CN112444665A - Electronic device, voltage detector and voltage detection method thereof - Google Patents
Electronic device, voltage detector and voltage detection method thereof Download PDFInfo
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- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
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Abstract
The invention provides an electronic device, a voltage detector and a voltage detection method thereof. The voltage detector comprises a rectifying and filtering circuit, a comparison circuit and a detection signal generator. The rectification filter circuit receives the alternating current input voltage, and performs rectification and filtering actions aiming at the alternating current input voltage so as 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 primary side and a secondary side. The primary side receives the comparison signal and generates a sensing signal according to the comparison signal. The secondary side receives the sensing signal to generate a detection signal. Wherein the primary side and the secondary side are isolated from each other. The power requirement of the load is adjusted according to the detection signal so as to prolong the holding time of the electronic device.
Description
Technical Field
The present invention relates to an electronic device, a voltage detector and a voltage detecting method thereof, and more particularly, to a power supply of an electronic device, a voltage detector and a voltage detecting method thereof.
Background
In an electronic device, it is a very important issue to provide a stable power supply. In the switching voltage converter in the prior art, it is important to provide a filter capacitor with a large capacitance. The filter capacitor is used for matching with the rectifying circuit to generate direct current voltage, and is also used for providing the direct current voltage to execute voltage conversion action so as to generate supply voltage. When the input ac voltage is powered off, the supply voltage is maintained in a stable state for a period of time, which is called a hold time, by the effect of the filter capacitor.
The holding time can provide the electronic device with the backup storage operation of important data or the switching operation of the backup power supply. In order to provide a sufficient sustain time, the conventional technique can be implemented by implementing a Power Factor Correction converter (PFC converter). However, the power factor correction converter occupies a circuit area with a relatively large size, and the cost of the electronic device is greatly increased.
Disclosure of Invention
The invention aims at an electronic device, a voltage detector and a voltage detection method thereof, which can improve the holding time of a power supply.
According to an embodiment of the present invention, a voltage detector includes a rectifying and filtering circuit, a comparing circuit, and a detection signal generator. The rectification filter circuit receives the alternating current input voltage, and performs rectification and filtering actions aiming at the alternating current input voltage so as to generate a processed voltage. The comparison circuit is coupled with the rectification filter circuit and compares the processed voltage with a reference voltage to generate a comparison signal. The detection signal generator has a primary side and a secondary side. The primary side is coupled to the comparison circuit to receive the comparison signal, and the primary side generates the sensing signal according to the comparison signal. The secondary side receives the sensing signal to generate a detection signal. Wherein the primary side and the secondary side are isolated from each other.
According to an embodiment of the present invention, an electronic device includes the voltage detector as described above and a load device. The load device is coupled with the voltage detector. The load device receives the detection signal and adjusts the power requirement according to the detection signal.
According to an embodiment of the present invention, a voltage detection method includes: receiving an alternating current input voltage, and performing rectification and filtering actions aiming at 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 with a primary side and a secondary side, receiving the comparison signal through the primary side, generating an induction signal according to the comparison signal, and receiving the induction signal through the secondary side to generate a detection signal, wherein the primary side and the secondary side are isolated from each other.
In the electronic device according to an embodiment of the invention, the voltage detector detects the ac input voltage, compares the processed voltage with the reference voltage at the primary side of the detection signal generator by the comparison circuit to generate the comparison signal, and generates the detection signal at the secondary side of the detection signal generator according to the comparison signal to indicate the power supply state of the ac input voltage by the detection signal. Wherein the primary side and the secondary side are isolated from each other.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG. 1 is a diagram of a voltage detector according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of a voltage detector according to another embodiment of the present invention;
FIG. 3 is a schematic diagram of another implementation of a filter according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a portion of a circuit of a voltage detector according to an embodiment of the present invention;
FIG. 5 is a diagram of an electronic device according to an embodiment of the invention;
FIG. 6 is a waveform diagram of an operation of an electronic device according to an embodiment of the invention;
FIG. 7 is a flowchart of a voltage detection method according to an embodiment of the invention.
Description of the reference numerals
100. 200: a voltage detector;
110. 210: a rectification filter circuit;
120. 220, and (2) a step of: a comparison circuit;
130. 230: a detection signal generator;
131: a primary side;
132: a secondary side;
211: a rectifying circuit;
212: a filter circuit;
231: an optical coupler;
410: an electromagnetic interference filter;
500: an electronic device;
510: a rectifying circuit;
520: a voltage converter;
530: a load device;
540: a voltage detector;
C21-C24, C41, C42 and C51: a capacitor;
CS: comparing the signals;
d1, D2: a diode;
FUSE: a fuse;
GND1, GND 2: a reference ground voltage terminal;
IS: sensing a signal;
l1, L: a fire wire end;
LED 1: a light emitting assembly;
n1, N: a neutral terminal;
OP 1: an operational amplifier;
PGI: detecting a signal;
PT 1: a phototransistor;
PV 1: voltage after treatment;
R21-R27: a resistance;
s710 to S730 voltage detection;
TH1, TH 2: maintaining the time;
VA 1: a DC-like voltage;
VAC, VACIN: an alternating input voltage;
VCC1, VCC: a supply voltage;
VLED 1: a voltage difference;
VR 1: a reference voltage;
VSUP: a supply voltage;
ZD1, ZD 2: zener diode
Detailed Description
Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a voltage detector according to an embodiment of the invention. The voltage detector 100 includes a rectifying and filtering circuit 110, a comparing circuit 120, and a detection signal generator 130. The rectifying-smoothing circuit 110 is coupled to the line terminal L1 and the neutral terminal N1, and receives the ac input voltage VAC through the line terminal L1 and the neutral terminal N1. The rectifying-smoothing circuit 110 performs rectifying and smoothing operations on the ac input voltage VAC to generate a processed voltage PV 1. 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 has a primary side 131 and a secondary side 132 coupled to each other. The primary side 131 is coupled to the comparison circuit 120 and receives the comparison signal CS. The primary side 131 generates the sensing signal IS according to the comparison signal CS. The secondary side 132 receives the sensing signal IS to generate a detection signal PGI. The primary side 131 and the secondary side 132 are isolated from each other and do not contact each other.
In detail, in the present embodiment, the ac input voltage VAC is used as a supply voltage for generating a load device. The voltage detector 100 generates the detection signal PGI by detecting a power supply state of the ac input voltage VAC. The rectifying and smoothing circuit 110 receives the ac input voltage VAC, rectifies the ac input voltage VAC, and generates a dc-like voltage, and the rectifying and smoothing circuit 110 further rectifies the dc-like voltage, and generates a processed voltage PV 1.
On the other hand, the comparator circuit 120 performs a comparison operation with respect to the processed voltage PV1 and the reference voltage VR1, and determines whether or not the voltage value of the processed voltage PV1 is higher than the voltage value of the reference voltage VR1, thereby determining whether or not the ac input voltage VAC is powered off. The comparison circuit 120 may generate the comparison signal CS indicating that the ac input voltage VAC is powered down when the processed voltage PV1 is smaller than the reference voltage VR 1. In contrast, when the processed voltage PV1 is not less than the reference voltage VR1, the comparison circuit 120 may generate the comparison signal CS indicating that the ac input voltage VAC is not powered down.
In addition, a comparison signal CS received by a primary test 131 of the signal generator 130 IS detected, and whether the sensing signal IS generated IS determined according to the comparison signal CS. Continuing with the above description, when the comparison signal CS indicates that the ac input voltage VAC IS not powered off, the primary test 131 may continuously generate the sensing signal IS according to the comparison signal CS. Meanwhile, the second test 132 of the detection signal generator 130 receives the sensing signal IS and generates the detection signal PGI according to a first condition that the sensing signal IS received. On the contrary, when the comparison signal CS indicates that the ac input voltage VAC IS powered off, the primary test 131 stops generating the sensing signal IS according to the comparison signal CS. Meanwhile, the second test 132 of the detection signal generator 130 may generate the detection signal PGI under a second condition that the sensing signal IS not received. It should be noted that the voltage values of the detection signal PGI generated by the detection signal generator 130 are different under the first condition and the second condition.
It should be noted that the voltage detector 100 according to the embodiment of the invention performs the determination operation on the ac input voltage VAC at the primary test 131 of the detection signal generator 130 to determine whether the ac input voltage VAC is powered off, generates the detection signal PGI at the secondary test 132 isolated from the primary test 131, and provides the detection signal PGI to the load device (not shown). Therefore, the load device does not affect the determination of whether the ac input voltage VAC is powered off, and the correctness of the detection signal PGI can be ensured. In addition, by detecting the PGI signal, the load device can appropriately adjust its power requirement, and can effectively perform the switching operation of load reduction, data backup or backup power when the ac input voltage is powered off.
Referring to fig. 2, fig. 2 is a circuit diagram of a voltage detector according to another embodiment of the invention. The voltage detector 200 includes a rectifying and filtering circuit 210, a comparing 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 the line terminal L1 and the neutral terminal N1 to receive the ac input voltage. The rectifier circuit 211 includes diodes D1 and D2. In the present embodiment, anodes of the diodes D1 and D2 are coupled to the hot terminal L1 and the neutral terminal N1, respectively, and cathodes of the diodes D1 and D2 are coupled to each other and to the filter circuit 212. The rectifying circuit 211 is used for rectifying an ac input voltage and generating a dc-like voltage VA 1.
The filter circuit 212 is coupled to the rectifying circuit 211 and receives the dc-like voltage VA 1. In the present embodiment, the filter circuit 212 includes resistors R21 and R22 and a capacitor C21. The first terminal of the resistor R21 receives the dc-like voltage VA1, the first terminal of the resistor R21 is coupled to the first terminal of the resistor R22, and the second terminal of the resistor R22 is coupled to the ground reference voltage GND 1. In addition, the capacitor C21 is coupled between the second terminal of the resistor R21 and the ground reference voltage GND 1. The resistors R21 and R22 and the capacitor C21 form a low pass filter, and are used for performing a low pass filtering operation on the dc-like voltage VA1 to generate the processed voltage PV 1.
The comparison circuit 220 is coupled to the rectifying and filtering circuit 210 and receives the processed voltage PV 1. In the present embodiment, the comparison circuit 220 includes an operational amplifier OP1, a Zener diode (Zener diode) ZD1, ZD2, a resistor R23, and capacitors C22, C23. The operational amplifier OP1 has a positive input terminal coupled to the cathode of the zener diode ZD1, and the operational amplifier OP1 has a negative input terminal for receiving the processed voltage PV 1. In addition, the anode of the zener diode ZD1 is coupled to the ground reference voltage GND1, and the cathode of the zener diode ZD1 receives the power voltage VCC1 through the resistor R23. Here, the resistor R23 and the zener diode ZD1 form a reference voltage generator, and provide the reference voltage VR to the positive input terminal of the operational amplifier OP 1. In the present embodiment, the reference voltage VR may be substantially equal to the breakdown voltage of the zener diode ZD 1.
In the present embodiment, the operational amplifier OP1 is used as a voltage comparator and compares the reference voltage VR with the processed voltage PV 1. When the reference voltage VR is greater than the processed voltage PV1, the output terminal of the operational amplifier OP1 may generate the comparison signal CS having a relatively high voltage (determined according to the voltage value of the operating voltage received by the operational amplifier OP 1). In contrast, when the reference voltage VR is not greater than the processed voltage PV1, the output terminal of the operational amplifier OP1 may generate the comparison signal CS having a relatively low voltage (e.g., equal to the first ground reference voltage on the first ground reference terminal GND 1).
Incidentally, in the present embodiment, the capacitor C23 is coupled between the ground reference voltage terminal GND1 and the positive input terminal of the operational amplifier OP1 to serve as a voltage stabilizing capacitor. The zener diode ZD2 and the capacitor C23 are sequentially connected in series between the power voltage VCC1 and the ground reference voltage GND1, wherein the cathode of the zener diode ZD2 receives the power voltage VCC1, and the anode of the zener diode ZD2 is coupled to the capacitor C23 and the detection signal generator 230.
The detection signal generator 230 includes an optocoupler 231 and resistors R24, R25, R26. The photo coupler 231 has a light emitting element LED1 and a photo transistor PT 1. The light emitting assembly LED1 is a light emitting diode. In fig. 2, the light emitting device LED1 and the resistor R26 form a primary side of the detection signal generator 230, and the phototransistor PT1 and the resistors R24 and R25 form a secondary side of the detection signal generator 230. In the connection relation, one end (anode) of the light emitting device LED1 is coupled to the anode of the zener diode ZD2, and is coupled to the power supply voltage VCC1 through the zener diode ZD 2. The other end (cathode) of the light emitting element LED1 passes through a resistor R26 to receive the comparison signal CS. On the other hand, one terminal of the phototransistor PT1 receives the power supply voltage VCC, and the other terminal of the phototransistor PT1 is coupled to the resistor R24. The resistors R24 and R25 are serially connected between the phototransistor PT1 and the ground reference voltage GND2, wherein the coupled terminals of the resistors R24 and R25 provide the detection signal PGI.
Please note that the light emitting device LED1 IS used for generating an optical sensing signal IS, and the control terminal of the photo transistor PT1 IS used for receiving the sensing signal IS. The phototransistor PT1 can be turned on when its control terminal receives a sensing signal IS of sufficient energy. In contrast, if the control terminal of the photo transistor PT1 does not receive the sensing signal IS with sufficient energy, the photo transistor PT1 IS turned off.
It should be noted that, since the primary side and the secondary side of the detection signal generator 230 are isolated from each other, the ground reference voltages GND1 and GND2 shown in fig. 2 are different.
In operation, when the comparison signal CS has a relatively low voltage value (equal to the first reference ground voltage), the light emitting component LED1 may be turned on to generate the sensing signal IS of light energy. At the same time, the phototransistor PT1 IS turned on based on the received sensing signal IS. Accordingly, the secondary side of the detection signal generator 230 may generate the detection signal PGI with a first voltage, wherein the voltage value of the first voltage may be determined according to the resistance values of the resistors R24 and R25, and the voltage value of the first voltage is greater than the second ground reference voltage on the second ground reference voltage terminal GND 2.
On the other hand, when the comparison signal CS has a relatively high voltage value, the light emitting assembly LED1 may be turned off without generating the sensing signal IS. At the same time, the phototransistor PT1 IS turned off without receiving a sense signal IS of sufficient energy. Accordingly, the secondary side of the detection signal generator 230 may generate the detection signal PGI equal to the second ground reference voltage.
It is worth mentioning that the detection signal PGI may be provided to the load device. The load device receives a supply voltage generated according to an alternating current input voltage to operate. The load device can know whether the alternating current input voltage is powered off or not according to the voltage value of the detection signal PGI, and accordingly adjust the power requirement of the load device. Specifically, when the load device detects that the PGI signal is equal to the second reference ground voltage, the load down operation can be performed, and the holding time can be effectively prolonged.
Referring to fig. 3, fig. 3 is a schematic diagram illustrating another implementation of a filter according to an embodiment of the invention. In fig. 3, the filter 212 includes resistors R21, R22, R27 and capacitors C21, C24. The resistors R21, R22, and R27 are connected in series in sequence, wherein the resistor R21 receives the dc-like voltage VA1, and the resistor R23 is coupled to the first ground reference voltage GND 1. The capacitor C21 is coupled between the coupling node of the resistors R21 and R22 and the first ground reference voltage terminal GND1, and the capacitor C24 is coupled between the coupling node of the resistors R22 and R27 and the first ground reference voltage terminal GND 1. In the present embodiment, the filter 212 is a low-pass filter circuit with two poles (poles), which can effectively filter the high-frequency noise.
It should be noted that the filter embodiments shown in fig. 2 and 3 are merely illustrative examples. In other embodiments of the present invention, the filter 212 of the present invention can be implemented by any other form of low-pass filter circuit without limitation.
Referring to fig. 4, fig. 4 is a schematic diagram illustrating a part of a circuit of a voltage detector according to an embodiment of the invention. In fig. 4, the voltage detector 400 includes a FUSE, capacitors C41, C42, and an electromagnetic interference filter (EMI filter)410 in addition to the circuit components shown in fig. 2. The FUSE is coupled between the line terminal L and the emi filter 410. The emi filter 410 is coupled between the line terminal L and the neutral terminal N, and the capacitor C41 is coupled in parallel with the emi filter 410.
The emi filter 410 filters the received ac input voltage VACIN and passes through the line side L1 and the neutral side N1 to produce a filtered ac input voltage VAC. In addition, in fig. 4, the ground terminal FG is directly connected to the second ground reference voltage terminal GND2 and is coupled to the first ground reference voltage terminal GND1 through the capacitor C42.
It is to be noted that the circuit architecture of the emi filter 410 shown in fig. 4 is only an example, and any emi filter circuit known to one skilled in the art can be applied to the present invention without specific limitation.
Referring to fig. 5, fig. 5 is a schematic view illustrating an electronic device according to an embodiment of the invention. The electronic device 500 includes a rectifying circuit 510, a voltage converter 520, a voltage detector 540, and a load device 530. The rectifier circuit 510 may be a bridge rectifier circuit and receives an alternating input voltage VAC. The capacitor C51 is a filter capacitor and is coupled in parallel between the rectifying circuit 510 and the voltage converter 520. The voltage converter 520 is a DC-to-DC voltage converter (DC-to-DC voltage converter) for performing a voltage conversion operation on the voltage provided by the capacitor C51 and generating a supply voltage VSUP.
The supply voltage VSUP is provided to the load device 530 as an operation power source of the load device. The voltage detector 540 receives the ac input voltage VAC, and generates a detection signal PGI by detecting whether the ac input voltage VAC is in a power-off state. The voltage detector 540 provides the detection signal PGI to the load device 530, and the load device 530 may perform an adjustment operation of power demand according to the voltage value of the detection signal PGI, specifically, when the ac input voltage VAC is in a power-off state, the load device 530 may perform a load reduction operation according to the detection signal PGI, and increase the retention time provided by the capacitor C51.
The details of the implementation of the voltage detector 540 have been described in the foregoing embodiments, and are not repeated herein. With respect to the implementation details of the voltage converter 520, the voltage converter 520 may be in any form, and is a dc-to-dc voltage conversion circuit known to those skilled in the art, and is not particularly limited.
Referring to fig. 2, fig. 5 and fig. 6 synchronously, fig. 6 is a waveform diagram illustrating an operation of an electronic device according to an embodiment of the invention. In fig. 6, when the ac input voltage VAC is not powered off and remains in a normal state, the voltage value of the processed voltage PV1 is maintained to be greater than the reference voltage VR1, and the voltage detector 200 generates the comparison signal CS with a relatively low voltage and maintains the voltage difference VLED1 between the two terminals of the light emitting element LED1 at a high voltage value. In this way, the light emitting device LED1 keeps sending the sensing signal IS, and keeps the detecting signal PGI at a relatively high voltage.
When the ac input voltage VAC is cut off, the voltage value of the processed voltage PV1 generated in response to the ac input voltage VAC gradually decreases. After the time TH1 after the ac 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 may generate the comparison signal CS with a relatively high voltage. By the comparison signal CS with a relatively high voltage, the voltage difference VLED1 between the two ends of the light emitting component LED1 IS reduced to a low voltage value, and the sending of the sensing signal IS stopped. In this way, the phototransistor PT1 is turned off and the detection signal PGI is lowered to the second reference ground voltage.
By reducing the detection signal PGI to the second ground reference voltage to a relatively high voltage level, the load device 530 may reduce the power requirement, and the voltage level of the supply voltage VSUP may start to be reduced after the holding time TH 2. It can be seen that, with the voltage detector according to the embodiment of the present invention, the electronic device 500 can maintain operation during the maintaining time TH1+ TH2 after the ac input voltage VAC is powered off, and the maintaining time is effectively prolonged without a power factor correction converter.
Incidentally, in the waveform shown in fig. 6, the horizontal axis represents a time axis t, and the vertical axis represents a voltage.
Referring to fig. 7, fig. 7 is a flowchart illustrating a voltage detection method according to an embodiment of the invention. In step S710, receiving an ac input voltage, and performing rectification and filtering operations on the ac input voltage to generate a processed voltage; step S720, comparing the processed voltage with a reference voltage to generate a comparison signal; step S730 provides a detection signal generator having a primary side and a secondary side, wherein the primary side receives the comparison signal and generates a sensing signal according to the comparison signal, and the secondary side receives the sensing signal and generates a detection signal, wherein the primary side and the secondary side are isolated from each other.
The details of the steps S710 to S730 have been described in the foregoing embodiments, and are not repeated herein.
In summary, the present invention provides a voltage detector, which performs the detection operation of the ac input voltage before the first measurement, and provides the detection signal to the load device at the second measurement. And the load device can adjust and reduce the power requirement according to the power-off state of the alternating current input voltage. The holding time can be prolonged without the need of providing a power factor correction converter.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (20)
1. A voltage detector, comprising:
the rectification filter circuit receives an alternating current input voltage, and performs rectification and filtering actions aiming at the alternating current input voltage to generate a processed voltage;
the comparison circuit is coupled with the rectification filter circuit and is used for comparing the processed voltage with a reference voltage to generate a comparison signal; and
a detection signal generator having a primary side and a secondary side, wherein the primary side is coupled to the comparison circuit to receive the comparison signal, the primary side generates a sensing signal according to the comparison signal, the secondary side receives the sensing signal to generate a detection signal,
wherein the primary side and the secondary side are isolated from each other.
2. The voltage detector of claim 1, wherein the comparison circuit comprises:
an operational amplifier having a positive input terminal for receiving the reference voltage and a negative input terminal for receiving the processed voltage, wherein the output terminal of the operational amplifier generates the comparison signal.
3. The voltage detector of claim 1, further comprising:
the reference voltage generator is coupled to the comparison circuit and used for providing the reference voltage.
4. The voltage detector of claim 3, wherein the reference voltage is a zener diode, an anode of the zener diode is coupled to a ground reference voltage terminal, and a cathode of the zener diode receives a power supply voltage.
5. The voltage detector according to claim 1, wherein the detection signal generator includes:
a photo coupler having a light emitting element and a phototransistor, wherein the light emitting element is disposed on the primary side and the phototransistor is disposed on the secondary side; and
a first resistor coupled between the phototransistor and a ground reference voltage terminal,
the end point of the first resistor coupled with the photosensitive transistor generates the detection signal, the first end of the light-emitting component receives a power supply voltage, and the second end of the light-emitting component receives the comparison signal.
6. The voltage detector according to claim 5, wherein the light emitting element generates the sensing signal as light energy when the comparison signal is a first ground reference voltage, the phototransistor is turned on according to the sensing signal, and the detection signal generator generates the detection signal as a first voltage.
7. The voltage detector of claim 6, wherein when the comparison signal is a second voltage higher than the reference voltage, the light emitting device stops generating the sensing signal and turns off the phototransistor, and the detection signal generator generates the detection signal as a second ground reference voltage, wherein the first voltage is greater than the second ground reference voltage.
8. The voltage detector of claim 6, wherein the detection signal generator further comprises:
the second resistor is connected between the first resistor and the photosensitive transistor in series; and
and the third resistor is connected between the light-emitting component and the detection signal generator in series.
9. The voltage detector of claim 1, wherein the rectifying-filtering circuit comprises:
a rectifying circuit coupled to the live line terminal and the neutral line terminal to receive the alternating input voltage and rectify the alternating input voltage to generate a direct-current-like voltage; and
and the filter circuit is coupled with the rectifying circuit, performs low-pass filtering action on the quasi-DC voltage and generates 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 fire wire end; and
a second diode having an anode coupled to the neutral terminal,
wherein cathodes of the first diode and the second diode are coupled to each other and generate the dc-like voltage.
11. The voltage detector of claim 9, wherein the filter circuit comprises:
a first resistor having a first end receiving the DC-like voltage;
a second resistor having a first terminal coupled to the second terminal of the first resistor, the second terminal of the second resistor being coupled to a ground reference voltage terminal; and
the first capacitor is coupled between the first end of the second resistor and the reference grounding voltage end.
12. The voltage detector of claim 11, wherein the filter circuit further comprises:
the third resistor is connected in series between the paths of the second resistor coupled with the reference grounding voltage end; and
the second capacitor is coupled between the second end of the second resistor and the reference ground voltage end.
13. The voltage detector of claim 1, further comprising:
and the electromagnetic interference filter is coupled on a path of the rectifying and filtering circuit receiving the alternating current input voltage.
14. An electronic device, comprising:
a voltage detector according to claim 1; and
the load device is coupled with the voltage detector, receives the detection signal and adjusts the power requirement according to the detection signal.
15. The electronic device of claim 14, wherein the load device regulates down the power demand when the detection signal indicates that the ac input voltage is powered down.
16. The electronic device of claim 14, further comprising:
the rectifying circuit receives and rectifies the alternating-current input voltage to generate direct-current input voltage; and
a voltage converter coupled to the rectifying circuit for performing a voltage conversion operation on the DC input voltage to generate a supply voltage,
wherein the supply voltage is supplied to the load device as an operation power source of the load device.
17. A voltage detection method, comprising:
receiving an alternating current input voltage, and performing rectification and filtering actions aiming at 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 primary side and a secondary side, receiving the comparison signal through the primary side, generating a sensing signal according to the comparison signal, and receiving the sensing signal through the secondary side to generate a detection signal, wherein the primary side and the secondary side are isolated from each other.
18. The voltage detection method of claim 17, wherein providing the detection signal generator having the primary side and the secondary side, generating the sense signal according to the comparison signal by receiving the comparison signal, and receiving the sense signal by the secondary side to generate the detection signal comprises:
providing a photo coupler having a light emitting element and a phototransistor, and arranging the light emitting element on the primary side and the phototransistor on the secondary side;
enabling a first end of the light-emitting component to receive a power supply voltage and enabling a second end of the light-emitting component to receive the comparison signal;
when the comparison signal is a first reference grounding voltage, the light emitting component generates the induction signal which is luminous energy, the photosensitive transistor is conducted according to the induction signal, and the detection signal generator generates the detection signal which is a first voltage; and
when the comparison signal is a second voltage higher than the reference voltage, the light emitting device stops generating the sensing signal, the phototransistor is turned off, and the detection signal generator generates the detection signal which is a second reference ground voltage, wherein the first voltage is higher than the second reference ground voltage.
19. The voltage detection method of claim 17, further comprising:
and providing the detection signal to a load device, so that the load device adjusts the power requirement according to the detection signal.
20. The voltage detection method of claim 17, wherein the detection signal is used to indicate whether the ac input voltage is powered down.
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