ELECTRIC HEATING SYSTEM USING LOW VOLTAGE
Technical Field
The present invention relates to an electric heating system using a low voltage, and more particularly, to an electric heating system which generates heat at a voltage not more than 30V.
Background Art
Recently, in addition to a traditional heating system, an electric floor, an electric blanket, an electric cushion, an electric mat, and so on are widely used. In general, as shown in FIG. 1, a power source
2 of 110/220V is connected to a heater 4. The temperature of the heater
4 is controlled by a temperature controller 6.
A reference numeral 8 denotes a sensor which can detect the heater 4 and a heated temperature of the heater 4. A reference numeral 20 denotes a temperature setter which is connected to the temperature controller 6 and controls the temperature controller 6 which controls a turn-on state and a turn-off state of the current to be applied to the heater 4, considering a value obtained by manipulating the temperature controller 6 and a value detected by the temperature sensor 8.
By the way, since the conventional heating system has a structure of supplying a commercial voltage of 110V/220V to the heater and performs the temperature control of the heater, users may run a risk of an electric
leakage and shock accident.
Disclosure of the Invention
To solve the above problems, it is an object of the present invention to provide an electric heating system using a low voltage by employing a perfectly insulated and inductively coupled transformer, in which a secondary voltage of the transformer is supplied to a heater as a low voltage of 30V or less and thus an electric leakage and shock accident does not happen.
To accomplish the above objects of the present invention, according to an aspect of the present invention, there is provided an electric heating system using a low voltage comprising: a mat (M) having a heater (4) and a sensor (8) ; and a temperature controller (Tc) which is electrically connected to the heater (4) in the mat (M) , wherein the temperature controller (Tc) comprises: a power switch (sw) which is electrically connected to a power source (2) of 110V/220V; a power connection indicator (10) which is electrically connected to the power switch (sw) ; a direct-current (DC) converter (12) which converts an alternating-current (AC) voltage applied to the power connection indicator (10) into a DC voltage; a 12V constant voltage generator (14) which is electrically connected to the DC converter (12) and maintains and outputs the DC voltage output from the DC converter (12) as a stable voltage of 12V; a comparator (16) which is electrically connected to the 12V constant voltage generator (14) so that the 12V voltage supplied from the 12V constant voltage generator (14) is used
as electric power of the comparator (16) , and which is electrically
connected to the sensor (8) so that a detected value of a heated temperature state of the heater (4) which is output from the sensor (8) is input to a first point "A" of the comparator (16) ; a photo-coupler (18) which is electrically connected to a third point "C" of the comparator (16) and an on/off switch (22) which performs a disconnection or connection function of current to be supplied to the heater (4) according to a value output from the third point "C" of the comparator (16) ; a temperature setter (20) which is electrically connected to a second point "B" of the comparator (16) so that a temperature set value output from the temperature setter (20) is input to the second point "B" of the comparator (16) ; and a voltage transformer (24 ) whose primary coil is electrically connected to the power switch (sw) and whose secondary coil is insulated and inductively coupled to the primary coil and is electrically connected to the on/off switch (22) , so that a voltage of 110V/220V is voltage-dropped into a low voltage of 30V or less.
Brief Description of the Drawings The above and other obj ects and advantages of the present invention will become more apparent by describing the preferred embodiment thereof in more detail with reference to the accompanying drawings in which:
FIG. 1 is a schematic block diagram showing a configuration of a conventional electric heating system;
FIG. 2 is a schematic block diagram showing a configuration of an electric heating system according to the present invention; and
FIG.3 is a detailed circuit diagram showing an electric heating system according "to the present invention.
Best Mode for Carrying out the Invention
Hereinbelow, an electric heating system according to the present inventionwill be describedwith reference to the accompanying drawings . Since the same elements as those of the conventional electric heating system are assigned the same reference numerals as those of the conventional electric heating system, the detailed description thereof will be omitted.
As shown in FIGs. 2 and 3, an electric heating system using a low voltage according to an embodiment of the present invention includes a mat (M) having a heater 4 and a sensor 8, and a temperature controller (Tc) which is electrically connected to the heater 4 in the mat (M) , in which controlled current is supplied to the heater 4 to thus allow the heater 4 to perform a heating function intermittently.
Meanwhile, the temperature controller (Tc) includes a power switch (sw) , a power connection indicator 10, a direct-current (DC) converter 12, a 12V constant voltage generator 14, a comparator 16, a photo-coupler 18 and an on/off switch 22, a temperature setter 20, and a voltage transformer 24.
The power switch (sw) is electrically connected to a power source
2 of 110V/220V, to thus allow a user to turn on and off the heater 4. The power connection indicator 10 made of light-emitting diodes such as LEDs is electrically connected to the power switch (sw) , to thereby indicate whether or not current is applied from the power source 2 to the heater .
The direct-current (DC) converter 12 is electrically connected to the power connection indicator 10 and made of a plurality of diodes Dl, D2, D3 and D4, which converts an alternating-current (AC) voltage applied to the power connection indicator 10 into a DC voltage. The 12V constant voltage generator 14 made of a Zener diode is electrically connected to the DC converter 12 and maintains and outputs the DC voltage output from the DC converter 12 as a stable voltage of 12V.
The comparator 16 is electrically connected to the 12V constant voltage generator 14, the sensor 8 and a temperature setter 20 so that the 12V voltage supplied from the 12V constant voltage generator 14 is used as electric power of the comparator 16, and which is electrically connected to the sensor 8 so that a detected value of a heated temperature state of the heater 4 which is output from the sensor 8 is input to a first point "A" of the comparator 16, and a temperature set value output from the temperature setter 20 is input to a second point "B", to then perform a comparison operation of the input values and output a comparison result.
The photo-coupler 18 is electrically connected to a third point
"C" of the comparator 16, and has a general structure that a triac is turned on or off according to turning-on or turning-off of the LED and thus a gate electrode of the triac is triggered. Accordingly, the function of the on/off switch 22 which is connected to the photo-coupler 18 is controlled.
The voltage transformer 24 which is electrically connected between the on/off switch 22 which is controlled by the power switch
(sw) and the heater 4 has an insulated and inductively coupling structure which transforms a 110V/220V AC voltage into a low voltage of 30V or less.
That is, the voltage transformer 24 whose primary coil is electrically connected to the power switch (sw), and whose secondary coil is insulated and inductively coupled to the primary coil and is electrically connected to the on/off switch 22, so that a voltage of the power source 2 is voltage-dropped into a low voltage of 30V or less .
The temperature setter 20 is electrically connected to a second point "B" of the comparator 16.
In the electric heating system according to the present invention, according to turning-on of the power switch (sw) , a 110V/220V power source is the primary coil of the voltage transformer 24 and the DC converter 12.
Thus, a DC voltage of 12V having no voltage fluctuation can be obtained through the DC converter 12 andthe 12Vconstantvoltage generator
14 .
The 12V DC voltage is supplied to the comparator 16 as power of the comparator 16. The comparator 16 compares a signal input from the sensor 8 in the mat (M) with a value set in the temperature setter 20, and a positive electric potential is given to the third point "C" in the case that an electric potential at the first point "A" becomes lower than that at the second point "B." Accordingly, the LED in the photo-coupler 18 is turned off.
Thus, the triac in the photo-coupler 18 is turned off, and thus the gate electrode of the on/off switch 22 is not triggered. As a result, the secondary voltage of the voltage transformer
is not supplied to the heater 4 in the mat structure (M) .
Reversely, when an electric potential at the first point "A" of the comparator 16 is higher than that at the second point "B, " a negative electric potential is given to the third point "C" in the case that an electric potential at the first point "A" becomes higher than that at the second point "B." Accordingly, the LED in the photo-coupler 18 is turned on.
Thus, the triac in the photo-coupler 18 is turned on, and thus the gate electrode of the on/off switch 22 is triggered. As a result, the secondary voltage of 30V or less of the voltage transformer 24 is supplied to the heater 4 in the mat structure (M) .
Industrial Applicability
As described above, the electric heating system according to the present invention can supply a low voltage of 30V or less from the heater. Accordingly, an electrical leakage and shock accident can be removed.
As described above, the present invention has been described with respect to particularly preferred embodiment. However, the present invention is not limited to the above embodiment, and it is possible for one who has an ordinary skill in the art to make various modifications andvariations, without departing off the spirit of the present invention .