CN107546838B - Power supply circuit, power supply recovery control circuit and method - Google Patents
Power supply circuit, power supply recovery control circuit and method Download PDFInfo
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- CN107546838B CN107546838B CN201610465364.6A CN201610465364A CN107546838B CN 107546838 B CN107546838 B CN 107546838B CN 201610465364 A CN201610465364 A CN 201610465364A CN 107546838 B CN107546838 B CN 107546838B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
Abstract
The invention discloses a power supply circuit, a power supply recovery control circuit and a method, wherein a sampling circuit of the power supply recovery control circuit samples the output of an AC/DC power supply in the power-off recovery process of the AC/DC power supply, and when the control circuit of the power supply recovery control circuit judges that the output voltage of the AC/DC power supply is lower than the output voltage of a standby power supply which supplies power currently according to the sampling result, the set output voltage of the AC/DC power supply is set to be a target voltage value which is larger than the output voltage of the standby power supply (such as a battery). Therefore, the output voltage Vout of the power supply can be normally established after the system is powered off for a short time, and the seamless switching of the standby battery and the AC/DC power supply to the system power supply is further realized in the power failure recovery process of the AC/DC power supply. Compared with the existing control mode of the oring circuit, the scheme provided by the embodiment of the invention is simpler, the cost is relatively lower, and the efficiency of the power supply is not obviously influenced.
Description
Technical Field
The invention relates to the field of power supplies, in particular to a power supply circuit, a power supply recovery control circuit and a power supply recovery control method.
Background
Some communication systems applying AC/DC communication power supplies, such as switches and the like, need to be equipped with storage batteries in certain application scenes so as to meet the requirement that the short-time power failure of mains supply does not affect certain services of the system. In these systems, the charging and discharging management circuit of the storage battery may be integrated inside the communication power supply, or may be integrated inside the system, as shown in fig. 1. In the system configuration shown in fig. 1, the output of the power supply is directly connected to the DC bus of the system, and when the commercial power is cut off, the charging management circuit in the system receives an AC power failure alarm signal sent from an AC/DC power supply (hereinafter referred to as power supply), and then controls the switch S1 to close, and the storage battery supplies power to the system. Because the action and the recovery of the AC power failure warning circuit are generally quick, after the mains supply is recovered, the battery charging and discharging management circuit can quickly detect that the AC power failure warning signal is recovered to be normal, and at the moment, if the switch S1 is immediately turned off, the output voltage Vout of the power supply is not established, so that the system is powered off for a short time.
The other situation is that after the system detects that the AC power failure alarm signal is recovered to be normal, the switch S1 is turned off after a delay, but there is a possibility that if the mains supply power failure time is short, the residual voltage of the storage battery is higher than the output voltage set by the power supply. If the power output does not have an Oring circuit, after the mains supply is recovered, the PWM control chip in the power supply starts to power on, the control loop of the power supply detects that the output of the power supply has a voltage (i.e., a battery voltage) and is higher than the output voltage set by the power supply itself, and then the PWM chip of the power supply cannot be driven any more, so that the Vout voltage of the power supply itself cannot be established all the time. In this case, even if the time-delay disconnection S1 is performed, the power supply output voltage cannot be immediately established, which may cause the system to be powered off for a short time. On the contrary, if the power output in fig. 1 has an Oring circuit, after the commercial power is recovered, the battery voltage will not affect the establishment of the power output voltage Vout, and after the system detects that the AC power-down alarm signal is recovered to normal, the switch S1 may be turned off after a certain time delay, so as to implement seamless switching of the battery and the AC/DC power supply to the system power supply. However, at present, seamless switching of the battery and the AC/DC power supply to the system power supply is realized through the Oring circuit, and another control scheme different from the Oring circuit is provided by the invention to realize seamless switching of the battery and the AC/DC power supply to the system power supply.
Disclosure of Invention
The embodiment of the invention aims to solve the problems that: in the AC/DC power supply power-off recovery process, seamless switching of a battery and an AC/DC power supply to system power supply is realized, and a power supply circuit, a power supply recovery control circuit and a power supply recovery control method are provided.
The power restoration control circuit provided by one embodiment of the invention comprises a sampling circuit and a control circuit; the sampling circuit is respectively connected with the output end of the AC/DC power supply and the input end of the control circuit; the output end of the control circuit is connected with the control end of the AC/DC power supply;
the sampling circuit is used for sampling the output of the AC/DC power supply in the power-off recovery process of the AC/DC power supply;
and the control circuit is used for setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when judging that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply for supplying power currently according to the sampling result.
Another embodiment of the present invention provides a power supply circuit, comprising an AC/DC power supply, a backup power supply, and a power restoration control circuit as described above;
the standby power supply is connected with the AC/DC power supply output end and is used for supplying power to a load when the AC/DC power supply is powered off;
the power restoration control circuit is used for sampling the output of the AC/DC power supply in the AC/DC power supply power-off restoration process, and setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply supplying power currently according to the sampling result.
Another embodiment of the present invention provides a power restoration control method, including:
sampling the output of the AC/DC power supply in the power-off recovery process of the AC/DC power supply;
and when the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which supplies power currently according to the sampling result, the output voltage set by the AC/DC power supply is set to be a target voltage value which is larger than the output voltage of the standby power supply.
One of the above technical solutions has the following beneficial effects:
the sampling circuit of the power restoration control circuit samples the output of the AC/DC power supply in the power failure restoration process of the AC/DC power supply, and when the control circuit of the power restoration control circuit judges that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply for supplying power at present according to the sampling result, the output voltage set by the AC/DC power supply is set to be a target voltage value which is larger than the output voltage of the standby power supply (such as a standby battery power supply and the like). Therefore, the output voltage of the power supply is higher than the voltage of the battery which is currently supplied with power, the output voltage Vout of the power supply is normally established, and the seamless switching of the standby battery and the AC/DC power supply to the power supply of the system is further realized in the power-off recovery process of the AC/DC power supply. Compared with the existing control mode of the oring circuit, the scheme provided by the embodiment of the invention is simpler, the cost is relatively lower, and the efficiency of the power supply is not obviously influenced.
Drawings
FIG. 1 is a block diagram of a power supply circuit system with a backup battery;
FIG. 2 is a flowchart illustrating a method for controlling power outage restoration according to a first embodiment of the present invention;
fig. 3 is a schematic structural diagram of a power restoration control circuit according to a first embodiment of the invention;
FIG. 4 is a schematic diagram of output voltage fluctuation of the AC/DC power supply according to the first embodiment of the present invention;
FIG. 5 is a schematic diagram of an alternative embodiment of the sampling circuit of FIG. 3;
FIG. 6 is a first diagram illustrating an alternative embodiment of the sampling circuit of FIG. 5;
FIG. 7 is a schematic diagram of an alternative embodiment of the sampling circuit of FIG. 5;
fig. 8 is a first schematic structural diagram of a power restoration control circuit according to a second embodiment of the invention;
fig. 9 is a schematic structural diagram of a power recovery control circuit according to a second embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The first embodiment is as follows:
the control of the present embodiment to the AC/DC power outage restoration is implemented by using the control process shown in fig. 2:
s201: sampling the output of the AC/DC power supply in the power-off recovery process of the AC/DC power supply;
in this step, at least one of the voltage and the current output from the AC/DC power supply may be sampled. And the specific sampling circuit and sampling rule can be flexibly set according to the actual application scene.
S202: judging whether the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply which supplies power currently according to the sampling result, if so, turning to S203; otherwise, go to S204.
And S203, setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply. Therefore, the output voltage of the AC/DC power supply is higher than the voltage of the standby power supply which supplies power currently, and the driving chip of the power supply normally outputs a driving signal, so that the power supply is started and the output voltage Vout is normally established.
S204: and the output voltage set by the AC/DC power supply is adjusted back to be set to be a normal output voltage value. During the power failure recovery process of the AC/DC power supply, the output voltage of the AC/DC power supply will fluctuate repeatedly, and when it is detected again through S201 that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply currently supplying power, the process goes to S203 to reset the output voltage set by the AC/DC power supply to a target voltage value larger than the output voltage of the standby power supply. Thus, a process of repeatedly fluctuating the power supply output voltage around the standby power supply voltage is started until the power supply switch of the standby power supply voltage is switched off, all system loads are borne by the AC/DC power supply, the AC/DC power supply output voltage does not fluctuate any more, and the AC/DC power supply output voltage is restored to a normal value. Therefore, seamless switching of the standby battery and the AC/DC power supply to the system power supply in the AC/DC power supply power failure recovery process is realized.
For a better understanding of the present invention, an example of implementing the control process shown in fig. 2 is described below in conjunction with a power restoration control circuit. It should be understood that all circuit configurations capable of implementing the control process shown in fig. 2 are within the scope of the present invention, and are not limited to the circuit configurations shown below in the present embodiment.
Referring to fig. 3, the power restoration control circuit in the present embodiment includes a sampling circuit 31 and a control circuit 32; the sampling circuit 31 is respectively connected with the output end of the AC/DC power supply and the input end of the control circuit; the control circuit output end is connected with an AC/DC power supply control end (not shown in the figure);
the sampling circuit 31 is used for sampling the output of the AC/DC power supply in the power-off recovery process of the AC/DC power supply;
the control circuit 32 is used for setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when judging that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply which supplies power currently according to the sampling result of the sampling circuit. Therefore, the output voltage of the AC/DC power supply is higher than the voltage of the standby power supply which supplies power currently, and the driving chip of the power supply normally outputs a driving signal, so that the power supply is started and the output voltage Vout is normally established. The backup power source in this embodiment may be various battery power sources.
When the control circuit 32 judges that the output voltage of the AC/DC power supply is higher than the output voltage of the standby power supply which supplies power currently according to the sampling result, the output voltage set by the AC/DC power supply is adjusted back to the normal output voltage value from the target voltage value.
During the power-off recovery process of the AC/DC power supply, the output voltage of the AC/DC power supply may fluctuate repeatedly, and when the control circuit 32 detects again through the sampling result that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply currently supplying power, the output voltage set by the AC/DC power supply is reset to the target voltage value larger than the output voltage of the standby power supply. The control circuit 32 may thus control the AC/DC power supply output voltage to fluctuate repeatedly around the standby supply voltage in accordance with the sampling results, as shown in fig. 4. Until the power supply switch of the standby power supply voltage is switched off, all system loads are borne by the AC/DC power supply, and the output voltage of the AC/DC power supply does not fluctuate any more and is restored to a normal value.
The sampling circuit 31 in this embodiment may specifically sample at least one of the output voltage and the current of the AC/DC power supply. And the specific sampling circuit and sampling rule can be flexibly set according to the actual application scene. For example, referring to fig. 5, the sampling circuit 31 may specifically include a main sampling circuit 311 and an auxiliary sampling circuit 312. The main sampling circuit 311 may be specifically configured to sample an output voltage of the AC/DC power supply, and the auxiliary sampling circuit 312 may be specifically configured to sample an output voltage or a current of the AC/DC power supply, and adjust an output of the main sampling circuit 311 according to a sampling result. The following description will take the example of the auxiliary sampling circuit 312 sampling the output voltage or current of the AC/DC power supply.
Referring to fig. 6, the main sampling circuit 311 in this example includes a first main voltage-dividing sub-circuit 3111 and a second main voltage-dividing sub-circuit 3112 connected in series, the first main voltage-dividing sub-circuit 3111 is connected to the main output of the flyback transformer of the AC/DC power supply, and the second main voltage-dividing sub-circuit 3112 is grounded; the main circuit output voltage of the flyback transformer is the output voltage of the AC/DC power supply.
The auxiliary sampling circuit 312 includes a first auxiliary voltage division acquisition circuit 3121 and a second auxiliary voltage division acquisition sub-circuit 3122 connected in series, the first auxiliary voltage division acquisition circuit 3121 is connected with an auxiliary circuit output of a flyback transformer of an AC/DC power supply, and the second auxiliary voltage division acquisition sub-circuit is grounded 3122;
the second auxiliary voltage division collection sub-circuit 3122 is connected to the second main voltage division collection sub-circuit 3112 through a single-pass circuit, when the voltage of the second main voltage division collection sub-circuit 3112 is higher than that of the second auxiliary voltage division collection sub-circuit 3122, the single-pass circuit is turned on, and at this time, the second auxiliary voltage division collection sub-circuit 3122 is connected to the second main voltage division collection sub-circuit 3112 in parallel. The voltage of the second main voltage-dividing sampling sub-circuit 3112 is the output voltage of the output terminal of the sampling circuit, and is input to the comparison circuit of the control circuit 32.
The control circuit 32 includes a comparison circuit 321, and two input terminals of the comparison circuit 321 are respectively connected to the output terminal of the sampling circuit 31 (i.e., the point a of the second main voltage-dividing and collecting sub-circuit 3112) and the reference voltage Vref. The comparison circuit 321 compares the output voltage of the sampling circuit 31 with the reference voltage Vref, and when the output voltage is smaller than the reference voltage, determines that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply currently supplying power, sends a boost voltage control signal to the AC/DC power supply control terminal, and sets the output voltage set by the AC/DC power supply as a target voltage value. And otherwise, judging that the output voltage of the AC/DC power supply is higher than the output voltage of the standby power supply which supplies power currently, sending a voltage-raising back-off control signal to the AC/DC power supply control end, and returning the output voltage set by the AC/DC power supply from the target voltage value to the normal output voltage value.
In fig. 6, the secondary winding of the flyback transformer is used to provide the auxiliary power needed by the secondary side control circuit of the power supply. In this embodiment, a filter capacitor may be further disposed in the main circuit output and the auxiliary circuit output for filtering.
The unidirectional circuit in this embodiment may be implemented by various components capable of implementing unidirectional conduction control, such as a diode, where an anode of the diode is connected to the point a and a cathode of the diode is connected to the point B.
After the mains supply is powered off and recovered for a short time, when the AC/DC power supply is just started, the standby battery voltage is already added to the main circuit output, but the auxiliary circuit output voltage is not established at the moment, so that the voltage at the point B is lower than the voltage at the point A, the unidirectional conduction circuit is conducted, the second auxiliary voltage division acquisition sub-circuit 3122 is connected with the second main voltage division acquisition sub-circuit 3112 in parallel, the voltage obtained at the point A is lower than the reference Vref voltage, a boost voltage control signal is sent to set the AC/DC power supply output voltage to be a target voltage value higher than the battery voltage, the power supply PWM chip outputs a driving signal, and the main circuit output is established.
Before the main circuit output voltage is lower than the battery voltage, because the main circuit output is not loaded, the auxiliary circuit output voltage is lower, and the condition that the voltage of a point B is lower than the voltage of a point A is ensured in parameter design, and the unidirectional conduction circuit is conducted. In order to ensure that the main circuit output voltage is greater than the voltage of the standby battery when the power supply is just started, if the resistor R1 of the first main voltage division acquisition sub-circuit, the resistor R2 of the second main voltage division acquisition sub-circuit and the resistor R4 of the second auxiliary voltage division acquisition circuit are arranged, the relationship among R1, R2, R4 and the reference voltage Vref needs to satisfy the following sub-requirements:
vbat is the output voltage of the standby power supply; vref equals the output voltage of the AC/DC power supply multiplied by
R2// R4 is the resistance of the parallel connection of the resistors R2 and R4.
Therefore, when the AC/DC power supply is normally started, the main circuit output voltage is greater than the voltage of the standby battery, the main circuit output of the power supply is loaded, the auxiliary circuit voltage rises, the voltage at the point B is higher than the voltage at the point A, the one-way conduction circuit is turned off, and the main circuit output voltage meets the following relational expression and is lower than the voltage of the standby battery.
At this time, because the main circuit voltage is lower than the battery voltage, the main circuit output is not loaded, the auxiliary circuit output voltage is reduced, the one-way conduction circuit is conducted again, and the first main branch voltage acquisition sub-circuit 3121 participates in the sampling network of the main circuit output again, so that the main circuit output voltage is increased and loaded again after being higher than the battery voltage. This begins a repetitive process in which the main output voltage continuously fluctuates around the battery voltage until switch S1 in fig. 1 opens to disconnect the backup battery from the dc bus on the system. At this time, because the AC/DC power supply is loaded, the output voltage of the auxiliary circuit is higher, the unidirectional conduction circuit is cut off, and the output of the main circuit restores to the normal voltage.
Fig. 7 is a schematic diagram of another sampling circuit of the present embodiment.
The main sampling circuit 311 includes a first main divided-voltage collecting sub-circuit 3111 and a second main divided-voltage collecting sub-circuit 3112 connected in series, the first main divided-voltage collecting sub-circuit 3111 is connected with a main output of a power transformer of an AC/DC power supply, and the second main divided-voltage collecting sub-circuit 3112 is grounded;
the auxiliary sampling circuit 312 includes a current collector 31211, a voltage allocation sub-circuit 31213, and a switch control sub-circuit 31212, the current collector 31211 is connected in series with a load on the main output of the power transformer of the AC/DC power supply, the voltage allocation sub-circuit 31213 is connected in parallel with the second main voltage division collecting sub-circuit 3112, and the voltage allocation circuit is provided with a turn-off switch; the input end of the switch control sub-circuit 31212 is connected to the current collector 31211 and the switch reference voltage, and the output end is connected to the turn-off switch, which compares the current collector with the switch reference voltage, and when the comparison result is smaller than the switch reference voltage, the turn-off switch is turned on, and at this time, the voltage adjusting sub-circuit 31213 is connected in parallel to the second main divided-voltage collecting sub-circuit 3112. The point a in fig. 7 is still the output of the sampling circuit 31.
The control circuit comprises a comparison circuit 321, two input ends of the comparison circuit 321 are respectively connected with an output end of the sampling circuit 31 and a reference voltage Vref, the output voltage of the sampling circuit 31 is compared with the reference voltage Vref, when the output voltage is smaller than the reference voltage, the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which is currently supplied with power, a voltage boosting control signal is sent to the control end of the AC/DC power supply, and the output voltage set by the AC/DC power supply is set to be a target voltage value. And otherwise, judging that the output voltage of the AC/DC power supply is higher than the output voltage of the standby power supply which supplies power currently, sending a voltage-regulating control signal to the AC/DC power supply control end, and regulating the output voltage set by the AC/DC power supply from the target voltage value to the normal output voltage value.
After the mains supply is recovered after power failure, the output of the AC/DC power supply is not established, at the moment, the output current of the power supply is zero, the switch control sub-circuit 31212 controls the switch to be switched on, therefore, the voltage obtained at the point A is lower than Vref voltage, the power supply PWM chip outputs a driving signal, and the output of the main circuit is established.
Before the output voltage of the main circuit is lower than the voltage of the battery, the switch-off switch is always conducted because the output of the main circuit is not loaded. In order to ensure that the output voltage is greater than the voltage of the standby battery when the power supply is just started, the resistor R11 of the first main voltage division collecting sub-circuit, the resistor R21 of the second main voltage division collecting sub-circuit, the resistor R31 of the voltage adjusting sub-circuit and the reference voltage VrefThe following relationships are ensured:
v in the above formulabatOutputting voltage for a backup power supply (battery); vrefEqual to the output voltage of the AC/DC power supply multiplied by
R21// R31 is the resistance of the parallel connection of the resistors R21 and R31.
Therefore, when the power supply is normally started, the output voltage of the main circuit is greater than the voltage of the battery, the output voltage of the main circuit of the power supply is loaded, the switch control sub-circuit 31212 controls the turn-off switch to be turned off, and the output voltage of the main circuit meets the following relational expression and is lower than the voltage of the battery.
At this time, because the voltage of the main circuit is lower than the voltage of the standby battery, the main circuit output is not loaded, the switch is turned off and turned on again, and the voltage adjusting sub-circuit 31213 participates in the sampling network output by the main circuit again, so that the voltage output by the main circuit rises and is loaded again after being higher than the voltage of the battery. This begins a repetitive process in which the main output voltage continuously fluctuates around the backup battery voltage until switch S1 in fig. 1 opens to disconnect the backup battery from the dc bus on the system. At this time, the power supply is loaded, the turn-off switch is turned off, and the main circuit outputs the recovered normal voltage.
Based on the power restoration control circuit, the embodiment further provides a power circuit, which includes an AC/DC power supply, a standby power supply, and the power restoration control circuit as described above;
the standby power supply is connected with the output end of the AC/DC power supply and is used for supplying power to a load when the AC/DC power supply is powered off; the power restoration control circuit is used for sampling the output of the AC/DC power supply in the power failure restoration process of the AC/DC power supply, and setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply supplying power currently according to the sampling result. And when the output voltage of the AC/DC power supply is judged to be higher than the output voltage of the standby power supply which supplies power currently according to the sampling result, the output voltage set by the AC/DC power supply is set back to be a normal output voltage value. In the AC/DC power supply power-off recovery process, the power supply recovery control circuit controls the power supply output voltage to fluctuate around the standby power supply voltage repeatedly until the power supply switch of the standby power supply voltage is switched off, all system loads are borne by the AC/DC power supply, the AC/DC power supply output voltage does not fluctuate any more, and the AC/DC power supply output voltage recovers to a normal value. Therefore, seamless switching of the standby battery and the AC/DC power supply to the system power supply in the AC/DC power supply power failure recovery process is realized.
Example two:
in order to better understand the present invention, two specific circuit structures are further illustrated below for the solution of the embodiment of the present invention.
Referring to fig. 8, a schematic diagram of a power control circuit is shown, which is a specific circuit structure diagram corresponding to the control block diagram shown in fig. 6. The first main voltage division acquisition sub-circuit 3111 and the second main voltage division acquisition sub-circuit 3112 are respectively R1 and R2, the first auxiliary voltage division acquisition sub-circuit 3121 and the second auxiliary voltage division acquisition sub-circuit 3122 are respectively R3 and R4, the single-phase conduction circuit is a diode VD1, and the auxiliary power supply is SVCC. The comparison circuit 321 is implemented using a voltage error amplifier.
The structure shown in fig. 8 is generally applied to the topology of a flyback transformer. In the figure, the main circuit output refers to a power output loop of the transformer (namely, the voltage of the power supply output to the system), and an auxiliary winding (the output of which is the auxiliary circuit output) is also arranged on the flyback transformer and is used for providing an auxiliary power supply SVCC required by the power supply secondary side control circuit. Capacitors C1 and C2 are filter capacitors for the main and auxiliary circuit outputs, respectively.
The main circuit output voltage is divided and sampled by resistors R1 and R2 and then is sent to a voltage error amplifier. The output of the auxiliary winding is divided by resistors R3 and R4 and then connected to the cathode of a diode VD1, and the anode of VD1 is connected with the point between R1 and R2.
The auxiliary winding output of the flyback transformer has a characteristic that when the main output is loaded, the auxiliary output voltage is higher than that when the main output is unloaded. The present example uses the difference between the main output voltage and the auxiliary output voltage under the different conditions of loading and unloading.
After the mains supply is powered off for a short time and recovered, when the AC/DC power supply is just started, the battery voltage is already added to the main circuit output, but the auxiliary circuit output voltage is not established at the moment, so that the voltage at the point B is lower than the voltage at the point A, the diode VD1 is conducted, the resistor R4 is connected with the resistor R2 in parallel, the voltage obtained at the point A is lower than the Vref voltage, the power supply PWM chip outputs a driving signal, and the main circuit output is established.
Before the main circuit output voltage is lower than the battery voltage, the auxiliary circuit output voltage is lower because the main circuit output is not loaded, and the VD1 is conducted because the voltage at the point B is lower than the voltage at the point A in the parameter design. In order to ensure that the output voltage is greater than the battery voltage when the power supply is just started, the following relation is ensured in parameter design, and R2// R4 in the following relation represents the parallel resistance of R2 and R4.
Therefore, when the power supply is normally started, the main circuit output voltage is greater than the battery voltage, the main circuit output of the power supply is loaded, the voltage of the auxiliary winding rises, the voltage at the point B is higher than the voltage at the point A, the diode VD1 is cut off, and the main circuit output voltage meets the following relational expression and is lower than the battery voltage.
At this time, because the voltage of the main circuit is lower than the voltage of the battery, the load is not carried out on the output of the main circuit, the output voltage of the auxiliary circuit is reduced, the diode VD1 is conducted again, and the R4 participates in the sampling network of the output of the main circuit, so that the output voltage of the main circuit is increased and is carried again after being higher than the voltage of the battery. This begins a repetitive process whereby the main output voltage continuously fluctuates around the battery voltage until switch S1 of fig. 1 opens to disconnect the battery from the dc bus on the system. At this time, because the power supply is loaded, the output voltage of the auxiliary circuit is higher, the VD1 diode is cut off, and the output of the main circuit restores to the normal voltage.
Referring to the schematic diagram of the power control circuit shown in fig. 9, a specific circuit structure diagram corresponding to the control block diagram shown in fig. 7 is shown. The first main voltage division acquisition sub-circuit 3111 and the second main voltage division acquisition sub-circuit 3112 are R11 and R21, the current collector 31211 is R (lscience), the voltage regulator sub-circuit 31213 is R31, the switch control sub-circuit 31212 is a comparator or an operational amplifier, the turn-off switch is a triode VT1, the switch reference voltage is v (lref), and the comparison circuit 321 is implemented by a voltage error amplifier.
After the mains supply is recovered after power failure, the output of the AC/DC power supply is not established, the output current of the power supply is zero at the moment, the VT1 is conducted under the control of the current detection operational amplifier or the comparator, the voltage obtained at the point A is lower than Vref voltage, the PWM chip of the power supply outputs a driving signal, and the output of the main circuit is established.
Before the main output voltage is lower than the battery voltage, VT1 is always on because the main output is not loaded. In order to ensure that the output voltage is greater than the battery voltage when the power supply is just started, the following relation is ensured in parameter design, wherein R21// R31 in the following relation represents the resistance value of the parallel connection of R21 and R31.
Therefore, when the power supply is normally started, the main circuit output voltage is greater than the battery voltage, the main circuit output of the power supply is loaded, the current detection operational amplifier or the comparator controls VT1 to be switched off, and the main circuit output voltage meets the following relational expression and is lower than the battery voltage.
At this time, because the main circuit voltage is lower than the battery voltage, the main circuit output is not loaded, the VT1 is turned on again, and the R3 participates in the sampling network of the main circuit output, so that the output voltage of the main circuit rises and is loaded again after being higher than the battery voltage. This begins a repetitive process in which the main output voltage continuously fluctuates around the battery voltage until switch S1 in fig. 1 opens to disconnect the battery from the dc bus on the system. At this time, the power supply is loaded, VT1 is turned off, and the main circuit output recovers to normal voltage.
By adopting the scheme of the embodiment of the invention, the seamless switching of the standby battery and the AC/DC power supply to the system power supply is realized in the AC/DC power supply power-off recovery process, and compared with the existing oring circuit control mode, the method is simpler, the cost is relatively lower, and the efficiency of the power supply is not obviously influenced.
The foregoing is merely exemplary embodiments of the present invention and is not intended to limit the present invention in any way, and any simple modifications, equivalent changes, combinations, or alterations made to the foregoing embodiments based on the technical spirit of the present invention may still fall within the technical scope of the present invention.
Claims (9)
1. A power supply recovery control circuit is characterized by comprising a sampling circuit and a control circuit, wherein the sampling circuit is connected with the control circuit; the sampling circuit is respectively connected with the output end of the AC/DC power supply and the input end of the control circuit; the output end of the control circuit is connected with the control end of the AC/DC power supply;
the sampling circuit is used for sampling the output of the AC/DC power supply in the power-off recovery process of the AC/DC power supply to obtain a sampling result;
the control circuit is used for setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when judging that the output voltage of the AC/DC power supply is lower than the output voltage of the standby power supply which supplies power currently according to the sampling result;
the sampling circuit comprises a main sampling circuit and an auxiliary sampling circuit;
the main sampling circuit comprises a first main voltage division collecting sub-circuit and a second main voltage division collecting sub-circuit which are connected in series, the first main voltage division collecting sub-circuit is connected with the main circuit output of a flyback transformer of the AC/DC power supply, and the second main voltage division collecting sub-circuit is grounded;
the auxiliary sampling circuit comprises a first auxiliary partial pressure acquisition circuit and a second auxiliary partial pressure acquisition sub-circuit which are connected in series, the first auxiliary partial pressure acquisition circuit is connected with the auxiliary circuit output of a flyback transformer of the AC/DC power supply, and the second auxiliary partial pressure acquisition sub-circuit is grounded;
the second main voltage division acquisition sub-circuit is connected with the second auxiliary voltage division acquisition sub-circuit through a single conduction circuit, and when the voltage of the second main voltage division acquisition sub-circuit is higher than that of the second auxiliary voltage division acquisition sub-circuit, the single conduction circuit is conducted; the voltage of the second main voltage-dividing collecting sub-circuit is the output voltage of the output end of the sampling circuit;
the control circuit comprises a comparison circuit, wherein two input ends of the comparison circuit are respectively connected with an output end of a sampling circuit and a reference voltage Vref, the output voltage of the sampling circuit is compared with the reference voltage Vref, when the output voltage of the sampling circuit is smaller than the reference voltage, the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which supplies power currently, and a voltage boosting control signal is sent to the control end of the AC/DC power supply.
2. The power restoration control circuit according to claim 1, wherein the control circuit is further configured to adjust the output voltage set by the AC/DC power supply back from the target voltage value to a normal output voltage value when the sampling result indicates that the output voltage of the AC/DC power supply is higher than the output voltage of the currently-supplied backup power supply.
3. The power restoration control circuit according to claim 1 or 2, wherein the resistor R1 of the first main voltage division acquisition sub-circuit, the resistor R2 of the second main voltage division acquisition sub-circuit, the resistor R4 of the second auxiliary voltage division acquisition sub-circuit, and the reference voltage VrefThe relationship of (c) is as follows:
the V isbatOutputting a voltage for the backup power supply; the V isrefEqual to the output voltage of the AC/DC power supply multiplied by
(ii) a The resistor R2// R4 is the resistance value of the resistor R2 and the resistor R4 which are connected in parallel.
4. The power restoration control circuit according to claim 1 or 2, wherein the sampling circuit includes a main sampling circuit and an auxiliary sampling circuit;
the main sampling circuit comprises a first main voltage division and collection sub-circuit and a second main voltage division and collection sub-circuit which are connected in series, the first main voltage division and collection sub-circuit is connected with the main circuit output of a power transformer of an AC/DC power supply, and the second main voltage division and collection sub-circuit is grounded; the voltage of the second main voltage-dividing collecting sub-circuit is the output voltage of the output end of the sampling circuit;
the auxiliary sampling circuit comprises a current collector, a voltage adjusting sub-circuit and a switch control sub-circuit, wherein the current collector is connected with a load on a main circuit output of a power transformer of the AC/DC power supply in series, the voltage adjusting sub-circuit is connected with the second main voltage adjusting sub-circuit in parallel, and a turn-off switch is arranged on the voltage adjusting circuit; the input end of the switch control sub-circuit is respectively connected with the current collector and the switch reference voltage, the output end of the switch control sub-circuit is connected with the turn-off switch, the current collector is compared with the switch reference voltage, and when the current collector is smaller than the switch reference voltage, the turn-off switch is closed;
the control circuit comprises a comparison circuit, two input ends of the comparison circuit are respectively connected with an output end of a sampling circuit and a reference voltage Vref, the output voltage of the sampling circuit is compared with the reference voltage Vref, when the output voltage of the sampling circuit is smaller than the reference voltage, the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which supplies power currently, and a voltage boosting control signal is sent to the control end of the AC/DC power supply.
5. The power recovery control circuit of claim 4, wherein the resistor R11 of the first main voltage division collection sub-circuit, the resistor R21 of the second main voltage division collection sub-circuit, the resistor R31 of the voltage regulation sub-circuit, and the reference voltage VrefThe relationship of (a) to (b) is as follows:
the V isbatOutputting a voltage for the backup power supply; the V isrefEqual to the output voltage of the AC/DC power supply multiplied by
Said R21/orR31 is the parallel resistance of R21 and R31.
6. The power restoration control circuit according to claim 1 or 2, wherein the backup power source is a battery.
7. A power supply circuit comprising an AC/DC power supply, a backup power supply, and a power restoration control circuit according to any one of claims 1-6;
the standby power supply is connected with the AC/DC power supply output end and is used for supplying power to a load when the AC/DC power supply is powered off;
the power restoration control circuit is used for sampling the output of the AC/DC power supply in the AC/DC power supply power-off restoration process, and setting the output voltage set by the AC/DC power supply to be larger than the target voltage value of the output voltage of the standby power supply when the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply supplying power currently according to the sampling result.
8. A power restoration control method, wherein the power supply is a communication power supply, and the method comprises the following steps:
in the AC/DC power supply power-off recovery process, sampling the output of the AC/DC power supply by using a sampling circuit;
when the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which supplies power currently according to the sampling result, the output voltage set by the AC/DC power supply is set to be a target voltage value which is larger than the output voltage of the standby power supply; wherein the content of the first and second substances,
the sampling circuit comprises a main sampling circuit and an auxiliary sampling circuit;
the main sampling circuit comprises a first main voltage division collecting sub-circuit and a second main voltage division collecting sub-circuit which are connected in series, the first main voltage division collecting sub-circuit is connected with the main circuit output of a flyback transformer of the AC/DC power supply, and the second main voltage division collecting sub-circuit is grounded;
the auxiliary sampling circuit comprises a first auxiliary partial pressure acquisition circuit and a second auxiliary partial pressure acquisition sub-circuit which are connected in series, the first auxiliary partial pressure acquisition circuit is connected with the auxiliary circuit output of a flyback transformer of the AC/DC power supply, and the second auxiliary partial pressure acquisition sub-circuit is grounded;
the second main voltage division acquisition sub-circuit is connected with the second auxiliary voltage division acquisition sub-circuit through a single conduction circuit, and when the voltage of the second main voltage division acquisition sub-circuit is higher than that of the second auxiliary voltage division acquisition sub-circuit, the single conduction circuit is conducted; the voltage of the second main voltage-dividing collecting sub-circuit is the output voltage of the output end of the sampling circuit;
the control circuit comprises a comparison circuit, two input ends of the comparison circuit are respectively connected with an output end of the sampling circuit and reference voltage Vref, the output voltage of the sampling circuit is compared with the reference voltage Vref, when the output voltage of the sampling circuit is smaller than the reference voltage, the output voltage of the AC/DC power supply is judged to be lower than the output voltage of the standby power supply which is supplied with power currently, and a voltage boosting control signal is sent to the control end of the AC/DC power supply.
9. The power restoration control method according to claim 8, further comprising:
and when the output voltage of the AC/DC power supply is higher than the output voltage of the standby power supply which supplies power currently according to the sampling result, the output voltage set by the AC/DC power supply is set back to be a normal output voltage value.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610465364.6A CN107546838B (en) | 2016-06-23 | 2016-06-23 | Power supply circuit, power supply recovery control circuit and method |
| PCT/CN2017/087902 WO2017219887A1 (en) | 2016-06-23 | 2017-06-12 | Power source circuit, and power source recovery control circuit and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201610465364.6A CN107546838B (en) | 2016-06-23 | 2016-06-23 | Power supply circuit, power supply recovery control circuit and method |
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| CN107546838A CN107546838A (en) | 2018-01-05 |
| CN107546838B true CN107546838B (en) | 2022-07-15 |
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| CN201610465364.6A Active CN107546838B (en) | 2016-06-23 | 2016-06-23 | Power supply circuit, power supply recovery control circuit and method |
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| WO (1) | WO2017219887A1 (en) |
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| CN109450049A (en) * | 2018-12-28 | 2019-03-08 | 郑州云海信息技术有限公司 | A kind of power supply unit and method of supplying power to |
| CN109586926A (en) * | 2019-01-16 | 2019-04-05 | 珠海格力电器股份有限公司 | Data transmission set and its control method |
| CN110739736B (en) * | 2019-09-10 | 2023-06-27 | 宁波中车新能源科技有限公司 | Super capacitor floodgate machine stand-by power supply circuit |
| CN114327236B (en) * | 2021-12-13 | 2024-04-09 | 昌辉汽车电器（黄山）股份公司 | Judgment method for adding voltage correction factor when singlechip receives AD signal |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH10309045A (en) * | 1997-05-07 | 1998-11-17 | Sony Corp | Standby power unit |
| CN2471015Y (en) * | 2000-12-14 | 2002-01-09 | 上海思源电气有限公司 | Frequency-variable resonant power supply |
| CN201274412Y (en) * | 2008-06-10 | 2009-07-15 | 北京意科通信技术有限责任公司 | Power control module in high frequency switch rectifying electric power and solar energy mixed switch cabinet |
| CN102185358A (en) * | 2011-05-24 | 2011-09-14 | 深圳茂硕电子科技有限公司 | Simple and practical movable uninterruptible power supply |
| CN103078615A (en) * | 2011-12-29 | 2013-05-01 | 上海寰创通信科技股份有限公司 | Delay circuit and method thereof |
| CN102811535B (en) * | 2012-06-28 | 2018-03-27 | 深圳市舜田电子技术有限公司 | Ultra-High Efficiency LED constant current power supply based on single stage shift controlled rectification |
| US8976548B2 (en) * | 2012-08-22 | 2015-03-10 | Sensus USA, Inc. | Method and apparatus for AC-to-DC power conversion |
| CN103715914B (en) * | 2012-10-08 | 2016-11-23 | 北京动力源科技股份有限公司 | Controlled rectification/the inversion controlling method of a kind of band power feedforward, device and a kind of high voltage converter |
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2016
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| WO2017219887A1 (en) | 2017-12-28 |
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