CN215898058U

CN215898058U - DC-DC control circuit of constant current of adjusting luminance

Info

Publication number: CN215898058U
Application number: CN202121733677.8U
Authority: CN
Inventors: 邹亮; 刘志刚; 肖军云
Original assignee: Suzhou Dongcan Photoelectric Technology Co ltd
Current assignee: Suzhou Dongcan Photoelectric Technology Co ltd
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2022-02-22
Anticipated expiration: 2031-07-28

Abstract

A DC-DC control circuit for dimming constant current enables brightness, darkness and brightness of an LED lamp to be controlled; the circuit is a multifunctional average current type LED constant current driving circuit with simple peripheral circuits, is suitable for the field of non-isolated constant current LED driving in a voltage range of 5-100V, realizes accurate current control by sampling current of a CS port, integrates various dimming modes on a chip, and expands system application.

Description

DC-DC control circuit of constant current of adjusting luminance

Technical Field

The utility model relates to the field of LED lighting circuits, in particular to a DC-DC control circuit for dimming constant current.

Background

The existing DMX512 protocol is a data dimming protocol proposed by the American stage lighting Association, can digitally control dimmers and other control devices in places such as stages, theaters, studios and the like, is suitable for one-point-to-multipoint master-slave controllers, is simple in connection and high in reliability, and is widely applied to the field of stage lighting.

The DMX512 protocol is applied to the field of landscape brightening, lamps need to be installed on buildings or bridges, however, the trouble of manually configuring or sequentially installing the lamps is needed, and a DC-DC control circuit for dimming and constant current needs to be developed, so that the brightness, darkness and brightness of LED lamps can be controlled; remote control based on DMX512 can be realized.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a DC-DC control circuit for dimming constant current, which can control the brightness, darkness and brightness of an LED lamp; the circuit is a multifunctional average current type LED constant current driving circuit with simple peripheral circuits, is suitable for the field of non-isolated constant current LED driving in a voltage range of 5-100V, realizes accurate current control by sampling current of a CS port, integrates various dimming modes on a chip, and expands system application.

A DC-DC control circuit of dimming constant current characterized in that: the output end of the positive pole of an input voltage VIN is connected with the input end of a diode D1, the output end of a diode D1 is respectively connected with the output ends of a capacitor C2, a resistor R3 and a diode D2, the output end of a diode D1 and the output end of a diode D2 are connected in parallel and then connected with the input end of the positive pole of an LED light-emitting diode, the output end of a resistor R3 is respectively connected with a capacitor C1, a pin 1 of a chip Hi7001 and a pin 3 of the chip Hi7001, the output ends of a capacitor C1 and a capacitor C2 are grounded, the output end of PWM dimming is connected with a pin 2 of the chip Hi7001, the output end of the negative pole of the input voltage VIN is connected with a pin 4 of the chip Hi7001, a pin 6 of the chip Hi7001 and a pin 5 of the chip Hi7001 are connected in parallel and then respectively connected with the input ends of a diode D2 and an inductor L1, the output end of an inductor L1 is connected with the input end of the negative pole of the LED light-emitting diode, and then connected in parallel and then grounded.

Further, a resistor R2 is connected between the PWM dimming and the 2 pin of the chip Hi 7001.

Further, a resistor R1 is connected between the negative electrode of the input voltage VIN and the 4 pins of the chip Hi 7001.

Furthermore, pin 1 of the chip Hi7001 is an LD analog/segment dimming port, and different dimming functions can be realized by setting the LD analog/segment dimming port, when the external resistor R3 of the LD analog/segment dimming port is pulled high (the pull-up current is greater than 20uA), the chip enters 1/2 low-brightness mode, when the LD analog/segment dimming port is suspended, the chip Hi7001 enters high-brightness working mode, when the LD analog/segment dimming port is connected with 0.2V-1.2V analog signal, the chip Hi7001 enters analog dimming mode, when the LD analog/segment dimming port is lower than 0.2V, the output is closed, the function is mainly designed for switching application of high beam and low beam of the electric vehicle, the peripheral system can be simplified, the cost is reduced, the improvement is improved, and the LD analog/segment dimming port can also realize PWM dimming function, the high level of the LD port exceeds 1.2V when PWM dimming is performed with the LLD analog/step dimming port.

Furthermore, pin 2 of the chip Hi7001 is a PWM port, the PWM port supports PWM dimming with ultra-small duty ratio, and can respond to a PWM pulse width waveform of <60ns, when the PWM signal is at low level, the output is turned off, and when the PWM signal is at high level, the output is turned on, and when the PWM signal is suspended, the port is defaulted to be at high level input.

Furthermore, pin 3 of the chip Hi7001 is a chip power pin VDD, and the chip Hi7001 mainly supplies a chip operating current to the chip power pin VDD through a power supply resistor R3, and normally, the chip power pin VDD satisfies a formula, and it can be seen that a system is powered insufficiently when the resistor R3 is too large, and power consumption is too large and the chip is overheated when the resistor R3 is too small.

Further, the relationship between the resistor R3 and the switching system frequency requires that the resistance of R3 is smaller as the switching system frequency is higher.

Further, the diode D2 and the diode D1 are flywheel diodes.

Further, the 6 pins of the chip Hi7001 and the 5 pins of the chip Hi7001 are heat dissipation pins, and heat dissipation treatment is necessary.

Further, pin 4 of chip Hi7001 is current detection resistor pin CS.

Furthermore, the constant current driver of the LED lighting lamp is suitable for the field of voltage-reducing BUCK high-power dimming constant current LEDs with the voltage range of 5-100V.

The utility model has the beneficial effects that: the utility model provides a DC-DC control circuit of constant current of adjusting luminance, charge the electric capacity connected to power pin VDD through starting the resistance R3 after the system is electrified, after the power supply voltage is higher than 4.2V, the chip Hi7001 circuit begins to work, until the power supply pin VDD port voltage stabilizes and reaches about 5.2V of clamping voltage, the power supply current of the chip Hi7001 is mainly provided by the resistance R3 that the power pin VDD port inserts, for different power MOS, need to adjust the magnitude of the resistance R3 in order to adapt to the current loss of the system, the larger the MOS is, the smaller the resistance is, the lower the input voltage is, the smaller the resistance is required; when the PWM port is at a high level, the chip works normally; when the chip is a low-level chip, the output of the chip is closed; the constant current precision of the output current of the chip Hi7001 is less than or equal to +/-3 percent, and the output current is slightly influenced by input and output voltage and system inductance; the loop compensation is integrated in the chip Hi7001, the peripheral circuit is simple, and the system is more stable and reliable. The chip realizes three-function switching by controlling the LD analog/segmented dimming port. When the LD analog/segmented dimming port is suspended, the system is in a high-brightness mode; when the LD analog/segmented dimming port is 1V higher than the chip power pin VDD, the system is in a low-light mode with 1/2 current; when the LD analog/segmented dimming port is connected with 0.2-1.2V analog dimming signal input, the system is in an analog dimming mode; and the LD high-low brightness switching mode is used for realizing the switching of the high beam and the low beam of the LED illumination of the automobile. When the LD simulates the dimming mode, the voltage of the LD simulation/subsection dimming port is lower than 0.2V, and the output is closed.

Drawings

Fig. 1 is a circuit diagram of a dimming constant current DC-DC control circuit according to the present application.

The drawings are described in detail below with reference to specific embodiments.

Detailed Description

The following examples are described to aid in the understanding of the present application and are not, and should not be construed to, limit the scope of the present application in any way.

In the following description, those skilled in the art will recognize that components may be described throughout this discussion as separate functional units (which may include sub-units), but those skilled in the art will recognize that various components or portions thereof may be divided into separate components or may be integrated together (including being integrated within a single system or component).

Also, connections between components or systems are not intended to be limited to direct connections, but rather, data between these components may be modified, reformatted, or otherwise changed by intervening components. Additionally, additional or fewer connections may be used. It should also be noted that the terms "coupled," "connected," or "input" should be understood to include direct connections, indirect connections through one or more intermediate devices, and wireless connections.

The specific embodiment is as follows:

fig. 1 is a circuit diagram of the dimming constant-current DC-DC control circuit according to the present application.

And a resistor R2 is connected between the PWM dimming and the pin 2 of the chip Hi 7001.

A resistor R1 is connected between the negative pole of the input voltage VIN and the 4 pins of the chip Hi 7001.

The pin 1 of the chip Hi7001 is an LD analog/sectional dimming port, the chip can realize different dimming functions by setting the LD analog/sectional dimming port, when an external resistor R3 of the LD analog/sectional dimming port is pulled high (the pull-up current is more than 20uA), the chip enters a 1/2 low-light mode, the LD analog/sectional dimming port is suspended, the chip Hi7001 enters a high-light working mode, when the LD analog/sectional dimming port is connected with an analog signal of 0.2V-1.2V, the chip Hi7001 enters an analog dimming mode, when the LD analog/sectional dimming port is lower than 0.2V, the output is closed, the function is mainly designed for switching application of high beam and low beam lamps of an electric vehicle, a peripheral system can be simplified, the cost is reduced, the improvement is realized, and the LD analog/sectional dimming port can also realize the PWM dimming function, the high level of the LD port exceeds 1.2V when PWM dimming is performed with the LLD analog/step dimming port.

The pin 2 of the chip Hi7001 is a PWM port, the PWM port supports PWM dimming with ultra-small duty ratio, the PWM port can respond to PWM pulse width waveform of <60ns, when the PWM signal is low level, the output is closed, when the PWM signal is high level, the output is opened, and when the PWM signal is suspended, the port is defaulted to be high level input.

Pin 3 of chip Hi7001 is chip power supply pin VDD, and chip Hi7001 mainly supplies chip operating current to chip power supply pin VDD through a power supply resistor R3, and usually, chip power supply pin VDD satisfies the formula, and it can be seen that too large resistor R3 will result in insufficient system power supply, and too small resistor R3 will result in too large power consumption and chip overheating.

The relation between the resistor R3 and the frequency of the switching system, the higher the frequency of the switching system is, the smaller the resistance of the R3 is required to be.

The diode D2 and the diode D1 are freewheeling diodes.

Pins 6 of the chip Hi7001 and pins 5 of the chip Hi7001 are heat dissipation pins, and heat dissipation treatment is necessary.

Pin 4 of chip Hi7001 is current sensing resistor pin CS.

The constant current driver of the LED lighting lamp is suitable for the field of voltage-reducing BUCK high-power dimming constant current LEDs with the voltage range of 5-100V.

While various aspects and embodiments have been disclosed herein, it will be apparent to those skilled in the art that other aspects and embodiments can be made without departing from the spirit of the disclosure, and that several modifications and improvements can be made without departing from the spirit of the disclosure. The various aspects and embodiments disclosed herein are presented by way of example only and are not intended to limit the present disclosure, which is to be controlled in the spirit and scope of the appended claims.

Claims

1. A DC-DC control circuit of dimming constant current characterized in that: the output end of the positive pole of an input voltage VIN is connected with the input end of a diode D1, the output end of a diode D1 is respectively connected with the output ends of a capacitor C2, a resistor R3 and a diode D2, the output end of a diode D1 and the output end of a diode D2 are connected in parallel and then connected with the input end of the positive pole of an LED light-emitting diode, the output end of a resistor R3 is respectively connected with a capacitor C1, a pin 1 of a chip Hi7001 and a pin 3 of the chip Hi7001, the output ends of a capacitor C1 and a capacitor C2 are grounded, the output end of PWM dimming is connected with a pin 2 of the chip Hi7001, the output end of the negative pole of the input voltage VIN is connected with a pin 4 of the chip Hi7001, a pin 6 of the chip Hi7001 and a pin 5 of the chip Hi7001 are connected in parallel and then respectively connected with the input ends of a diode D2 and an inductor L1, the output end of an inductor L1 is connected with the input end of the negative pole of the LED light-emitting diode, and then connected in parallel and then grounded.

2. The dimming constant current DC-DC control circuit of claim 1, wherein: and a resistor R2 is connected between the PWM dimming and the pin 2 of the chip Hi 7001.

3. The dimming constant current DC-DC control circuit of claim 1, wherein: a resistor R1 is connected between the negative pole of the input voltage VIN and the 4 pins of the chip Hi 7001.

4. The dimming constant current DC-DC control circuit of claim 1, wherein: pin 1 of the chip Hi7001 is an LD analog/segment dimming port.

5. The dimming constant current DC-DC control circuit of claim 1, wherein: pin 2 of the chip Hi7001 is a PWM port, and the PWM port supports PWM dimming with ultra-small duty ratio.

6. The dimming constant current DC-DC control circuit of claim 1, wherein: pin 3 of chip Hi7001 is chip power supply pin VDD.

7. The dimming constant current DC-DC control circuit of claim 1, wherein: pins 6 of chip Hi7001 and pins 5 of chip Hi7001 are heat dissipation pins.

8. The dimming constant current DC-DC control circuit of claim 1, wherein: pin 4 of chip Hi7001 is current sensing resistor pin CS.

9. The dimming constant current DC-DC control circuit of claim 1, wherein: the constant current driver of the LED lighting lamp is suitable for the field of voltage-reducing BUCK high-power dimming constant current LEDs with the voltage range of 5-100V.