Electrical transmission or interconnection systems – Plural supply circuits or sources – Substitute or emergency source
Reexamination Certificate
2000-06-02
2003-02-04
Sircus, Brian (Department: 2836)
Electrical transmission or interconnection systems
Plural supply circuits or sources
Substitute or emergency source
C307S130000, C363S143000, C323S271000
Reexamination Certificate
active
06515379
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a power supply apparatus for use with a television receiver, a monitor or the like, for example. More particularly, this invention relates to a power supply apparatus comprising a main power supply section for rectifying a voltage in either a full-wave rectification fashion or a voltage-doubler rectification fashion in response to a voltage supplied from a commercial alternating-current power supply and a standby power supply section for rectifying a voltage of a commercial alternating-current (hereinafter simply referred to as an AC) in which a full-wave rectification and a voltage-doubler rectification may be switched by detecting rectified outputted voltages from the standby power supply section and the main power supply section.
2. Description of the Related Art
FIG. 1
of the accompanying drawings shows an arrangement of a related-art power supply apparatus for use with a television receiver, a monitor or the like. A power supply apparatus
200
, generally depicted by reference numeral
200
in
FIG. 1
can be used in the area in which a voltage of a AC power supply is 100V and in the area in which a voltage of a AC power supply is 220V.
As shown in
FIG. 1
, in the power supply apparatus
200
, one end of a AC power supply
1
may be connected to one input terminal of a bridge-type rectifier
2
. The other end of this AC power supply
1
may be connected to the other input terminal of the bridge-type rectifier
2
through a contact
3
a
of a relay
3
. The relay
3
may be adapted to supply or to interrupt the AC power supply
1
. A relay drive circuit
3
D which may drive the relay
3
may be driven under control of a power supply control signal (hereinafter simply referred to as “CPW”) supplied from a control section (not shown). When the signal CPW is held at high level, the relay
3
may be driven to close the contact
3
a thereby to supply the voltage of the AC power supply
1
.
When a contact
7
a
of a relay
7
is opened, the voltage of the AC power supply
1
may be rectified by the bridge-type rectifier
2
in a full-wave rectification fashion. Then, a DC voltage smoothed by capacitors
4
and
5
connected in series may be inputted to a main DC/DC converter 6. Also, when the contact
7
a
of the relay
7
is closed, a DC voltage (hereinafter simply referred to as a DC voltage) which was smoothed by the capacitor
4
after it had been rectified by one diode of the bridge-type rectifier
2
and a DC voltage smoothed by the capacitor
5
after it had been rectified by another one diode of the bridge-type rectifier
2
may be added and a voltage-doubler rectification can be performed. The main DC/DC converter
6
may convert the supplied DC voltage into DC voltages of a variety of voltages necessary for a television, a monitor or the like, for example.
The voltage from the AC power supply
1
may be rectified/smoothed by a diode
8
and a capacitor
9
and then inputted to a standby DC/DC converter
10
. This standby DC/DC converter
10
may supply a DC voltage necessary for maintaining functions of the control section, the relay drive, the voltage detection circuit or the like when the main DC/DC converter
6
is disabled.
A voltage detection circuit
11
may compare a voltage Vs rectified/smoothed by the diode
8
and the capacitor
9
with a predetermined threshold voltage. The voltage detection circuit
11
may output a detection output (hereinafter simply referred to as “VDE”) which goes to low level when the voltage Vs is higher than the predetermined threshold voltage and which goes to high level when the voltage Vs is lower than the predetermined threshold voltage. The voltage detection circuit
11
may have a hysteresis characteristic in which a high threshold voltage may be set to DC225V and a low threshold voltage may be set to DC190V, for example. The output VDE may be supplied to a relay drive circuit
7
D as a control signal. When the output VDE is held at high level, the relay drive circuit
7
D may drive the relay
7
to close: a relay contact
7
a
, whereby a voltage-doubler rectification can be performed.
FIG. 2
shows an example of an arrangement of this voltage detection circuit
11
more concretely. As shown in
FIG. 2
, a voltage Vcc applied to a power supply terminal
51
may be supplied through a resistor R
7
to a shunt regulator IC
2
which may be used to generate a reference voltage. A series circuit of resistors R
8
and R
9
may be connected to the shunt regulator IC
2
in parallel. A voltage developed at a junction between the resistors R
8
and R
9
may be supplied to the shunt regulator IC
2
. The shunt regulator IC
2
may increase or decrease a current flowing thereto such that the above-mentioned voltage may become constant. Thus, a predetermined reference voltage Vrf may be developed at the junction between the resistors R
7
and R
8
.
As shown in
FIG. 2
, a voltage Vs may be supplied to a detection voltage input terminal
53
as a detection voltage. A voltage Va that was voltage-divided by resistors R
5
and R
6
may be supplied to a negative input terminal of a comparator IC
1
. The reference voltaege Vrf may be supplied through a resistor R
4
to a positive input terminal of the comparator IC
1
. The resistors R
3
and R
4
may be give a hysteresis characteristic to the comparator IC
1
, and a diode D
2
may be used in order to block a reverse current.
An output terminal of the comparator IC
1
may be connected to the base of a transistor Q
1
, and a bias may be applied to the base of the transistor Q
1
from the resistors R
1
and R
2
. The collector of the transistor Q
1
may be connected through a coil
7
b
of the relay
7
to the power supply terminal
51
. A diode D
1
which is connected in parallel to the coil
7
b
may be used to suppress the collector voltage of the transistor Q
1
from increasing due to a back electromotive force generated in the relay
7
when the transistor Q
1
is turned off.
When the voltage of the AC power supply
1
is low (e.g. 100V), accordingly, the detection voltage Vs is low, the voltage Va supplied to the negative input terminal of the comparator IC
1
may become lower than the voltage supplied to its positive input terminal so that the output VDE of the comparator IC
1
goes to high level. At that very moment, since the transistor Q
1
is turned on to drive the relay
7
, the contact
7
a
of the relay
7
may be closed, whereby the voltage-doubler rectification operation can be performed.
When on the other hand the voltage of the AC power supply
1
is high (e.g. 200V), accordingly, the detection voltage Vs is high, the voltage Va supplied to the negative input terminal of the comparator IC
1
becomes higher than the voltage supplied to its positive input terminal so that the output VDE of the comparator IC
1
goes to low level. At that very moment, since the transistor Q
1
is turned off and the relay
7
may not be driven, the full-wave rectification operation may be performed.
When the AC voltage is fluctuated suddenly, in particular, a voltage rises or when a power failure of a short period of time occurs or when a relay drive circuit is operated abnormally, it is unavoidable that the main DC/DC converter is considerably affected by a resultant stress.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a reliable power supply apparatus in which the aforementioned problem can be obviated.
According to the present invention, there is provided a power supply apparatus which is comprised of a main power supply section including a rectifying circuit supplied with a AC voltage through a first or second contact, the rectifying circuit for rectifying the AC voltage in a full-wave rectification fashion or in a voltage-doubler rectification fashion, a standby power supply section including a rectifying circuit for rectifying the AC voltage, a first voltage detection section for detecting whether the rectified output from the standby power supply section is higher than
Nagahara Kiyokazu
Nojima Koichi
Maioli Jay H.
Rios Roberto J.
Sircus Brian
LandOfFree
Power supply apparatus, method, and electronic apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Power supply apparatus, method, and electronic apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Power supply apparatus, method, and electronic apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3147872