KR20040026356A - Power saving circuit of micro wave - Google Patents

Abstract

PURPOSE: A power-saving circuit of a microwave oven is provided to obtain practically a power-saving effect by using a two-way switch instead of a door switch and adding a main relay. CONSTITUTION: A power-saving circuit of a microwave oven includes a plurality of normal open type relays(311,313,315), a two-way door switch(303), and a micro computer(309). The normal open type relays(311,313,315) are connected to a front end of a low-voltage transformer(301). The two-way door switch(303) is used for supplying the power to the low-voltage transformer or each load according to an opening state of a microwave oven door. The micro computer(309) is used for turning off the normal open type relays(311,313,315) according to a power-saving mode.

Description

Power saving circuit of microwave oven {POWER SAVING CIRCUIT OF MICRO WAVE}

The present invention relates to a microwave oven, and more particularly, to a power saving circuit of a microwave oven capable of completely power saving by turning off the system power when the microwave oven is not in use.

In general, in the power saving mode of the microwave, when a predetermined time elapses after the use of the microwave, the power supplied to the plurality of loads is switched to the standby state. Therefore, the microcomputer performs a continuous counter on whether the predetermined time has elapsed. Then, the controller proceeds to the power saving mode under the preprogrammed control according to the elapsed time.

The power saving mode cuts off the power of the load requiring high power and maintains only the power of the microcomputer. The power of the microcomputer is to detect the power saving mode. Therefore, it is inevitable to apply commercial power as a low voltage transformer (LVT) for supplying DC power to the microcomputer. As a result, the power supply to the high voltage transformer (HVT) and the display device is cut off in the power saving mode.

1 is a circuit diagram showing a power supply pattern of a conventional microwave oven. As shown, a low voltage transformer (LVT) 101 for generating a low voltage, a door switch 103 for detecting the opening and closing of the microwave door, a high voltage transformer (HVT: 105) for driving a magnetron, a lamp for lighting a high chamber ( 117, fan motor 119, drive motor 121, a plurality of power contact relay (109-113), display unit 123, microcomputer 107 and key panel 115 for displaying the operating status of the system )

The microcomputer 107 performs operation control of the microwave oven based on a signal input from the key panel 115 and preprogrammed control information. In addition, the door switch 103 is switched off when the door of the microwave oven.

The user commands the power saving mode of the system through the key panel 115. The microcomputer 107 fetches the programmed control information according to the input of the power saving mode command. The non-operation counter of the microwave oven is performed based on the fetched control information. The non-operation counter is a counter that is performed after the operation of the microwave is stopped. The microcomputer 107 determines, for example, whether there is no user control until 10 minutes have elapsed since the operation of the microwave oven was stopped.

As a result, when there is no user control, the power of the display unit 123 is cut off. Then, the low level power applied to the plurality of relays 109-113 is cut off, that is, maintained in a high impedance state. At this time, the display unit 123 maintains an unlit state. The input terminal of each relay RL1-RL3 is also not input low level signal. Therefore, the minimum power consumption provided to the display unit 123 and each relay is reduced.

On the other hand, the microcomputer 107 determines whether a signal from the key panel 115 in response to the power saving mode is released from the user. If it is determined that the power saving mode release signal is input, the microcomputer 107 provides the display unit 123 with information such as initial data, for example, time information and mode setting information. In addition, the input terminal of each relay applies a low-level power according to the non-operation of the microwave oven.

In this way, in the power saving mode, the microcomputer 107 cuts power consumption for non-operational control of the display or the relay in order to reduce unnecessary power consumption. However, the power consumption of the microcomputer 107 itself is not reduced. This is to receive a power saving mode release signal, which is a situation in which full power saving is not achieved.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power saving circuit of the microwave for maximizing the power saving efficiency, so that the power provided to the microcomputer in the power saving mode of the microwave is also saved. have.

A microwave power saving circuit according to an aspect of the present invention for achieving the above object is a relay of the normal open type (NO) connected to the front end of the low-voltage transformer; Two way door switch for supplying power to the low voltage transformer or each load in accordance with opening and closing the door of the microwave oven; And a microcomputer for turning off the relay according to a power saving mode operation.

1 is a view showing a power saving circuit of a conventional microwave oven.

2 is a perspective view of a microwave oven to which the present invention is applied.

3 is a view showing a power saving circuit according to the present invention.

<Explanation of symbols for the main parts of the drawings>

301: low voltage transformer 303: door switch

305: high voltage transformer 307: main relay

309: Micom 311-315: Relay

317: key panel

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view of a microwave oven used to describe the present invention. The microwave oven 200 includes a housing and includes a key panel 201 for operating a user key in front of the housing. The interior chamber 205 is provided in a predetermined space of the housing, and the door 203 is mounted to the opening surface of the interior chamber 205. The hook 209 is mounted at one end of the door 203, and a hook groove 207 having a door switch is provided at a position of the housing opposite to the hook 209.

The user controls a predetermined cooking process through the key panel 201. Power saving mode can be set during cooking. When the power saving mode is set, a predetermined time count is performed after the cooking process is completed. Completion of the cooking process is to withdraw the food from the interior chamber 205 through the door 203, the microcomputer of the microwave 200 detects the withdrawal of the food and the closing of the door 203.

The microcomputer enters the power saving mode based on the user setting. Thereafter, the microcomputer performs a predetermined time count according to the preprogrammed time information. The microcomputer detects the completion of the time count. The microcomputer cuts off the main power supply to the microwave oven. At this time, the operation of the key panel 201 is also blocked.

The user opens the door 203 to use the microwave 200 and seats the food in the chamber 205. At this time, opening of the door 203 of the microwave oven 200 induces switching of the door switch. The switched door switch supplies commercial power (AC) to the low voltage transformer. From this, the microcomputer is powered up and initializes the program. Initialization of the program initiates the power saving mode, which immediately cancels the power saving mode.

3 is a circuit diagram for implementing the above operation. Low voltage transformer 301 for receiving commercial power and converting it into low voltage, high voltage transformer 305 for driving magnetron, door switch 303 for switching and switching according to opening and closing of microwave door, microcomputer 309, key panel ( 317, a plurality of relays 311, 313, 315, a lamp for lighting the high chamber room 319, a fan motor 321, a drive motor 323 for driving a tray, and a power supply of the low voltage transformer 301 under the control of the microcomputer 309. It consists of a main relay 307 for controlling.

The relay 311 is connected to the microcomputer 309 to control the high voltage transformer 305. The microcomputer 309 controls the relay 313 to operate the fan motor 321 and the driving motor 323. The relay 315 is connected to the lamp 319, and the relay 307 turns on and off the low voltage transformer 301 under the control of the microcomputer 309.

On the other hand, the door switch 303 is a 2WAY switch, and when the door of the microwave oven is closed, the power is connected to each of the relays (311, 313, 315). When the door is opened, the power supplied to the relays 311, 313, 315 is cut off and the power is supplied to the low voltage transformer 301.

The microwave oven circuit operation of the present invention configured as described above is as follows.

The user enters the cooking mode through the key panel 317 after seating the food in the chamber 205. At this time, the microcomputer 309 provides a high level control signal to the main relay 307 as an initial state. Thus, the main relay 307 is in a state where the contact is maintained. As a result, the low voltage transformer 301 is supplied with power through the contacts of the main relay 307.

In addition, the microcomputer 309 fetches a cooking program corresponding to the cooking mode and performs magnetron control based on the program. First, the relay 315 is controlled to turn on the lamp 319. The relay 313 is turned on to operate the fan motor 321 and the driving motor 323. In addition, the relay 311 is switched so that power is supplied to the high voltage transformer 305.

Commercial power is supplied to the relays 311, 313, 315 via the door switch 303. Therefore, the microcomputer 309 allows power to be supplied to the plurality of loads through the operation control of each relay.

The user outputs a key signal for power saving mode through the key panel 317 during cooking or after completion of cooking. The key signal for the power saving mode is provided to an input port of the microcomputer 309. The microcomputer 309 determines the completion state of the current cooking according to the key signal input. When the cooking is completed, it is determined whether the predetermined time has elapsed through the counter built in the microcomputer 309.

The predetermined time is pre-programmed, and about 10 minutes will be in an appropriate range. Therefore, the microcomputer 309 determines whether 10 minutes corresponding to the predetermined time has elapsed. When it is determined that 10 minutes has elapsed, the microcomputer 309 cuts off the high level power supplied to the main relay 307. From this, the commercial power supplied to the low voltage transformer 301 is cut off. The low voltage generated on the secondary side of the low voltage transformer 301 is also cut off, and the operation of the microcomputer 309 is stopped.

When the operation of the microcomputer 309 is stopped, the relays 311, 313, and 315 are switched to and maintained in the NO (Normal Open) state, so that power is not supplied to a plurality of loads. That is, power is also not supplied to the display unit of the microwave oven described. This is to cut off the power of the display unit which causes a lot of power consumption in the non-operation state of the microwave oven.

On the other hand, when the user opens the door 203 to use the microwave 200, the door switch 303 is switched so that power is supplied to the low voltage transformer 301. The commercial power is applied to the low voltage transformer 301 via the door switch 303. The microcomputer 309 receives power from the low voltage transformer 301 and is switched to an initial state.

In the initial state of the microcomputer 309, the microcomputer 309 provides a high level signal to the main relay 307. The main relay 307 is switched on in the on state. The commercial power supplies continuous power to the low voltage transformer 301 through the main relay 307. Therefore, the power supply of the microcomputer 309 is maintained regardless of whether the door 203 is opened. Thereafter, the microcomputer 309 normally operates according to the cooking mode input of the user.

As described above, the power saving circuit of the microwave oven according to the present invention includes a display unit having a large power consumption in the non-operating state of the microwave by changing the door switch to 2WAY switch and adding a main relay, thereby consuming each load. By blocking possible residual current and current for maintaining the initial state of the microcomputer, a substantial power saving effect can be obtained.

What has been described above is only one embodiment for implementing a power saving circuit of a microwave oven according to the present invention, and the present invention is not limited to the above-described embodiment, as claimed in the following claims. Without departing from the gist of the present invention, one of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (2)

A normal open type (NO) relay connected to the front end of the low voltage transformer; Two way door switch for supplying power to the low voltage transformer or each load in accordance with opening and closing the door of the microwave oven; And And a microcomputer for turning off the relay according to a power saving mode operation. The power saving circuit of the microwave oven according to claim 1, wherein the power saving mode operation is performed after a predetermined time elapses when the power saving mode is selected.