TWI517760B - Lamp brightness adjusted circuit - Google Patents

Description

Fluorescent lamp drive control circuit

The invention relates to a fluorescent lamp driving circuit, and more particularly to a driving and control circuit for a dimmable fluorescent lamp.

Conventional lighting equipment, such as light bulbs or lamps, can only provide a fixed-light source when illuminated. For environments that do not require too much brightness at a particular time, the lamp provides too much brightness and not only causes electrical energy. The waste, and the electric light can not change the brightness according to the environmental demand, to achieve the most suitable brightness of the electric light.

Therefore, some so-called energy-saving lamps or dimming lamps and other dimmable electric lamps have been invented. For the bulb (white light), the principle of dimming is to change the current through the tungsten by the knob. The size of the wire, in order to change the brightness of the bulb, but for fluorescent lamps, because the fluorescent lamp does not use tungsten to emit light through the current, it is impossible to switch the brightness by the same method as the bulb, and the conventional method is Switch the different brightness by the number of times the switch is turned.

However, changing the brightness of the fluorescent lamp through the number of times of the switch may cause trouble to the user. Usually, the brightness of the fluorescent lamp changes sequentially through the number of times of the switch, for example, the first time the light is turned on is the brightest brightness, and the light is turned off. Immediately after re-opening once, it will switch to the brightness of the medium bright. Switching once will switch to the low brightness. If the user wants to adjust to the low brightness at the beginning, he must endure the flashing of the switch twice. And the brightness switching causes the burden on the eyes, in addition, the first two switching flashes also cause a waste of electrical energy, The life of the lamp that will be seriously affected, even if it is to adjust to the medium brightness, it needs to endure the flicker once, which will cause trouble for the user. Therefore, how to solve such a problem has become an urgent problem to be solved.

Therefore, one of the objects of the present invention is to provide a fluorescent lamp driving circuit for lighting a fluorescent lamp, the fluorescent lamp driving circuit comprising: a converting portion for converting the received alternating current power a control unit that outputs a control signal according to the input of the detected alternating voltage to control the current value outputted to the fluorescent lamp; an output unit is coupled to the control unit and the conversion unit for Controlling the signal output current to the fluorescent lamp, wherein the control portion includes a delay unit for providing a specific buffering time to delay the lighting of the fluorescent lamp before the fluorescent lamp is illuminated.

1 is a circuit diagram of a fluorescent lamp driving circuit according to a preferred embodiment of the present invention. As shown in FIG. 1, the fluorescent lamp driving circuit 1 includes an AC power supply AC input, a conversion unit 11, and a control unit 12, The output unit 13 and the fluorescent lamp 14.

The converting portion 11 receives the AC voltage supplied from the AC power source AC input and converts it into DC power, wherein the converting portion 11 includes four diodes, which are the first diode 111, the second diode 112, and the first The third diode 113 and the fourth diode 114, the first diode 111 and the second diode 112 are coupled to each other and connected in series, and the third diode 113 and the fourth diode 114 are The mutual coupling and the series connection, and the first and second diodes 111, 112 and the third and fourth diodes 113, 114 are coupled in parallel, and the driving conversion portion forms a bridge type circuit. The two input ends of the AC power source AC input are respectively coupled between the first diode 111 and the second diode 112, and between the third diode 113 and the fourth diode 114, and the conversion portion. 11 includes a virtual ground 15 coupled to the second diode 112 and the fourth diode 114.

The control unit 12 is coupled to the AC power input AC, and can detect the status of the AC voltage input, and control the current value outputted by the output unit 13 to the fluorescent lamp according to the AC voltage input condition, and simultaneously output the control signal to the output unit 13 and borrow The output current output from the control unit 13 to the fluorescent lamp 14 is changed by the control signal.

The output unit 13 is coupled to the control unit 12 and the conversion unit 11, and receives the DC voltage outputted from the conversion unit 11 and the control signal output by the control unit 12, and outputs a driving current to the fluorescent lamp 14 according to the control signal to point. Bright fluorescent light 14. The output portion 13 includes a first N-type metal oxide semiconductor (NMOS) 131 and a second N-type metal oxide semiconductor 132. The drain of the first NMOS 131 is coupled to the conversion portion 11 and receives the DC voltage outputted from the conversion portion 11. The gate is coupled to the control terminal 12 for receiving the control signal, the gate of the second NMOS 132 is coupled to the source of the first NMOS 131, the gate is coupled to the control terminal 12 for receiving the control signal, and the source is coupled to the virtual ground 15 . The output portion 13 further includes an inductor 133 and a first capacitor 134. The first end of the inductor 133 is coupled between the source of the first NMOS 131 and the drain of the second NMOS 132, and the first end of the first capacitor 134 is coupled to The second end of the inductor 133 outputs a driving current to the fluorescent lamp 14 at the second end of the first capacitor 134.

There is a second capacitor 141 and a resistor 142 between the fluorescent lamp 14 and the output portion 13. The first end of the second capacitor 141 is coupled to the second end of the first capacitor 134 and the first end of the fluorescent lamp 14. The first end of the 142 is coupled to the second end of the fluorescent lamp 14 , and the second end of the resistor 142 is coupled to the second end of the second capacitor 141 , the virtual ground 15 , and the control unit 12 .

The fluorescent lamp 14 receives the drive current from the output of the output unit 13 to illuminate, and feeds back the voltage to the control unit 12 for controlling the output signal.

2 is a block diagram of a control unit according to a preferred embodiment of the present invention. As shown in FIG. 2, the control unit 12 includes a voltage source 21, a backup power source 22, a voltage voltage stabilizing unit 23, and a logic unit 24. The control unit 25, the delay unit 27 and the detection unit 28.

The voltage source 21 is for providing a voltage sufficient to illuminate the fluorescent lamp when the fluorescent lamp is turned on, and the backup power source 22 supplies the power required by the other peripheral components of the control unit 12 when the voltage source 21 is inactive.

The voltage regulator unit 23 is coupled to the voltage source and the backup power source, receives the voltage supplied from the voltage source, and is used to stabilize the voltage of the entire system. When the voltage drops below a predetermined value, the voltage regulator unit 23 will apply the voltage. Maintain above the preset value.

The logic unit 24 is coupled to the voltage voltage stabilizing unit 23, and can provide a voltage signal according to the voltage source and the detecting unit 28 to output a logic signal, and the logic signal controls the operation of the delay unit 27, and the delay of the feedback output according to the delay unit 27 The signal outputs a logic signal to the control unit 25.

The delay unit 27 is coupled to the logic unit 24, and includes a micro current source 271, a first switch 272, a second switch 273, a third capacitor 274, and a A comparator 275. The micro current source 271 stably provides a small current. The preferred value in the embodiment is 1 u amp, but not limited thereto, the first switch 272 is coupled to the micro current source 271, and the second switch 271 is first. The switch 272 is connected in series and coupled to the virtual ground 15 . The opening or closing of the first switch 272 and the second switch 273 is controlled by the logic signal output by the logic unit 24 . The first end of the third capacitor 274 is coupled to the first end. A switch 272 is between the second switch 273.

When the fluorescent lamp 14 is operated to be lit, the voltage source 21 supplies a voltage, and the indirect control logic unit 24 outputs a logic signal. At this time, the logic signal controls the first switch 272 to be turned off, and the second switch 273 is turned on to make it virtual. The ground terminal 15 causes an open circuit. Because the first switch 272 is turned off, the micro current source 271 will charge the third capacitor 274. When the charged voltage reaches a certain value Vref after a certain period of time (3.8V in the preferred embodiment, but not In this case, when the voltage source continues to supply voltage, the delay unit 27 outputs a delay signal to the logic unit 24 through the first comparator 275, and the logic unit can output a logic signal to the control unit 25 according to the delay signal.

The control unit 25 is coupled to the logic unit 24, and can output current to the output unit 13 according to the logic signal output by the logic unit 24.

In addition, the detecting unit 28 is coupled to the logic unit 24 and the AC power source AC input, and the detecting unit 28 can detect the number of times the fluorescent lamp 14 is switched, and according to the AC voltage triggered by the switch fluorescent lamp 14 switch. The number of times the fluorescent lamp 14 is switched outputs a luminance signal to the logic unit 24, and the logic unit 24 also outputs a luminance signal to the control unit 25. The control unit 25 changes the frequency of the oscillator according to the brightness signal, thereby changing the square wave. Width to adjust the amount of current output.

According to the above technology, after the fluorescent lamp is turned on, due to the action of the delay unit, when the fluorescent lamp is repeatedly turned on or off, the lighting time is delayed for a certain time, and can be based on the function of the detecting unit. , to achieve different brightness with different opening times, fully solve the problem of adjusting the brightness of the fluorescent lamp, there is no need to flash the user's eyes, and the waste of electrical energy.

Please refer to FIG. 3, which is a step diagram of a fluorescent lamp dimming method according to a preferred embodiment of the present invention. As shown in FIG. 3, a voltage source (S1) is first provided, and a current is supplied after the voltage source is supplied. The source performs the charging operation (S2). When the charging operation is completed, the output driving power source illuminates the fluorescent lamp (S31). Otherwise, when the charging operation is not completed, the fluorescent lamp is not turned on (S32), and when the charging is completed, the charging is completed. The fluorescent lamp is turned on, then the voltage source is stopped (S4). After the power supply is stopped, the current source is also interrupted, and the discharging operation is started (S5). At this time, the number of times the voltage source is supplied is detected, and the number of times is provided according to the voltage source. In step S31, the brightness of the fluorescent lamp is turned on (S6). By re-providing the voltage source, you can get different brightness of the fluorescent light, and have a buffer charging time when turning on the fluorescent light, avoiding the damage caused by the flashing of the fluorescent light, and saving unnecessary power waste. It can extend the life of fluorescent lamps.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

1‧‧‧Fluorescent lamp drive circuit

11‧‧‧Transition Department

111‧‧‧First Diode

112‧‧‧Secondary diode

113‧‧‧ Third Dipole

114‧‧‧Fourth dipole

12‧‧‧Control Department

13‧‧‧Output Department

131‧‧‧First NMOS

132‧‧‧second NMOS

133‧‧‧Inductance

134‧‧‧first capacitor

14‧‧‧Flood light

141‧‧‧second capacitor

142‧‧‧resistance

15‧‧‧virtual ground

AC input‧‧‧AC power supply

21‧‧‧Voltage source

22‧‧‧Reserved power supply

23‧‧‧Voltage regulator unit

24‧‧‧Logical unit

25‧‧‧Control unit

27‧‧‧Delay unit

271‧‧‧Microcurrent source

272‧‧‧First switch

273‧‧‧second switch

274‧‧‧ third capacitor

275‧‧‧ comparator

28‧‧‧Detection unit

S1~S6‧‧‧ method steps

1 is a circuit diagram of a fluorescent lamp driving circuit of a preferred embodiment of the present invention; FIG. 2 is a block diagram of a control portion of a preferred embodiment of the present invention; and FIG. 3 is a fluorescent lamp of a preferred embodiment of the present invention; Dimming method step diagram.

12‧‧‧Control Department

15‧‧‧virtual ground

21‧‧‧Voltage source

22‧‧‧Reserved power supply

23‧‧‧Voltage detection unit

24‧‧‧Logical unit

25‧‧‧Control unit

27‧‧‧Delay unit

28‧‧‧Detection unit

271‧‧‧Microcurrent source

272‧‧‧First switch

273‧‧‧second switch

274‧‧‧ third capacitor

275‧‧‧ comparator

Claims (18)

A fluorescent lamp driving circuit for lighting a fluorescent lamp, the fluorescent lamp driving circuit comprising: a converting portion for converting the received alternating current power into a continuous current, and outputting the direct current; a control unit configured to control a current value outputted to the fluorescent lamp and output a control signal; an output unit coupled to the control unit and the conversion unit for receiving the DC power, and outputting a current according to the control signal The fluorescent lamp, wherein the control unit comprises a delay unit for providing a specific buffering time to delay lighting the fluorescent lamp before the fluorescent lamp is turned on. The fluorescent lamp driving circuit of claim 1, wherein the converting portion comprises a plurality of diodes. The fluorescent lamp driving circuit of claim 1, wherein the delay unit comprises a current source, a plurality of switches and a capacitor, and the plurality of open relationships are determined to be turned on and off according to whether the AC power source is supplied or not. And controlling whether the current source charges the capacitor by turning on and off the plurality of switches. The fluorescent lamp driving circuit of claim 3, further comprising a logic unit for controlling opening and closing of the plurality of switches according to the direct current. The fluorescent lamp driving circuit of claim 1, wherein the control unit further comprises a detecting unit, wherein the detecting unit is configured to detect the number of times the AC power is supplied, and output according to the number of times the AC power is supplied. a detective A test signal that controls the brightness of the fluorescent light. A fluorescent lamp dimming circuit for controlling a brightness-adjustable fluorescent lamp, the fluorescent lamp dimming circuit comprising: a voltage source for providing a voltage; a logic unit coupled to the voltage source, Outputting a logic signal; a control unit is coupled to the logic unit, and outputting an output current according to the logic signal output by the logic unit; an output end coupled to the control unit, receiving the output current and outputting to the firefly a delay unit coupled to the logic unit, the logic unit controls the delay unit to perform a specific time delay, and transmits a delay signal to the logic unit; wherein the logic unit outputs the logic according to the delay signal Signal to the control unit. The fluorescent lamp dimming circuit of claim 6, wherein the delay unit comprises a current source, a plurality of switches and a capacitor, and the plurality of open relationships are determined to be turned on and off according to whether the AC power source is supplied or not. And controlling whether the current source charges the capacitor by turning on and off the plurality of switches. The fluorescent lamp dimming circuit of claim 7, wherein the specific time is a time during which the current source charges the capacitor. The fluorescent lamp dimming circuit of claim 7, wherein the current source provides a current of 1 u amp, and the capacitor is charged with a voltage of 3.8 V. The fluorescent lamp dimming circuit of claim 6, further comprising a detecting unit coupled to the logic unit, wherein the detecting unit is configured to detect the number of times the AC power is supplied, and according to the AC power source The number of times provided is a detection signal, and the detection signal is used to control the brightness of the fluorescent lamp. The fluorescent lamp dimming circuit of claim 6, further comprising a voltage stabilizing unit coupled between the voltage source and the logic unit, receiving a voltage supplied from the voltage source, and Stabilize the voltage of the fluorescent lamp dimming circuit. The fluorescent lamp dimming circuit of claim 6, further comprising a control unit coupled to the logic unit for outputting a current according to the logic signal output by the logic unit. The fluorescent lamp dimming circuit of claim 12, further comprising an output coupled to the control unit, the output comprising a plurality of comparators for receiving current output from the control unit, and Output to the fluorescent light. The fluorescent lamp dimming circuit of claim 12, wherein the control unit comprises an oscillator that changes the frequency of the oscillator according to the logic signal to output currents of different current values. A fluorescent lamp dimming method for controlling a brightness-adjustable fluorescent lamp, the method comprising: providing a voltage source; providing a charging power source; determining whether the charging power source is performed according to whether the voltage source is supplied or not Charging It is judged whether the charging is completed or not; after the charging is completed, a driving power source is output to the fluorescent lamp to illuminate the fluorescent lamp. The fluorescent lamp dimming method according to claim 15, wherein when the voltage source stops supplying the voltage, the number of times the voltage source supplies the voltage is detected. The fluorescent lamp dimming method according to claim 16, wherein the driving power source determines the current value according to the number of times the voltage source supplies the voltage. The fluorescent lamp dimming method according to claim 15, wherein the charging power source discharges when the voltage source does not supply a voltage.