High energy-saving circuit for a display apparatus

A high energy-saving circuit for a display apparatus controls turn on and/or off of an AC voltage supply terminal by the simple circuitry of a sensor, an operation controller and an output unit for effecting automatic reset on an analog basis without supplying power to a microprocessor by providing an auxiliary power supply circuit in an input signal off-mode, whereby power is economized and the total AC power pauses to save the power consumed heretofore in peripheral equipment such as printers.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a power reduction circuit of a display 
apparatus, and more particularly to a high energy-saving circuit of a 
display apparatus for effecting an automatic reset on an analog basis when 
receiving an input signal in an input signal off-mode to perform an 
associated operation without forming an auxiliary power reduction device 
that operates a display apparatus in the input signal off-mode. 
2. Description of the Prior Art 
In supplying power to display apparatuses of computer peripheral equipment, 
a method for supplying auxiliary power in place of main power to a 
microprocessor for monitor on/off control has been generally utilized to 
inhibit unnecessary power dissipation and save electrical power when an 
input signal is not received for a certain time. A power reduction circuit 
adopting the method is shown in FIG. 1. 
Here, the power reduction circuit is operated by an operational logic in 
terms of the operational states of horizontal and vertical sync signals 
for providing data to a screen of the display apparatus via an input 
device. In other words, the operational logic is classified into: an input 
signal off-mode for producing the horizontal and vertical sync signals in 
a DC level when receiving no signal for a certain time, an input signal 
on-mode for normally producing the horizontal and vertical sync signals 
when receiving the input signal, an input signal standby mode for normally 
producing the horizontal sync signal while providing the vertical sync 
signal in the DC level, and an input signal stop mode for normally 
producing the vertical sync signal while providing the horizontal sync 
signal in the DC level. 
That is, the main power must be supplied in the on-mode, standby mode or 
stop mode, but there is no need to supply the main power in the off-mode. 
Therefore, in order to maintain a standby state of a display output for 
supplying an output signal when the microprocessor for monitor on/off 
control monitors the receipt of an input signal in the off-mode, the main 
power pauses while continuously supplying the auxiliary power in the input 
signal off-mode to the microprocessor, thereby providing a monitor on/off 
control signal. 
The above-described power reduction circuit is favorable for freely 
controlling the monitor and, further, can be effectively employed in a 
system embodying a display data channel system which is one method of 
gradually maintaining data transmission. 
However, the monitor that economizes in terms of power by means of the 
auxiliary power results in increased cost due to adding the secondary 
power circuit, raising the need of power due to the operation of the 
secondary power circuit in the off-mode, and allowing for current flow 
along a degaussing coil to eliminate magnetism of a circuit connected to 
an AC power supply terminal and a magnetized magnetic body. Thus, power of 
at least 5W is wasted by the continuous supply of the power even though 
the input signal is not received. 
A technique concerning the power reduction is suggested in U.S. Pat. No. 
4,959,594 which relates to a display system having an electromagnetically 
deflected cathode ray tube random stroke and periodic raster display, and 
more particularly to a system of developing bi-directional raster scan for 
decreasing the power dissipated during the operation of a patch raster 
mode. 
SUMMARY OF THE INVENTION 
The present invention is devised to solve the above-described problems. 
Accordingly, it is an object of the present invention to provide a high 
energy-saving circuit for a display apparatus capable of effecting an 
automatic reset on an analog basis upon the receipt of an input signal in 
an input signal off-mode even if power is not supplied to a 
microprocessor. 
To achieve the above object of the present invention, there is provided a 
high energy-saving circuit for a display apparatus including a sensor for 
monitoring the receipt of a horizontal sync signal and a vertical sync 
signal, an operation controller for converting a signal input from the 
sensor into a voltage of DC type for supply to an output unit, and an 
output unit for supplying a power control signal to an AC power supply 
terminal in accordance with the operation controller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 2, a high energy-saving circuit according to the present 
invention will be described below. 
Here, a sensor 10 includes transistors Q4 and Q5 which consist of 
collectors respectively connected to a horizontal sync signal H-sync and a 
vertical sync signal V sync for generating a monitor output signal by 
monitoring the input signals, bases connected to circuit stabilizing 
resistors R7 and R8, and emitters which are grounded. An operation 
controller 20 includes transistors Q2 and Q3 which consist of collectors 
for respectively receiving a similar DC voltage via diodes D5 and D7, 
capacitors C2 and C4, and resistors R3 and R5 when the horizontal and 
vertical sync signals are received from the sensor 10, bases for receiving 
the horizontal and vertical sync signals via diodes D6 and D8, resistors 
R4 and R6, and capacitors C3 and C5, and emitters which are grounded. By 
this connection, the transistors Q2 and Q3 perform switching operations in 
accordance with inverted waveforms so as to charge a capacitor C1 via 
diodes D3 and D4, the alter being commonly connected to a base of a 
transistor Q1 incorporated into an output unit 30 which will be described 
later. Additionally, the voltage of DC type is supplied via the diodes D5, 
D7 and capacitors C2 and C4 and commonly connected diodes D1 and D2 to a 
collector of the transistor Q1 of the output unit 30. The output unit 30 
includes the transistor Q1, the base of which receives a signal via the 
commonly connected diodes D3 and D4 in the operation controller 20 and via 
a circuit-stabilizing resistor R2 for performing the switching operation 
that supplies the voltage signal of DC type via the diodes D1 and D2 
commonly connected in the operation controller 20 prior to being input to 
the collector thereof via a resistor R1 and a photo-coupler OPTO2 to an AC 
power voltage terminal. Furthermore, an output operator 40' shown in FIG. 
3B interlinked to a light-emitting portion of the photo-coupler OPTO1 is 
formed of a triac and a gate trigger voltage source of the triac for 
permitting a light-receiving portion Q9 of the photo-coupler OPTO1 to turn 
on/off an AC input. 
The operation controller 20 can be divided into a first switch 21 and a 
second switch 22, in which the first switch 21 includes the diode D6, 
capacitor C3 and resistor R4 for supplying bias to the transistor Q2 upon 
the receipt of the horizontal sync signal, and the diodes D5 and D3, 
resistor R3 and capacitor C2 for making the horizontal sync signal have a 
DC characteristic to supply it to the output unit 30. Also, the second 
switch 22 includes the diode D8, capacitor C5 and resistor R6 for 
supplying bias to the transistor Q3 upon the receipt of the vertical sync 
signal, and the diodes D7 and D4, resistor R5 and capacitors C1 and C4 for 
making the vertical sync signal have a DC characteristic to supply it to 
the output unit 30. 
Briefly, the high energy-saving circuit according to the present invention 
is formed by the sensor 10, operation controller 20, output unit 30, and 
output operator 40' shown in FIG. 3B or 40" shown in FIG. 3A. Here, the 
output operator 40" has an auxiliary power switching transistor Q6, and a 
light-receiving transistor Q7 for supplying bias to the transistor Q6 and 
being associated with the light-emitting portion of the photo-coupler 
OPTO1. 
FIGS. 3A and 3B illustrate the output operators 40" and 40', respectively. 
Referring to FIG. 3A, the output operator 40" is constructed in such a 
manner that the light-receiving transistor Q7 associated with the 
light-emitting portion of the photo-coupler OPTO1 in the output unit 30 is 
connected to a resistor R9 and to a base of the transistor Q6, thereby 
turning on/off a driving circuit of a main voltage source connected to a 
collector of the transistor Q6. 
Referring to FIG. 3B, the output operator 40' is constructed in such a 
manner that the light-receiving transistor Q9 associated with the 
light-emitting portion of the photocoupler OPTO1 in the output unit 30 is 
connected to the gate of the triac and to the gate trigger voltage source 
via a resistor R10. 
In the high energy-saving circuit according to the present invention formed 
as above, the horizontal sync signal H-sync or vertical sync signal V-sync 
supplied to the sensor 10 insulated from an AC input line as shown in FIG. 
2, which is named as a secondary circuit, is input to the operation 
controller 20 when required in a video port of a computer. At this time, 
the horizontal and vertical sync signals supply a smooth DC voltage to the 
collectors of the transistors Q2 and Q3 by connecting resistors R3 and R5 
via respective diodes D5 and D7. Simultaneously, the horizontal and 
vertical sync signals (assuming on-mode as in FIG. 5) passing through the 
diodes D6 and D8 drive the transistors Q2 and Q3 and cause them to perform 
switching operations. Since the emitters of the transistors Q2 and Q3 are 
grounded as a common collector and each of the horizontal and vertical 
sync signals is of a pulse, the periodically high level waveforms (in 
fact, the similar DC voltage level through a group of a diode D5, 
condenser C2 and resistor R3) inverted during the switching operation 
charge up the capacitor C1 via the diodes D3 and D4 in the case that each 
pulse level in the sync signals is low level. Successively, the transistor 
Q1 is supplied with the charged voltage which is biased by the resistor R2 
to be turned on. 
Consequently, the voltage of DC characteristic supplied to the diodes D1 
and D2 drives the light-emitting portion of the photo-coupler OPTO1 via 
the resistor R1. However, as the horizontal and vertical sync signals have 
fixed levels, transistors (Q2, Q3) (Q1) are sequentially turned to the off 
state. 
FIG. 4 shows another embodiment of the high energy-saving circuit according 
to the present invention, in which a power voltage for driving a circuit 
of a display data channel system is shifted to drive a microprocessor for 
monitor on/off control. 
More specifically, a sensor 10' corresponding to the sensor 10 of FIG. 2 
receives respective data horizontal and vertical sync signals while 
receiving a data channel power voltage from a hard disc of a computer. An 
operation controller 20' corresponding to the operation controller 20 is 
formed by a first switch 21 having a transistor Q2 which is turned on by 
receiving the horizontal sync signal and a second switch 22 having a 
transistor Q3 which is turned on by receiving the vertical sync signal, 
thereby supplying an output via commonly connected diodes D3 and D4. Also, 
an output unit 30' corresponding to the output unit 30 includes a 
transistor Q1 which turns on the light-emitting portion of the 
photo-coupler OPTO1 by means of the data channel power voltage supplied to 
a collector thereof when the operation controller 20' is turned on, 
thereby operating the output operator 40' which is interlinked to the 
light-emitting portion of the photo-coupler OPTO1 to make the 
light-receiving portion of the photo-coupler OPTO1 turn on/off the AC 
input at one end of a primary circuit of the AC input side by being 
connected to the gate of the triac; or operating the output operator 40" 
formed of the auxiliary power switching transistor Q6 and light-receiving 
transistor Q7 which is interlinked to the light-emitting portion of the 
photo-coupler OPTO1 for supplying the bias to the transistor Q6. 
In the high energy-saving circuit according to the present invention formed 
as shown in FIG. 4, the horizontal sync signal H-sync or vertical sync 
signal V-sync supplied to the sensor 10' insulated from the AC input line, 
which is named as a secondary circuit, is input to the operation 
controller 20' when required in the video port of the computer. Here, the 
data channel supply power voltage supplied to the sensor 10' provides a 
bias voltage to overall circuitry. At this time, the horizontal and 
vertical sync signals supply a smooth DC voltage to the collectors of the 
transistors Q2 and Q3 by connecting resistors R3 and R5 via respective 
diodes D5 and D7. Simultaneously, the horizontal and vertical sync signals 
passing through the diodes D6 and D8 drive the transistors Q2 and Q3 and 
cause them to perform switching operations. Since the emitters of the 
transistors Q2 and Q3 are grounded, the waveforms inverted during the 
switching operation charge up the capacitor Cl via the diodes D3 and D4 
such as in FIG. 2. Successively, the transistor Q1 is supplied with the 
charged voltage biased by the resistor R2 to be turned on. 
Consequently, the data channel supply power voltage supplied to the sensor 
10' drives the light-emitting portion of the photo-coupler OPTO1 via the 
resistor R1. 
The operational logic of the horizontal and vertical sync signals in the 
present invention is represented in FIG. 5 of the Vesa or NYUTEK system, 
and the output operator shown in FIG. 3 is operated in accordance with the 
operational logic. 
Especially, the output operator 40" of FIG. 3A controls the driving circuit 
of the main power shown in FIG. 1 by supplying power to the driving 
circuit of the main power only when a signal of the light-receiving 
portion Q7 of the photo-coupler OPTO1 exists. As a result, the power for 
controlling the microprocessor is not continuously demanded in the 
off-mode to economize the high energy-saving circuit as much as possible. 
Moreover, the output operator 40' of FIG. 3B embodied in the AC input stage 
supplies AC power to the circuit (the monitor circuit, peripheral 
equipment, printer, etc.) because the gate of the triac is driven upon the 
turn on of the light-receiving portion Q9 successively to the 
light-emitting portion of the photo-coupler OPTO1 of the output units 30 
or 30'. 
In other words, the output operator 40 is driven via the operation 
controller 20 and output unit 30 only when the horizontal and vertical 
sync signals are supplied through the sensor 10 to supply AC power to the 
circuit side (i.e., the monitor or peripheral equipments) according to one 
embodiment of the high energy-saving circuit as shown in FIG. 2. In 
accordance with another embodiment of the invention as shown in FIG. 4, 
the output operator 40' is driven via the operation controller 20' and 
output unit 30' only when the horizontal and vertical sync signals are 
supplied through the sensor 10' while providing the bias of the overall 
circuitry as the data channel supply power to supply the AC power to the 
circuit side (i.e., the monitor or peripheral equipments) Therefore, the 
primary circuit (AC input side) is controlled to pause in the off-mode to 
maintain the power below 1[W], so that the power can be saved. 
In addition, power of approximately 3[W] has been dissipated by both the 
monitor and printer in an energy-saving mode when turning on a dot printer 
in view of the conventional system. However, there is no need to form the 
secondary power circuit according to the present invention, which 
considerably cuts down the cost as such. 
While the present invention has been particularly shown and described with 
reference to particular embodiment thereof, it will be understood by those 
skilled in the art that various changes in form and details may be 
effected therein without departing from the spirit and scope of the 
invention as defined by the appended claims.