TW201304595A - Constant current driving device with load of voltage clamp characteristics - Google Patents

Abstract

The present invention provides a constant current driving device with load of voltage clamp characteristics, which includes a mutually-connected power source, a rectifying unit, an adjustable work ratio unit, a transformer, a diode, an inductor, a capacitor, and a load unit with voltage clamp characteristics, which can be applied to isolated type AC to DC load unit with voltage clamp characteristics ( e.g.: the light emitting device such as LED, OLED, or the like), while using the way of the primary-side fixing work ratio and secondary-side inductance smoothing current to complete the requirement of fixation root mean square current, high power factor, and without electrolytic capacitance, to achieve the effect of increasing the lifetime; further, the present invention can be incorporated with the output current correction unit, so that the light emitting unit can obtain fixed RMS current in different starting voltage, without necessary for the additional optical coupling feedback device; or with the power detection and correction unit to perform voltage correction and detection to be able to perform operation under the common voltage range; and further with the dimming control unit to adjust the intensity of light required by the light emitting unit.

Description

Steady flow drive with voltage clamp characteristic load

The invention relates to a steady current driving device with a voltage clamping characteristic load, in particular to an AC-DC direct-isolated load cell with voltage clamping characteristics, which is used as a steady current driving device for LED, OLED and the like.

At present, the commonly used isolated light source load driving device includes at least the following three types: one is a flyback converter, and although it has the advantage of low cost, at least some circuit components in the circuit must use electrolytic capacitors. Therefore, its power factor, efficiency and longevity can not meet the current use requirements; the second is a combination of the high power factor of the pre-stage and the back-stage converter of the latter stage, although it has the advantage of high power factor, but because it is The two-stage architecture makes the overall cost significantly higher, and it also inevitably requires the use of electrolytic capacitors, thus resulting in a lower lifetime; the third is a single-stage converter, but the single-stage converter has a high power factor. With the advantage of good efficiency, but still need to use electrolytic capacitors, so it also has the disadvantage of lower service life; in addition, with the above three kinds of illumination driving devices, in addition to the above-mentioned shortcomings, it is impossible to carry out the light source intensity in practical applications. The common lack of adjustment; therefore, the three types of isolated illumination drivers are still not fully compatible. Use the occasion required.

In view of the above-mentioned shortcomings of the steady-current driving device with voltage-clamping characteristic load, the inventor feels that he has not perfected it, exhausted his mind and researched and overcome it, and developed his experience based on his accumulated experience in the industry for many years. A illuminating device with steady flow driving, in order to enable the invention to be applied to an alternating current to direct current isolated illuminating device, and to fix the mean square by fixing the working ratio and the secondary side inductance softening current on the primary side Demand for constant RMS current, high power factor (PF), etc., while at the same time increasing the service life by eliminating the need for electrolytic capacitors.

Another object of the present invention is to adjust the secondary side voltage to enable the illuminating unit to obtain a constant RMS current under design specifications at different turn-on voltages. No additional optical coupling feedback device is required.

Still another object of the present invention is to enable operation correction using the detected power supply voltage while operating over a universal voltage range.

Still another object of the present invention is to adjust the output light intensity required for the light unit.

To achieve the above objective, the illuminating device with steady current driving of the present invention comprises: a rectifying unit connected to an external AC power source and capable of rectifying the AC power source into a DC power source; and an adjustable working ratio unit Connected to the rectifying unit, which can be set to maintain a fixed working ratio and output; a transformer having a primary side and at least one secondary side, the primary side being connected to the adjustable working ratio unit; a diode connected in series to one end of the secondary side of the transformer; an inductor connected in series with the diode; a capacitor disposed between the inductor and the diode, and the transformer The other end of the secondary side is connected; and a load cell having voltage clamping characteristics is connected in parallel with the inductor and the capacitor.

According to the above structure, the load cell having the voltage clamping characteristic may be a light emitting diode (LED) or an organic light emitting diode (OLED).

According to the above structure, the adjustable working ratio unit is further connected with a current output correcting unit, and the current output correcting unit is mainly composed of a sample and hold circuit and a working ratio correction circuit, and is further provided on the secondary side of the transformer. An auxiliary coil is used to obtain a reference output voltage via the auxiliary coil, and the working ratio correction circuit adjusts the working ratio of the adjustable working ratio unit, so that the load unit can obtain design specifications under different conduction voltages. The lower constant RMS current.

According to the above structure, the adjustable working ratio unit is further connected with a power correcting unit, wherein the power correcting unit is composed of a power detecting circuit and a working ratio correcting circuit, and the power detecting circuit can be detected by the output of the rectifying unit. The voltage of the power source, and the working ratio correction circuit adjusts the working ratio of the adjustable working ratio unit, thereby correcting the output power.

According to the above structure, the adjustable working ratio unit is further connected with a dimming control unit, which is disposed between the power source and the adjustable working ratio unit, which can be jumped or masked by a work ratio (skip duty) The way to reduce the output power of the adjustable working ratio unit.

According to the above structure, the dimming control unit can sequentially control the output power of the adjustable working ratio unit to decrease in equal proportion, and the above-mentioned actions can be repeated in a loop.

In order to fully understand the technical features and the efficacies of the present invention, the present invention will be described in detail by the following specific embodiments and the accompanying drawings. The structure of the first embodiment includes at least a rectifying unit 2, an adjustable working ratio unit 3, a transformer 4, a diode 5, an inductor 6, a capacitor 7, and a load unit 8; wherein the rectifying unit 2 It is a common bridge rectifier, which is connected to an external power supply 1 (the power supply 1 can be a general AC mains), and can rectify the AC power supply 1 into a DC power supply, and an adjustable working ratio unit 3 Connected to the rectifying unit 2, the equivalent circuit is as shown in the second figure, has a basic structure of PWM, can be set to maintain a fixed working ratio and output, and the transformer 4 has a primary side and at least one secondary side. The primary side system is connected to the adjustable working ratio unit 3, and the diode 5 and the inductor 6 are connected in series to one end of the secondary side of the transformer 4, and the capacitor 7 is disposed on the inductor 6 and the second pole. Between body 5, and with this change The other end (grounding end) of the secondary side of the device 4 is connected, and the load unit 8 is a load having a voltage clamping characteristic (which can be a light emitting component or device such as an LED or an OLED), and the inductor 6 and the capacitor 7 Connected in parallel.

Referring to the third figure, it can be seen that the structure of the first embodiment is operated, and the power source 1 of the alternating current is rectified by the rectifying unit 2, and the duty ratio of the adjustable working ratio unit 3 is fixed (the output thereof) The waveform is as shown by curve A), which provides a fixed power on the primary side of the transformer 4 (the waveform of the current is as shown by curve B), and since the output is a fixed load, it can be generated on the secondary side of the transformer 4. A fixed RMS current, and since the fixed RMS current is a pulsed current (the current waveform is as shown by curve C), it can be applied to the load unit 8 after the inductor 6 is softened (the current waveform is as shown by the curve D). In order to enable the light-emitting unit 8 to obtain a relatively compliant current, and at the same time, because the load unit 8 has the characteristics of voltage clamping (CLAMP), a stable load output voltage will be established when the current is turned on, thereby satisfying the fixed rms. Current (constant RMS current) output, high power factor (high PF) requirements, while eliminating the need for electrolytic capacitors in the circuit, can also effectively improve the overall service life.

4 and 5, it can be seen that the architecture of the second embodiment of the present invention is based on the architecture of the first embodiment described above, except that the adjustable working ratio unit 3 can be further connected to a current. The correction unit 31 is outputted, and the current output correction unit 31 is mainly composed of a sample and hold circuit 311 and a work ratio correction circuit 312. In practical applications, an auxiliary device can be additionally provided on the secondary side of the transformer 40. The coil 41 is used to obtain a reference output voltage VE1 via the auxiliary coil 41, and the working ratio correction circuit 312 adjusts the working ratio of the adjustable working ratio unit 3, so that the load unit 8 is under different conduction voltages. The constant RMS current under the design specification can be obtained, and the operational relationship of the current output correction unit 31 is Pin × E ff = Pout = Vout × I ( RMS ), for example: when the load unit When the startup voltage of 8 becomes larger, the output voltage (Vout) becomes larger, and the rms current I(RMS) is made smaller; therefore, the input power is improved by detecting the current output (Vout). , You can make the rms current I (RMS) back into the design specifications, without the use of additional coupling feedback device light.

Referring to the sixth and seventh figures, it can be seen that the architecture of the third embodiment of the present invention is also based on the architecture of the foregoing first embodiment, which is different in that the adjustable working ratio unit 3 can be further connected to The power correcting unit 32 is composed of a power detecting circuit 321 and a working ratio correcting circuit 322. The power detecting circuit 321 can detect the voltage of the power source 1 from the output of the rectifying unit 2, and The working ratio correction circuit 322 adjusts the operating ratio of the adjustable working ratio unit 3, thereby correcting the output power thereof, so that the present invention can obtain the current within the design specification within the range of the universal voltage; that is, when the adjustable type is used When the working ratio of the working ratio unit 3 is switched to obtain the constant power output, the output power will be changed by the power source 1 input. Therefore, the working ratio of the adjustable working ratio unit 3 can be changed by the detecting power source 1 and then via the power correcting unit 32. To keep the rms current I (RMS) within the design specifications.

Referring to FIG. 8 and FIG. 9 , it can be seen that the architecture of the fourth embodiment of the present invention is also based on the architecture of the foregoing first embodiment, which is different in that the adjustable working ratio unit 3 can be further connected to a dimming control unit 33, the dimming control unit 33 is disposed between the power source 1 and the adjustable working ratio unit 3, which can reduce the adjustable working ratio unit by jumping or masking duty (skip duty) 3 output power; when the output waveform of the adjustable working ratio unit 3 is as curve E, it has 100% power output when the dimming control unit 33 does not perform the skip operation (mask) at all (as shown by curve F) And when the dimming control unit 33 performs a jump operation (mask), it has a power output of 75% (as shown by a curve G), and when the dimming control unit 33 performs a second jump operation (mask) With 50% power output (as shown by curve H), finally, if dimming control unit 33 performs three jump operations (mask), it has 25% power output (as shown by curve I), and the above action system Repeatable cycle; in practical applications, The user switches the power switch as an operation signal, and counts the operation signal under the specified logic, and then correspondingly jumps or masks the duty ratio according to the counting result, for example, repeatedly switching within the specification time. When the power switch is once, it is to count the operation signal once. At this time, the 25% duty ratio (Duty) can be masked, so that the output power is reduced to the original 75%. This is the second stage output current; if it is in the specification time again If you switch it again and again (that is, count the operation signal twice), you can mask the 50% duty ratio (Duty), so that the output power is reduced to the original 50%, which is the third stage output current; Repeatedly switching once in the specification time (that is, counting the operation signal three times), it can mask 75% of the working ratio (Duty), so that the output power is reduced to the original 25%, which is the fourth stage output current; Repeatedly switching once again within the normal time (counting the operation signal five times), you can return to the mask 0% working ratio (Duty), so that the output power returns to the original 100% (that is, return to the first stage) The state of the output current); thereby, the load unit 8 can be The illuminating element or device) forms an operational control that cyclically adjusts the intensity of the output light.

As described above, the present invention fully complies with the three requirements of the patent: novelty, advancement, and industrial applicability.

The invention has been described above in terms of preferred embodiments, and it should be understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations, substitutions, and modifications equivalent to the embodiments are intended to fall within the scope of the present invention.

1. . . power supply

2. . . Rectifier unit

3. . . Adjustable working ratio unit

31. . . Current output correction unit

311. . . Sample and hold circuit

312, 322. . . Working ratio correction circuit

32. . . Power correction unit

321. . . Power detection circuit

33. . . Dimming control unit

4, 40. . . transformer

41. . . Auxiliary coil

5. . . Dipole

6. . . inductance

7. . . capacitance

8. . . Load unit

The first figure is a schematic diagram of the architecture of the first embodiment of the present invention.

The second figure is an equivalent circuit diagram of the adjustable working ratio unit in the first embodiment of the present invention.

The third figure is a schematic diagram of the current waveform of each program in the first embodiment of the present invention.

The fourth figure is a schematic diagram of the architecture of the second embodiment of the present invention.

Fig. 5 is an equivalent circuit diagram of the current output correction unit in the second embodiment of the present invention.

Figure 6 is a block diagram showing the architecture of a third embodiment of the present invention.

Fig. 7 is an equivalent circuit diagram of the power supply correcting unit in the third embodiment of the present invention.

The eighth figure is a schematic diagram of the architecture of the fourth embodiment of the present invention.

Figure 9 is a schematic diagram showing current waveforms of respective programs in the fourth embodiment of the present invention.

1. . . power supply

2. . . Rectifier unit

3. . . Adjustable working ratio unit

4. . . transformer

5. . . Dipole

6. . . inductance

7. . . capacitance

8. . . Load unit

Claims (6)

A steady current driving device with a voltage clamping characteristic load, comprising: a rectifying unit connected to an external alternating current power source and capable of rectifying the alternating current power source into a direct current power source; and an adjustable working ratio unit The rectifying unit is connected, which can be set to maintain a fixed working ratio and output; a transformer having a primary side and at least one secondary side, the primary side being connected to the adjustable working ratio unit; a diode, Connected in series to one end of the secondary side of the transformer; an inductor is connected in series with the diode; a capacitor is disposed between the inductor and the diode, and the other side of the transformer One end is connected; and a load cell having voltage clamping characteristics is connected in parallel with the inductor and the capacitor. The steady current driving device with a voltage clamping characteristic load as described in claim 1, wherein the load cell having a voltage clamping characteristic may be a light emitting diode (LED) or an organic light emitting diode (OLED). The steady current driving device with a voltage-clamping characteristic load according to the first aspect of the invention, wherein the adjustable working ratio unit is further connected with a current output correcting unit, and the current output correcting unit is mainly composed of a sample and hold circuit and a working ratio correction circuit is formed, and an auxiliary coil is further disposed on the secondary side of the transformer, and the reference output voltage is obtained by the sampling and holding circuit via the auxiliary coil, and the adjustable ratio ratio unit is adjusted by the working ratio correction circuit. The working ratio allows the load cell to achieve a constant RMS current at the design specification at different turn-on voltages. The steady current driving device with a voltage clamp characteristic load according to claim 1, wherein the adjustable working ratio unit is further connected with a power correcting unit, wherein the power correcting unit is configured by a power detecting circuit and a working ratio The correction circuit is composed of a power detecting circuit capable of detecting the voltage of the power source by the output end of the rectifying unit, and adjusting the working ratio of the adjustable working ratio unit by the working ratio correction circuit, thereby correcting the output power. The steady current driving device with a voltage clamp characteristic load according to claim 1, wherein the adjustable working ratio unit is further connected with a dimming control unit, and the dimming control unit is set at a power supply and an adjustable working ratio. Between the units, the output power of the adjustable working ratio unit can be reduced by skipping the duty. The steady current driving device with a voltage clamping characteristic load according to claim 1, wherein the dimming control unit can sequentially control the output power of the adjustable working ratio unit to decrease in equal proportion, and the above action system Repeatable cycles can be performed.