CN216595294U - Input voltage sampling circuit and charger with same - Google Patents
Input voltage sampling circuit and charger with same Download PDFInfo
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- CN216595294U CN216595294U CN202123073149.7U CN202123073149U CN216595294U CN 216595294 U CN216595294 U CN 216595294U CN 202123073149 U CN202123073149 U CN 202123073149U CN 216595294 U CN216595294 U CN 216595294U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model provides an input voltage sampling circuit which is connected with a secondary winding of a transformer in parallel and used for collecting input voltage of the primary winding of the transformer, wherein the input voltage sampling circuit comprises a first switch, a first capacitor, a first resistor and a second resistor, the first switch is connected with the first capacitor in series and then connected with the secondary winding of the transformer in parallel, a first end of the first resistor and a second end of the second resistor after being connected in series is connected with a series midpoint of the first switch and the first capacitor, a second end of the first resistor and a second end of the second resistor are connected with direct current voltage, and the middle end of the first resistor and the second resistor is an output end of the input voltage sampling circuit. The input voltage sampling circuit provided by the utility model has the advantages of simple circuit structure, small occupied area and reduced cost.
Description
Technical Field
The utility model relates to the technical field of electronic circuits, in particular to an input voltage sampling circuit and a charger with the same.
Background
With the application of the planar transformer, the volume and weight of the transformer in the charger are greatly reduced. The electrolytic capacitor in the charger needs to store energy of power frequency, and the volume of the electrolytic capacitor is not reduced, so that the volume of the electrolytic capacitor becomes a bottleneck for reducing the volume of the charger. In order to reduce the capacity and the volume of the electrolytic capacitor, the charger needs to output different powers according to different input voltages, for example, under the condition of a 110V power grid, the charger can only output smaller power; under 220V grid conditions, the charger can output large power. Therefore, detecting the input voltage becomes one key point in order to distinguish between outputting different powers.
As shown in fig. 1, after the alternating voltage Uin is rectified by the rectifier circuit 11, a direct current voltage is obtained on the capacitor C1, the comparator 121 samples the voltage on the capacitor C1, the voltage is compared with the reference voltage Vref, a high-low logic signal is obtained on the primary side, then the logic signal is transmitted to the control circuit 13 on the secondary side of the transformer T1 through the optocoupler 122, and the control circuit 13 judges the level of the input voltage according to the logic signal, so as to determine the magnitude of the output power. The sampling circuit shown in fig. 1 samples voltage on the primary side of the transformer T1, the circuit is relatively complex, the area of the PCB board occupied by the primary side is increased, the reduction in size and weight of the charger is prevented, and the comparator 121 in the sampling circuit 12 on the primary side increases the power consumption on the primary side, thereby increasing the standby power consumption of the charger.
As shown in fig. 2, an additional auxiliary winding Ns2 is added to the secondary side of the transformer T1 to realize the detection of the input voltage, and the same-name end of the auxiliary winding Ns2 is opposite to the secondary winding Ns 1. When the switching tube S1 is turned on, the voltage across the primary winding Np is Vin, and at this time the voltage across the secondary winding Ns1 is-Vin × Ns1/Np, the diode D5 is turned off, and the diode D6 is turned on, and the voltage across the auxiliary winding Ns2 is Vin × Ns2/Np, proportional to the input voltage Vin, and is a positive voltage. The positive voltage is sent to the control circuit 23 through the sampling circuit 22, and the control circuit 23 can judge the level of the input voltage by comparing the voltage with the internal voltage reference, so that the charger can output different powers. The sampling circuit shown in fig. 2 needs to add an additional auxiliary winding, which increases the complexity of the transformer, reduces the utilization rate of the transformer window, and increases the cost of the transformer.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems, the utility model provides an input voltage sampling circuit which is simple in circuit structure, small in occupied board area and low in cost.
In order to achieve the above object, the present invention provides an input voltage sampling circuit, which is connected in parallel with a secondary winding of a transformer to collect an input voltage of a primary winding of the transformer, and includes a first switch, a first capacitor, a first resistor, and a second resistor, wherein the first switch is connected in series with the first capacitor and then connected in parallel with the secondary winding of the transformer, a first end of the first resistor connected in series with the second resistor is connected to a midpoint of the first switch connected in series with the first capacitor, a second end of the first resistor connected in series with the second resistor is connected to a dc voltage, and a middle end of the first resistor is an output end of the input voltage sampling circuit.
In an embodiment of the present invention, the secondary winding of the transformer is connected in series with a second switch, the secondary winding of the transformer is connected to a load through the second switch, and a switching state of the first switch is opposite to a switching state of the second switch.
In an embodiment of the present invention, an output end of the input voltage sampling circuit is connected to a control circuit, and the dc voltage is a supply voltage of the control circuit.
In an embodiment of the utility model, the control circuit is connected to a USB interface, and the USB interface is connected to the secondary winding of the transformer in parallel and connected to the load.
The utility model also provides a charger, comprising,
a transformer, a primary winding of which receives an input voltage, a secondary winding of which is connected to a load,
the input voltage sampling circuit comprises a first switch, a first capacitor, a first resistor and a second resistor, wherein the first switch is connected with the first capacitor in series and then connected with a secondary winding of the transformer in parallel, a first end of the first resistor connected with the second resistor in series is connected with a series midpoint of the first switch and the first capacitor, a second end of the first resistor connected with the second resistor in series is connected with a direct current voltage, and a middle end of the middle end is an output end of the input voltage sampling circuit and outputs an input voltage sampling signal,
and the control circuit is connected with the output end of the input voltage sampling circuit, receives the input voltage sampling signal, calculates the power grade which can be provided by the charger according to the input voltage sampling signal, and outputs the power grade to the load.
In an embodiment of the present invention, the charger further includes a USB interface, the control circuit is connected to the load through the USB interface, and the load adjusts the power of the load according to a power level that can be provided by the charger.
In an embodiment of the utility model, the charger further includes a DC/DC converter, and the DC/DC converter transmits electric energy by using the transformer.
In a specific embodiment of the present invention, the DC/DC converter is a flyback converter, and the transformer is disposed in the flyback converter.
In an embodiment of the utility model, the charger further includes an AC/DC converter, and the AC/DC converter transmits electric energy by using the transformer.
In an embodiment of the utility model, the AC/DC converter includes a rectifier converter and a DC/DC converter, the rectifier converter and the DC/DC converter are connected in series, and the transformer is disposed in the DC/DC converter.
According to the input voltage sampling circuit provided by the utility model, under the condition that an extra winding of the transformer is not added, the original winding is utilized, the negative voltage which is in a fixed proportion with the input voltage of the primary side of the transformer is obtained in the sampling circuit, then the voltage is raised according to the reference power supply voltage of the protocol chip, and the information of the input voltage of the charger is obtained through sampling, so that the defects of complex circuit, large occupied area of a board, high standby power consumption and high cost in the prior art are reduced, meanwhile, the defects of adding the winding of the transformer, increasing the complex structure of the transformer and increasing the cost in the prior art are avoided, the sampling of the input voltage can be realized by using a very simple circuit, and the sampling circuit has economic and practical values.
Drawings
Fig. 1 is a schematic diagram of a prior art sampling circuit.
Fig. 2 is a schematic diagram of another prior art sampling circuit.
Fig. 3 is a schematic structural diagram of an input voltage sampling circuit according to the present invention.
Fig. 4 is a schematic circuit structure diagram of the charger provided by the present invention.
Fig. 5 is a schematic circuit structure diagram of the charger according to the present invention.
Description of reference numerals:
11-input rectifying circuit, 12, 22, 32, 42, 52-input voltage sampling circuit, 13, 23, 33, 43, 53-control circuit, 14, 34, 44, 54-USB interface, 121-comparator, 122-optical coupler, 411, 511-flyback converter, 512-AC/DC converter and 51-power circuit.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
It should be understood that the drawings attached hereto are only for the purpose of illustration and description, and are not intended to limit the scope of the present invention, which is defined by the claims, so as not to limit the scope of the present invention.
The utility model provides an input voltage sampling circuit, as shown in fig. 3, this input voltage sampling circuit 32 is parallelly connected with the secondary winding Ns of transformer T1, gathers the input voltage Vin of the primary winding Np of transformer T1, input voltage sampling circuit 32 includes switch S3, electric capacity C3, resistance R1, resistance R2 and direct current voltage Vdd, and switch S3 and electric capacity C3 are parallelly connected with secondary winding Ns after establishing ties, and the one end of resistance R1 is connected between diode D4 and electric capacity C3, and the other end is connected with direct current voltage Vdd again after establishing ties with second resistance R2, and the middle series connection point of resistance R1 and resistance R2 is input voltage sampling circuit 32' S output P. The secondary winding Ns of the transformer is connected with the switch S2 in series to output an output voltage Vo. The switch states of the switch S3 and the switch S2 are complementary.
The voltage across the primary winding Np is Vin, at this time, the voltage induced across the secondary winding Ns is Vin × Ns/Np, the switch S2 is turned off, the switch S3 is turned on, and the voltage across the secondary winding Ns is applied across the capacitor C3 through the switch S3, so that the voltage across the capacitor C3 is Vin × Ns/Np, which is proportional to the input voltage Vin. Input voltage sampling signal output by output end P
When the switch S2 is turned on, the secondary winding of the transformer is coupled to the output voltage Vo, and the switch S3 is turned off.
As shown in fig. 4, the input voltage sampling circuit 42 of the present invention is applied to a flyback converter 411 to form a charger, where the flyback converter 411 includes a transformer T1, a primary winding Np of the transformer T1 is connected in series with a switch S1 and then connected in parallel with an input voltage Vin, and the input voltage Vin is generally a rectified dc voltage. Two ends of the secondary winding Ns of the transformer T1 are rectified and filtered by a diode D5 and a capacitor C2, and then are connected in parallel with the USB interface 44, where the USB interface 44 is, for example, TYPE C. The anode of the diode D5 is connected to the dotted terminal of the secondary winding Ns, one end of the capacitor C2 is connected to the cathode of the diode D5, the other end of the capacitor C2 is connected to the dotted terminal of the secondary winding Ns, the USB interface 44 is connected in parallel to the capacitor C2, the USB interface 44 is used for being connected to a load in a butt joint manner and transmitting data, and the USB interface 44 can support any suitable TYPE C protocol, where the load is any suitable electronic device.
The input voltage sampling circuit 42 is also connected in parallel to two ends of the secondary winding Ns of the transformer T1, the input voltage sampling circuit 42 includes a diode D6, a capacitor C3, a resistor R1, a resistor R2 and a dc voltage Vdd, a cathode of the diode D6 is connected to the dotted end of the secondary winding Ns, an anode of the diode D6 is connected to one end of the capacitor C3, the other end of the capacitor C3 is connected to the dotted end of the secondary winding Ns, one end of the resistor R1 is connected between the diode D4 and the capacitor C3, and the other end of the resistor R2 is connected in series and then connected to the dc voltage Vdd. An input end of the control circuit 43 is connected to the output end P of the input voltage sampling circuit 42, and an output end of the control circuit 43 is connected to an input end of the USB interface 44. In this embodiment, the control circuit 43 includes a protocol chip, which supports TYPE C protocol, and the protocol chip may use, for example, WT6636F, and the dc voltage Vdd may be a reference power supply voltage of the protocol chip itself.
As shown in fig. 4, when the switch S1 on the primary side of the transformer T1 is turned off, the diode D5 is turned on, the voltage on the secondary winding Ns is clamped by the output voltage Vo, and the diode D6 is turned off; when the switching tube S1 on the primary side of the transformer T1 is turned on, the voltage on the primary winding Np is Vin, at this time, a negative voltage of-Vin × Ns/Np is induced on the secondary winding Ns, the diode D5 is turned off, the diode D6 is turned on in the forward direction, and the voltage on the secondary winding Ns is loaded on the two ends of the capacitor C3 through the diode D6, so that the voltage on the two ends of the capacitor C3 is-Vin × Ns/Np, which is proportional to the input voltage Vin and is a negative dc voltage. Thus, the output terminal P outputs the input voltage sampling signal
The input voltage sampling signal Up is transmitted to the protocol chip in the control circuit 43, the input interface of the protocol chip cannot bear negative pressure, and the input voltage sampling signal Up can be ensured within the acceptable safety range of the input interface of the protocol chip by reasonably configuring the resistance values of the resistor R1 and the resistor R2. The protocol chip compares the input voltage sampling signal Up with a given reference voltage, determines the level of the input voltage Vin, calculates the power level which can be provided by the charger, provides the power level which can be provided by the charger to a load through a USB interface 44, and the load adjusts the required power according to the power level which can be provided by the charger. The protocol chip can also calculate the input voltage of the primary side of the transformer T1 according to the input voltage sampling signal Up
As shown in fig. 5, the input voltage sampling circuit 52 is applied to a charger, the main power circuit 51 of the charger includes an AC/DC converter 512 and a DC/DC converter 511, after an AC voltage Uin is rectified by the AC/DC converter 512, a DC voltage Vin is obtained at a primary side of a transformer T1 in the DC/DC converter 511, the control circuit 53 calculates a power level that can be provided by the charger according to an input voltage sampling signal Up output by the input voltage sampling circuit 52, and transmits the power level that can be provided by the charger to a load, and the load adjusts the power requested by the charger according to the power level that can be provided by the charger.
According to the input voltage sampling circuit provided by the utility model, under the condition that an extra winding of a transformer is not added, the original winding is utilized to sample to obtain the negative voltage which is in a fixed proportion with the input voltage, then the reference power supply voltage of a protocol chip is used for boosting, and the input voltage sampling signal is obtained through sampling, so that the defects of complex circuit, large occupied area, high standby power consumption and high cost in the prior art are overcome, and the defects of complex structure and cost increase of the transformer due to the addition of the winding of the transformer in the prior art are also overcome.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the utility model. Those skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. An input voltage sampling circuit is connected in parallel with a secondary winding of a transformer to collect input voltage of the primary winding of the transformer and is characterized by comprising a first switch, a first capacitor, a first resistor and a second resistor, wherein the first switch is connected in series with the first capacitor and then connected in parallel with the secondary winding of the transformer, a first end of the first resistor, which is connected in series with the second resistor, is connected with a series midpoint of the first switch and the first capacitor, a second end of the first resistor is connected with direct-current voltage, a middle end of the first resistor is an output end of the input voltage sampling circuit, and an input voltage sampling signal is output by the output end.
2. The input voltage sampling circuit of claim 1, wherein the secondary winding of the transformer is connected in series with a second switch, the secondary winding of the transformer being connected to a load through the second switch, the switching state of the first switch being opposite to the switching state of the second switch.
3. The input voltage sampling circuit of claim 2, wherein the output of the input voltage sampling circuit is connected to a control circuit, and the dc voltage is a supply voltage of the control circuit.
4. The input voltage sampling circuit of claim 3, wherein the control circuit is connected to a USB interface, the USB interface being connected in parallel with the secondary winding of the transformer and connected to the load.
5. A charger, characterized by comprising,
a transformer, a primary winding of which receives an input voltage, a secondary winding of which is connected to a load,
the input voltage sampling circuit comprises a first switch, a first capacitor, a first resistor and a second resistor, wherein the first switch is connected with the first capacitor in series and then connected with a secondary winding of the transformer in parallel, a first end of the first resistor connected with the second resistor in series is connected with a series midpoint of the first switch and the first capacitor, a second end of the first resistor connected with the second resistor in series is connected with a direct current voltage, and a middle end of the middle end is an output end of the input voltage sampling circuit and outputs an input voltage sampling signal,
and the control circuit is connected with the output end of the input voltage sampling circuit, receives the input voltage sampling signal, calculates the power grade which can be provided by the charger and outputs the power grade to the load.
6. The charger of claim 5, further comprising a USB interface, wherein the control circuit is coupled to the load via the USB interface, and wherein the load adjusts its power according to a power level that the charger is capable of providing.
7. The electrical charger according to claim 6, comprising a DC/DC converter, wherein the DC/DC converter is configured to transmit electrical energy using the transformer.
8. The charger of claim 7, wherein the DC/DC converter is a flyback converter, and the transformer is disposed in the flyback converter.
9. The charger of claim 6, comprising an AC/DC converter, wherein the AC/DC converter utilizes the transformer for power transmission.
10. The charger according to claim 9, wherein said AC/DC converter comprises a rectifying converter and a DC/DC converter, said rectifying converter and said DC/DC converter being connected in series, said transformer being disposed in said DC/DC converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123073149.7U CN216595294U (en) | 2021-12-08 | 2021-12-08 | Input voltage sampling circuit and charger with same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123073149.7U CN216595294U (en) | 2021-12-08 | 2021-12-08 | Input voltage sampling circuit and charger with same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216595294U true CN216595294U (en) | 2022-05-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123073149.7U Active CN216595294U (en) | 2021-12-08 | 2021-12-08 | Input voltage sampling circuit and charger with same |
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| CN (1) | CN216595294U (en) |
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2021
- 2021-12-08 CN CN202123073149.7U patent/CN216595294U/en active Active
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