U.S. patent application number 16/662039 was filed with the patent office on 2021-03-04 for electronic apparatus, voltage detector and voltage detection method thereof.
This patent application is currently assigned to LITE-ON ELECTRONICS (GUANGZHOU) LIMITED. The applicant listed for this patent is LITE-ON ELECTRONICS (GUANGZHOU) LIMITED, Lite-On Technology Corporation. Invention is credited to Yen-Liang Chen, Yu-Ho Lin.
Application Number | 20210063448 16/662039 |
Document ID | / |
Family ID | 72601862 |
Filed Date | 2021-03-04 |
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United States Patent
Application |
20210063448 |
Kind Code |
A1 |
Chen; Yen-Liang ; et
al. |
March 4, 2021 |
ELECTRONIC APPARATUS, VOLTAGE DETECTOR AND VOLTAGE DETECTION METHOD
THEREOF
Abstract
An electronic apparatus, a voltage detector, and a voltage
detection method thereof are provided. The voltage detector
includes a rectifying and filtering circuit, a comparison circuit,
and a detection signal generator. The rectifying and filtering
circuit receives an alternating current input voltage and performs
a rectifying and filtering operation on the alternating current
input voltage to generate a processed voltage. The comparison
circuit compares the processed voltage with a reference voltage to
generate a comparison signal. The detection signal generator has a
first side and a second side. The first side receives the
comparison signal and generates an induction signal according to
the comparison signal. The second side receives the indication
signal to generate a detection signal. The first side and the
second side are isolated.
Inventors: |
Chen; Yen-Liang; (Taipei,
TW) ; Lin; Yu-Ho; (Taipei, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LITE-ON ELECTRONICS (GUANGZHOU) LIMITED
Lite-On Technology Corporation |
GUANGZHOU
Taipei |
|
CN
TW |
|
|
Assignee: |
LITE-ON ELECTRONICS (GUANGZHOU)
LIMITED
GUANGZHOU
CN
Lite-On Technology Corporation
Taipei
TW
|
Family ID: |
72601862 |
Appl. No.: |
16/662039 |
Filed: |
October 24, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02M 7/06 20130101; G01R
19/16523 20130101; G01R 19/16547 20130101 |
International
Class: |
G01R 19/165 20060101
G01R019/165 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 28, 2019 |
TW |
108130778 |
Claims
1. A voltage detector, comprising: a rectifying and filtering
circuit, receiving an alternating current input voltage, and
performing a rectifying and filtering operation on the alternating
current input voltage to generate a processed voltage; a comparison
circuit, coupled to the rectifying and filtering circuit, and
comparing the processed voltage with a reference voltage to
generate a comparison signal; and a detection signal generator,
having a first side and a second side, the first side coupled to
the comparison circuit to receive the comparison signal, the first
side generating an induction signal according to the comparison
signal, and the second side receiving the indication signal to
generate a detection signal, wherein the first side and the second
side are isolated, wherein the detection signal generator
comprises: an optical coupler, having a light-emitting element and
a phototransistor, wherein the light-emitting element is arranged
on the first side, and the phototransistor is arranged on the
second side; and a first resistor, coupled between the
phototransistor and a reference grounding voltage end, wherein an
end point, coupled to the phototransistor, of the first resistor
generates the detection signal, a first end of the light-emitting
element receives a power voltage, and a second end of the
light-emitting element receives the comparison signal.
2. The voltage detector according to claim 1, wherein the
comparison circuit comprises: an operational amplifier, having a
positive input end to receive the reference voltage and having a
negative input end to receive the processed voltage, and an output
end of the operational amplifier generating the comparison
signal.
3. The voltage detector according to claim 1, further comprising: a
reference voltage generator, coupled to the comparison circuit and
configured for providing the reference voltage.
4. The voltage detector according to claim 3, wherein the reference
voltage is a Zener diode, an anode of the Zener diode is coupled to
the reference grounding voltage end, and a cathode of the Zener
diode receives the power voltage.
5. (canceled)
6. The voltage detector according to claim 1, wherein, the
light-emitting element generates the induction signal being optical
energy when the comparison signal is a first reference grounding
voltage, the phototransistor is turned on according to the
induction signal, and the detection signal generator generates the
detection signal being a first voltage.
7. The voltage detector according to claim 6, wherein, the
light-emitting element stops generating the induction signal and
sets the phototransistor to be turned off when the comparison
signal is a second voltage higher than the reference voltage, and
the detection signal generator generates the detection signal being
a second reference grounding voltage, wherein the first voltage is
greater than the second reference grounding voltage.
8. The voltage detector according to claim 6, wherein the detection
signal generator further comprises: a second resistor, connected
between the first resistor and the phototransistor in series; and a
third resistor, connected between the light-emitting element and
the detection signal generator in series.
9. The voltage detector according to claim 1, wherein the
rectifying and filtering circuit comprises: a rectifying circuit,
coupled to a live wire end and a neutral wire end to receive the
alternating current input voltage and performing rectifying on the
alternating current input voltage to generate a quasi-direct
current voltage; and a filtering circuit, coupled to the rectifying
circuit, performing a low-pass filtering operation on the
quasi-direct current voltage, and generating the processed
voltage.
10. The voltage detector according to claim 9, wherein the
rectifying circuit comprises: a first diode, having an anode
coupled to the live wire end; and a second diode, having an anode
coupled to the neutral wire end, wherein cathodes of the first
diode and the second diode are coupled to each other, and generate
the quasi-direct current voltage.
11. The voltage detector according to claim 9, wherein the
filtering circuit comprises: a first resistor, having a first end
to receive the quasi-direct current voltage; a second resistor,
having a first end coupled to a second end of the first resistor,
and a second end of the second resistor coupled to the reference
grounding voltage end; and a first capacitor, coupled between the
first end of the second resistor and the reference grounding
voltage end.
12. The voltage detector according to claim 11, wherein the
filtering circuit further comprises: a third resistor, connected in
a path where the second resistor is coupled to the reference
grounding voltage end in series; and a second capacitor, coupled
between the second end of the second resistor and the reference
grounding voltage end.
13. The voltage detector according to claim 1, further comprising:
an electromagnetic interference filter, coupled to a path where the
rectifying and filtering circuit receives the alternating current
input voltage.
14. An electronic apparatus, comprising: the voltage detector
according to claim 1; and a load device, coupled to the voltage
detector, the load device receiving the detection signal and
adjusting a power demand according to the detection signal.
15. The electronic apparatus according to claim 14, wherein the
load device lowers the power demand when the detection signal
indicates that the alternating current input voltage is cut
off.
16. The electronic apparatus according to claim 14, further
comprising: a rectifying circuit, receiving and rectifying the
alternating current input voltage to generate a direct current
input voltage; and a voltage converter, coupled to the rectifying
circuit, and executing a voltage converting operation on the direct
current input voltage to generate a supply voltage, wherein the
supply voltage is sent to the load device to serve as an operating
power source of the load device.
17. A voltage detection method, comprising: receiving an
alternating current input voltage, and performing a rectifying and
filtering operation on the alternating current input voltage to
generate a processed voltage; comparing the processed voltage with
a reference voltage to generate a comparison signal; and providing
a detection signal generator having a first side and a second side,
receiving the comparison signal through the first side, generating
an induction signal according to the comparison signal, and
receiving the induction signal through the second side to generate
a detection signal, wherein the first side and the second side are
isolated, wherein the step of providing the detection signal
generator having the first side and the second side, receiving the
comparison signal through the first side, generating the induction
signal according to the comparison signal, and receiving the
induction signal through the second side to generate the detection
signal comprises: providing an optical coupler having a
light-emitting element and a phototransistor, and arranging the
light-emitting element on the first side and the phototransistor on
the second side; and setting a first end of the light-emitting
element to receive a power voltage and setting a second end of the
light-emitting element to receive the comparison signal.
18. The voltage detection method according to claim 17, wherein the
step of providing the detection signal generator having the first
side and the second side, receiving the comparison signal through
the first side, generating the induction signal according to the
comparison signal, and receiving the induction signal through the
second side to generate the detection signal further comprises:
setting the light-emitting element to generate the induction signal
being optical energy when the comparison signal is a first
reference grounding voltage, turning on the phototransistor
according to the induction signal, and setting the detection signal
generator to generate the detection signal being a first voltage;
and setting the light-emitting element to stop generating the
induction signal when the comparison signal is a second voltage
higher than the reference voltage, setting the phototransistor
being turned off, and setting the detection signal generator to
generate the detection signal being a second reference grounding
voltage, wherein the first voltage is greater than the second
reference grounding voltage.
19. The voltage detection method according to claim 17, further
comprising: providing the detection signal for a load device and
setting the load device to adjust a power demand according to the
detection signal.
20. The voltage detection method according to claim 17, wherein the
detection signal is configured for indicating whether the
alternating current input voltage is cut off or not.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 108130778, filed on Aug. 28, 2019. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention generally relates to an electronic
apparatus, a voltage detector and a voltage detection method
thereof, in particular, to a power supply unit of an electronic
apparatus, a voltage detector therein and a voltage detection
method thereof.
2. Description of Related Art
[0003] In an electronic apparatus, it is a very important issue to
provide a stable power supply. In a switching type voltage
converter in the known technical field, it is very important to
arrange a filter capacitor with a large capacitance value. The
filter capacitor is matched with a filtering circuit to generate a
direct current voltage. In addition, the filter capacitor is also
configured for providing the direct current voltage to execute a
voltage converting operation and thus generating a supply voltage.
When an input alternating current voltage is cut off power, due to
an effect of the filter capacitor, the supply voltage is held to be
kept in a stable state to continue for a period of time, and the
time is called hold time.
[0004] During the hold time, the electronic apparatus performs a
back-up storing operation of important data, or a switching
operation of a redundant power source is performed. In order to
provide long enough hold time, in the known art, it is completed by
building a PFC converter (Power Factor Correction converter).
However, the PFC converter needs to occupy a circuit area in an
equivalently large size, and cost of the electronic apparatus is
substantially increased.
SUMMARY OF THE INVENTION
[0005] Accordingly, the present invention is directed to an
electronic apparatus, a voltage detector, and a voltage detection
method thereof, and hold time of a power supply is prolonged.
[0006] The voltage detector of the present invention includes a
rectifying and filtering circuit, a comparison circuit and a
detection signal generator. The rectifying and filtering circuit
receives an alternating current input voltage and performs a
rectifying and filtering operation on the alternating current input
voltage to generate a processed voltage. The comparison circuit is
coupled to the rectifying and filtering circuit, and compares the
processed voltage with a reference voltage to generate a comparison
signal. The detection signal generator includes a first side and a
second side. The first side is coupled to the comparison signal to
receive the comparison signal. The first side generates an
induction signal according to the comparison signal. The second
side receives the indication signal to generate a detection signal.
The first side and the second side are isolated.
[0007] The electronic apparatus of the present invention includes
the voltage detector as mentioned above and a load device. The load
device is coupled to the voltage detector. The load device receives
the detection signal, and adjusts a power demand according to the
detection signal.
[0008] The voltage detection method of the present invention
includes the following steps. An alternating current input voltage
is received, and a rectifying and filtering operation is performed
on the alternating current input voltage to generate a processed
voltage. The processed voltage is compared with a reference voltage
to generate a comparison signal. A detection signal generator
having a first side and a second side is provided. The comparison
signal is received through the first side. An induction signal is
generated according to the comparison signal. The induction signal
is received through the second side to generate a detection signal.
The first side and the second side are isolated.
[0009] Based on the above, the present invention performs detection
on the alternating current input voltage, by means of the
comparison circuit, on the first side of the detection signal
generator, the processed voltage is compared with the reference
voltage to generate the comparison signal, the detection signal is
generated on the second side of the detection signal generator
according to the comparison signal, and a power supply state of the
alternating current input voltage is indicted by means of the
detection signal. The first side and the second side are
isolated.
[0010] In order to make the aforementioned and other objectives and
advantages of the present invention comprehensible, embodiments
accompanied with figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram of a voltage detector
according to an embodiment of the present invention.
[0012] FIG. 2 is a circuit schematic diagram of a voltage detector
according to another embodiment of the present invention.
[0013] FIG. 3 is a schematic diagram of another implementation
manner of a filter according to an embodiment of the present
invention.
[0014] FIG. 4 is a schematic diagram of part of a circuit of a
voltage detector according to an embodiment of the present
invention.
[0015] FIG. 5 is a schematic diagram of an electronic apparatus
according to an embodiment of the present invention.
[0016] FIG. 6 is an operation waveform diagram of an electronic
apparatus according to an embodiment of the present invention.
[0017] FIG. 7 is a flow chart of a voltage detection method
according to an embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
[0018] Referring to FIG. 1, FIG. 1 is a schematic diagram of a
voltage detector according to an embodiment of the present
invention. A voltage detector 100 includes a rectifying and
filtering circuit 110, a comparison circuit 120 and a detection
signal generator 130. The rectifying and filtering circuit 110 is
coupled to a live wire end L1 and a neutral wire end N1, and
receives an alternating current input voltage VAC through the live
wire end L1 and the neutral wire end N1. The rectifying and
filtering circuit 110 performs a rectifying and filtering operation
on the alternating current input voltage VAC so as to generate a
processed voltage PV1. The comparison circuit 120 is coupled to the
rectifying and filtering circuit 110. The comparison circuit 120
compares the processed voltage PV1 with a reference voltage VR1 to
generate a comparison signal CS. The detection signal generator 130
is coupled to the comparison circuit 120. The detection signal
generator 130 includes a first side 131 and a second side 132 which
are mutually coupled. The first side 131 is coupled to the
comparison signal 120 so as to receive the comparison signal CS.
The first side 131 generates an induction signal IS according to
the comparison signal CS. The second side 132 receives the
indication signal IS to generate a detection signal PGI. The first
side 131 and the second side 132 are isolated, but are not in
contact.
[0019] Speaking in detail, in the present embodiment, the
alternating current input voltage VAC is used as a supply voltage
of a load device. The voltage detector 100 generates the detection
signal PGI by detecting a power supply state of the alternating
current input voltage VAC. The rectifying and filtering circuit 110
receives the alternating current input voltage VAC, and performs a
rectifying operation on the alternating current input voltage VAC
so as to generate a quasi-direct current voltage, and the
rectifying and filtering circuit 110 further performs filtering on
the quasi-direct current voltage so as to generate the processed
voltage PV1.
[0020] On the other hand, the comparison circuit 120 performs a
comparing operation on the processed voltage PV1 and the reference
voltage VR1, and determines whether the alternating current input
voltage VAC is powered off or not by determining whether a voltage
value of the processed voltage PV1 is higher than a voltage value
of the reference voltage VR1 or not. When the processed voltage PV1
is less than the reference voltage VR1, the comparison circuit 120
generates the comparison signal CS indicating that the alternating
current input voltage VAC is powered off. Relatively, when the
processed voltage PV1 is not less than the reference voltage VR1,
the comparison circuit 120 generates the comparison signal CS
indicating that the alternating current input voltage VAC is not
powered off.
[0021] In addition, the first side 131 of the detection signal
generator 130 receives the comparison signal CS, and determines
whether to generate the induction signal IS or not according to the
comparison signal CS. Subsequent to the above illustration, when
the comparison signal CS indicates that the alternating current
input voltage VAC is not powered off, the first side 131
continuously generates the induction signal IS according to the
comparison signal CS. In the meanwhile, the second side 132 of the
detection signal generator 130 receives the induction signal IS,
and generates the detection signal PGI according to a first
condition for receiving the induction signal IS. Relatively, when
the comparison signal CS indicates that the alternating current
input voltage VAC is powered off, the first side 131 stops
generating the induction signal IS according to the comparison
signal CS. In the meanwhile, the second side 132 of the detection
signal detector 130 generates the detection signal PGI under a
condition without receiving the induction signal IS. It should be
noted here that under the first condition and the second condition,
voltage values of the detection signal PGI generated by the
detection signal generator 130 are different.
[0022] It should be mentioned that the voltage detector 100 of the
embodiments of the present invention performs a determining
operation whether the alternating current input voltage VAC is
powered off or not through the first side 131 of the detection
signal generator 130, and generates the detection signal PGI
through the second side 132 isolated from the first side 131, and
then the detection signal PGI is provided for the load device (not
shown). Thus, the load device does not affect the determining
operation whether the alternating current input voltage VAC is
powered off or not, and guarantees correctness of the detection
signal PGI. In addition, through the detection signal PGI, the load
device properly adjusts power demand thereof, and effectively
executes load shedding, data backup or a switching operation of
redundant power under the condition that the alternating current
input voltage VAC is powered off.
[0023] Referring to FIG. 2 below, FIG. 2 is a circuit schematic
diagram of a voltage detector according to another embodiment of
the present invention. A voltage detector 200 includes a rectifying
and filtering circuit 210, a comparison circuit 220 and a detection
signal generator 230. The rectifying and filtering circuit 210
includes a rectifying circuit 211 and a filtering circuit 212. The
rectifying circuit 211 is coupled to a live wire end L1 and a
neutral wire end N1 to receive an alternating current input
voltage. The rectifying circuit 211 includes diodes D1 and D2. In
the present embodiment, anodes of the diodes D1 and D2 are
respectively coupled to the live wire end L1 and the neutral wire
end N1, and cathodes of the diodes D1 and D2 are coupled to each
other and coupled to the filtering circuit 212. The rectifying
circuit 211 is configured for performing rectifying on the
alternating current input voltage, and generates a quasi-direct
current voltage VA1.
[0024] The filtering circuit 212 is coupled to the rectifying
circuit 211 and receives the quasi-direct current voltage VA1. In
the present embodiment, the filtering circuit 212 includes
resistors R21 and R22 and a capacitor C21. A first end of the
resistor R21 receives the quasi-direct current voltage VAL and a
second end of the resistor R21 is coupled to a first end of the
resistor R22, and a second end of the resistor R22 is coupled to a
reference grounding voltage end GND1. Besides, the capacitor C21 is
coupled between the second end of the resistor R21 and the
reference grounding voltage end GND1. The resistors R21 and R22 and
the capacitor C21 form a low-pass filter to be configured for
performing a low-pass filtering operation on the quasi-direct
current voltage VA1 so as to generate a processed voltage PV1.
[0025] The comparison circuit 220 is coupled to the rectifying and
filtering circuit 210, and receives the processed voltage PV1. In
the present embodiment, the comparison circuit 220 includes an
operational amplifier OP1, Zener diodes ZD1 and ZD2, a resistor R23
and capacitors C22 and C23. The operational amplifier OP1 includes
a positive input end to be coupled to a cathode of the Zener diode
ZD1, and further includes a negative input end to receive the
processed voltage PV1. In addition, an anode of the Zener diode ZD1
is coupled to the reference grounding voltage end GND1, and the
cathode of the Zener diode ZD1 receives a power voltage VCC1
through the resistor R23. Herein, the resistor R23 and the Zener
diode ZD1 form a reference voltage generator, and provide a
reference voltage VR to the positive input end of the operational
amplifier OP1. In the present embodiment, the reference voltage is
substantially equal to a breakdown voltage of the Zener diode
ZD1.
[0026] In the present embodiment, the operational amplifier OP1
serves as a voltage comparator, and compares the reference voltage
VR with the processed voltage PV1. When the reference voltage VR is
greater than the processed voltage PV1, an output end of the
operational amplifier OP1 generates a comparison signal CS with a
relatively high voltage (determined according to a voltage value of
an operating voltage received by the operational amplifier OP1).
Relatively, when the reference voltage VR is not greater than the
processed voltage PV1, the output end of the operational amplifier
OP1 generates a comparison signal CS with a relatively low voltage
(for example, equal to a first reference grounding voltage on the
first reference grounding voltage end GND1).
[0027] It should be mentioned incidentally that in the present
embodiment, the capacitor C23 is coupled between the reference
grounding voltage end GND1 and the positive input end of the
operational amplifier OP1, and is used as a voltage stabilizing
capacitor. The Zener diode ZD2 and the capacitor C23 are connected
between the power voltage VCC1 and the reference grounding voltage
end GND1 in series in sequence. A cathode of the Zener diode ZD2
receives the power voltage VCC1, an anode of the Zener diode ZD2 is
coupled to the capacitor C23, and is coupled to the detection
signal generator 230.
[0028] The detection signal generator 230 includes an optical
coupler 231 and resistors R24, R25 and R26. The optical coupler 231
includes a light-emitting element LED1 and a phototransistor PT1.
The light-emitting element LED1 is a light-emitting diode. In FIG.
2, the light-emitting element LED1 and the resistor R26 form a
first side of the detection signal generator 230, and the
phototransistor PT1 and the resistors R24 and R25 form a second
side of the detection signal generator 230. In a connection
relationship, one end (anode) of the light-emitting element LED1 is
coupled to the anode of the Zener diode ZD2 to be coupled to the
power voltage VCC1 through the Zener diode ZD2. The other end
(cathode) of the light-emitting element LED1 receives the
comparison signal CS through the resistor R26. On the other hand,
one end of the phototransistor PT1 receives the power voltage VCC,
and the other end of the phototransistor PT1 is coupled to the
resistor R24. The resistors R24 and R25 are connected between the
phototransistor PT1 and a reference grounding voltage end GND2 in
series in sequence. Coupled end points of the resistors R24 and R25
provide a detection signal PGI.
[0029] It should be noted that the light-emitting element LED1 is
configured for generating an optics induction signal IS, and a
control end of the phototransistor PT1 is configured for receiving
the induction signal IS. The phototransistor PT1 is turned on when
the control end thereof receives the induction signal IS of enough
energy. Relatively, if the control end of the phototransistor PT1
does not receive the induction signal IS of enough energy, the
phototransistor PT1 is in a turning-off state.
[0030] It should be mentioned that based on that the first side and
the second side of the detection signal generator 230 are isolated,
the reference grounding voltage ends GND1 and GND2 shown in FIG. 2
are different.
[0031] In the aspect of an operation, when the comparison signal CS
has a relatively low voltage value (equal to a first reference
grounding voltage), the light-emitting element LED1 is turned on so
as to generate the induction signal IS of optical energy. In the
meanwhile, the phototransistor PT1 is turned on based on the
received induction signal IS. Accordingly, the second side of the
detection signal generator 230 generates the detection signal PGI
for a first voltage, a voltage value of the first voltage is
determined according to resistance values of the resistors R24 and
R25, and the voltage value of the first voltage is greater than a
second reference grounding voltage on the second reference
grounding voltage end GND2.
[0032] On the other hand, when the comparison signal CS has a
relatively high voltage value, the light-emitting element LED1 is
turned off and does not generate the induction signal IS. In the
meanwhile, the phototransistor PT1 is turned off under a condition
without receiving the induction signal IS of enough energy.
Accordingly, the second side of the detection signal generator 230
generates the detection signal PGI equal to the second reference
grounding voltage.
[0033] It should be mentioned that the detection signal PGI is
provided to the load device. The load device receives a supply
voltage generated according to the alternating current input
voltage to operate. The load device acquires whether the
alternating current voltage is powered off or not according to an
amplitude of the voltage value of the detection signal PGI, and
accordingly adjusts the powder demand thereof. Specifically
speaking, when the load device detects that the detection signal
PGI is equal to the second reference grounding voltage, a load
shedding operation is performed, and the hold time is effectively
prolonged.
[0034] Referring to FIG. 3 below, FIG. 3 is a schematic diagram of
another implementation manner of a filter according to an
embodiment of the present invention. In FIG. 3, the filter 212
includes resistors R21, R22 and R27 and capacitors C21 and C24. The
resistors R21, R22 and R27 are connected in series in sequence, the
resistor R21 receives the quasi-direct current voltage VAL and the
resistor R23 is coupled to the first reference grounding voltage
end GND1. The capacitor C21 is coupled between a coupling point of
the resistors R21 and R22 and the first reference grounding voltage
end GND1, and the capacitor C24 is coupled between a coupling point
of the resistors R22 and R27 and the first reference grounding
voltage end GND1. In the present implementation manner, the filter
212 is a low-pass filtering circuit with two poles, and is
configured for filtering out high-frequency noise more
efficiently.
[0035] It should be noted that the implementation manners for the
filter shown in FIG. 2 and FIG. 3 are only an example for
illustration. In other embodiments of the present invention, the
filter 212 of the present invention is implemented through a
low-pass filtering circuit in any type, and there is no certain
limitation.
[0036] Then referring to FIG. 4, FIG. 4 is a schematic diagram of
part of a circuit of a voltage detector according to an embodiment
of the present invention. In FIG. 4, in addition to a plurality of
circuit elements as shown in FIG. 2, the voltage detector 400
further includes a FUSE, capacitors C41 and C42 and an
electromagnetic interference filter (EMI filter)410. The FUSE is
coupled between a live wire end L and the electromagnetic
interference filter 410. The electromagnetic interference filter
410 is coupled between the live wire end L and a neutral wire end
N, and the capacitor C41 is coupled to the electromagnetic
interference filter 410 in parallel connection.
[0037] The electromagnetic interference filter 410 performs
filtering on a received alternating current input voltage VACIN,
and generates an alternating current input voltage VAC after being
filtered through the live wire end L1 and the neutral wire end N1.
In addition, in FIG. 4, a grounding end FG is directly connected to
the second reference grounding voltage end GND2, and is coupled to
the first reference grounding voltage end GND1 through the
capacitor C42.
[0038] It should be noted that a circuit architecture of the
electromagnetic interference filter 410 shown in FIG. 4 is only an
example, electromagnetic interference filtering circuits known to
those of ordinary skill in the art are all applied to the present
invention, and there is no specific limitation.
[0039] Referring to FIG. 5, FIG. 5 is a schematic diagram of an
electronic apparatus according to an embodiment of the present
invention. The electronic apparatus 500 includes a rectifying
circuit 510, a voltage converter 520, a voltage detector 540 and a
load device 530. The rectifying circuit 510 is a bridge type
rectifying circuit, and receives an alternating current input
voltage VAC. A capacitor C51 is a filtering capacitor and is
coupled between the rectifying circuit 510 and the voltage
converter 520 in parallel connection. The voltage converter 520 is
a direct current to direct current voltage converter (DC to DC
voltage converter), is configured for performing a voltage
converting operation on a voltage provided by the capacitor C51,
and generates a supply voltage VSUP.
[0040] The supply voltage VSUP is provided to the load device 530
to serve as an operating power source of the load device. In
addition, the voltage detector 540 receives the alternating current
input voltage VAC, and generates a detection signal PGI by
detecting whether the alternating current input voltage VAC is
powered off or not. The voltage detector 540 provides the detection
signal PGI to the load device 530, and the load device 530 performs
an adjusting operation of a power demand according to a voltage
value of the detection signal PGI. Specifically speaking, when the
alternating current input voltage VAC is powered off, the load
device performs a load shedding operation according to the
detection signal PGI, and the hold time provided by the capacitor
C51 is prolonged.
[0041] Implementing details of the voltage detector 540 are
illustrated in detail in the above-mentioned embodiments, and the
descriptions thereof are omitted herein. About implementing details
of the voltage converter 520, the voltage converter 520 is in any
type, is the direct current to direct current voltage converter
known to a person of ordinary skill in the art, and is not
specifically limited.
[0042] Referring to FIG. 2, FIG. 5 and FIG. 6 synchronously, FIG. 6
is an operation waveform diagram of an electronic apparatus
according to an embodiment of the present invention. In FIG. 6,
when the alternating current input voltage VAC is not powered off
and a normal state is maintained, a voltage value of the
correspondingly generated processed voltage PV1 is kept in a state
to be greater than the reference voltage VR1, the voltage detector
200 correspondingly generates the comparison signal CS with the
relatively low voltage, and a voltage difference VLED1 of two ends
of the light-emitting element LED1 is enabled to be maintained at a
high voltage value. Thus, the light-emitting element LED1 is
maintained to send the induction signal IS, and the detection
signal PGI is maintained at the relatively high voltage value.
[0043] When the alternating current input voltage VAC is powered
off, the voltage value of the correspondingly generated processed
voltage PV1 gradually decreases. After a hold time TH1 generated
when the alternating current input voltage VAC is powered off, when
the voltage value of the processed voltage PV1 is less than the
reference voltage VR1, the voltage detector 200 correspondingly
generates the comparison signal CS with the relatively high
voltage. Through the comparison signal CS with the relatively high
voltage, the voltage difference VLED1 of the two ends of the
light-emitting element LED1 is lowered to the voltage value, and
the induction signal IS is stopped from being sent. Thus, the
phototransistor PT1 is turned off, and the detection signal PGI is
lowered to the second reference grounding voltage.
[0044] Since the detection signal PGI, lowered to the second
reference grounding voltage, is maintained at a relatively high
voltage value, the load device 530 lowers the power demand, and
after ahold time TH2, the voltage value of the supply voltage VSUP
starts to decrease. It can be known that herein that through the
voltage detector of the embodiments of the present invention, in
the hold time TH1+TH2 after the alternating current input voltage
VAC is powered off, the electronic apparatus 500 is maintained to
operate, and under a condition that a power factor correction
converter is not arranged, the hold time is effectively
maintained.
[0045] It should be incidentally mentioned that in a waveform shown
in FIG. 6, a horizontal axis is a time axis t, and a vertical axis
is a voltage.
[0046] Referring to FIG. 7 below, FIG. 7 is a flow chart of a
voltage detection method according to an embodiment of the present
invention. In step S710, an alternating current input voltage is
received, and a rectifying and filtering operation is performed on
the alternating current input voltage to generate a processed
voltage. In step S720, the processed voltage is compared with a
reference voltage to generate a comparison signal. In step S730, a
detection signal generator having a first side and a second side is
provided, the comparison signal is received through the first side
and an induction signal is generated according to the comparison
signal, and the induction signal is received through the second
side to generate a detection signal. The first side and the second
side are isolated.
[0047] Implementation details of the above-mentioned steps
S710-S730 are illustrated in detail in the plurality of
above-mentioned embodiments, and the descriptions thereof are
omitted herein.
[0048] Based on the above, the present invention provides the
voltage detector, the detection operation of the alternating
current input voltage is performed in front of the first side, and
the detection signal is provided to the load device on the second
side. The load device is enabled to lower the power demand through
adjustment according to whether the alternating current input
voltage is powered off or not. On a premise that no need to arrange
the power factor correction converter exists, the hold time is
prolonged accordingly.
[0049] Although the invention is described with reference to the
above embodiments, the embodiments are not intended to limit the
invention. A person of ordinary skill in the art may make
variations and modifications without departing from the spirit and
scope of the invention. Therefore, the protection scope of the
invention should be subject to the appended claims.
* * * * *