CN213186623U

CN213186623U - Constant-power ballast circuit with dimming function

Info

Publication number: CN213186623U
Application number: CN202021722199.6U
Authority: CN
Inventors: 许剑钢; 秦锋
Original assignee: Universelite Co ltd
Current assignee: Universelite Co ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2021-05-11
Anticipated expiration: 2030-08-18

Abstract

The utility model provides a constant power ballast circuit of area adjusting luminance, energy-concerving and environment-protective electron relates to technical field, change DC15V power module, DC15V and change DC5V power module, half-bridge circuit, half-bridge control scheme, half-bridge drive amplifier circuit, MCU, the module of adjusting luminance and constitute including EMC device, boost circuit, boost control scheme, AC. The utility model collects the current of the half-bridge circuit, the pipe flow and the resonance voltage of the lamp tube, and transmits the signal to the MCU, and the MCU is utilized to calculate the resonance voltage and the power of the lamp tube, thereby controlling the starting voltage of the lamp tube and adjusting the power of the lamp tube; and after the dimming signal is calculated by the MCU, the signal is transmitted to the half-bridge control circuit to adjust the power of the lamp tube, so that the product cost is reduced under the conditions of uniform illumination of the lamp tube and dimming comfort.

Description

Constant-power ballast circuit with dimming function

Technical Field

The utility model relates to a constant power ballast circuit of area adjusting luminance belongs to energy-concerving and environment-protective electron technical field.

Background

The existing electrodeless lamp ballast comprises an electrodeless lamp ballast with a dimming function, has large output power deviation, and can cause uneven illumination when being used in large-area places such as a factory building and the like, thereby giving uncomfortable visual feeling to people; meanwhile, the dimming ballast in the market is basically designed by a 2-segment mixed frequency, so that the stroboscopic phenomenon exists, and the visual sense is very uncomfortable; the second mixing, with a frequency of 1KHz, produces a sound that is perceived as unpleasant. In order to solve the above problems, a chinese patent No. ZL201510995640.5 provides a solution, and the described 3-segment solution solves the problems of stroboflash and noise, but causes the cost to rise, the selling price to increase, and the user cost to increase.

The present application was made based on this.

SUMMERY OF THE UTILITY MODEL

In order to solve the above-mentioned defect that exists among the prior art, the utility model provides a constant power ballast circuit that area was adjusted luminance utilizes MCU control half-bridge operating frequency, realizes ballast constant power's output and output's adjustment, makes fluorescent tube illuminance even and under the condition of the travelling comfort of adjusting luminance, has reduced product cost.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a constant-power ballast circuit with dimming function comprises an EMC device connected with mains supply, a booster circuit connected with the output end of the EMC device, a boost control circuit connected with the input end of the booster circuit, a power conversion module I connected with the output end of the EMC device, a power conversion module II connected with the output end of the power conversion module I, a half-bridge circuit connected with the output end of the booster circuit, a half-bridge driving amplification circuit connected with the half-bridge circuit, a half-bridge control circuit connected with the input end of the half-bridge driving amplification circuit, an MCU connected with the input end of the half-bridge control circuit and a dimming module connected with the input end of the MCU; the power supply conversion module provides power supply for the boost control circuit, the half-bridge drive amplification circuit and the half-bridge control circuit; the power supply conversion module II is used for providing power supply for the MCU;

MCU includes power detection end, voltage detection end, current detection end, the input of adjusting luminance, power control output and enable control output, connects half-bridge circuit's power detection signal output part, half-bridge circuit's voltage detection signal output part, half-bridge circuit's current detection signal output part, the output of the module of adjusting luminance, two control input of half-bridge control circuit respectively.

Furthermore, the half-bridge driving control circuit adopts a fluorescent lamp chip with a preheating ignition function.

Further, the BOOST circuit and the BOOST control circuit adopt a conventional BOOST voltage.

Furthermore, the first power supply conversion module adopts an AD-to-DC 15V power supply module; and the second power supply conversion module adopts a 15V to 5V power supply module.

Further, the half-bridge circuit adopts an asymmetric half-bridge circuit, and comprises a MOS transistor Q1, a MOS transistor Q2, a half-bridge DC blocking capacitor C1, a choke coil L1, resonant capacitors C2 and C3, a resonant voltage sampling capacitor C4, C5 and C6, a rectifier diode, a divider resistor, a sampling resistor R1 and a current transformer; the source electrode of the MOS tube Q1 is connected with the drain electrode of the MOS tube Q2, the half-bridge blocking capacitor C1 is connected with the source electrode of the MOS tube Q1, the half-bridge blocking capacitor C1 and the choke coil L1 are connected with the lamp tube in series, the resonant capacitors C2 and C3 are connected with the lamp tube in parallel after being connected with the lamp tube in series, and the resonant voltage sampling capacitors C4, C5 and C6 are connected with the lamp tube in parallel after being connected with the lamp tube in series.

Furthermore, the current transformer detects the current of the lamp tube, and outputs a current detection signal to the MCU;

the boost circuit outputs DC-BUS constant voltage, R1 is MOS tube current sampling and is transmitted to a half-bridge control circuit to control the switching of the MOS tube, and the sampled MOS tube current is transmitted to the MCU as a power detection signal of the lamp tube;

the capacitors C4, C5 and C6 are resonance voltage sampling capacitors, and output voltage detection signals are transmitted to the MCU after the capacitors are rectified by the diodes and divided by the resistors.

The utility model has the advantages of:

the utility model collects the current of the half-bridge circuit, the pipe flow and the resonance voltage of the lamp tube, and transmits the signal to the MCU, and the MCU is utilized to calculate the resonance voltage and the power of the lamp tube, thereby controlling the starting voltage of the lamp tube and adjusting the power of the lamp tube; and after the dimming signal is calculated by the MCU, the signal is transmitted to the half-bridge control circuit to adjust the power of the lamp tube, so that the product cost is reduced under the conditions of uniform illumination of the lamp tube and dimming comfort.

Drawings

Fig. 1 is a schematic circuit diagram of a constant power ballast circuit with dimming according to the present embodiment.

Detailed Description

In order to make the technical means and the technical effects achieved by the technical means of the present invention clearer and more complete, the following embodiments are provided and are described in detail with reference to the accompanying drawings as follows:

as shown in fig. 1, the constant power ballast circuit with dimming of the present embodiment includes: EMC device, boost circuit, boost control circuit, AC changes DC15V power module, and DC15V changes DC5V power module, half-bridge circuit, half-bridge control circuit, half-bridge drive amplifier circuit, MCU, the module of adjusting luminance constitutes. The system comprises an EMC device, a BOOST circuit and a BOOST control circuit, wherein the BOOST control circuit is conventional BOOST voltage, and BOOSTs alternating current into high-voltage direct current after rectifying the alternating current; the AC-to-DC 15V power supply module is a conventional flyback or BUCK voltage reduction circuit and provides power supply for the control circuit; the DC 15V-DC 5V power supply module is a conventional BUCK voltage reduction circuit and provides power supply for the MCU; the half bridge is a conventional circuit, and the embodiment adopts an asymmetric half bridge circuit; the half-bridge driving control circuit generally adopts a fluorescent lamp chip with a preheating ignition function (such as IR2153\ L6574 and the like) because the starting of the electrodeless lamp tube needs high energy; the half-bridge driving amplification circuit provides enough energy for driving the MOS tube; the dimming module converts the dimming signal into a PWM waveform, transmits the PWM waveform to the MCU for internal calculation and control, and the signal is defined as a dimming input signal. R1 samples MOS tube current, transmits to the half-bridge control circuit, carries on the control of MOS tube switch, because the voltage of DC-BUS is the invariable value, this current signal can also be regarded as the power detection signal of the modulator tube at the same time, and transmit MCU after amplifying this signal, this signal is defined as the power detection signal. C1 is a half-bridge DC blocking capacitor; l1 is a choke coil, which participates in the resonance process when the lamp tube is started; C2/C3 is resonance capacitance; C4/C5/C6 is resonance voltage sampling, and is transmitted to the MCU after being rectified by a diode and divided by a resistor, and the signal is defined as a voltage detection signal; the current transformer detects the current of the lamp tube, and transmits the current to the MCU after the current is rectified by the diode and divided by the resistor, and the signal is defined as a current detection signal.

The following describes the analysis and judgment of the MCU after receiving the above signals.

Step 1, in the starting process, judging with an internal reference after receiving a voltage signal by an MCU; if the voltage reaches the internal reference, the resonance voltage is considered to reach the set value, the frequency sweeping cannot be continued, the situation that the resonance voltage is too high and the ballast is damaged is prevented, and the step 2 is carried out; if the voltage signal does not reach the internal reference voltage, the MCU considers that the current state is safe, and executes the step 4;

step 2, switching off the output of the MOS transistor by enabling the control output; when the MCU turns off the MOS tube signal, detecting a current signal at the same time, judging whether the lamp tube works normally, and if the lamp tube works, executing the step 3; if the lamp tube does not work, executing the step 3;

step 3, the half-bridge control circuit is preheated and ignited again through enabling control output so as to keep the lamp tube working normally, and the times of the process can be preset through the MCU;

step 4, after the lamp tube works normally, the MCU receives the power detection signal and judges whether the power of the lamp tube reaches the preset power; if the power signal is lower than or higher than a preset value, the working frequency of a half-bridge control circuit is adjusted through power control output, the output power of the lamp tube is adjusted, and constant power output is realized;

and 5, receiving the dimming input signal by the MCU, and changing a preset value for power detection comparison, thereby changing power control output, adjusting the output power of the lamp tube and realizing the dimming function of the lamp tube.

The principle and the beneficial effects of the embodiment are as follows:

1. the frequency of the half-bridge control circuit is adjusted in a small range through the MCU, so that the output power is constant.

2. The frequency of the half-bridge control circuit is adjusted in a large range through the MCU, so that the dimming function of the lamp tube is realized.

3. And when the lamp tube is started, the preheating ignition control time sequence of the MCU is carried out.

4. The output of the lamp tube is adjusted by adjusting the working frequency of the half-bridge circuit.

5. The 2-section constant-power ballast circuit with the dimming function and the control method are adopted, so that the product cost is reduced under the conditions of uniform illumination of the lamp tube and dimming comfort.

The above is a detailed description of the technical solutions provided in connection with the preferred embodiments of the present invention, and it should not be assumed that the embodiments of the present invention are limited to the above description, and it will be apparent to those skilled in the art that the present invention can be implemented in a variety of ways without departing from the spirit and scope of the present invention.

Claims

1. A constant power ballast circuit with dimming function is characterized in that: the power supply comprises an EMC device connected with mains supply, a booster circuit connected with the output end of the EMC device, a booster control circuit connected with the input end of the booster circuit, a power conversion module I connected with the output end of the EMC device, a power conversion module II connected with the output end of the power conversion module I, a half-bridge circuit connected with the output end of the booster circuit, a half-bridge driving amplification circuit connected with the half-bridge circuit, a half-bridge control circuit connected with the input end of the half-bridge driving amplification circuit, an MCU connected with the input end of the half-bridge control circuit and a dimming module connected with the input end of the MCU; the power supply conversion module provides power supply for the boost control circuit, the half-bridge drive amplification circuit and the half-bridge control circuit; the power supply conversion module II is used for providing power supply for the MCU;

2. The constant power ballast circuit with dimming of claim 1, wherein: the half-bridge drive control circuit adopts a fluorescent lamp chip with a preheating ignition function.

3. The constant power ballast circuit with dimming of claim 1, wherein: the BOOST circuit and the BOOST control circuit adopt conventional BOOST voltage.

4. The constant power ballast circuit with dimming of claim 1, wherein: the first power supply conversion module adopts an AD-to-DC 15V power supply module; and the second power supply conversion module adopts a 15V to 5V power supply module.

5. The constant power ballast circuit with dimming of claim 1, wherein: the half-bridge circuit adopts an asymmetric half-bridge circuit and comprises an MOS tube Q1, an MOS tube Q2, a half-bridge blocking capacitor C1, a choke coil L1, resonant capacitors C2 and C3, resonant voltage sampling capacitors C4, C5 and C6, a rectifier diode, a divider resistor, a sampling resistor R1 and a current transformer; the source electrode of the MOS tube Q1 is connected with the drain electrode of the MOS tube Q2, the half-bridge blocking capacitor C1 is connected with the source electrode of the MOS tube Q1, the half-bridge blocking capacitor C1 and the choke coil L1 are connected with the lamp tube in series, the resonant capacitors C2 and C3 are connected with the lamp tube in parallel after being connected with the lamp tube in series, and the resonant voltage sampling capacitors C4, C5 and C6 are connected with the lamp tube in parallel after being connected with the lamp tube in series.

6. The constant power ballast circuit with dimming of claim 5, wherein: the current transformer detects the current of the lamp tube, and outputs a current detection signal to the MCU;