JPS5881832A - Flasher circuit for turn signal indicator - Google Patents

Abstract

PURPOSE:To increase reliability of a flasher circuit, by generating a pulse from an oscillator circuit, dividing the pulse in a divider circuit, turning a relay circuit on and off with the divided pulse, selecting a lamp with a turn flasher switch and resetting the divider circuit with a reset circuit when the lamp is turned off. CONSTITUTION:An oscillator circuit 1 is connected to a divider circuit, consisting of T-type FF circuits 2-4, and a pulse is given to a relay driving TR11 as a flasher pulse via a divided pulse FF circuit 20, then lamps are flashed by a relay 13. While a transistor TR17 is turned on in lamp-off timing, in which a switch 14 is turned off and a contact 13a is opened, and its output is applied to an NOR gate 7 and inverter 6, then a reset condition of the divider circuit is obtained in an AND gate 5. Further the reset condition can be obtained also when an output of the oscillator circuit 1 is H and an output of an NOR gate 8 is L. In this way, only a turn signal flasher switch is used as the switch contact except the relay contact 13a, and a number of contacts can be decreased to improve reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flasher circuit for flashing a direction indicator lamp of a vehicle.

Conventional 7 lasier circuits have a large number of switches, including a switch contact to select the direction indicator lamp, a switch contact to turn off the relay circuit when no direction is given, and a switch contact to turn on and off the power line of the control circuit. I needed a point of contact.

However, a circuit configuration using such a large number of mechanical switch contacts is not suitable for Francia circuits that require particularly high reliability, and also has the disadvantage of increasing costs.

The purpose of this invention is to reduce the number of switch contacts as much as possible to reduce costs and improve reliability.The purpose of this invention is to reduce the number of switch contacts as much as possible to reduce costs and improve reliability.Furthermore, the 7-lash circuit is designed to increase safety by forming the lighting timing immediately after turning on the direction indicator switch. Our goal is to provide the following.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a flasher circuit according to an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of the flasher circuit.

In FIG. 1, the oscillation circuit 1 is a T-type flip 70 tube 2.
．． 3.4 are connected to a cascaded frequency divider circuit, and the divided pulses are applied to a flip-flop 20 consisting of a NOR gate 7.8. The output of the 7-lip 70-tube 20 is applied as a flashing pulse to the relay driving transistor 11, which opens and closes the relay contact 13a of the relay 13. Further, the direction indicating switch 14 and the direction indicating lamps 15 and 15' are connected in series to the relay contact 13aK, and the lamp selected by the switch 14 is connected to the switch contact 13a.

The transistor 17 is a timing detector that detects the potential of the common contact 14a of the direction indicator switch 14, and is turned off at the lighting timing when the relay contact 13a is closed, and when the relay contact 13a is open when the switch 14 is on. It turns on when the lights go out. The output thereof is applied to the NOR gate 7 and the inverter 6, and the AND gate 5 constitutes a reset condition for the frequency dividing circuit. Further, the reset conditions for the frequency dividing circuit include the ``High'' level of the output of the oscillation circuit 1 and the ``LOW'' level of the output of the NOR gate 8. As will be described later, this AND gate 5 and the transistor 17 operate as a reset circuit that resets the frequency dividing circuit when the direction indicating switch 14 is turned off.

Next, the operation of this flasher circuit will be explained with reference to FIG. Note that the correspondence between the extraction position of each Id number and the timing waveform is indicated by the symbols A to G attached to both FIGS. 1 and 2.
It is indicated by K.

Normally, a control section consisting of an oscillation circuit 1 frequency divider circuit and other gates is connected to the power supply VCC. In this state, when the direction switch 14 is off, the transistor 17 is also off, so the output of the AND gate 5 becomes the output pulse of the oscillation circuit 1, inhibiting the operation of the branch circuit.

Turn on the direction indicator switch 14 and turn the lamp 15° = 15' is selected.

The moment the switch 14 is turned on, a forward bias is applied between the base and emink of the transistor 17, so the AND gate 5 closes and the frequency dividing circuit starts operating. At the same time, the flip-flop 20 consisting of a NOR gate 7.8 is inverted, turning on the transistor 11, and the relay 13 is activated, closing the relay contact 13a. That is, the direction switch 14
When turned on, the relay contact 13a immediately closes to form the lamp lighting timing. and relay contact 13a
When the transistor 17 is opened, the transistor 17 is turned off, so the input of the NOR gate 7 is held "LOW" and the flip 7 is turned off.
A re-inversion wait state for the 0-tube 20 is created.

When the free tube 70 and the tube 20 are re-inverted, that is, the relay 13 is turned off, the output of the clip-flop 4 becomes "High".
It will be done at the right time. When the relay 13 is turned off, the relay contact 13a opens, and at the same time the light goes out, the transistor 17 is turned on and the input of the NOR gate 7 is held at "High". After that, Flip 70 Tsubu 2
0 performs the above-mentioned inversion operation in synchronization with the output pulse of the 7-lip-flop 4, that is, the frequency-divided pulse, and the lamp 15 or 15' repeatedly flashes in response.

Note that during this blinking period, since any output of the inverter 6.9 is 'LOW', resetting of the frequency dividing circuit is prohibited.

Turn off direction switch 14 T+? : Then, if the timing is the light-off timing, the transistor 17 is immediately turned off and the AND gate 5 is enabled. That is, the frequency dividing circuit is reset at the rise of the next pulse of the oscillation circuit 1, and then returned to its original state. Also, if the turn-off timing of the direction indicator switch 14 is the turn-on timing,
While the light goes out at the same time as turning off, at the next off timing, the frequency dividing circuit goes through the same process as above, and the frequency dividing circuit is reset and returns to the original state.In this way, when the direction indicator switch is turned off, the frequency dividing circuit The circuit is reset, and the next time it is turned on, the 7-lip 70-tube 20 comes into operation immediately due to the action of the transistor 17.

As described above, according to the present invention, the elements constituting the switch contacts of the circuit, except for the relay contacts, are in the direction indicating switch 1.
Since there are only 4 contacts, the number of contacts is reduced, and reliability can be improved and costs reduced. Also, as soon as you turn on the direction indicator switch, the lighting timing will start, so
It is possible to create a highly safe flasher circuit.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a flasher circuit according to an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of the seven flasher circuit. l...Oscillation circuit, 13...Relay, 13a.
・・Relay contact, 14・One-way indication switch, 15
．． 15'...Direction indicator lamp. Applicant Sharp Corporation Representative Patent Attorney Hisao Komori

Claims (1)

[Claims] (1) An oscillation @l path and frequency divider circuit that is always connected to a power supply, a relay circuit that is turned on and off by a branch pulse, a plurality of direction indicator lamps connected in series to the relay contacts, and this lamp. A direction indicator flasher circuit comprising: a direction indicator switch that selects a direction indicator; and a reset circuit that resets the frequency dividing circuit when the switch is turned off.