HK1192097B - Driving system for semiconductor light source and semiconductor lighting device - Google Patents

Description

Driving system of semiconductor light source and semiconductor lighting device

Technical Field

The present invention relates to a driving system of a semiconductor light source, and more particularly, to a driving system of a buck-boost semiconductor light source.

Background

Semiconductor Light Sources (LEDs) are light sources and display devices made of third-generation semiconductor materials, have the characteristics of low power consumption, long service life, no pollution, rich colors, strong controllability and the like, and are a revolution in the lighting source and light industry. With the development of LEDs, more and more LED lighting products are coming into the market. The electronic driving part of the LED is an indispensable component in LED lighting products.

In the angle of LED market, the selling price of the LED lighting terminal is still higher than that of the traditional bulb and energy-saving lamp, and price reduction becomes the key for expanding the market acceptance.

With the continuous decrease of the price of the LED particles, the price ratio of the electronic driving part is more important, and most of the LED driving circuits which are popularized and used in the market at present adopt IC control, and the main defect is that the price cost is higher. If IC control is not used, a flyback-back circuit is generally adopted, which has low efficiency, poor stability and narrow applicable output voltage range.

Disclosure of Invention

The invention aims to provide an electronic driving circuit which is simple in structure, wide in application range and low in cost and mainly aims at LED lighting products. The LED electronic driver is formed by combining a small number of components to form a self-oscillation circuit and combining a buck-boost circuit. The invention uses less components to realize the electronic driving part of the LED, greatly reduces the quantity and cost of the components, greatly reduces the proportion of the electronic driving part in the LED lighting system, and has the characteristics of high efficiency and wide applicable output voltage range.

An embodiment of the present invention provides a driving system of a semiconductor light source, where the driving system includes: a transforming device including a first coil and a second coil coupled to each other, the second coil receiving an input voltage; the switching device is connected with the second coil of the voltage transformation device in series and is used for controlling the energy storage and energy release of the second coil; and the output device is connected with the second coil of the voltage transformation device in parallel and used for supplying power to the semiconductor light source, wherein the first coil of the voltage transformation device is induced by the second coil to generate an induction signal for controlling the on and off of the switch device.

According to an embodiment of the invention, the drive system further comprises: and a starting means for starting the switching means when an input voltage is initially applied.

According to an embodiment of the invention, the switching device comprises a switch and at least one discrete component, the at least one discrete component is connected between the first coil and the control terminal of the switch, and the sensing signal passes through the at least one discrete component to control the switch. It will be understood by those skilled in the art that the discrete components are discrete resistors, capacitors, inductors, etc. corresponding to the integrated circuit. According to an embodiment of the invention, the at least one discrete component comprises a capacitive element.

According to an embodiment of the present invention, the at least one discrete component further includes a resistive element, and the resistive element and the capacitive element are connected in series.

According to the embodiment of the invention, the starting device comprises a resistive element and a one-way conducting element which are connected in series, and a connection point between the resistive element and the one-way conducting element is connected with the control end of the switching device.

According to another embodiment of the present invention, there is also provided a semiconductor lighting device including: a semiconductor light source load; a transforming device including a first coil and a second coil coupled to each other, the second coil receiving an input voltage; the switching device is connected with the second coil of the voltage transformation device in series and is used for controlling the energy storage and energy release of the second coil; and the output device is connected with the second coil of the voltage transformation device in parallel and used for supplying power to the semiconductor light source load, wherein the first coil of the voltage transformation device is induced by the second coil to generate an induction signal for controlling the on and off of the switch device.

Other objects and utilities of the present invention will become apparent from the following description of the invention with reference to the accompanying drawings and the reader will be a full understanding of the invention.

Drawings

Fig. 1 is a schematic diagram of a driving system of a semiconductor light source.

Fig. 2 is a circuit diagram of a semiconductor light source driving system according to an embodiment of the invention.

Fig. 3A is a schematic diagram of a start-up phase of a semiconductor light source driving system according to an embodiment of the invention.

Fig. 3B is a schematic diagram of a first energy storage stage of the semiconductor light source driving system according to the embodiment of the invention.

FIG. 3C is a schematic diagram of a power-down phase of the semiconductor light source driving system according to the embodiment of the invention.

Fig. 3D is a diagram illustrating a second energy storage phase of the semiconductor light source driving system according to the embodiment of the invention.

Fig. 4 illustrates waveforms of voltage and current when the semiconductor light source driving system according to the embodiment of the present invention operates.

In the above figures, the same reference numerals indicate the same, similar or corresponding elements or functions.

Detailed Description

Specific embodiments of the present invention will be described in detail below by way of embodiments with reference to the drawings.

Fig. 1 is a schematic diagram of a driving system of a semiconductor light source according to the present invention.

In fig. 1, Vin represents an input voltage. The input voltage is a dc input voltage, which may be a rectified dc voltage or a rectified and filtered dc voltage. I represents a starting device, II represents a voltage transformation device, III represents a switching device, IV represents an output device, and V represents a semiconductor light source load.

The startup device I is used to put the switching device in a conducting state at startup (i.e., at the initial application of the input voltage Vin). The transformation device II comprises a first coil and a second coil which are coupled with each other, and the second coil is used for receiving input voltage and storing and releasing energy under the control of the switching device III. The first coil is induced by the second coil to generate an induction signal for controlling the on and off of the switching device III. The output device is used for supplying power to the semiconductor light source differently according to the stored energy and the released energy of the second coil.

Fig. 2 is a detailed circuit diagram of a driving system of a semiconductor light source according to an embodiment of the present invention.

In fig. 2, the starting means I comprises a first resistor 101 and a first diode 102 connected in series. A first terminal of the first resistor 101 is connected to a first voltage input terminal, a second terminal of the first resistor 101 is connected to a second terminal of the first diode 102, and a second terminal of the first diode 102 is connected to a second voltage input terminal. The second voltage input may be directly connected to ground. It will be appreciated by those skilled in the art that the resistor may be replaced by other resistive elements and the diode may be replaced by other unidirectional conducting elements (e.g., a transistor).

The transforming device II comprises a first coil 201 and a second coil 202 coupled to each other. The first coil 201 is connected in series with a first capacitor 203 and a second resistor 204. A first end of the first coil 201 is connected to a first end of a first capacitor 203, and a second end of the first capacitor 203 is connected to a first end of a second resistor 204. A second end of the first coil 201 is grounded. A first end of the second coil 202 is connected to a first voltage input terminal. The first end of the first coil 201 and the first end of the second coil 202 are homonymous ends. The second coil 202 is connected in series with the switching device, thereby storing and releasing energy under the control of the switching device. It will be appreciated by those skilled in the art that the capacitor may be replaced by other elements having a capacitive function and the resistor may be replaced by other elements having a resistive function.

The switching device III in fig. 2 comprises a transistor 300 comprising a base 301, a collector 302, and an emitter 303. In this embodiment, the emitter 303 is connected to the second voltage input terminal.

The switching device III may also be a MOS transistor, in which case the gate of the MOS transistor corresponds to the base of the transistor, the source corresponds to the collector of the transistor, and the drain corresponds to the emitter of the transistor.

A second terminal of the second resistor 204 is coupled to the base 301 of the transistor 300 and to a second terminal of the first resistor 101. A second terminal of the second coil 202 is coupled to a collector 302 of the transistor 300.

The output means IV comprises a second diode 401 and a second capacitor 402 connected in series, the series connection of the second diode 401 and the second capacitor 402 being connected in parallel with the second coil 202. A first end of the second diode 401 is connected to the second end of the second coil 202, a second end of the second diode 401 is connected to the second end of the second capacitor 402, and a first end of the second capacitor 402 is connected to the first voltage input terminal. In addition, a first terminal of the second capacitor 402 is connected to a first terminal of the semiconductor light source load V, and a second terminal of the second capacitor 402 is connected to a second terminal of the semiconductor light source load V.

The semiconductor light source load V comprises one or more semiconductor light sources, such as light emitting sources like LEDs or OLEDs, connected together in various ways.

With reference to fig. 3A-D, the operation principle of the semiconductor light source driving system according to the present invention is described as follows:

in the start-up phase, as shown in fig. 3A, when the semiconductor light source driving system according to the present invention is connected to the dc input voltage Vin, Vin is discharged through the first resistor 101 and the base 301 and the emitter 303 of the transistor 300 to generate a current I1, so that the collector 302 and the emitter 303 of the transistor 300 are turned on. Vin is discharged through the second coil 202 and the collector 302 and emitter 303 of the transistor 300 to generate a current I2. After that, the semiconductor light source driving system of the invention enters a first energy storage stage.

In the first energy storage stage, as shown in fig. 3B, I2 passes through the second coil 202, the second coil 202 stores energy and generates a voltage V2 across it, and at the same time, the first coil 201 is induced by the second coil 202 to generate an induced electromotive force V1, and V1 discharges through the first capacitor 203, the second resistor 204, and the base 301 and the emitter 303 of the transistor 300 to generate a current I3. I3 charges first capacitor 203. A directional voltage V3 is shown developed across the first capacitor 203. As V3 rises, I3 falls and subsequently turns off transistor 300. However, since the current flowing through the second coil 202 cannot abruptly change, the current flows to the semiconductor light source load through the second diode 401, and the voltage V2 across the second coil 202 is reversed. Thereafter, the semiconductor light source driving system of the present invention enters a power release stage, and the semiconductor light source load V starts emitting light.

In the energy release stage, as shown in fig. 3C, the induced electromotive force V1 induced by the second coil 202 in the first coil 201 is also reversed. The V1 discharges through the first diode 102, the second resistor 204, and the first capacitor 203 to generate the current I4. The transistor 300 is turned off. The voltage V2 across the second coil 202 is discharged to the semiconductor light source load V through the second diode 401, and the second coil 202 releases energy and charges the second capacitor 402 to generate the voltage V5. The current I4 charges the first capacitor 203 in reverse to generate a reverse voltage V4. When the voltage V2 across the second coil 202 drops below the voltage V5 across the second capacitor 402, the discharging is stopped. After that, the semiconductor light source driving system of the invention enters a second energy storage stage. The second energy storage phase is different from the first energy storage phase, and the semiconductor light source load V emits light in the second energy storage phase.

In the second energy storage phase, as shown in fig. 3D, the voltage V5 across the second capacitor 402 is discharged through the semiconductor light source load, and the voltage V4 across the first capacitor 203 is discharged through the resistor 204, the base 301 and the emitter 303 of the transistor 300, and the first coil 201, so as to generate a current I5, and make the collector 302 and the emitter 303 of the transistor 300 conductive. Vin is discharged through the second coil 202 and the collector 302 and emitter 303 of the transistor 300 to generate a current I2. The second coil 202 stores energy and generates a voltage V2 across it. Next, the description is continued with reference to the voltage transforming device II and the switching device III in fig. 3B. The first coil 201 is induced by the second coil 202 to generate an induced electromotive force V1, and V1 discharges through the first capacitor 203, the second resistor 204, and the base 301 and the emitter 303 of the transistor 300 to generate a current I3. I3 charges first capacitor 203. A directional voltage V3 is shown developed across the first capacitor 203. As V3 rises, I3 falls and subsequently turns off transistor 300. However, since the current flowing through the second coil 202 cannot abruptly change, the current flows to the semiconductor light source load through the second diode 401, and the voltage V2 across the second coil 202 is reversed. After that, the semiconductor light source driving system of the invention enters the energy releasing stage again.

Then, the semiconductor light source driving system enters the second energy storage phase again from the energy release phase, and the process is circulated.

The operation of the transistor 300 at each stage is further described below.

As shown in fig. 3A, during the start-up phase, Vin generates a current I1 through the first resistor R1 and the base 301 and emitter 303 of the transistor 300, so that the transistor 300 is turned on and operates in the amplification region.

Then, as shown in fig. 3B, in the first energy storage phase, the induced electromotive force V1 on the first coil 201 generates a current I3 through the first capacitor 203, the second resistor 204, and the base 301 and the emitter 303 of the transistor 300, so that the transistor 300 enters a saturation region; as the current I3 charges the first capacitor 203 such that the voltage V3 across the first capacitor 203 increases, the current I3 decreases, which in turn causes the diode 300 to move out of the saturation region and into the cutoff region. However, since the current I2 flowing through the second coil 202 cannot abruptly change, the current I2 flows to the semiconductor light source load through the second diode 401 and reverses the voltage V2 across the second coil 202.

Next, as shown in fig. 3C, in the energy release phase, the diode 300 is turned off, the voltage across the first coil 201 is reversed with the reversal of the voltage across the second coil 202, and the first capacitor 203 is reversely charged through the second resistor 204 and the first diode 102.

Then, as shown in fig. 3D, in the second energy storage phase, the induced electromotive force V1 on the first coil 201 generates a current I3 through the first capacitor 203, the second resistor 204, and the base 301 and the emitter 303 of the transistor 300, so that the transistor 300 enters the saturation region again, and the second coil 202 starts to store energy; then, as the current I3 charges the first capacitor 203 such that the voltage V3 across the first capacitor 203 increases, the current I3 decreases, which in turn causes the diode 300 to move out of the saturation region and into the cutoff region.

And then, circulating to an energy release stage again, and circulating the second energy storage stage and the energy release stage.

As shown in fig. 4, a waveform diagram of voltage and current when the semiconductor light source driving system according to the embodiment of the present invention operates is shown. It should be noted that the waveform diagram of the start-up phase is not shown in fig. 4.

At time t0, Vin discharges through the second coil 202 and the collector 302 and emitter 303 of the transistor 300 to generate a current I2, and the second coil 202 starts to store energy; and the first coil 201 induces and generates an induced electromotive force V1, the V1 discharges through the first capacitor 203, the second resistor 204, the base 301 and the emitter 303 of the triode 300 to generate a current I3, and the I3 charges the first capacitor 203.

At time t1, the voltage V3 across the first capacitor 203 is approximately equal to the induced electromotive force V1 generated by the first coil 201, I3 decreases to turn off the transistor 300, however, since the current I2 flowing through the second coil 202 cannot suddenly change, the second coil 202 generates a current Io, the current Io flows through the second diode 401 to start lighting the semiconductor light source load V, the current Io gradually decreases, the voltage V2 across the second coil 202 reverses, and the second coil 202 starts to discharge energy.

Next, at time t2, the voltage across the second capacitor 402 is equal to the voltage V2 across the second coil 202, and the second coil 202 stops discharging and the semiconductor light source load V is supplied with power from the second capacitor 402. On the other hand, the voltage V4 across the first capacitor 203 is discharged through the resistor 204, the base 301 and the emitter 303 of the transistor 300 and the first coil 201, so as to generate a current I5, and the collector 302 and the emitter 303 of the transistor 300 are turned on; vin is discharged through the second coil 202 and the collector 302 and emitter 303 of the transistor 300 to generate a current I2, and the second coil 202 starts to store energy.

Then, at time t3, the voltage V3 across the first capacitor 203 is approximately equal to the induced electromotive force V1 generated by the first coil 201, I3 decreases to turn off the transistor 300, however, since the current I2 flowing through the second coil 202 cannot abruptly change, the second coil 202 generates a current Io, the current flows through the second diode 401 to start the light emission of the semiconductor light source load V, and the current Io gradually decreases, the voltage V2 across the second coil 202 reverses, and the second coil 202 starts to discharge energy.

Next, the sequence of operations from t2 to t4, i.e., from t4 to t6, t6 to t8, etc., from time t4 is repeated from t2 to t 4.

Although the switching device III is formed by using the NPN type transistor in the embodiment of the present invention, the present invention is not limited thereto, and it is easily contemplated by those skilled in the art to form the switching device III by using the PNP type transistor and to change the connection structures of the starting device I, the transforming device II, the switching device III, and the output device IV accordingly, and such changes should be included in the scope of the present invention.

In addition, those skilled in the art can easily understand that N-type or P-type MOS transistors are used to form the switching device and the connection structure of the starting device I, the transforming device II, the switching device III and the output device IV is changed accordingly, and such changes should be included in the scope of the present invention.

The above-described embodiments are merely illustrative, and they are not intended to limit the technical method of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that the technical method of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention, and that such modifications and equivalents also fall within the scope of the claims of the present invention.

Claims (10)

1. A driving system for a semiconductor light source, comprising:

a transforming device including a first coil and a second coil coupled to each other, the second coil receiving an input voltage;

the switching device is connected with the second coil of the voltage transformation device in series and is used for controlling the energy storage and energy release of the second coil;

an output device connected in parallel with the second coil of the transforming device and for supplying power to the semiconductor light source,

the first coil of the transformer device is induced by the second coil to generate an induction signal for controlling the on and off of the switch device.

2. A drive system according to claim 1 wherein power is supplied to the semiconductor light source by the second coil and is charged to the output device by the second coil when the second coil is de-energised and is supplied to the semiconductor light source by the output device when the second coil is energised.

3. The drive system of claim 1, further comprising: and a starting means for starting the switching means when an input voltage is initially applied.

4. A drive system according to claim 1, wherein the switching arrangement comprises a switch and at least one discrete component connected between the first coil and a control terminal of the switch, and the sense signal passes through the at least one discrete component to control the switch.

5. A drive system according to claim 4 wherein the at least one discrete component comprises a capacitive element.

6. The drive system of claim 5, the at least one discrete component further comprising a resistive element in series with the capacitive element.

7. The drive system of claim 3, the start-up device comprising a resistive element and a unidirectional conducting element connected together in series, a connection point between the resistive element and the unidirectional conducting element being connected to the control terminal of the switching device.

8. A semiconductor lighting device comprising:

a semiconductor light source load;

a transforming device including a first coil and a second coil coupled to each other, the second coil receiving an input voltage;

the switching device is connected with the second coil of the voltage transformation device in series and is used for controlling the energy storage and energy release of the second coil;

an output device connected in parallel with the second coil of the voltage transforming device and configured to supply power to the semiconductor light source load;

the first coil of the transformer device is induced by the second coil to generate an induction signal for controlling the on and off of the switch device.

9. The semiconductor lighting device of claim 8, wherein the switching device comprises a switch and at least one discrete component connected between the first coil and a control terminal of the switch, and the induced signal passes through the at least one discrete component to control the switch.

10. The semiconductor illumination device of claim 8, further comprising: and a starting means for starting the switching means when an input voltage is initially applied.