CN200997701Y - Constant-current LED illuminating light with pyroelectric infrared control - Google Patents

Abstract

The utility model discloses a pyroelectric infrared control constant current LED lighting lamp, which comprises an LED array, an AC/DC conversion rectification circuit and a control circuit, wherein the control circuit is composed of a pyroelectric infrared control circuit and a PWM voltage/current converter , which is characterized in that the output end of the pyroelectric infrared control circuit is connected to the pulse output enabling pin (PWM_D) of the HV series PWM control chip (HV9910) in the PWM voltage/current converter. The LED lighting lamp of the utility model has the following remarkable effects: 1. It is directly powered by AC 220V mains, which can directly replace the existing sound and light control corridor lights; 2. Wide voltage (AC90-265V) constant current drive, and the current is continuous , The ripple coefficient is small, the LED has high luminous efficiency and long life; 3. All control circuits are powered by the DC power supply provided by the HV series PWM control chip, the circuit is obviously simplified, and the power saving is remarkable.

Description

A pyroelectric infrared control constant current LED lighting lamp

technical field

The utility model relates to a circuit device for a general electric light source, in particular to a pyroelectric infrared control LED lighting lamp.

Background technique

The advent of high-brightness and high-power LEDs has brought new opportunities for the development of electric light sources. Due to the nonlinear IV characteristic of LED, a small change in the forward voltage V _F will also cause a large change in the forward current I _F , which may shorten the life of the LED, reduce the brightness of the LED, and burn the LED if it is severe. Stream-driven solutions have been launched one after another. Among them, the more successful one is the HV series drive PWM chip launched by the American Supertex company. With this chip as the core, the peripheral circuit with simple configuration can be connected to a PWM constant current control circuit, and then cooperate with the voltage/current conversion circuit to drive the LED with constant current. The product brochure published by Supertex Company of the United States discloses a specific solution, in which the main circuit of the voltage/current conversion circuit is composed of an LED array, an inductor, a power field effect tube, and a current sampling resistor connected in series, and the LED array is connected in parallel with the inductor in series. The freewheeling diode on the circuit turns off the power FET for half a cycle and feeds the electric energy stored in the inductor to the LED, thus providing continuous DC power for the LED; furthermore, a capacitor is connected in parallel to the LED array to smooth the output current and reduce the current Ripple factor. However, the technical solution mentioned in the product manual does not involve the control of the LED power supply, and still cannot meet the requirements of avoiding permanent lights and needing to turn on the lights when people come and turn them off when people leave (such as warehouses, corridors, public toilets, etc.).

With the development of pyroelectric infrared sensor technology, its cost is getting lower and lower, and it has been widely used in the power control of lighting lamps. However, the inventor's retrieval of Chinese patent data shows that this technology is currently only used to control common lighting sources such as incandescent lamps and fluorescent lamps. Since incandescent lamps, fluorescent lamps, etc. are all lamps directly lit by the mains, the control devices disclosed in the Chinese patent database are basically electronic switches controlled by human body infrared. For example, the publication on July 12, 1995 is the authorized announcement It is a utility model patent of 2203401 and an invention patent of 1168210 published on January 16, 2002. The patented solution is mainly composed of a pyroelectric infrared sensor and a photosensitive element connected with a signal amplifier circuit, a logic control circuit and a switch element, so it is impossible to directly realize the driving and control of the LED. In order to improve the reliability of infrared control of the human body and the simplicity of design and manufacture, some large chip developers have successively developed various ASICs designed in conjunction with pyroelectric infrared sensors in recent years, such as the CS9803GP chip publicly developed by the US ETC. The chip has the advantages of high integration, complete functions and reliable operation, but according to the design information disclosed in the company's product brochure, it can only produce electronic switches with various control functions, which cannot match the voltage/voltage of driving LEDs. The current converter is organically combined, and the infrared radiation of the human body is used to control the LED lighting.

Contents of the invention

In view of the above-mentioned shortcomings in the prior art, the purpose of this utility model is to provide a pyroelectric infrared control constant current LED lighting lamp, which not only can be directly powered by AC or DC high voltage, but also has high luminous efficiency and long life of LEID.

The technical solution that the present invention realizes above-mentioned purpose is:

A pyroelectric infrared control constant current LED lighting lamp, which includes an LED array, an AC/DC conversion rectifier circuit and a control circuit, wherein the control circuit is composed of a pyroelectric infrared control circuit and a PWM voltage/current converter, and is characterized in that The output terminal of the pyroelectric infrared control circuit is connected with the pulse output enabling pin PWM_D of the HV series PWM control chip in the PWM voltage/current converter.

The PWM voltage/current converter described in the utility model is mainly composed of a main circuit and a control circuit, wherein the main circuit is composed of an LED array, an inductor, a power field effect tube and a current sampling resistor connected in series in sequence, and a current smoothing filter capacitor is connected in parallel with the LED On the array, a Schottky freewheeling diode is connected in parallel on the loop of the LED array and the inductor in series; the control circuit is composed of HV series PWM chips and their peripheral components, in which the current feedback pin CS of the HV series PWM chips and the upper end of the current sampling resistor Connection, the PWM output pin GATE is connected to the control pole of the power FET. The PWM voltage/current converter is a known technology, and those skilled in the art can refer to the product specification of the HV series PWM type DC-DC step-down conversion dedicated IC published by Supertex Corporation of the United States to carry out deformation design.

The pyroelectric infrared control circuit described in the utility model can be designed with reference to the CS9803GP chip disclosed by the U.S. ETC company or the product manual of similar chips produced by other companies.

A pyroelectric infrared control constant current LED lighting lamp described in the utility model, the power supply input end of the pyroelectric infrared control circuit is respectively connected with the power supply voltage pin of the HV series PWM control chip in the PWM voltage/current converter VDD is connected to the common ground GND. Furthermore, a current-limiting resistor is connected in series between the positive pole of the power input terminal of the pyroelectric infrared control circuit and the power supply voltage pin VDD of the HV series PWM control chip in the PWM voltage/current converter, and the current-limiting resistor is connected across the ground There is an energy storage capacitor, which constitutes the power circuit of the pyroelectric infrared control circuit. Its purpose is not only to ensure the instantaneous high current operation of the pyroelectric infrared control circuit, but also to ensure the stable operation of the HV series PWM control chip.

Compared with the prior art, the utility model has the following advantages:

1. Directly powered by AC 220V mains, it can directly replace various civilian lighting controlled by pyroelectric infrared;

2. Wide voltage (AC90～265V) constant current drive, continuous current, small ripple coefficient, high luminous efficiency and long life of LED;

3. All the control circuits in the further improvement scheme of the utility model are powered by the DC power supply provided by the HV series PWM control chip, which not only greatly simplifies the circuit of the whole device, but also significantly saves electric energy.

Description of drawings

Fig. 1 is the electric schematic diagram of a kind of specific embodiment of PWM voltage/current converter described in the utility model;

Fig. 2 is an electrical schematic diagram of a specific embodiment of the pyroelectric infrared control circuit described in the present invention.

Detailed ways

Fig. 1 and Fig. 2 are the electric schematic diagram of a kind of specific embodiment of pyroelectric infrared control constant current LED illuminating lamp described in the utility model, wherein Fig. 1 is the electric schematic diagram of PWM voltage/current converter, Fig. 2 is The electrical schematic diagram of the pyroelectric infrared control circuit, the terminals with the same names shown in Figure 1 and Figure 2 are connected.

Referring to Fig. 1, the AC/DC conversion and rectification circuit is composed of a full bridge B1, filter capacitors C1 and C2. The PWM voltage/current converter is mainly composed of a main circuit and a control circuit, wherein the main circuit is composed of an LED array, an inductor L, an N-channel power type field effect transistor Q1 and a current sampling resistor Rfb connected in series in sequence, and a current smoothing filter The capacitor Co is connected in parallel to the LED array, and a Schottky freewheeling diode D1 is connected in parallel to the loop of the LED array and the inductor L in series; the control circuit is composed of the PWM chip HV9910 and its peripheral voltage stabilizing capacitor C3 and the pulse frequency adjustment resistor Rosc. The current feedback pin CS of the PWM chip HV9910 is connected to the upper end of the current sampling resistor Rfb, and the PWM output terminal GATE is connected to the control pole of the N-channel power field effect transistor Q1. The specific working process of the circuit shown in Figure 1 is as follows:

After the voltage is rectified by the rectifier bridge B1 (if it is powered by DC mode, the rectifier circuit can also be _omitted ), it is filtered by capacitors C1 and C2 to form a DC voltage. The device provides the working voltage V _DD for HV9910. When the PWM_D pin of HV9910 is high level, HV9910 is allowed to generate a fixed switching frequency on the GATE pin by the frequency setting resistor Rosc on the RT pin and the internal oscillator capacitor. The PWM pulse is output, and the duty cycle of the PWM pulse is adjusted by comparing the feedback voltage on the CS pin with the internal constant reference voltage Vref. When the PWM pulse voltage output by HV9910 is applied to the gate level of N-channel power field effect transistor Q1, the LED array is lit. When the gate-level voltage of Q1 is at a high level, Q1 is turned on, and the DC voltage begins to be across the LED array and the two ends of the inductor L, and the LED array is lit by the electric energy provided by the power supply, and the inductor L stores electric energy at the same time; when the gate-level voltage of Q1 When the level is low, Q1 is turned off, and the energy stored in the inductor L continues to provide current to the LED array through the fast recovery Schottky freewheeling diode D1. It can be seen that no matter in the positive half cycle or the negative half cycle of the PWM pulse, a pulsating voltage is applied to both ends of the LED array. After the voltage is smoothed by the capacitor Co, the LED array can obtain a continuous and smooth current. Since the LED array always works in a continuous constant current mode, it is not only beneficial to improve the luminous efficiency of the LED, but also beneficial to prolong the service life of the LED.

Referring to Fig. 2, the pyroelectric infrared control circuit is composed of a power supply circuit mainly with an ASIC CS9803GP as the core and configured with peripheral circuits. The working power of the whole pyroelectric infrared control circuit is taken from the power supply voltage pin V _DD of HV9910 in the PWM voltage/current converter, specifically, a current limiting resistor R8 is connected in series on the power supply voltage pin V _DD of HV9910, and then the current limiting It is realized by connecting an energy storage capacitor C9 and a Zener diode between the other end of the resistor R8 and the ground. In order to prevent the reverse connection of the power supply, a diode D2 can be connected in series with R8. Because the illuminating lamp described in the utility model does not work during the day, and at night when people come, the light is on, and when people leave, the light is off, so the joint control of natural light and human body infrared rays is adopted. Among them, the natural light is collected by the photoresistor RG connected to the CS9803GP chip CDS detection terminal CDS (pin 9) and converted into an electrical signal, which is sent to the internal Schmitt trigger of the CS9803GP. During the day, the resistance of the CDS is low, and the output of the Schmitt inverter is Low, inhibit the output; the opposite is the case when the sky is dark, the output of the Schmidt inverter is high; the human body infrared signal is connected to the positive input terminal NII1 (pin 2) of the operational amplifier of CS9803GP and the reference voltage terminal V _REF by the pyroelectric infrared sensor PIR (4 pins) pyroelectric infrared sensor PIR is converted into electrical signal, the signal is amplified by CS9803GP internally, if it is judged that there is a trigger, the op amp outputs a high level. At this time, the timing detection circuit starts timing, counts a certain internal clock cycle, and jumps to a high level (to avoid false triggering). The CS9803GP system clock terminal TB (pin 6) is connected to R3 and C6 to determine the internal clock of the IC. CS9803GP timing clock terminal TCI (pin 8) is connected to R4 and C7 to determine the cycle of the IC internal timer, and the frequency also satisfies F=(1±20%)/1.1R3×C6. Adjusting R4 and C7 can adjust the length of output control time, which depends on the actual requirements of the application. The working process of the circuit shown in Figure 2 is as follows: the infrared signal of the human body sensed by the PIR is amplified by the second stage inside the CS9803GP, and then the window voltage is compared to determine whether there is a trigger, and if there is, the output is high. At this time, the timer is controlled to start counting and enter the delay state. When the time of the infrared signal of the human body detected by the PIR is longer than the predetermined clock period, it will output a high level to prevent false triggering. During the daytime, the photoresistor RG has a low light resistance value, the RELAY output terminal (pin 11) of CS9803GP outputs a low level, HV9910 has no PWM pulse output, and the LED array is always off. At night, the resistance of the photoresistor RG is high without light. When the PIR detects the infrared signal of the human body, the RELAY output terminal (pin 11) of the CS9803GP outputs a high level, and the HV9910 outputs a PWM pulse, and the LED array lights up; after the person walks away, the LED The array goes off after a delay, and turns on again when the next person comes.

Claims (3)

1, a kind of rpyroelectric infrared control constant-current LED illuminating lamp, it comprises led array, AC/DC conversion rectification circuit and control circuit, wherein control circuit is made up of rpyroelectric infrared control circuit and PWM voltage/current converter, it is characterized in that the output of rpyroelectric infrared control circuit is connected with the pulse output permission pin (PWM_D) of HV Series P WM control chip (HV9910) in the PWM voltage/current converter.

2, the described a kind of rpyroelectric infrared control of claim 1 constant-current LED illuminating lamp according to the rules, the power input that it is characterized in that described rpyroelectric infrared control circuit respectively with PWM voltage/current converter in the supply voltage pin (V of HV Series P WM control chip (HV9910) _DD) be connected with common land (GND).

3, claim 2 rpyroelectric infrared control constant-current LED illuminating lamp according to the rules is characterized in that the supply voltage pin (V of HV Series P WM control chip (HV9910) in the positive pole of power input of described rpyroelectric infrared control circuit and the PWM voltage/current converter _DD) between be in series with current-limiting resistance (R1), this current-limiting resistance (R1) cross-over connection over the ground has storage capacitor (C1), constitutes the power circuit of rpyroelectric infrared control circuit.

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