LED emitting device
View Patent ↗The present invention relates to an LED emitting device. The LED emitting device includes: a converter converting an input voltage according to a switching operation of a power source switch to generate at least two output voltages; an LED panel unit including a plurality of LED channels having a plurality of LEDs; a micom board operated by a first output voltage among the at least two output voltages to control the operation of the LED emitting device; a regulator converting a second output voltage among the at least two output voltages into a voltage suitable for the operation of the LED panel unit; and a multi-channel control unit controlling an operation of the regulator according to a lowest minimum voltage among the voltages of a plurality of LED channels and receiving the first output voltage to generate a first feedback voltage VF 1.
1. An LED emitting device operated by at least two output voltages, comprising:
a converter converting an input voltage according to a switching operation of a power source switch to generate at least two output voltages;
an LED panel unit including a plurality of LED channels having a plurality of LEDs;
a micom board operated by a first output voltage among the at least two output voltages to control the operation of the LED emitting device;
a regulator converting a second output voltage among the at least two output voltages into a voltage suitable for the operation of the LED panel unit; and
a multi-channel control unit controlling an operation of the regulator according to a lowest minimum voltage among the voltage of a plurality of LED channels and receiving the first output voltage to generate a first feedback voltage VF 1 .
2. The LED emitting device of claim 1 , wherein
the multi-channel control unit detects a load of the LED panel unit to stop the operation of the regulator when the LED panel is in a no-load state.
3. The LED emitting device of claim 1 , wherein
the converter includes:
a transformer converting the input voltage input to a primary first winding according to operation of a power source switch to transmit to a secondary second winding and a third winding;
a first rectifying diode connected to the second winding;
a second rectifying diode connected to the third winding; and
a first capacitor connected to the first rectifying diode,
wherein the first output voltage is a voltage of the first capacitor.
4. The LED emitting device of claim 3 , wherein
the regulator includes:
a power source supply switch connected to the second rectifying diode and operated according to control of the multi-channel control unit to output the voltage of the third winding passing through the second rectifying diode; and
a second capacitor connected to the power source supply switch,
wherein the second output voltage is a voltage of the second capacitor.
5. The LED emitting device of claim 4 , wherein
the multi-channel control unit includes:
a minimum voltage detecting unit sampling a plurality of channel voltages as a unit of a predetermined time to detect the lowest minimum voltage; and
a switch control unit generating a gate signal to control the switching operation of the power source supply switch for the minimum voltage to be maintained as a predetermined reference voltage.
6. The LED emitting device of claim 5 , wherein
the switch control unit detects a plurality of dimming signals controlling each on/off function of the plurality of LED channels generated from the micom board to determine the LED panel to be in the no-load state and to turn off the power source supply switch when the plurality of dimming signals turn off all the plurality of LED channels.
7. The LED emitting device of claim 4 , wherein
the multi-channel control unit includes:
a first resistor including one terminal transmitted with the output voltage; and
a shunt regulator including an input terminal connected to one terminal of the resistor and an output terminal of which the voltage is maintained as a constant voltage if the voltage of the input terminal is more than a predetermined threshold voltage,
wherein the voltage of the output terminal is the first feedback voltage, and as the voltage of the input terminal is increased to be more than the threshold voltage, the current from the output terminal of the shunt regulator to the ground is increased.
8. The LED emitting device of claim 7 , further comprising
an opto-diode connected between the output terminal of the shunt regulator and the predetermined reference voltage, and an opto-coupler including an opto-transistor flowing with the current corresponding to the brightness of the opto-diode.
9. The LED emitting device of claim 8 , further comprising
a switch control unit generating a gate signal controlling a switching operation of the power source switch according to the current flowing in the opto-transistor.
10. The LED emitting device of claim 8 , wherein
the multi-channel control unit further includes
a third capacitor connected between the output terminal of the shunt regulator and the input terminal.
11. The LED emitting device of claim 4 , wherein
the multi-channel control unit determines an overflowed voltage of the second output voltage by using the second feedback voltage according to the second output voltage and detects the LED channel that is in an open state among the plurality of LED channels by using a plurality of channel feedback voltages corresponding to a plurality of channel currents flowing in the plurality of LED channels.
12. The LED emitting device of claim 11 , wherein
the multi-channel control unit further includes a protection circuit unit comparing the second feedback voltage with the predetermined first reference voltage to determine it as the overflowed voltage if the second output voltage is a higher voltage than the reference voltage, determining the generation of the LED channel that is in the open state if a smaller voltage than the predetermined second reference voltage is detected among the plurality of channel feedback voltages, and generating a protection signal to stop the switching operation of the power source supply switch.
13. The LED emitting device of claim 1 , further comprising
a current balancing unit connected to an end terminal of the plurality of LED channel and controlling a channel current of the plurality of LED channels.
14. The LED emitting device of claim 13 , wherein
the current balancing unit includes:
a plurality of transistors respectively connected to the plurality of LED channels; and
a plurality of resistors connected to the plurality of transistors and generating a plurality of channel feedback voltages corresponding to a plurality of channel currents flowing in the plurality of LED channels.
15. The LED emitting device of claim 14 , wherein
the multi-channel control unit further includes a gate signal generator receiving a dimming signal controlling the duty of the plurality of LED channels from the micom board to control each on/off function of the plurality of LED channels, and receiving the plurality of channel feedback voltages to generate a plurality of gate signals controlling the plurality of transistors such that the plurality of LED channels flow with a constant current.