U.S. patent application number 09/933844 was filed with the patent office on 2002-06-13 for power supply for both ac and dc.
Invention is credited to Kim, Hun-June, Youn, Dae-Young.
Application Number | 20020071290 09/933844 |
Document ID | / |
Family ID | 19703026 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020071290 |
Kind Code |
A1 |
Youn, Dae-Young ; et
al. |
June 13, 2002 |
Power supply for both AC and DC
Abstract
A power supply for both alternating current (AC) and direct
current (DC) which has an AC/DC converter and DC/DC converter
detachably coupled with each other. The AC/DC converter is adapted
to convert an AC input voltage into a DC signal, and the DC/DC
converter is adapted to convert a DC input voltage into a DC
signal. An output voltage selector is provided to obtain a DC
output voltage appropriate to an associated device. The present
power supply can be conveniently carried, supply power to an
associated device regardless of AC and DC input voltages and select
a level of an output DC voltage. Therefore, the present power
supply can be used universally irrespective of the types of
associated devices and manufacturers.
Inventors: |
Youn, Dae-Young; (Daejeon,
KR) ; Kim, Hun-June; (Daejeon, KR) |
Correspondence
Address: |
PENNIE AND EDMONDS
1155 AVENUE OF THE AMERICAS
NEW YORK
NY
100362711
|
Family ID: |
19703026 |
Appl. No.: |
09/933844 |
Filed: |
August 21, 2001 |
Current U.S.
Class: |
363/15 |
Current CPC
Class: |
H01R 13/6675 20130101;
H02J 2207/20 20200101; H02M 1/10 20130101; H02J 2207/40 20200101;
H01R 31/065 20130101 |
Class at
Publication: |
363/15 |
International
Class: |
H02J 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2000 |
KR |
2000-76132 |
Claims
What is claimed is:
1. A power supply for both alternating current (AC) and direct
current (DC), comprising: an AC/DC converter including a first line
filter for attenuating electromagnetic noise contained in an AC
input voltage, a rectifier for converting a filtered AC signal from
said first line filter into a DC signal, a transformer for
transforming the DC signal converted by said rectifier into a
desired DC voltage, and a first pulse width modulation (PWM)
controller for controlling an operation of said transformer; and a
DC/DC converter detachably coupled with said AC/DC converter, said
DC/DC converter including a second line filter for inputting said
DC voltage from said AC/DC converter or an external DC voltage and
attenuating electromagnetic noise contained in the inputted DC
voltage, a drive voltage output unit for converting a filtered DC
signal from said second line filter into a drive voltage to drive
an associated device, a second PWM controller for controlling an
operation of said drive voltage output unit, and an output voltage
controller for controlling a voltage level of an output DC signal
from said drive voltage output unit.
2. The power supply as set forth in claim 1, further comprising an
output voltage selector connected to said DC/DC converter, said
output voltage selector selecting a voltage level appropriate to
the associated device and controlling an operation of an oscillator
in said second PWM controller according to the selected voltage
level so as to control the voltage level of the output DC signal
from said drive voltage output unit.
3. The power supply as set forth in claim 1 or 2, wherein said
output voltage controller includes: a resistor array; and a
multiplexer for selecting a resistance of said resistor array in
response to a value selected by a dip switch in said output voltage
selector and outputting a control signal based on the selected
resistance to said oscillator in said second PWM controller to
select the voltage level of the output DC signal from said drive
voltage output unit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in general to a power supply
for both alternating current (AC) and direct current (DC), and more
particularly to a power supply for both AC and DC which is capable
of selectively inputting AC and DC voltages from external power
sources and converting the inputted voltages into a DC voltage
appropriate to an associated device.
[0003] 2. Description of the Prior Art
[0004] Portable small-sized power supplies, which are typically
called adapters, are adapted for converting or transforming input
voltages into voltages necessary to drive associated devices.
Examples of such conventional portable small-sized power supplies
are shown in FIGS. 1a to 1c herein.
[0005] FIG. 1a is a block diagram showing the construction of a
conventional AC/DC power supply. As shown in this drawing, the
conventional AC/DC power supply comprises a line filter 11 for
attenuating electromagnetic noise contained in an AC input voltage,
a transformer 12 for transforming a filtered AC signal from the
line filter 11 into a voltage appropriate to an associated device,
a controller 13 for controlling an output voltage of the power
supply in response to a voltage fed from a secondary coil of the
transformer 12 back thereto, and a rectifier 14 for rectifying a
transformed AC signal from the transformer 12 into a DC signal and
outputting the rectified DC signal as a drive voltage to the
associated device.
[0006] In the above-mentioned conventional AC/DC power supply, the
controller 13 controls the output voltage by adjusting a pulse
duration of a pulse width modulation (PWM) signal in a trimmer
manner or by setting the number of turns of the secondary coil of
the transformer 12 to different values by regions in order to raise
efficiency. However, this control method increases the volume and
weight of the power supply, thereby making it inconvenient for a
user to carry the power supply.
[0007] FIG. 1b is a block diagram showing the construction of a
conventional DC/DC power supply. As shown in this drawing, the
conventional DC/DC power supply comprises a line filter 21 for
attenuating electromagnetic noise contained in a DC input voltage,
a transformer 22 for transforming a filtered DC signal from the
line filter 21 into a voltage appropriate to an associated device,
and a controller 23 for controlling an output voltage of the power
supply in response to a voltage fed from a secondary coil of the
transformer 22 back thereto.
[0008] The above-mentioned DC/DC power supply is convenient to
carry owing to its small size, but is disadvantageous in that a
user has the trouble of having to carry it together with an AC/DC
power supply while in motion for a lengthy period of time.
[0009] In order to solve the above problems with the conventional
AC/DC power supply and DC/DC power supply, there has been proposed
a power supply for both AC and DC having an AC/DC converter and
DC/AC converter integral with each other, which power supply is
disclosed in Korean Utility Model Laidopen Publication No.
1999-15641 and shown in FIG. 1c herein.
[0010] The proposed power supply comprises a constant-voltage
circuit for maintaining a DC input voltage constant, a first filter
for attenuating electromagnetic noise contained in the DC input
voltage, a DC/DC converter integrated circuit (IC) for controlling
the operation of a transistor in response to an output voltage of
the transistor fed back thereto, a second filter for attenuating
electromagnetic noise contained in an AC input voltage, a first
rectifier for rectifying a filtered AC signal from the second
filter into a DC signal, and a PWM control IC for driving a field
effect transistor (FET) in a main switch to induce energy in a
transformer. The switch acts to perform a switching operation to
induce the energy in the transformer. The power supply further
comprises a second rectifier for rectifying a voltage induced in a
secondary coil of the transformer, and an error amplifier for, when
overcurrent is generated in the secondary coil of the transformer,
feeding the generated overcurrent back to the PWM control IC to
drop the voltage induced in the secondary coil of the transformer
so as to protect the power supply and associated circuitry from the
overcurrent.
[0011] However, in the case where the proposed power supply is
applied to large-capacity portable equipment, such as a notebook
computer, to supply power thereto, it must be constructed with a
heavy weight and large volume, resulting in an increase in
manufacturing cost. Further, it is very inconvenient to use within
transportation means, such as an airplane, vehicle, vessel and the
like.
SUMMARY OF THE INVENTION
[0012] Therefore, the present invention has been made in view of
the above problems, and it is an object of the present invention to
provide a power supply for both alternating current (AC) and direct
current (DC) which has an AC/DC converter and DC/DC converter
detachably coupled with each other.
[0013] It is another object of the present invention to provide a
power supply for both AC and DC which is capable of selecting a
level of an output DC voltage.
[0014] In accordance with the present invention, the above and
other objects can be accomplished by the provision of a power
supply for both alternating current (AC) and direct current (DC),
comprising an AC/DC converter including a first line filter for
attenuating electromagnetic noise contained in an AC input voltage,
a rectifier for converting a filtered AC signal from the first line
filter into a DC signal, a transformer for transforming the DC
signal converted by the rectifier into a desired DC voltage, and a
first pulse width modulation (PWM) controller for controlling an
operation of the transformer; and a DC/DC converter detachably
coupled with the AC/DC converter, the DC/DC converter including a
second line filter for inputting the DC voltage from the AC/DC
converter or an external DC voltage and attenuating electromagnetic
noise contained in the inputted DC voltage, a drive voltage output
unit for converting a filtered DC signal from the second line
filter into a drive voltage to drive an associated device, a second
PWM controller for controlling an operation of the drive voltage
output unit, and an output voltage controller for controlling a
voltage level of an output DC signal from the drive voltage output
unit.
[0015] Preferably, the power supply may further comprise an output
voltage selector connected to the DC/DC converter, the output
voltage selector selecting a voltage level appropriate to the
associated device and controlling an operation of an oscillator in
the second PWM controller according to the selected voltage level
so as to control the voltage level of the output DC signal from the
drive voltage output unit.
[0016] More preferably, the output voltage controller may include a
resistor array; and a multiplexer for selecting a resistance of the
resistor array in response to a value selected by a dip switch in
the output voltage selector and outputting a control signal based
on the selected resistance to the oscillator in the second PWM
controller to select the voltage level of the output DC signal from
the drive voltage output unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0018] FIG. 1a is a block diagram showing the construction of a
conventional AC/DC power supply;
[0019] FIG. 1b is a block diagram showing the construction of a
conventional DC/DC power supply;
[0020] FIG. 1c is a block diagram showing the construction of a
conventional power supply for both AC and DC;
[0021] FIG. 2 is a block diagram showing the construction of a
power supply for both AC and DC in accordance with the present
invention; and
[0022] FIG. 3 is a view showing different embodiments of
connections of the power supply in accordance with the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] FIG. 2 is a block diagram showing the construction of a
power supply for both AC and DC in accordance with the present
invention and FIG. 3 is a view showing different embodiments of
connections of the power supply in accordance with the present
invention.
[0024] The power supply for both AC and DC according to this
invention comprises an AC/DC converter 100, DC/DC converter 200 and
output voltage selector 300.
[0025] The AC/DC converter 100 is adapted to input an AC voltage
and output a desired DC signal.
[0026] The DC/DC converter 200 is adapted to input a DC voltage and
output a desired DC signal. This converter 200 preferably has means
(not shown) detachably coupled with the AC/DC converter 100 or
receiving a jack 401 of an input cable 400 that inputs an external
DC voltage. As a result, the converter 200 inputs the DC voltage
from the AC/DC converter 100 or the external DC voltage from the
input cable 400 and outputs a desired DC signal.
[0027] The output voltage selector 300 is adapted to select a level
of a DC output voltage from the DC/DC converter 200, appropriate to
an associated device (not shown), such as a notebook computer,
camcorder, mobile telephone or the like. To this end, the output
voltage selector 300 is installed in a coupled portion between the
DC/DC converter 200 and an output cable 500 connected to the
associated device.
[0028] In more detail, the AC/DC converter 100 includes a line
filter 101, rectifier 102, transformer 103 and PWM controller
104.
[0029] The line filter 101 acts to attenuate electromagnetic noise
contained in the AC input voltage.
[0030] The rectifier 102 acts to convert a filtered AC signal from
the line filter 101 into a DC signal.
[0031] The transformer 103 acts to transform the DC signal
converted by the rectifier 102 into a desired DC signal.
[0032] The PWM controller 104 acts to control the operation of the
transformer 103.
[0033] That is, in the AC/DC converter 100, the line filter 101
inputs the AC voltage and attenuates electromagnetic noise
contained in the inputted AC voltage. The rectifier 102 converts
the noise-attenuated AC voltage into a DC signal, and the
transformer 103 transforms the converted DC signal into a desired
DC signal under the control of the PWM controller 104 and outputs
the transformed DC signal as an input voltage to the DC/DC
converter 200.
[0034] The DC/DC converter 200 includes a line filter 201, drive
voltage output unit 202, PWM controller 203 and output voltage
controller 204.
[0035] The line filter 201 acts to attenuate electromagnetic noise
contained in the DC input voltage.
[0036] The drive voltage output unit 202 acts to convert a filtered
DC signal from the line filter 201 into a drive voltage to drive an
associated device (not shown), such as a notebook computer,
camcorder, mobile telephone or the like.
[0037] The PWM controller 203 acts to control the operation of the
drive voltage output unit 202. To this end, the PWM controller 203
includes an operational (OP) amplifier 203a for comparing an output
voltage from the drive voltage output unit 202, fed back thereto,
with a reference voltage, and an oscillator 203b for outputting a
drive signal to drive the drive voltage output unit 202 when the
result of comparison by the OP amplifier 203a indicates that the
output voltage from the output unit 202 is lower in level than the
reference voltage. As a result, the OP amplifier 203a compares the
output voltage from the drive voltage output unit 202, fed back
thereto, with the reference voltage and provides the compared
result to the oscillator 203b. Where the result of comparison by
the OP amplifier 203a indicates that the output voltage from the
drive voltage output unit 202 is lower in level than the reference
voltage, the oscillator 203b outputs the drive signal to the output
unit 202 to drive it.
[0038] The output voltage controller 204 includes a resistor array
204b, and a multiplexer 204a for selecting a resistance of the
resistor array 204b in response to a value selected by a dip switch
in the output voltage selector 300 and outputting a control signal
based on the selected resistance to the oscillator 203b in the PWM
controller 203 to control the level of the DC output voltage from
the drive voltage output unit 202.
[0039] The output voltage selector 300 is adapted to select a level
of the DC output voltage from the DC/DC converter 200, appropriate
to an associated device, such as a notebook computer, camcorder,
mobile telephone or the like. To this end, the output voltage
selector 300 includes a dip switch for controlling an operation
timing of the drive voltage output unit 202 in the DC/DC converter
200 so as to control the output voltage from the output unit
202.
[0040] As described above, in the power supply for both AC and DC
according to the present invention, the AC/DC converter 100 for
conversion of an AC input voltage into a DC signal and the DC/DC
converter 200 for conversion of a DC input voltage into a DC signal
are detachably coupled with each other. Therefore, in order to
supply power to an associated device, such as a notebook computer,
camcorder, mobile telephone or the like, the AC/DC converter 100
and the DC/DC converter 200 are used together where an AC power
source is employed, whereas only the DC/DC converter 200 is used
where a DC power source is employed. As a result, the present power
supply is convenient to carry and use.
[0041] It is common practice that notebook computers, camcorders,
mobile telephones and so forth employ different rated
voltage/current values according to manufacturers. For example, for
notebook computers, a rated voltage is 24V for Powerbook series by
Apple, 19V for Presario series by Compaq and Sensenote series by
Samsung, 18V for Satellite series by Toshiba, 16V for ThinkPad
series by IBM and Vaio series by Sony, and 12V for Omnibook series
by HP. DC output voltages appropriate to associated devices can be
obtained by means of the output voltage selector 300, so that the
present power supply can be used universally irrespective of the
types of the devices and manufacturers.
[0042] In a different manner from conventional techniques, the
DC/DC converter can be separated from the AC/DC converter to supply
power to an associated device by itself. Hence, the present power
supply is usefully applicable to facilities sensitive to
electromagnetic waves, such as airplanes, in that it can prevent
high-power electromagnetic waves from being generated during a
high-voltage switching operation.
[0043] Therefore, the power supply for both AC and DC according to
the present invention can accomplish the aforementioned
objects.
[0044] As apparent from the above description, the present
invention provides a power supply for both alternating current (AC)
and direct current (DC) which has an AC/DC converter and DC/DC
converter detachably coupled with each other. The present power
supply can be conveniently carried, supply power to an associated
device regardless of AC and DC input voltages and select a level of
an output DC voltage. Therefore, the present power supply can be
used universally irrespective of the types of associated devices
and manufacturers.
[0045] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *