JPH09152187A - Electric warm air heater drive circuit - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an electric warm air heater drive circuit in which the influence of switch operation related to operation on the life of a relay is suppressed. SOLUTION: By using relays 3a, 3b, 3c, 3d which operate according to the states of switches 7a, 7b related to driving operation, a fan motor 4a, which is a load contributing to the generation of warm air, and a first heater element 4b. , And the second heater element 4
Controls the operation of c. Timer 1 that gives a predetermined delay time from the switch operation to the relay operation
a, 1b. The switch may be the start switch 7a. In this case, the relay may define one of the plurality of operation modes according to the operation of the start switch. The switch is mode switch 7
It can also be b. In this case, the relay may select one operation mode from a plurality of operation modes according to the operation of the mode changeover switch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric warm air heater drive circuit, and more particularly to controlling the operation of a load that contributes to the generation of warm air by using a relay that operates according to the state of a switch related to a driving operation. The present invention relates to an electric warm air heater drive circuit.

[0002]

2. Description of the Related Art Conventionally, some electric warm air heater drive circuits are capable of selecting one operation mode from a plurality of operation modes. In that case, the operation mode is determined by combining the states of a plurality of relays. Normally, immediately after the start switch is turned on, a plurality of relays are simultaneously driven in accordance with the selected operation mode to determine the actual operation mode. Also, immediately after another operating mode is selected by operating the mode changeover switch,
Multiple relays are driven simultaneously according to the selected mode to determine the actual operating mode. According to the determined actual operation mode, drive control of a fan motor, a heater element, etc. as a load contributing to the generation of warm air is performed.

[0003]

However, immediately after the operation of the start switch, a rush current exceeding the rating flows in the relay, and there is a problem that the contacts of the relay are welded or the life of the relay is shortened. Further, if the start switch or the mode changeover switch is frequently operated in a short time, the relay is switched accordingly, which also causes a problem that the life of the relay is shortened. As described above, the operation of the switch related to the driving operation such as the start switch and the mode change switch has a great influence on the life of the relay.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric warm air heater drive circuit in which the influence of switch operation related to driving operation on the life of the relay is suppressed.

[0005]

According to the present invention, an electric warm air which controls the operation of a load that contributes to the generation of warm air by using a relay that operates according to the state of a switch related to a driving operation. In the heater driving circuit, there is provided an electric warm air heater driving circuit including a timer for allowing a predetermined delay time from the operation of the switch to the operation of the relay.

[0006]

1 is a block diagram showing an electric warm air heater drive circuit according to an embodiment of the present invention. This electric warm air heater drive circuit is provided in the microcomputer 1
And the first and second transistor arrays 2a and 2b whose input side is connected to the output end of the microcomputer 1.
A relay group 3 connected to the output side of the first transistor array 2a, a load group 4 connected to the AC power supply AC via the contacts of the relay group 3, and an output side of the second transistor array 2b. First, second, and third light emitting diodes 6a, 6b, 6c as display devices connected to resistors 5a, 5b, 5c, and a start switch 7a connected to an input end of the microcomputer 1. And a mode changeover switch 7b. The start switch 7a is a switch for starting operation, and is composed of a push button switch. The mode changeover switch 7b is a switch for selecting one of a plurality of operation modes, for example, a heating mode, a drying mode, and a ventilation mode as the current mode, and is composed of a push button switch. Note that 5d and 5e are resistors.

The relay group 3 includes first, second, third, and fourth relays.
The relays 3a, 3b, 3c and 3d are included. The load group 4 is connected to the fan motor 4a connected to the AC power supply AC via the contacts of the first and second relays 3a and 3b, and to the AC power supply AC via the first and third relays 3a and 3c. It includes a first heater element 4b which is operated and a second heater element 4c which is connected to the AC power supply AC via the first and fourth relays 3a and 3d. Microcomputer 1
Has first and second timers 1a and 1b, and depending on the operation mode, the first, second, third and fourth relays 3a and 3b.
b, 3c, 3d are switched to drive the fan motor 4a, the first heater element 4b, and the second heater element 4c.

The first relay 3a is a common relay for supplying power to the fan motor 4a, the first heater element 4b, and the second heater element 4c of the load group 4.
When the second relay 3b is off, the contact is on the side b and the fan motor 4a operates with a weak air volume. When the second relay 3b is on, its contact is on the side a and the fan motor 4
A operates with a strong air flow.

The fan motor 4a, the first and second heater elements 4b and 4c, and the first, second and third light emitting diodes 6a, 6a, 6b and 6c show the state shown in FIG.

As described in detail below, when the start switch 7a is turned on, the first timer 1a starts counting. After that, the first mode determination described later is performed to determine the current mode. And the first, second and third light emitting diodes 6
One of a, 6b, and 6c corresponding to the current mode is turned on. In the relay drive, as will be described later, the first to fourth relays 3a to 3d are sequentially driven while waiting for the time by the second timer 1b in the current mode. When the mode switch 7b is turned on, the first timer 1a starts counting. After that, the second mode determination described later is performed to determine the current mode. And the first, second,
And, of the third light emitting diodes 6a, 6b, 6c, the one corresponding to the current mode is turned on.

Next, the operation will be described in detail with reference to FIG. After the start, known initialization is performed in step 11. Various other processes are performed in step 12, and the process proceeds to step 13 to determine whether the start switch 7a has been accepted, that is, whether the start switch 7a has been operated.
When the start switch 7a is accepted, step 14
Then, it is determined whether or not the first timer 1a is in operation. First
When the timer 1a is not operating, the time counting of the first timer 1a is started in step 15. Step 16
Then, as will be described later, a first mode determination is performed, and in step 17, one of the first, second and third light emitting diodes 6a, 6b, 6c is driven in order to represent the operation mode at that time. Furthermore, it moves to step 18 and the first timer 1a
Determines whether the clock has finished counting. First timer 1
When a has finished measuring the time, the relay is driven in step 19 as will be described later, and the routine proceeds to step 20. Even when the start switch is not accepted in step 13 or when the first timer 1a has not finished timing in step 18, the process proceeds to step 20.

In step 20, it is judged whether or not the mode changeover switch has been accepted. When the mode switch is not accepted, the process returns to step 12. When the mode changeover switch is accepted, the routine proceeds to step 21, where it is judged whether or not the current mode is off, that is, whether or not the current mode is in a stopped state after the operation is completed. If the vehicle is in a stopped state after the operation is completed, the process returns to step 12. Otherwise, in step 22, it is determined whether or not the current mode is standby, that is, whether or not it is in the state of waiting for the start switch input when the power is turned on. If the current mode is standby, the process returns to step 12. Otherwise, step 23
Then, it is determined whether or not the first timer 1a is operating. When the first timer 1a is not running, step 24
Then, the timing of the first timer 1a is started. When the first timer 1a is measuring time, in step 25, a second mode determination is performed as will be described later, and in step 26, the first, second and third light emitting diodes 6a are displayed to indicate the operation mode at that time. , 6b, 6c is driven. Further, the process proceeds to step 27, and it is determined whether or not the first timer 1a has finished counting time. When the first timer 1a has not finished timing, the process returns to step 12. When the first timer 1a finishes measuring time, in step 28,
The relay is driven as will be described later, and the process returns to step 12.

The first mode determination in step 16 of FIG. 3 will be described with reference to FIG. In step 31, it is judged whether or not the current mode is the standby mode, that is, whether or not the current mode is waiting for the start switch input. When the current mode is standby, both the current mode and the previous mode are set to the ventilation mode in step 32. When the current mode is not on standby, the routine proceeds to step 33, where it is judged if the current mode is off. When the current mode is off, the current mode is returned to the previous mode in step 34. When the current mode is on, the current mode is turned off at step 35.

The second mode determination in step 25 of FIG. 3 will be described with reference to FIG. At step 41, it is judged if the current mode is the ventilation mode. When the current mode is the ventilation mode, both the current mode and the previous mode are set to the drying mode in step 43. When the current mode is not the ventilation mode, the routine proceeds to step 42, where it is judged if the current mode is the drying mode. When the current mode is the drying mode, both the current mode and the previous mode are set to the heating mode in step 44. When the current mode is not the dry mode, that is, when the current mode is the heating mode, both the current mode and the previous mode are set to the ventilation mode in step 45.

The relay driving in steps 19 and 28 of FIG. 3 will be described with reference to FIG. First step 51
Then, it is determined whether or not the current mode is the heating mode. When the current mode is the heating mode, the second relay 3b is turned off in step 52a, the second timer 1b waits for the time in step 52b, and then the first relay 3a is turned on in step 52c and then in step 52d. After waiting for the time by the second timer 1b, the third relay 3c is turned on in step 52e, and after waiting for the time by the second timer 1b in step 52f, the fourth relay 3d is turned on in step 52g.

When the current mode is not the heating mode in step 51, it is determined in step 53 whether the current mode is the drying mode. When the current mode is the dry mode, the second relay 3b is turned on in step 54a,
After waiting the time by the second timer 1b in step 54b, the first relay 3a is turned on in step 54c, and after waiting the time by the second timer 1b in step 54d, the third relay 3c is turned on in step 54e. After waiting for the time by the second timer 1b in step 54f, the fourth relay 3d is turned off in step 54g.

When the current mode is not the drying mode in step 53, it is determined in step 55 whether the current mode is the ventilation mode. When the current mode is the ventilation mode, the second relay 3b is turned on in step 56a,
After waiting the time by the second timer 1b in step 56b, the first relay 3a is turned on in step 56c, and the third relay 3c is turned off in the step 56e after waiting for time by the second timer 1b. After waiting the time by the second timer 1b in step 56f, the fourth relay 3d is turned off in step 56g.

When the current mode is not the ventilation mode at step 55, the fourth relay 3d is turned off at step 57a, and after waiting the time by the second timer 1b at step 57b, the third relay 3c is turned off at step 57c. Then, after waiting for the time by the second timer 1b in step 57d, the first relay 3a is turned off in step 57e,
After waiting the time by the second timer 1b in step 57f, the second relay 3b is turned off in step 57g.

In the above description, the heating mode, the drying mode,
Although the electric warm air heater drive circuit capable of coping with the three operation modes of the ventilation mode and the ventilation mode has been described, the present invention can be implemented for those having two operation modes and those having four or more operation modes. Needless to say.

[0020]

As described above, according to the present invention,
Since the load is not driven at the same time, it is possible to prevent a current exceeding the rated value from flowing through the contacts of the relay. Moreover, by not switching the relays more than necessary, the number of times the relays are operated can be reduced, so that the life of the relays is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric warm air heater drive circuit according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing the operation of each part of the electric warm air heater drive circuit of FIG. 1 in correspondence with each mode.

3 is a flowchart for explaining the overall operation of the electric warm air heater drive circuit in FIG.

FIG. 4 is a flowchart for explaining the first mode determination in FIG.

5 is a flowchart for explaining the second mode determination in FIG.

FIG. 6 is a flowchart for explaining relay driving in FIG.

[Explanation of symbols]

 1 Microcomputer 1a 1st timer 1b 2nd timer 2a 1st transistor array 2b 2nd transistor array 3a 1st relay 3b 2nd relay 3c 3rd relay 3d 4th relay 4a Fan motor 4b 4th 1 heater element 4c 2nd heater element 6a 1st light emitting diode 6b 2nd light emitting diode 6c 3rd light emitting diode 7a start switch 7b mode switch

Claims (5)

[Claims] 1. An electric warm air heater drive circuit configured to control the operation of a load that contributes to the generation of warm air using a relay that operates according to the state of the switch related to driving operation, and the switch is operated. An electric warm air heater drive circuit comprising a timer for allowing a predetermined delay time from the start of operation to the operation of the relay. 2. The electric warm air heater according to claim 1, wherein the switch is a start switch, and the relay defines one operation mode among a plurality of operation modes according to an operation of the start switch. Drive circuit. 3. The electric temperature controller according to claim 1, wherein the switch is a mode changeover switch, and the relay selects one operation mode from a plurality of operation modes according to an operation of the mode changeover switch. Wind heater drive circuit. 4. The electric warm air heater drive circuit according to claim 1, wherein the relay is plural, and the timer is for individually setting the delay time in each of the plural relays. 5. An electric warm air heater provided with the electric warm air heater drive circuit according to claim 1.