor R19 is connected to an external MCU.

[0015] Among them, the pulse constant current module includes a digital-to-analog converter U7 and four independent channels. The model of the digital-to-analog converter U7 is AD5696. The digital-to-analog converter U7 is connected to the load through four independent channels respectively, and the digital-to-analog converter U7 is communicatively connected to the central processor AX58200 through the SCL pin and the SDA pin.

[0016] Among them, the four independent channels include a first ADC channel, a second ADC channel, a third ADC channel, and a fourth ADC channel; the first ADC channel includes a resistor R37, a resistor R40, a resistor R45, a resistor R49, a resistor R54, a resistor R58, a resistor R62, a capacitor C34, a capacitor C38, a capacitor C47, a capacitor C51, a capacitor C54, a capacitor C55, a comparator U9.1, a comparator U9.2, a switching transistor Q20, a fuse F2, a capacitor C18, a capacitor C22, a capacitor C26, a capacitor C30, a resistor R21, a resistor R25, a resistor R29, a resistor R33, a switching transistor Q4, a switching transistor Q8, a switching transistor Q12, a switching transistor Q13, a zener diode D6, and a diode D7. The digital-to-analog converter U7 is connected to one end of the resistor R37 through the VOUTA pin. The other end of the resistor R37 is connected to one end of the resistor R45, one end of the capacitor C34, and the positive input terminal of the comparator U9.1. The other ends of the resistor R45 and the capacitor C34 are grounded respectively. The output terminal of the comparator U9.1 is connected to one end of the resistor R40 and one end of the capacitor C37. The capacitor C38 is connected in parallel with the resistor R40. The other end of the resistor R40 is connected to the gate of the switching transistor Q20. The other end of the capacitor C47 is connected to the negative input terminal of the comparator U9.1 and one end of the resistor R49 respectively. The other end of the resistor R49 is connected to the positive input terminal of the comparator U9.2, one end of the capacitor C51, the source of the switching transistor Q20, and one end of the resistor R54 respectively. The other ends of the capacitor C51 and the resistor R54 are grounded. The negative input terminal of the comparator U9.2 is connected to one end of the resistor R61 and one end of the resistor R58. The capacitor C355 is connected in parallel with the resistor R58. The other end of the resistor R62 is grounded. The output terminal of the comparator U9.2 is connected to the PB.0 pin of the processor AX58200 and the other end of the resistor R58 respectively; a load is connected between the drain of the switching transistor Q20 and the drain of the switching transistor Q4. The cathode of the diode D7 is connected to one end of the capacitor C22. The other end of the capacitor C22 is connected to the drain of the switching transistor Q4. The source of the switching transistor Q4 is connected to the anode of the diode D7, the cathode of the zener diode D6, and one end of the fuse tube F2 respectively. The other end of the fuse tube F2 is connected to the power supply; the resistor R21 is connected in parallel with the diode D7. The gate of the switching transistor Q4 is connected to one end of the resistor R25. The other end of the resistor R25 is connected to the anode of the zener diode D6, one end of the resistor R29, and one end of the capacitor C26 respectively. The other end of the capacitor C26 is grounded. The other end of the resistor R29 is connected to the drain of the switching transistor Q8. The source of the switching transistor Q8 is grounded. The gate of the switching transistor Q8 is connected to one end of the capacitor C30, the drain of the switching transistor Q12, one end of the resistor R33, and the drain of the switching transistor Q13 respectively. The other end of the capacitor C30 is grounded. The source of the switching transistor Q12 is grounded. The gate of the switching transistor Q12 is connected to the PB. of the processor AX58200The 6-pin connection is such that the source of the switching transistor Q13 is grounded, and the gate of the switching transistor Q13 is connected to the PWM output terminal of the external MCU.

[0017] Advantages of the present invention:

[0018] The present invention is ingeniously designed. During its operation, a sawtooth oscillation signal is generated by the cooperation of the oscillator and the power management chip U1, and the output is jointly controlled by two error amplifiers. The two error amplifiers are respectively responsible for voltage feedback and current limiting to ensure the stability and safety of the system. The first error amplifier is finely adjusted by the voltage signal output by the MCU DAC, and the second error amplifier is used for current detection to prevent overcurrent situations. The present invention provides an efficient, flexible and reliable synchronous trigger pulse type current source, which is particularly suitable for applications such as camera flashlights or other similar application scenarios that require high-precision control. It not only improves the reliability and flexibility of the system, but also greatly enhances the controllability of the photo-taking quality. Description of the drawings

[0019] Figure 1 It is the circuit diagram of the adjustable voltage Boost power supply module of the present invention.

[0020] Figure 2 It is the circuit diagram of the processor module of the present invention.

[0021] Figure 3 It is the circuit diagram of the digital-to-analog converter U7 of the present invention.

[0022] Figure 4 It is the circuit diagram of the first ADC channel of the present invention.

[0023] Figure 5 It is the circuit diagram of the second ADC channel of the present invention.

[0024] Figure 6 It is the circuit diagram of the third ADC channel of the present invention.

[0025] Figure 7 It is the circuit diagram of the fourth ADC channel of the present invention. Detailed implementation manners

[0026] For the convenience of those skilled in the art to understand, the present invention will be further described below in conjunction with the embodiments and the drawings. The content mentioned in the implementation manners is not a limitation to the present invention. The present invention will be described in detail below in conjunction with the drawings.

[0027] A pulse constant current power supply circuit for intermittent triggering LED constant current control of a camera, as Figures 1 to 7As shown in the figure, it includes: a Boost power supply module with adjustable voltage, the Boost power supply module with adjustable voltage includes an oscillator, a power management chip U1, a first error amplifier and a second error amplifier. The oscillator cooperates with the power management chip U1 to generate a sawtooth oscillation signal. The first error amplifier is used to receive a voltage signal from an external MCU and input it to the inverting input terminal of a comparator to adjust the duty cycle of the PWM signal; the second error amplifier is used to limit the maximum current; a pulse constant current module, powered by an internal BOOST boost power supply or an external constant voltage source; a processor module, used to control the pulse width and detect pulse input; the Boost power supply module with adjustable voltage and the pulse constant current module are respectively connected to the processor module; the oscillator includes a resistor R10 and a capacitor C8, the model of the power management chip U1 is TL494, one end of the resistor R10 is connected to the RT pin of the power management chip U1, one end of the capacitor C8 is connected to the CT pin of the power management chip U1, and the other ends of the resistor R10 and the capacitor C8 are connected and grounded. Specifically, the design of the present invention is ingenious. When it works, a sawtooth oscillation signal is generated by the cooperation of the oscillator and the power management chip U1, and two error amplifiers are used to jointly control the output. The two error amplifiers are respectively responsible for voltage feedback and current limitation to ensure the stability and safety of the system. The first error amplifier is finely adjusted by the voltage signal output by the MCU DAC, and the second error amplifier is used for current detection to prevent overcurrent situations; the present invention provides an efficient, flexible and reliable synchronous trigger pulse type current source, which is particularly suitable for applications such as camera flashes or other similar application scenarios that require high-precision control, not only improving the reliability and flexibility of the system, but also greatly enhancing the controllability of the photo-taking quality.

[0028] In the embodiment of the present application, the Boost power supply module with adjustable voltage further includes a half-bridge gate driver chip U2 and a resistor R4. The half-bridge gate driver chip U2 is used to receive the PWM output of the power management chip U1 and provide built-in dead-time protection. The HIN pin and LIN# pin of the half-bridge gate driver chip U2 are connected and then connected to the E2 pin of the power management chip U1 and one end of the resistor R4. The other end of the resistor R4 is grounded, and the E2 pin of the power management chip U1 is connected to the E1 pin of the power management chip U1.

[0029] In the embodiment of the present application, the oscillator circuit is composed of R10 and C8 to form an RC oscillation circuit, which determines the basic oscillation frequency. The embodiment of the present application uses the TL494 chip as the core controller to achieve stable output of high-frequency pulses through precise PWM control and feedback regulation. The adjustable-voltage Boost power supply module mainly includes the following parts: The oscillator circuit is composed of R10 and C8, which determines the basic oscillation frequency; Dead-time control is achieved through the resistors connected to the DTC pin and the RT pin; The error amplifier uses two internal error amplifiers of the chip for feedback control; Output drive outputs PWM signals through pins E1 and E2. Under the above settings, a pulse frequency of up to 200 kHz can be achieved to meet the high-speed control requirements; Precise duty-cycle control can achieve duty-cycle adjustment with a resolution of 0.1% through the internal comparator and the sawtooth wave generator; Low jitter: The optimized circuit design ensures the timing stability of the output pulses, and the jitter is controlled at the ns level.

[0030] In the embodiment of the present application, the adjustable-voltage Boost power supply module further includes an MOS transistor Q3, a capacitor C7, a resistor R9, a resistor R12, and a resistor R13. The DTC pin of the power management chip U1 is connected to one end of the resistor R9, and the other end of the resistor R9 is grounded. The gate of the MOS transistor Q3 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to the processor module, the source and drain of the MOS transistor Q3 are connected in parallel with the resistor R13, the capacitor C7 is connected in parallel with the resistor R13, and the source of the MOS transistor Q3 is connected to the DTC pin of the power management chip U1. Specifically, the oscillator in the adjustable-voltage Boost power supply module consists of a resistor R10 and a capacitor C8 to form an RC oscillator, which is started by TL494 to form a sawtooth wave oscillation; the input of the error amplifier is jointly controlled by two inputs; for the first path of the error amplifier, the output Vout is connected to the non-inverting input terminal of the comparator after voltage division by a resistor, and the inverting input terminal uses the DAC of the MCU, which is amplified by 100 times and input to the output terminal of the comparator; when the output voltage of the error amplifier of TL494 ranges from 0.5V to 3.5V, the output pulse width changes from 97% of the period to 0, that is, the inverting input is limited to DAC_VREF to DAC_VREF+(3.5 - DAC_VREF / 100), the DAC output is designed to be 0.8V to 1.5V, and the output; using a reference voltage of 0.8V, the output voltage accuracy can also be controlled within ±1.5%, and the output voltage is adjustable within the range of 24.8 to 46.5V; for the second path of the error amplifier, a resistor is used as the current detection input and connected to the non-inverting input terminal of the comparator, and the inverting input terminal is set to 0.5V. When the BOOST peak current exceeds 6.25A, the PWM output will be limited, so as to achieve the effect of limiting the maximum current; when the gate input of the switching transistor Q3 is at a low level, the switching transistor Q3 is turned off, ensuring that the DTC input is 0.5V. At this time, the output of the PWM controller is 50%, and it can be regarded as a PWM controller with a period of 250KHz. The PWM output is adjusted from 97% to 0% according to the input of the error amplifier; when the gate input of the switching transistor Q3 is at a high level, the switching transistor Q3 is turned on, and the DTC input is higher than 1V. At this time, the output of the PWM controller is 0%, and the PWM output at this time is not affected by other signals, and the PWM output is all 0%.

[0031] The half-bridge gate driver chip U2 is a half-bridge gate driver chip. The PWM output of TL494 is input to the high-side input and the inverting input of the low-side input, with a built-in dead time to protect the high-side and low-side NMOS from being fully turned on.

[0032] In the embodiment of the present application, the processor module includes a central processor AX58200. The central processor AX58200 is communicatively connected to an external host computer through an EtherCAT interface. The AX58200 core board is used as the main controller and communicates with each functional module through SPI and I2C interfaces, realizing flexible digital control and parameter adjustment. Specifically, the processor communicates with the host through the EhterCAT bus, modifies parameters such as pulse width and current magnitude according to the host, and resets the timer when an external pulse is input, which can synchronize the outputs of four channels. The zener diode D5 and the resistor R20 achieve external input clamping not exceeding 3.6V to ensure that the input of the MCU does not exceed the safe voltage. After a 24V input, the zener diode D4 (transient suppression diode) and F1 (self - restoring fuse) are added to ensure that the input current does not exceed 1.1A and the input voltage does not exceed 26V.

[0033] Furthermore, the embodiment of the present application can design a multi - stage DC - DC conversion circuit, including step - down conversions from 24V to 6.8V, 5V, and 3.3V to ensure the power supply requirements of each functional module. It mainly includes the following conversion stages: 24V to 6.8V: Use a switching step - down module; 6.8V to 5V: Adopt a linear voltage regulator REG1117 - 5; 3.5V to 3.3V: Use another linear voltage regulator REG1117 - 3.3.

[0034] In the embodiment of the present application, the processor module further includes a BUCK step - down chip U4, a transient suppression diode D5, a resistor R19, and a resistor R20. The BUCK step - down chip U4 is used to step down the 24V input voltage to 6.8V. The twelfth pin of the central processor AX58200 is connected to one end of the resistor R20. The other end of the resistor R20 is respectively connected to one end of the resistor R19 and the cathode of the transient suppression diode D5. The anode of the transient suppression diode D5 is grounded, and the other end of the resistor R19 is connected to an external MCU. Specifically, under the above settings, the BUCK step - down chip U4 steps down the 24V input voltage to 6.8V. Combining the transient suppression diode D5 and an appropriate resistor network protects the central processor AX58200 from over - voltage damage. In this setting, the stability of the power supply voltage is ensured, and at the same time, the system's resistance to abnormal conditions (such as over - voltage) is improved.

[0035] In the embodiment of the present application, the pulsed constant current module includes a digital-to-analog converter U7 and four independent channels. The model of the digital-to-analog converter U7 is AD5696. The digital-to-analog converter U7 is connected to the load through four independent channels respectively, and the digital-to-analog converter U7 is communicatively connected to the central processor AX58200 through the SCL pin and the SDA pin. Specifically, the digital-to-analog converter AD5696 is connected to the load through four independent channels, and the current magnitude of each channel can be independently controlled. The SCL and SDA pins communicate with the AX58200 to achieve precise current regulation. High-precision current control of multiple channels is realized, and complex multi-channel synchronous control requirements are supported. By using a combination of the AD5696 digital-to-analog converter and a precision operational amplifier, high-precision current control of multiple channels is realized. Four independent constant current output channels are designed, and each channel is equipped with an independent DAC and operational amplifier, which can realize synchronous or asynchronous multi-channel pulse output.

[0036] Further, the four independent channels include a first ADC channel, a second ADC channel, a third ADC channel, and a fourth ADC channel; the first ADC channel includes resistors R37, R40, R45, R49, R54, R58, R62, capacitors C34, C38, C47, C51, C54, C55, comparators U9.1, U9.2, switching transistor Q20, fuse F2, capacitors C18, C22, C26, C30, resistors R21, R25, R29, R33, switching transistors Q4, Q8, Q12, Q13, zener diode D6, and diode D7. The digital-to-analog converter U7 is connected to one end of resistor R37 through the VOUTA pin. The other end of resistor R37 is connected to one end of resistor R45, one end of capacitor C34, and the positive input terminal of comparator U9.1. The other ends of resistor R45 and capacitor C34 are grounded respectively. The output terminal of comparator U9.1 is connected to one end of resistor R40 and one end of capacitor C37. Capacitor C38 is in parallel with resistor R40. The other end of resistor R40 is connected to the gate of switching transistor Q20. The other end of capacitor C47 is connected to the negative input terminal of comparator U9.1 and one end of resistor R49 respectively. The other end of resistor R49 is connected to the positive input terminal of comparator U9.2, one end of capacitor C51, the source of switching transistor Q20, and one end of resistor R54 respectively. The other ends of capacitor C51 and resistor R54 are grounded. The negative input terminal of comparator U9.2 is connected to one end of resistor R61 and one end of resistor R58. Capacitor C355 is in parallel with resistor R58. The other end of resistor R62 is grounded. The output terminal of comparator U9.2 is connected to the PB.0 pin of processor AX58200 and the other end of resistor R58 respectively; A load is connected between the drain of switching transistor Q20 and the drain of switching transistor Q4. The cathode of diode D7 is connected to one end of capacitor C22. The other end of capacitor C22 is connected to the drain of switching transistor Q4. The source of switching transistor Q4 is connected to the anode of diode D7, the cathode of zener diode D6, and one end of fuse tube F2 respectively. The other end of fuse tube F2 is connected to the power supply; Resistor R21 is in parallel with diode D7. The gate of switching transistor Q4 is connected to one end of resistor R25. The other end of resistor R25 is connected to the anode of zener diode D6, one end of resistor R29, and one end of capacitor C26 respectively. The other end of capacitor C26 is grounded. The other end of resistor R29 is connected to the drain of switching transistor Q8. The source of switching transistor Q8 is grounded. The gate of switching transistor Q8 is connected to one end of capacitor C30, the drain of switching transistor Q12, one end of resistor R33, and the drain of switching transistor Q13 respectively. The other end of capacitor C30 is grounded. The source of switching transistor Q12 is grounded. The gate of switching transistor Q12 is connected to PB. of processor AX58200The 6-pin connection is such that the source of the switching transistor Q13 is grounded, and the gate of the switching transistor Q13 is connected to the PWM output terminal of the external MCU. Among them, the 36V input can be the input of an external constant voltage source or the internal BOOST boost circuit can be used. When the internal BOOST boost power supply is provided, the maximum current is 6A and is shared by four channels.

[0037] Specifically, TRI is both the camera trigger signal and a hardware synchronization. TRI is detected and input by the processor and used as the synchronization signal of the clock to synchronize with the PWM clock signal input. EN, as the PWM output of the MCU, can control the pulse conduction time. The zener diode D6 is used as a voltage clamp to protect the PMOS gate voltage from being higher than 13V and can also ensure that the conduction voltage of the switching transistor Q4 is sufficient to be fully conducted when the switching transistor Q8 is conducting. The resistor R29 is used as a current-limiting resistor to protect the zener diode D6 from being burned out due to excessive current. Further, the diode D7, the resistor R21, and the capacitor C22 can suppress the current overshoot when the switching transistor Q4 starts to conduct. The comparator U9.1 and the switching transistor Q20 form a current source. The MCU controls the AD5696 to output different DACs to control the current magnitude, and the current magnitude is amplified by the comparator U9.1 and then sent to the ADC of the MCU for detection.

[0038] Among them, when CH+ / CH- is connected to the load, the voltage DA_CH1 controls the voltage input to be 0 - 2.5V. After proportional voltage division, the voltage at the non-inverting input terminal of the comparator U9.1 is 0 - 1.2V. The gate of Q20 is connected to the output terminal of the comparator U9.1. At this time, a negative feedback loop is formed. Adding R40, R49, C38, and C47 reduces the operational amplifier oscillation, making the current more stable. At this time, the output current is controlled by DA_CH1, and the current is DA_CH1 / 2.5V * 1.2V / 1Ω;

[0039] Under the above settings, the first ADC channel includes a series of components such as resistors, capacitors, comparators, and switching transistors, forming a complete current control loop. During the conversion process from the DAC output to the actual current, the precision of the current is ensured through precision operational amplifiers and sampling resistors; it provides a high-resolution current regulation ability, ensuring the accuracy and stability of the current output, and is suitable for application scenarios that require fine control.

[0040] As described above, it is only the preferred embodiment of the present invention, and there is no restriction on the present invention in any form. Although the present invention is disclosed above in the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, when making some changes or modifications using the above-disclosed technical content as equivalent embodiments of equivalent changes, but as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical solution of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A pulsed constant current power supply circuit for intermittent triggering of an LED constant current control of a camera, characterized in that, Including: A Boost power supply module with adjustable voltage, the Boost power supply module with adjustable voltage includes an oscillator, a power management chip U1, a first error amplifier and a second error amplifier. The oscillator and the power management chip U1 cooperate to generate a sawtooth oscillation signal. The first error amplifier is used to receive a voltage signal from an external MCU and input it to the inverting input terminal of a comparator to adjust the duty cycle of the PWM signal. The second error amplifier is used to limit the maximum current; A pulse constant current module, powered by an internal BOOST boost power supply or an external constant voltage source; A processor module, used to control the pulse width and detect the pulse input; The Boost power supply module with adjustable voltage and the pulse constant current module are respectively connected to the processor module.

2. The pulsed constant current power supply circuit for intermittent triggering LED constant current control of a camera according to claim 1, wherein: The oscillator includes a resistor R10 and a capacitor C8. The model of the power management chip U1 is TL494. One end of the resistor R10 is connected to the RT pin of the power management chip U1, one end of the capacitor C8 is connected to the CT pin of the power management chip U1, and the other ends of the resistor R10 and the capacitor C8 are connected and grounded.

3. The pulse constant current power supply circuit for intermittent triggering LED constant current control of a camera according to claim 2, wherein: The Boost power supply module with adjustable voltage further includes a half-bridge gate driver chip U2 and a resistor R4. The half-bridge gate driver chip U2 is used to receive the PWM output of the power management chip U1 and provide built-in dead time protection. The HIN pin and the LIN# pin of the half-bridge gate driver chip U2 are connected and then connected to the E2 pin of the power management chip U1 and one end of the resistor R4. The other end of the resistor R4 is grounded, and the E2 pin of the power management chip U1 is connected to the E1 pin of the power management chip U1.

4. A pulsed constant current power supply circuit for intermittent triggering of LED constant current control of a camera, characterized in that: The Boost power supply module with adjustable voltage further includes a MOS tube Q3, a capacitor C7, a resistor R9, a resistor R12 and a resistor R13. The DTC pin of the power management chip U1 is connected to one end of the resistor R9, the other end of the resistor R9 is grounded, the gate of the MOS tube Q3 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to the processor module, the source and drain of the MOS tube Q3 are connected in parallel with the resistor R13, the capacitor C7 is connected in parallel with the resistor R13, and the source of the MOS tube Q3 is connected to the DTC pin of the power management chip U1.

5. A pulse constant current power supply circuit for intermittent triggering LED constant current control of a camera, characterized in that: The processor module includes a central processor AX58200, and the central processor AX58200 is communicatively connected to an external host computer through an EtherCAT interface.

6. The pulsed constant current power supply circuit for intermittent triggering of an LED constant current control of a camera according to claim 5, wherein: The processor module further includes a BUCK bucking chip U4, a transient suppression diode D5, a resistor R19 and a resistor R20. The BUCK bucking chip U4 is used to reduce the 24V input voltage to 6.8V. The twelfth pin of the central processor AX58200 is connected to one end of the resistor R20, the other end of the resistor R20 is respectively connected to one end of the resistor R19 and the cathode of the transient suppression diode D5, the anode of the transient suppression diode D5 is grounded, and the other end of the resistor R19 is connected to an external MCU.

7. A pulsed constant current power supply circuit for intermittent triggering of LED constant current control of a camera, characterized in that: The pulse constant current module includes a digital-to-analog converter U7 and four independent channels. The model of the digital-to-analog converter U7 is AD5696. The digital-to-analog converter U7 is connected to the load through four independent channels respectively, and the digital-to-analog converter U7 is communicatively connected to the central processor AX58200 through the SCL pin and the SDA pin.

8. A pulse constant current power supply circuit for intermittent triggering LED constant current control of a camera, characterized in that: The four independent channels include a first ADC channel, a second ADC channel, a third ADC channel, and a fourth ADC channel; the first ADC channel includes resistor R37, resistor R40, resistor R45, resistor R49, resistor R54, resistor R58, resistor R62, capacitor C34, capacitor C38, capacitor C47, capacitor C51, capacitor C54, capacitor C55, comparator U9.1, comparator U9.2, switching transistor Q20, fuse F2, capacitor C18, capacitor C22, capacitor C26, capacitor C30, resistor R21, resistor R25, resistor R29, resistor R33, switching transistor Q4, switching transistor Q8, switching transistor Q12, switching transistor Q13, zener diode D6, and diode D7. The digital-to-analog converter U7 is connected to one end of resistor R37 through the VOUTA pin. The other end of resistor R37 is connected to one end of resistor R45, one end of capacitor C34, and the positive input terminal of comparator U9.

1. The other ends of resistor R45 and capacitor C34 are grounded respectively. The output terminal of comparator U9.1 is connected to one end of resistor R40 and one end of capacitor C37. Capacitor C38 is in parallel with resistor R40. The other end of resistor R40 is connected to the gate of switching transistor Q20. The other end of capacitor C47 is connected to the negative input terminal of comparator U9.1 and one end of resistor R49 respectively. The other end of resistor R49 is connected to the positive input terminal of comparator U9.2, one end of capacitor C51, the source of switching transistor Q20, and one end of resistor R54 respectively. The other ends of capacitor C51 and resistor R54 are grounded. The negative input terminal of comparator U9.2 is connected to one end of resistor R61 and one end of resistor R58. Capacitor C355 is in parallel with resistor R58. The other end of resistor R62 is grounded. The output terminal of comparator U9.2 is connected to the PB.0 pin of the processor AX58200 and the other end of resistor R58 respectively; a load is connected between the drain of switching transistor Q20 and the drain of switching transistor Q4. The cathode of diode D7 is connected to one end of capacitor C22. The other end of capacitor C22 is connected to the drain of switching transistor Q4. The source of switching transistor Q4 is connected to the anode of diode D7, the cathode of zener diode D6, and one end of fuse F2 respectively. The other end of fuse F2 is connected to the power supply; resistor R21 is in parallel with diode D7. The gate of switching transistor Q4 is connected to one end of resistor R25. The other end of resistor R25 is connected to the anode of zener diode D6, one end of resistor R29, and one end of capacitor C26 respectively. The other end of capacitor C26 is grounded. The other end of resistor R29 is connected to the drain of switching transistor Q8. The source of switching transistor Q8 is grounded. The gate of switching transistor Q8 is connected to one end of capacitor C30, the drain of switching transistor Q12, one end of resistor R33, and the drain of switching transistor Q13 respectively. The other end of capacitor C30 is grounded. The source of switching transistor Q12 is grounded. The gate of switching transistor Q12 is connected to the PB.6-pin connection, the source of the switching transistor Q13 is grounded, and the gate of the switching transistor Q13 is connected to the PWM output terminal of the external MCU.

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