TWI400007B - Lamp driving device - Google Patents

Description

Lamp driving device

The present invention relates to a lamp driving device, and more particularly to a driving device for a liquid crystal display (LCD) lamp group.

In a larger liquid crystal display (LCD) panel, multiple sets of lamps need to be provided in different areas to provide sufficient brightness, and the plurality of sets of lamps are driven by an inverter circuit. It can supply AC signals to the lamp. Generally, a plurality of sets of control circuits are often disposed in the inverter circuit for respectively controlling the lamp groups disposed in different regions to drive the lamp groups separately.

The inverter circuit shown in FIG. 1 includes a complex transformer circuit 30, a plurality of lamp groups 40, a feedback circuit 50, a phase separation control circuit 60, and a drive control circuit 10. The drive control circuit 10 includes a complex power conversion circuit 102, a complex pulse width modulation (PWM) control circuit 100, and a synchronization circuit 101. In the drive control circuit 10, the synchronizing circuit 101 is for outputting a synchronizing signal. The PWM control circuit 100 is connected between the synchronization circuit 101 and the phase separation control circuit 60, and is configured to respectively receive the plurality of phase separation control signals output by the phase separation control circuit 60 and the synchronization signals output by the synchronization circuit 101. And outputting a plurality of control signals according to the synchronization signal. The power conversion circuit 102 is connected to the PWM control circuit 100 for converting the received DC signal into an AC signal according to the control signals to respectively drive the complex voltage conversion circuit 30, thereby correspondingly driving the lamp groups. 40. The transformer circuit 30 is connected between the power conversion circuit 102 and the lamp group 40 for converting the AC signals into electrical signals, respectively. The tube sets 40 are driven.

However, in such a lamp driving device, each lamp tube group needs to be separately controlled by a PWM control circuit, that is, the number of PWM control circuits must be correspondingly increased according to the number of lamp tube groups, and thus the cost is high. Moreover, it is also necessary to set a synchronization circuit so that the operating frequencies of the PWM control circuits are the same, thus causing the circuit to be complicated and inefficient.

In view of the above, it is desirable to provide a lamp driving system that avoids the use of a synchronizing circuit and that can control a plurality of lamp groups separately through a pulse width modulation (PWM) control circuit.

A lamp driving device for driving a plurality of lamp groups, comprising a phase separation control circuit, a drive control circuit and a plurality of transformer circuits. The driving control circuit includes a plurality of switching circuits, a plurality of power conversion circuits, and a PWM control circuit. The phase separation control circuit is used to output a complex phase splitting control signal. The switching circuit is configured to receive an external voltage signal and a plurality of phase splitting control signals transmitted by the phase splitting control circuit, and respectively turn on or off according to the phase splitting control signals to determine whether to output the voltage signal. The power conversion circuits are respectively connected to the switch circuits for converting the external power source into an AC signal output when the switch circuits are closed. The PWM control circuit is used to output the same PWM control signal to the power conversion circuits. The voltage conversion circuits are connected to the power conversion circuit for respectively converting the AC signals outputted by the drive control circuit into electrical signals that can drive the lamps to drive the lamp groups.

The above and many of the advantages of the invention will be readily apparent from the Detailed Description of the Detailed Description.

10, 20‧‧‧ drive control circuit

100, 201‧‧‧ PWM control circuit

101‧‧‧Synchronous circuit

102, 202‧‧‧ power conversion circuit

200‧‧‧Switch circuit

30‧‧‧Transformer circuit

40‧‧‧Light tube group

50‧‧‧Return circuit

60‧‧‧phase separation control circuit

Figure 1 is a schematic view of a lamp driving device shown in the prior art; 2 is a schematic view of a lamp tube driving device of the present invention.

2 is a lamp driving device according to an embodiment of the present invention, including a drive control circuit 20, a complex transformer circuit 30, a plurality of lamp groups 40, a feedback circuit 50, and a phase separation control circuit 60. The driving control circuit 20 includes a plurality of switching circuits 200, a pulse width modulation (PWM) control circuit 201, and a plurality of power conversion circuits 202 for selectively converting an external voltage signal into an AC signal output to the variable. Voltage circuit 30.

The phase splitting control circuit 60 is for outputting a complex phase splitting control signal. In the drive control circuit 20, the plurality of switch circuits 200 are connected to the phase split control circuit 60 for receiving the split control signals and respectively turning on or off according to the split control signals. At the same time, the switch circuit 200 receives an external DC voltage signal, which determines whether to output the DC voltage signal according to its opening or closing.

The power conversion circuit 202 is connected to the switch circuit 200 for converting the external voltage signal into an AC signal output when the corresponding switch circuit 200 is closed.

The PWM control circuit 201 is configured to output a control signal to the power conversion circuits 202. In the present embodiment, the PWM control circuit 201 is configured to output a PWM control signal. In the present embodiment, only one PWM control circuit 201 is used to provide control signals to the plurality of power conversion circuits 202, thereby ensuring that the outputs of the power conversion circuits 202 have the same phase and frequency, thereby eliminating the need in the conventional lamp driving device. Synchronous line.

The plurality of transformer circuits 30 are respectively connected between the power conversion circuit 202 and the lamp group 40 for respectively converting the received AC signals into electrical signals to drive the lamp groups 40 correspondingly.

The feedback circuit 50 is connected between the lamp group 40 and the PWM control circuit 201 for feeding back the current flowing through the lamp group 40 to the PWM control circuit 201.

For example, when each switching circuit 200 is respectively turned on or off according to the received phase separation control signal, the closed switching circuit 200 outputs the received voltage signal to the power conversion circuit 202, and the opened switching circuit 200 does not The received voltage signal is output to the power conversion circuit 202. In this embodiment, the voltage signal is a direct current signal. The power conversion circuit 202 that receives the DC signal converts the DC signal into an AC signal according to the control signal outputted by the PWM control circuit 201, and outputs the AC signal to the transformer circuit 30 correspondingly. The transformer circuit 30 converts the alternating current signals into electrical signals to drive the corresponding group of lamps 40.

In this embodiment, the voltage signal is a variable-size DC signal, and the current flowing through each of the lamp groups 40 is a change value. In other words, the current flowing through the lamp group 40 varies with the input DC signal. In order to prevent the current of the lamps from changing with the input DC signal, the lamp driving device of the present embodiment is a closed circuit structure, and the current flowing through the lamp group 40 is fed back through the feedback circuit 50. To the PWM control circuit 201. Then, regardless of how the DC signal changes, the PWM control circuit 201 can adjust the current flowing through the lamp group 40 to a constant value.

In other embodiments, the input DC signal can be a fixed-size DC signal, and the current flowing through each of the tube groups 40 is approximately constant. Then, the lamp driving device can be an open circuit structure, that is, the current flowing through the lamp group 40 is not required to be returned by the feedback circuit 50, and the details are not described herein.

The present invention adopts a plurality of switching circuits 200 to be turned on and off according to the external phase control signals to selectively control the output of the DC signals to the power conversion circuit 202 while controlling the output of all the power conversion circuits 202 through only one PWM control circuit 201. The same phase and frequency drive the complex lamp tube group, which achieves the same effect of using the array PWM control circuit and the synchronization circuit in the conventional circuit, thereby saving the use of the PWM control circuit and the synchronization circuit.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art of the present invention should be included in the following claims.

20‧‧‧Drive Control Circuit

200‧‧‧Switch circuit

201‧‧‧PWM control circuit

202‧‧‧Power conversion circuit

30‧‧‧Transformer circuit

40‧‧‧Light tube group

50‧‧‧Return circuit

60‧‧‧phase separation control circuit

Claims (4)

A lamp driving device for driving a plurality of lamp groups, comprising: a phase separation control circuit for outputting a plurality of phase separation control signals; and a driving control circuit connected to the phase separation control circuit for receiving the phase separation control a signal, and an external voltage signal, and selectively converting the external voltage signal into an AC signal output according to the phase separation control signals, the driving control circuit comprising: a plurality of switching circuits for receiving the phase separation control signals, And determining whether to output the external voltage signal according to the phase separation control signals; and the plurality of power conversion circuits are connected to the switch circuits for converting the external voltage signals into alternating current signals when the corresponding switch circuit is closed And a PWM control circuit for outputting the same PWM control signal to the power conversion circuit; and a plurality of voltage conversion circuits correspondingly connected between the power conversion circuit and the lamp group for controlling the drive The AC signal output by the circuit is converted into a signal that can drive the lamp groups. The lamp driving device of claim 1, wherein the external voltage signal is a variable-size DC signal. The lamp driving device of claim 2, further comprising a feedback circuit connected between the lamp group and the PWM control circuit for feeding back current flowing through the lamp groups To the PWM control circuit. The lamp driving device of claim 1, wherein the external voltage signal is a fixed-size DC signal.