Cross reference

This patent application claims the priority of the Chinese application 201720629305.8, filed May 27, 2017, which is incorporated by reference herein, in the entirety and for all purposes .

Technical Field

The present invention relates to the field of charging, and in particular relates to a charging circuit for a socket. In addition, the present invention further relates to a socket for which the charging circuit is adopted.

Background Art

With the rapid development of technologies, various smart devices have become indispensable tools in people's daily life. Since the power consumption of smart devices is generally very high, users often need to charge their smart devices.

In most cases, users fail to remove their smart devices from a socket in time after they connect their smart devices to the socket to charge their smart devices. In this way, even if their smart devices are fully charged, the socket will still continuously transmit power to their smart devices, and then the temperature of their smart devices will rise and trickle charging will be formed. The temperature rise and trickle charging will greatly damage the batteries in their smart devices .

Summary

In view of this, the present invention provides a charging circuit for a socket and the socket thereof so as to cut off the power supply to a fully charged device in time.

On the one hand, the present invention provides a charging circuit for a socket and the charging circuit comprises a first rectifier circuit, a first filter circuit, a DC-to-DC conversion circuit, a master control circuit, a second rectifier circuit, a second filter circuit, a control circuit, and a power output circuit .

The input end of the first rectifier circuit is connected to an AC power supply. The input end of the first filter circuit is connected to the output end of said first rectifier circuit. The input end of the DC-to-DC conversion circuit is connected to the output end of said first filter circuit. The master control circuit is connected to said DC-to-DC conversion circuit and is used to control the voltage conversion value of said DC-to-DC conversion circuit. The input end of the second rectifier circuit is connected to the output end of said DC-to-DC conversion circuit. The input end of the second filter circuit is connected to the output end of said second rectifier circuit. The input end of the control circuit is connected to the output end of said second filter circuit. The power output circuit is connected to the output end of said control circuit. Said control circuit is used to cut off said power output circuit when the detected current in said power output circuit is less than or equal to a preset threshold.

Through the setting of the control circuit, the charging circuit according to the present embodiment automatically cuts off the power output circuit to stop supplying power to the device connected to the charging circuit after the control circuit detects that the current in the power output circuit is less than or equal to a preset threshold. In this way, damage, which is caused because the device is not removed in time after the device is fully charged, can be avoided.

According to the above-mentioned charging circuit, alternatively, said control circuit comprises a detection circuit, a MOS transistor, a first resistor, and a second resistor.

The detection circuit has a first end, a second end, and at least a sampling end, and said sampling end is connected to said power output circuit. The drain electrode of the MOS transistor is connected to the output end of said second filter circuit, the source electrode is connected to said power output circuit, and the gate electrode is connected to said second end so as to cut off said power output circuit by turning off said MOS transistor. One end of the first resistor is connected between the source electrode of said MOS transistor and said power output circuit, and the other end is connected to the first end of said detection circuit. One end of the second resistor is connected between said first resistor and said first end, and the other end is grounded.

According to the above-mentioned charging circuit, alternatively, there is at least one sampling resistor between said sampling end and said power output circuit. According to the above-mentioned charging circuit, alternatively, said detection circuit comprises a determination sub-circuit and a delay sub-circuit.

The determination sub-circuit comprises said first end and said sampling end and is used to determine whether the current in said power output circuit is less than or equal to the preset threshold. The delay sub-circuit comprises said second end, is connected to said determination sub-circuit and said power output circuit, respectively, and is used to cut off said power output circuit after a preset delay time if said determination sub-circuit detects that the current in said power output circuit is less than or equal to the preset threshold.

After the determination sub-circuit detects that the current in the power output circuit is less than or equal to the preset threshold, the delay sub-circuit is triggered and a preset time delay is implemented to ensure that the power output circuit is cut off only after the device is really in a saturated state.

According to the above-mentioned charging circuit, alternatively, said control circuit further comprises: a charging state indication circuit, with one end connected to a third end of said detection circuit and the other end grounded. The charging state indication circuit is used to remind the user of whether the device is fully charged.

According to the above-mentioned charging circuit, alternatively, said charging state indication circuit comprises a current- limiting resistor and an LED. One end of the current-limiting resistor is connected to said third end. The positive electrode of the LED is connected to the other end of said current-limiting resistor and the negative electrode is grounded.

According to the above-mentioned charging circuit, alternatively, said control circuit further comprises a first filter capacitor. One end of the first filter capacitor is connected to the junction of said first resistor, said second resistor, and said detection circuit, and the other end is grounded.

According to the above-mentioned charging circuit, alternatively, said control circuit further comprises a second filter capacitor and a third resistor. One end of the second filter capacitor is connected to a fourth end of said detection circuit, and the other end is grounded. One end of the third resistor is connected to the junction of said second filter capacitor and said fourth end, and the other end is connected to an AC power supply.

The second filter capacitor and the third resistor are used to provide a reference voltage for the detection circuit.

Alternatively, the above-mentioned charging circuit further comprises an RCD snubber circuit. The input end of the RCD snubber circuit is connected to the output end of said first filter circuit and the output end is connected to the input end of said DC-to-DC conversion circuit. The RCD snubber circuit can be used for overload, overvoltage, and undervoltage protection.

On the other hand, the present invention provides a socket, which alternatively comprises the above-mentioned charging circuit .

Through the setting of the control circuit in the socket, the control circuit automatically cuts off the power output circuit to stop supplying power to the device connected to the charging circuit after the control circuit detects that the current in the power output circuit is less than or equal to a preset threshold. In this way, damage, which is caused because the device is not removed in time after the device is fully charged, can be avoided.

Brief Description of the Drawings

The following will describe in detail the embodiments of the present invention by reference to the drawings so that those skilled in the art can have a clearer idea of the above-mentioned and other characteristics and advantages of the present utility model .

Figure 1 shows the structure of the charging circuit according to one embodiment of the present utility model.

Figure 2 shows the structure of the charging circuit according to another embodiment of the present utility model.

Figure 3 shows the structure of the charging circuit according to a third embodiment of the present utility model.

Description of reference numbers in the drawings

10- AC power supply 20- First rectifier 30- First filter circuit circuit

40- RCD snubber 50- DC-to-DC 60- Master control circuit conversion circuit circuit

70- Second 80- Second filter 90- Control circuit rectifier circuit circuit

100- Power output 901- MOS transistor 902- First resistor circuit

903- Second 904- Current- 905- LED

resistor limiting resistor

906- First filter 907- Second filter 908- Third resistor capacitor capacitor

909- Third filter 910- Detection 911- Fourth capacitor circuit resistor

9101- Sampling 9102- Sampling

resistor resistor

Detailed Description

To make clearer the objectives, technical solutions, and advantages of the present utility model, the following gives embodiments to further describe the present invention in detail.

Embodiment 1

The present embodiment provides a charging circuit for a socket.

Figure 1 shows a charging circuit according to the present embodiment. The charging circuit comprises a first rectifier circuit (20), a first filter circuit (30), a DC-to-DC conversion circuit (50), a master control circuit (60), a second rectifier circuit (70), a second filter circuit (80), a control circuit (90), and a power output circuit (100) .

The input end of the first rectifier circuit (20) is connected to an AC power supply (10) and is used to rectify AC into DC. The input end of the first filter circuit (30) is connected to the output end of the first rectifier circuit (20) and is used to filter the ripples of the DC voltage output by the first rectifier circuit (20) . The input end of the DC-to-DC conversion circuit (50) is connected to the output end of the first filter circuit (30) and is used to convert a voltage value. The master control circuit (60) is connected to the DC-to-DC conversion circuit (50) and is used to control the DC-to-DC conversion circuit (50), for example, adjust the voltage value converted by the DC-to-DC conversion circuit (50) . The input end of the second rectifier circuit (70) is connected to the output end of the DC-to-DC conversion circuit (50) and performs the function of secondary rectification. The input end of the second filter circuit (80) is connected to the output end of the second rectifier circuit (70) and performs the function of secondary filtering. The control circuit (90) in the present embodiment is used to cut off the power output circuit (100) when the detected current in the power output circuit (100) is less than or equal to a preset threshold. The power output circuit (100) is used to charge a device.

The first rectifier circuit (20), the first filter circuit (30), the DC-to-DC conversion circuit (50), the master control circuit (60), the second rectifier circuit (70), the second filter circuit (80), and the power output circuit (100) in the present embodiment can be any circuits having the corresponding functions in the prior art, and no details about these circuits will be given here.

Figure 3 shows the realization of the control circuit provided in the present embodiment. The control circuit (90) comprises a detection circuit (910), a MOS transistor (901), a first resistor (902), and a second resistor (903) .

The detection circuit (910) has a first end, a second end, and at least a sampling end, and said sampling end is connected to the power output circuit (100) . The drain electrode of the MOS transistor (901) is connected to the output end of the second filter circuit (80), and the source electrode is connected to the power output circuit (100) . Specifically, the power output circuit (100) can be cut off by turning off the MOS transistor

(901) . One end of the first resistor (902) is connected between the source electrode of the MOS transistor (901) and the power output circuit (100), and the other end is connected to the first end of the detection circuit (910) . One end of the second resistor (903) is connected between the first resistor (902) and the first end, and the other end is grounded. The first resistor

(902) and the second resistor (903) form a bleeder circuit. The second end of the detection circuit (910) is connected to the gate electrode of the MOS transistor (901) so as to cut off the power output circuit (100) by turning off the MOS transistor. Alternatively, there is a fourth resistor (911) between the second end and the gate electrode of the MOS transistor (901) .

In the present embodiment, the sampling end of the detection circuit (910) is used to acquire the sampled current of the power output circuit (100) so as to determine whether the current in the power output circuit (100) is less than or equal to a preset threshold according to the sampling current. In addition, through the connection of the sampling end, the detection circuit (910) can communicate with a device based on the handshake protocol. Thus, the charging mode of a mobile phone can be identified and the output power of a socket can realize the charging effect of the original socket of the device.

As a realization, the detection circuit (910) in the present embodiment can be packaged into a chip and the detection circuit is connected through the pins of the chip. The first end is PIN2, the second end is PIN3, and there are two sampling ends, which are PIN1 and PIN7, respectively. The two sampling ends are connected to the interface data lines (D+, D-) of the power output circuit (100), respectively. Of course, more sampling ends can be set in practical operations, depending on the practical requirements.

There can be one or more sampling resistors between each sampling end and the power output circuit (100) . As a realization, there are two sampling resistors, which are respectively sampling resistors (9101 and 9102), between one sampling end and the power output circuit (100), as shown in Figure 3. Specifically, there is a sampling resistor (9101) between PIN1 and D-, and a sampling resistor (9102) between PIN7 and D+ .

More specifically, the detection circuit (910) in the present embodiment can comprise a determination sub-circuit and a delay sub-circuit. The determination sub-circuit comprises a first end (PIN2) and a sampling end and is used to determine whether the current in the power output circuit (100) is less than or equal to the preset threshold. The delay sub-circuit comprises a second end (PIN3), is connected to the determination sub-circuit and the power output circuit (100), respectively, and is used to cut off the power output circuit (100) after a preset delay time if the determination sub-circuit detects that the current in the power output circuit (100) is less than or equal to the preset threshold. In practical applications, when a device is charged, the device usually undergoes three stages: quick charging, continuous charging, and trickle charging. In the quick charging stage, the battery of the device can be charged to 80% of the capacity. However, the battery still needs to be charged before the battery is fully charged. The charging current in the continuous charging stage gradually decreases to ensure that the battery goes into the critical state of full charge. Trickle charging is micro-current charging, which ensures that the battery is really saturated. In the present embodiment, after the determination sub-circuit detects that the current in the power output circuit (100) is less than or equal to the preset threshold, the delay sub-circuit is triggered and a preset time delay, for example, 30 minutes, is implemented fully to ensure that the power output circuit (100) is cut off only after the device is really in a saturated state.

Alternatively, the control circuit (90) in the present embodiment further comprises a charging state indication circuit One end of the charging state indication circuit is connected to a third end (PIN5) of the detection circuit (910), and the other end is grounded. The charging state indication circuit is used to remind the user of whether the device is fully charged. For example, after the detection circuit (910) determines that the current in the power output circuit (100) is less than or equal to the preset threshold, light is given out to remind the user that the device is fully charged. Of course, the charging state indication circuit can also give out light only after the delay sub-circuit works. Figure 3 shows a specific realization of the charging state indication circuit in the present embodiment. The charging state indication circuit comprises a current-limiting resistor (904) and an LED (905) . The current- limiting resistor (904) is connected the third end (PIN5) of the detection circuit (910), and the positive electrode of the LED (905) is connected to the other end of the current-limiting resistor (904) and the negative electrode is grounded.

Alternatively, the control circuit (90) in the present embodiment further comprises a first filter capacitor (906) . One end of the first filter capacitor is connected to the junction of the first resistor (902), the second resistor (903), and the detection circuit (910), and the other end is grounded. The first filter capacitor (906) is used to filter the current.

Alternatively, the control circuit (90) in the present embodiment further comprises a second filter capacitor (907) and a third resistor (908) . One end of the second filter capacitor (907) is connected to a fourth end (PIN8) of the detection circuit (910), and the other end is grounded. One end of the third resistor (908) is connected to the junction of the second filter capacitor (907) and the fourth end (PIN8), and the other end is connected to an AC power supply. The second filter capacitor (907) and the third resistor (908) jointly provide a reference voltage for the detection circuit (910) so that the detection circuit (910) compares the sampled voltage with the reference voltage to determine whether the current in the power output circuit (100) is less than or equal to the preset threshold .

Alternatively, the control circuit (90) in the present embodiment further comprises a third filter capacitor (909) . One end of the third filter capacitor (909) is connected to a fifth end (PIN6) of the detection circuit (910), and the other end is grounded. The third filter capacitor (909) is used to filter the current .

Alternatively, a sixth end (PIN4) of the detection circuit (910) in the present embodiment is grounded.

Alternatively, the charging circuit in the present embodiment further comprises an RCD snubber circuit (40) . The input end of the RCD snubber circuit (40) is connected to the output end of the first filter circuit (30), and the output end of the RCD snubber circuit (40) is connected to the input end of the DC- to-DC conversion circuit (50) . The RCD snubber circuit (40) can be used for overload, overvoltage, and undervoltage protection.

Through the setting of the control circuit (90), the charging circuit according to the present embodiment automatically cuts off the power output circuit (100) to stop supplying power to the device connected to the charging circuit after the control circuit (90) detects that the current in the power output circuit (100) is less than or equal to the preset threshold. In this way, damage, which is caused because the device is not removed in time after the device is fully charged, can be avoided.

Embodiment 2

The present embodiment provides a specific example of the above- mentioned charging circuit. It should be pointed out that the first rectifier circuit (20), the first filter circuit (30), the RCD snubber circuit (40), the DC-to-DC conversion circuit (50), the master control circuit (60), the second rectifier circuit (70), the second filter circuit (80), the control circuit (90), and the power output circuit (100) in the present embodiment can all be realized in other ways and are included in the charging circuit, and they are not limited in the present embodiment.

Figure 3 shows the structure of a charging circuit according to the present embodiment.

The first rectifier circuit (20) in the present embodiment generally comprises a bridge circuit consisting of four diodes, and thus AC can be converted into unidirectionally pulsating DC through the diodes.

The first filter circuit (30) in the present embodiment comprises a first branch, a second branch, and capacitors (301 and 302) connected in parallel between the first branch and the second branch, the first branch comprises an inductor (LI), one end of the first branch is connected between two diodes of the bridge circuit, and the other end is connected to the input end of the RCD snubber circuit (40) . The second branch comprises an inductor (L2), one end of the second branch is connected between the other two diodes of the bridge circuit, and the other end is grounded.

The RCD snubber circuit (40) in the present embodiment comprises a first sub-circuit and a diode (Dl) connected in series with the first sub-circuit, and the first sub-circuit comprises three resistors (Rl, R2, and R3) and a capacitor (CI) . The two resistors (Rl and R3) are connected in parallel, the resistor (R2) is connected in parallel with the capacitor (CI), and the resistors (Rl and R3) connected in parallel are connected in series with the resistors (R2 and Rl) connected in parallel.

The DC-to-DC conversion circuit (50) in the present embodiment comprises a transformer (Tl), the transformer (Tl) comprises a primary coil, a secondary coil, and a tickler coil, and is used to modulate the primary DC, convert the primary DC into load DC, and transfer the feedback voltage to the master control circuit (60) . The secondary coil is connected to the second rectifier circuit (70) and the tickler coil is connected to the master control circuit (60) .

The master control circuit (60) in the present embodiment mainly comprises a chip (601) and the chip (601) is used to control the voltage conversion value of the DC-to-DC conversion circuit by controlling the secondary coil.

The second rectifier circuit (70) in the present embodiment comprises a capacitor (C6) , a resistor (R12), a diode (D5) , and a MOS transistor (Ql) . The capacitor (C6) and the resistor (R12) are connected in series, the capacitor (C6) and the resistor (R12) connected in series are connected in parallel with the MOS transistor (Ql), the parallel end is connected to the positive electrode of the diode (D5), and the negative electrode of the diode (D4) is connected to the tickler coil.

The second filter circuit (80) in the present embodiment comprises a capacitor (C4), a capacitor (C8), and a Zener diode (D7) connected in parallel.

The power output circuit (100) in the present embodiment can comprise a plurality of USB ports and they are used to connect different devices to be charged. That is to say, the power output circuit (100) can be a USB output circuit.

The present invention further provides a socket, and the socket comprises the charging circuit in any of the above-mentioned embodiments. The socket further comprises a casing and the charging circuit is equipped in the casing. The socket is not limited to a fixed socket, and is also applicable to a mobile socket .

The above-mentioned embodiments are only preferred embodiments of the present utility model, but are not used to restrict the present utility model. Without departing from the spirit and principle of the present utility model, modifications, equivalent replacements, and improvements should all fall within the scope of protection of the present utility model.