|Title of Invention||
"A POWER SUPPLY CIRCUIT"
|Abstract||Abstract A power supply circuit connected to a battery for use in a television that provides uninterrupted viewing of televisions comprising: a control module that controls the entire operation of the circuit; a degaussing module for providing a degaussing current to the DC degaussing coil; a charging module for charging the battery (12V) when circuit is operating on AC mains; a power switch for switching the battery supply and AC mains supply; and; a SMPS transformer (2.5) connected to the output of the control module to provide requited secondary voltages. Said control module, degaussing module, charging module, power switch and SMPS transformer are interconnected by means of transistors, capacitors and resistors, such that when the AC mains supply fails, the circuit automatically switches over to the battery supply.|
|Full Text||BATTERY OPERATION AND DEGAUSSING FOR OPERATING COLOUR TELEVISION SETS USING 12/24-VOLT BATTERY
Field of the invention:
The present invention relates to the field of battery operation and degaussing for operating color television sets using 12/24V battery.
Background of the invention:
A majority, close to 70%, of the Indian population resides in rural areas. This rural population is mostly devoid of normal electricity by way of acute shortage or its total non-availability. Under such circumstances, it is very difficult for consumer electronics goods manufacturers such as television unit producers to increase the demand for their units in the rural market. However, television unit producers cannot overlook this sector of the market because it has the potential of a very big market if the electricity concerns are taken care of.
However, till date no manufacturer has been able to address the requirements of such a market for providing better technology television sets that can be easily operated in a rural setup where availability of electricity is very uncertain.
Need was felt for providing a Color TV that was capable of operating on a standard 12/24V DC car Battery.
Objects and summary of the invention:
The object of the present invention is to provide a power supply for battery operation and degaussing that can be interfaced to a color television allowing it to operate using a 12/24-volt car battery.
Another object of the present invention is to provide a power supply that allows a color television to operate on AC voltage as well as on battery power with a hassle free changeover from AC to DC operation, in case of power failure, or vice versa.
Yet another object of the invention is to provide a power supply that allows automatic degaussing of a Colour TV picture tube using a negligible amount of initial power.
Brief description of the accompanying drawings:
The accompanying drawings illustrate preferred embodiments of the invention and together with the following detailed description, serve to explain the principles of the invention.
Figure 1 shows the block diagram of a television unit interfaced with the power supply for battery operation and degaussing, as provided by the present invention.
Figure 2 shows an exploded view of the power supply for batten- operation and degaussing (BOND) in accordance with the invention.
Detailed description of the accompanying drawings:
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
Through out the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.
The present invention provides a power supply circuit for battery operation and degaussing (BOND) that can be interfaced with electronic circuits of existing television sets as shown in Figure 1.
Figure 1 shows the block diagram of the power supply circuit interconnected with the main Colour TV circuit in accordance with the instant invention. It comprises of a mains power supply (1.3), a power supply circuit for battery operation and degaussing (BOND) (1.4), a main color TV circuit (1.5), a speaker (1.6) and a CRT (1.7).
The power supply circuit based on BOND technology (1.4) in accordance with the instant invention, when interfaced to a color television allows the TV to operate and degauss using both a 12/24V DC battery (1.2) or 220V AC mains (1.1) as required. The power supply circuit can be connected to the circuitry of any color TV of any size between 14" and 21" and needs no separate ON/OFF switch for operating the TV on a 12/24V car batter)-.
The said power supply circuit (1.4) is an additional unit in the color TV, which bye-passes the regular mains power supply (1.3) of the TV and thus,
eliminates power losses that would otherwise be inherent. As the TV is
connected to two power sources, the AC mains (1.1) and the car battery (1.2) and with the help of an inbuilt threshold switch, it automatically starts operating on the car battery voltage in case of power failure, allowing the viewer to watch TV programs uninterrupted. Similarly, when the AC mains power supply is restored, the TV set interfaced with the mains power supply (1.3), automatically switches over to the AC mains and also starts charging the battery (12V).
Generally when a Colour TV set is switched ON, to eliminate undesired color patches, a huge surge of current is drawn from the mains by the degaussing circuit consisting of the degaussing coil and a Positive Temperature Coefficient Resistor (PTC). As stated earlier, the instant invention provides automatic degaussing of the picture tube on DC also. The degaussing module uses a very small amount of initial power from the supply it is operating on thereby loading the Television working circuits negligibly. In this circuit we have utilized storage capacitors, which store current from pulses taken from the FBT (Fly Black Transformer) of the TV and discharge the same through the degaussing coil, both at switch ON and at switch OFF. This dual low current degaussing is sufficient to maintain the clarity of the picture tube.
The power supply circuit based on BOND technology (1.4) when interfaced to a color television allows it to operate and degauss using a 12/24V DC battery (1.2). The mains power supply (1.3) and the power supply circuit for battery operation and degaussing (BOND) (1.4) is connected to the AC degaussing coil and DC degaussing coil (additionally provided) respectively of any colour television whose size ranges between 14" to 21" as shown.
When the TV is switched ON, it operates on the mains power supply (1.3) but when power failure occurs, it automatically switches over to the battery
supply and starts operating on the battery through the power supply circuit for battery operation and degaussing (BOND) (1.4). It thus facilitates the user to view TV programs uninterruptedly. As soon as the AC mains is restored, the TV set interfaced with the mains power supply circuit (1.3) automatically switches back to the AC mains supply (1.1). This arrangement therefore avoids the need for separate ON/OFF switching. The said power supply circuit utilizes a Fixed Frequency Pulse Width Modulation Technology (FFPWMT) based Switched Mode Power Supply (SMPS) for the colour TV to operate on 12/24V battery supply.
Figure 2 discloses the circuit diagram for battery operation and degaussing
(BOND) (1.4). The power supply circuit based on BOND technology incorporates a degaussing module (2.1), control module (2.2), charging module (2.3), power switch (2.4) and interconnection of the said elements, diodes, transistors, Mosfets, capacitors and resistors.
The power supply circuit in accordance with this invention is a stand alone type of power supply capable of operating a 14"/ 20"/21" Color Television directly from a 12V/ 24V battery and is capable of delivering usable power to the TV even if the battery voltage drops down to around 9VDC. The circuit however would not operate if the battery voltage drops below 9VDC as that signifies the battery is in a state of deep discharge. This protects the main circuit from damage due to over currents that may be drawn by such a battery during the charge cycle, as well as it protects the battery itself, in case connected, from deep discharge.
As also stated earlier, during operation, this circuit has the unique advantage of keeping the current drain on the battery at a minimum as it completely by-
passes the AC power supply of the Colour TV and takes over all its functions including that of Degaussing the Color Picture Tube.
The control module controls the entire operation of the circuit through pins Bl, B2, B3, B4 and B5. It ensures that the DC voltage +B3 (110 V) generated by the DC supply is kept slightly lower than that of the SMPS of the AC mains supply so that the DC supply does not operate or get connected to the circuit during normal operation on AC. To achieve this, a built in sensing switch in the control module is provided, this automatically switches off the DC power supply in the presence of AC mains. This feedback is obtained through pin Bl of the module. Thus pin Bl is employed for Output voltage regulation.
The said control module (2.2) incorporates a PWM (Pulse Width Modulated) oscillator that is the fundamental circuit of said module with its output available at pin B4 of the module. It drives the MOSFET, which delivers the desired pulses to the SMPS transformer to give the desired secondary voltages.
Pin B2 of the control module is used for the fly back pulses to the module from the FBT output stage of the Colour TV. These pulses are used to lock the internal oscillator of the module to the TV line frequency for better stability.
The Degaussing module (2.1) only performs the function of providing the desired degaussing current to the DC degaussing coil. It stores the desired charge by rectifying the fly back pulses. The relay (2.6) provides the degaussing current pulse to the coil, both at switch ON and switch OFF
The protection for reverse polarity connection of battery is provided for with the help of Relay 2 (2.7), the winding of which is connected through LM7812 and a diode in series. Reverse connection from the battery therefore deactivates the Relay 2 (2.7) and the power supply does not operate.
The trickle charge for charging a!2V battery during AC operation/standby is provided with the help of an additional winding on the SMPS Transformer of the main Colour TV circuit. The voltage generated here is rectified and then made available for charging the battery through charging module (2.3), which is switched ON from the 12V DC of the Battery itself.
While the TV set is operating on AC mains supply, the battery used by said BOND circuit is being charged and as soon as the power failure occurs, the battery gets connected to the BOND circuit for uninterrupted viewing.
The power supply for battery operation and degaussing (BOND) as described above thus enables uninterrupted viewing for 6 to 7 hours on a standard (35 Ah) car battery
1. A power supply circuit connected to a battery for use in a television
that provides uninterrupted viewing of televisions comprising:
- a control module that controls the entire operation of the
- a degaussing module for providing a degaussing current to the
DC degaussing coil;
- a charging module for charging the battery (12V) when circuit is
operating on AC mains;
- a power switch for switching the battery supply and AC mains
- a SMPS transformer (2.5) connected to the output of the control
module to provide required secondary voltages.
Said control module, degaussing module, charging module, power switch and SMPS transformer are interconnected by means of transistors, capacitors and resistors, such that when the AC mains supply fails, the circuit automatically switches over to the battery supply.
2. A power supply circuit as claimed in claim 1 wherein the control
module comprises of an inbuilt sensing switch that automatically switches off the D.C. power supply in the presence of AC mains.
3. A power supply circuit as claimed in claim 1 wherein the control
module has a PWM oscillator.
4. A power supply circuit as claimed in claim 1 wherein the degaussing
module provides automatic degaussing of the picture tube.
5. A power supply circuit as claimed in claim 1 wherein the charging
module gets connected with the SMPS transformer of the main colour
TV circuit having an additional winding for providing the trickle
charge that charges a 12V battery during AC mains ON or standby.
6. A power supply circuit substantially as herein described and as
illustrated by the accompanying drawings.
|Indian Patent Application Number||100/DEL/2003|
|PG Journal Number||31/2008|
|Date of Filing||07-Feb-2003|
|Name of Patentee||JOLLY VIDEOTRONICS|
|Applicant Address||CIVIL LINES, RAMPUR, U.P.-244901, INDIA.|
|PCT International Classification Number||H01F 13/00|
|PCT International Application Number||N/A|
|PCT International Filing date|