Charge apparatus of an extension cord plug

A charge apparatus of an extension cord plug is provided. The charge apparatus is set inside an outlet and connected to an USB interface outside the outlet. When the outlet is electrified, the plug thereon is able to provide power to an electric appliance for normal operation through the USB interface after processing of the charge apparatus. By the time, the user may select demanded voltage to achieve objective of charging by various voltage sources.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a charge apparatus of an extension cord plug. More particularly, the present invention relates to a charge apparatus with an USB charge interface outside an outlet for user to charge electronic devices.

2. Descriptions of the Related Art

Extension cord plugs are widely used with frequency, due to its character of supplying insufficient plugs at home or working place for indoor electronic devices, such as lamps that hang on the tree, or outdoor workers. Therefore, extension cord plugs are almost daily necessaries for every family.

Although the extension cord plug is practical, it can only provide plugs to alternating-current electronic devices but have no additional functions. Since the utility rate of the extension cord plug is high, the extension cord plug still needs improvement.

It can be tell that the conventional apparatus still has many drawbacks and is not good in design, thus the conventional apparatus needs improvement.

The inventor considers improvement in view of the aforementioned drawbacks of the conventional extension cord plug, and develops the present invention of charge apparatus of an extension cord plug after a long term of research.

SUMMARY OF THE INVENTION

The invention is to provide a charge apparatus inside an outlet. The charge apparatus is connected to an USB interface outside the outlet to charge a device through the USB interface.

Another, this invention is to provide a charge apparatus of an extension cord plug with different charging voltage sources that can be selected by a user to charge different devices.

A extension cord plug comprises an outlet, a charge, and an USB interface. The outlet is configured with an over current protection circuit, a filter-rectify circuit to prevent over current due to short circuit or other reasons by the over current protection circuit, and to provide a steady direct current (DC) power to the charge apparatus by the filter-rectify circuit that filters and rectifies an input AC power. The charge apparatus comprises a start-up circuit, a high-voltage snub circuit, a power tube, an over-current sampling circuit, a steady-voltage control circuit, a positive feedback circuit, a high-frequency transformer, an output filter-rectify circuit, an output voltage sampling circuit, a voltage selection switch, a photo-isolator, a load sense circuit and a load monitor. The start-up circuit receives the DC power from the filter-rectify circuit and then drives the power tube to control the output voltage of the high-frequency transformer, and senses the current flowing through the power tube by the over-current sampling circuit as well as stabilizes the voltage of the power tube by the steady-voltage control circuit. The high-frequency transformer transforms the received power into the output voltage. The high-voltage snub circuit limits an induced voltage generated by the leakage inductance of the high-frequency transformer to prevent the voltage being applied on the power tube from being too large and damaging the power tube. The positive feedback circuit controls status of the power tube according to amplitude of the primary-side current flowing through the high-frequency transformer. The output filter-rectify circuit filters and rectifies the AC power being outputted by the high-frequency transformer, and senses variation of the output voltage via the (output) voltage sampling circuit as well as transfers the sensing result to the photo-isolator. The photo-isolator then transforms the output signal into photo signal for being fed back to the input and then the photo signal is transformed into electrical signal by photo-sensor to achieve lowest-interference and high-efficiency feedback. The load sense circuit is connected to the USB interface outside the outlet to sense whether there is any load being connected to the USB interface. If there is a load, then the load monitor is driven to emit light.

These features and advantages of the present invention will be fully understood and appreciated from the following detailed description of the accompanying Drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 1-3, in which the charge apparatus of an extension cord plug of the present invention is shown. An extension cord plug of the present invention mainly comprises an outlet1, a charge apparatus2, and an USB interface3.

The outlet1is configured with a plug13outside the surface of the outlet1, and internally configured with an over-current protection circuit11and a filter-rectify circuit12. The over-current protection circuit11is configured to sense whether there is any short-circuit or abnormal status around the whole circuitry to prevent damaging the whole circuitry. The filter-rectify circuit12is configured to filter and rectify the inputted AC current and provide a steady DC current to a charge apparatus2, and the over-current protection circuit11may be a fuse.

The USB interface3is outside the outlet1and connected to the charger2.

The charge apparatus2comprises a power tube21, a start-up circuit23, a over-circuit sampling circuit24, a steady-voltage control circuit25, a high-voltage snub circuit27, a positive feedback circuit26, an output filter-rectify circuit28, a voltage selection switch29, a voltage sampling circuit30, a load sense circuit32, a voltage sampling circuit35,

The power tube21is a high-speed, high-voltage switching triode and is configured to control an output voltage of a high-frequency transformer22.

The start-up circuit23is configured to drive the power tube21to work.

The over-sampling circuit24is configured to sense the current flowing through the power tube21and co-function with a steady-voltage control circuit25to prevent the current flowing through the power tube21from being too large to damage the power tube21.

The steady-voltage control circuit25receives a sampling signal from the over-current sampling circuit24to control base voltage of the power tube25.

The high-frequency transformer22is configured to generate various magnetic field in response to the current flowing through the primary side of the high-frequency transformer22, then the secondary side of the high-frequency transformer22derives induced current and output voltage for a positive feedback circuit26according to the magnetic filed and the coils of the high-frequency transformer22.

The high-voltage snub circuit27is configured to limit a induced voltage generated by the leakage inductance of the high-frequency transformer22to prevent the voltage being applied on the power tube21from being too large and damaging the power tube21.

The positive feedback circuit26is configured to control status of the power tube21according to amplitude of the primary-side current flowing through the high-frequency transformer22.

The output filter-rectify circuit28is configured to filter and rectify the AC power being outputted by the high-frequency transformer22to output a steady DC power.

The voltage selection switch29has a multi-voltage selection button291, and is configured to transmit the selection to the output filter-rectify circuit28to make the output filter-rectify circuit28output demanded DC voltage according to the selection.

The voltage sampling circuit30is configured to sense variation of the output voltage, and transmit the sense result to a photo-isolator31.

The photo-isolator31is configured to receive the sampling signal from the voltage sampling circuit30, transform the sampling signal into photo signal, and then the photo signal is transformed into electrical signal by photo-sensor and the electrical signal is transmitted to the steady-voltage control circuit25for controlling the high-frequency transformer22to output demanded voltage via controlling the power tube21by the positive feedback circuit26to achieve high-efficiency feedback.

The load sense circuit32is configured to receive the direct power of the output filter-rectify circuit28and be connected to the USB interface3to check whether there is any load being connected to the USB interface3, in which once there is load, the load sense circuit32then drive a load monitor33to present the status, and the load monitor33may be a LED or other luminous source.

The voltage sampling circuit35is connected to the load sense circuit32and configured to retrieve a voltage signal from the voltage sampling circuit35, and transmit the voltage signal to a voltage comparing circuit36. If the comparing result denotes abnormal, the signal would be amplified by an amplifier circuit37for driving an over-loading alarm38to notify the user that load of the USB interface is over-loading. Meanwhile, an over-voltage protection circuit34is activated to protect the load from being damaged. Besides, the over-loading alarm38can be a luminary or a buzzer to alarm by flashing or buzzing respectively.

Referring toFIG. 4, which shows an embodiment of the present invention, when the outlet1is electrified, the plug13thereon is able to provide power to an electric appliance for normal operation. The USB interface3on the outlet1is able to provide connection to an USB connector4for charging a battery or other electric appliance needed to be charged. By the time, the user may select demanded voltage via the multi-voltage selection button291of the voltage selection switch29, and tell the charging status by demonstration of the load monitor33.

Referring toFIG. 5, which shows another embodiment of the present invention, the outlet1is set inside a chest6or a box for containing the outlet1with artistic effect. Moreover, an electric appliance needed to be charged can be placed on the chest6or the box for convenience.

Referring toFIG. 6, which shows another embodiment of the present invention, a pin14is directly set on the outlet1to induce AC power to the plug13and induce DC power to the USB interface3.

Further, referring to prior arts, the extension cord plug of the present invention has at least the advantages as following:

1. The present invention brings up a charge apparatus inside the outlet, and the charge apparatus is connected to an USB interface outside the outlet to charge an electric appliance by the USB interface.

2. The present invention is able to provide various charging voltages for the user to voluntarily select to charge different electric appliances by different voltages.