CN210274617U

CN210274617U - LED dimming system adaptive to different power sections

Info

Publication number: CN210274617U
Application number: CN201920907192.2U
Authority: CN
Inventors: 邹勇; 袁波; 吴殿升; 钟国良
Original assignee: Wuxi Grand Microelectronics Technology Co ltd
Current assignee: Wuxi Grand Microelectronics Technology Co ltd
Priority date: 2019-06-17
Filing date: 2019-06-17
Publication date: 2020-04-07
Anticipated expiration: 2029-06-17

Abstract

The utility model provides a LED dimming system of different power sections of self-adaptation, include: the LED load, be connected with MOS, voltage output detection circuit on the LED load, be connected with the back cut PWM module on the MOS, be connected with sampling circuit, chopper CC/CV control chip on the voltage output detection circuit, sampling circuit passes through the MCU chip and connects in chopper CC/CV control chip, chopper CC/CV control chip passes through the rectifier filter circuit and connects in the commercial power, the utility model discloses can the application of variable output voltage in certain extent of self-adaptation; the product types and stock inventory are reduced, the production and processing are improved, and the production efficiency and the first pass rate are improved.

Description

LED dimming system adaptive to different power sections

Technical Field

The utility model relates to a LED intelligent dimming technical field specifically is a LED dimming system of different power sections of self-adaptation.

Background

At present, people demand LED intelligent dimming products more and more, under the compression of cost, more manufacturers can adopt one path of constant-current constant-voltage chip to output two paths of different color lamp beads to connect MOS tubes in series at the output end, and the brightness and the color temperature are adjusted through PWM (pulse-width modulation), the chip is customarily called as half-power dimming (working in a constant-current mode when single-path full-brightness and two paths of full-brightness are performed, and working in a constant-voltage mode when PWM is performed), but because the main control chip is the constant-current constant-voltage chip, the chip can only default one voltage output, and can not be compatible with the lamp bead load with lower voltage (string number) at the same time.

For example, the dimming power supply is required to be 52-72V/150mA, the constant voltage and the constant current of the power supply are only designed to be 72V/150mA, then if the lamp bead voltage carried by the power supply is 52V, the normal lighting single-circuit and full lighting can be normally operated (the constant current state, the output voltage can be automatically adjusted according to the lamp bead load voltage), only the constant voltage state is entered when the PWM dimming is performed (Vout can default to be constant at 72V), the redundant 20V voltage can be forcibly added to two ends of the MOS tube, and the PWM dimming ratio preset when 72V is carried can lead to the fact that the output current is increased due to the increase of the 20V voltage and even exceeds the 150mA set by us, so that the MOS and the lamp bead can be damaged due to the excess power, obviously, 52-72V cannot be compatible, and can only be realized by a specific voltage; thus, multiple specifications and versions need to be customized to address this problem.

Disclosure of Invention

The utility model provides a technical problem provide a LED dimming system of different power sections of self-adaptation to solve the problem of proposing in the above-mentioned background art.

The utility model provides a technical problem adopt following technical scheme to realize: an LED dimming system adaptive to different power segments, comprising: the LED load, be connected with MOS, voltage output detection circuitry on the LED load, be connected with the back-cut PWM module on the MOS, be connected with sampling circuit, chopper CC/CV control chip on the voltage output detection circuitry, sampling circuit passes through the MCU chip and connects in chopper CC/CV control chip, chopper CC/CV control chip passes through rectifier filter circuit and connects in the commercial power.

And an L1A winding is connected to the chopped CC/CV control core, a winding is connected to the MCU chip, and an R5 resistor and an R6 resistor are connected to the L1B winding.

The rear-cut PWM module is connected with an R9 resistor and an R11 resistor, the R9 resistor is connected with a Q4 triode, and the R11 resistor is connected with a Q5 triode.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model can be self-adaptive to the application of variable output voltage within a certain range; the product types and stock inventory are reduced, the production and processing are improved, and the production efficiency and the first pass rate are improved.

Drawings

Fig. 1 is a schematic diagram of the system of the present invention.

Fig. 2 is a schematic diagram of a circuit diagram of the present invention.

Detailed Description

In order to make the technical means, the creative features, the purpose and the efficacy of the present invention easily understood and appreciated, the present invention will be further explained with reference to the specific drawings, and in the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "mounted", "connected" and "connected" should be understood broadly, for example, they may be fixed connection, detachable connection, or integrally connected, mechanically connected or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements.

As shown in fig. 1 and fig. 2, an LED dimming system adaptive to different power segments includes: the LED load is connected with an MOS (metal oxide semiconductor) and a voltage output detection circuit, the MOS is connected with a back-cut PWM (pulse-width modulation) module, the voltage output detection circuit is connected with a sampling circuit and a chopping CC/CV control chip, the sampling circuit is connected with the chopping CC/CV control chip through an MCU (microprogrammed control unit) chip, the chopping CC/CV control chip is connected with a mains supply through a rectifying and filtering circuit, after the LED load is powered on, if Vout is 72V, the voltage of two ends of a winding L1A is equal to 72V when a main control chip demagnetizes a loop, then the voltage of 24V is induced by an L1B, the voltage of 24V is divided through R5 and R6, and the U2 samples the 238mV voltage value; sampling to a voltage value of 198mV, assuming Vout is 60V, and sampling to a voltage value of 171mV, assuming Vout is 52V; setting AD values corresponding to a plurality of Vout; then, which AD value is detected is selected to be conducted to Q1, Q2 or Q3 through the high-low level overlapping of I/O1, I/O2 and I/O3; this results in a different FB resistance, thereby achieving automatic regulation of Vout.

The MCU remembers the VD value sampled through the built-in EEPROM, so that a proper I/O port is selected to control the required no-load voltage, the state is always stored when the VDD of the MCU is not cleared, the no-load voltage in the operation of the time period is ensured to be the value set by the MCU, and PWM dimming can be performed according to the obtained no-load voltage in the time period.

The utility model discloses a theory of operation does:

1) after power-on, assuming that Vout is 72V, the voltage across the winding L1A when the master control chip is in the demagnetization loop is equal to 72V, then L1B can sense the voltage of 24V (since L1A is 108 turns and L1B is 36 turns), the voltage of 24V is divided by R5(200K) and R6(2K), and the voltage value (AD value) of 238mV can be sampled by U2; sampling to a voltage value of 198mV, assuming Vout is 60V, and sampling to a voltage value of 171mV, assuming Vout is 52V; by analogy, the lower the Vout, the lower the sampled voltage value, so that a plurality of AD values corresponding to Vout can be set; then, which AD value is detected is selected to be conducted to Q1, Q2 or Q3 through the high-low level overlapping of I/O1, I/O2 and I/O3; thus, different FB resistances can be obtained, and the voltage of Vout can be automatically adjusted.

2) When the MCU is electrified, the MCU is used for memorizing the VD value sampled by the EEPROM built in the MCU so as to select a proper I/O port to control the required no-load voltage, and when the VDD of the MCU is not cleared, the state is stored all the time, so that the no-load voltage in the operation of the time period can be ensured to be the value set by people, and the PWM dimming can be carried out according to the obtained no-load voltage in the time period; because such products generally require that the color temperature and the small night light are switched by a wall switch (repeated switching), it is enough that the VDD holding time of the MCU is set to about 1.5S during switching; after the power is turned off for 1.5S, the process is repeated as long as VDD is cleared, and the AD value is re-sampled to start automatic control.

The utility model discloses a MCU samples, the first time is gone up the electricity and is set up to the one way full bright (work at the constant current mode this moment, also be the lamp pearl maximum voltage), MCU samples output voltage's AD value and preserves EEPROM this moment, then MCU's control foot control "chopper CC/CV" the FB foot, adjust VOUT to suitable no-load voltage, just so can self-adaptation Vout, this is that just can obtain suitable output voltage and carry out PWM and adjust luminance, as long as MCU's VDD is not reset, this control logic just exists always; if VDD is cleared after power down, it is resampled and the process is repeated.

The basic principles and the main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. An LED dimming system adaptive to different power segments, comprising: an LED load, characterized in that: the LED load is connected with an MOS (metal oxide semiconductor) and a voltage output detection circuit, the MOS is connected with a back-cut PWM (pulse-width modulation) module, the voltage output detection circuit is connected with a sampling circuit and a chopping CC/CV (constant current/constant current) control chip, the sampling circuit is connected with the chopping CC/CV control chip through an MCU (micro control unit) chip, and the chopping CC/CV control chip is connected with a commercial power through a rectification filter circuit.

2. The LED dimming system adaptive to different power segments according to claim 1, wherein: and an L1A winding is connected to the chopped CC/CV control core, a winding is connected to the MCU chip, and an R5 resistor and an R6 resistor are connected to the L1B winding.

3. The LED dimming system adaptive to different power sections according to claim 1 or 2, wherein: the rear-cut PWM module is connected with an R9 resistor and an R11 resistor, the R9 resistor is connected with a Q4 triode, and the R11 resistor is connected with a Q5 triode.