JPS605376Y2 - Electric circuit reset device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reset device for an electric circuit constituting, for example, an integrated circuit.

Conventionally, for example, when looking at an electronic watch, its electric circuit has a mechanism that is reset at the same time as a battery is attached and is automatically maintained in an initial state.

However, sometimes the electric circuit is not reset to its initial value due to noise or the like that occurs when the battery is installed.

In addition, in integrated circuits that have a power supply circuit that boosts the battery voltage and employ a dynamic drive method, the reference clock is not generated until a certain period of time has passed after the battery is installed. Even if the electric circuit that receives the supply is reset, there is a risk that the initial value will be changed afterwards.

Therefore, the present invention provides a reset device that resets a predetermined electric circuit with a predetermined delay time after power is supplied to the device.

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

Reference numeral 1 indicates an example of an integrated circuit consisting of functional circuits of a counter 2, a decoder 3, and a booster circuit 4, and 5 is a battery that supplies voltage to the integrated circuit 1 and the pulse generation circuit 6.

Output a of decoder 3. For example, b is a display device (not shown).

)It is connected to the.

The booster circuit 4 boosts the voltage of the battery 5 to the operating voltage of all electric circuits.

7 is a capacitor connected externally to the integrated circuit 1;
It forms a differential circuit together with the resistance component inside.

In the above configuration, when the voltage of the battery 5 is applied to the integrated circuit 1 and the pulse generation circuit 6 as shown in FIG. 2A,
The output pulse of the pulse generating circuit 6 causes the output voltage of the booster circuit 4 to become -2V as shown in FIG. 2C.

During this time, the output pulse of the pulse generating circuit 6 is below the trigger level of the counter 2, so the counter 2 is not driven.

Further, the voltage change when the battery 5 is applied is differentiated by a differentiation circuit including a capacitor C shown in FIG. 1, and a differential signal d□ shown in FIG. 2 is generated.

However, since this signal does not rise to the level required for resetting, the circuit system is not reset.

When the voltage of the booster circuit 4 reaches 12V, a pulse shown in FIG. 2B is generated and supplied to the counter 2.

On the other hand, when the output voltage of the booster circuit 4 changes to -2V as shown in FIG. 2C, the differential circuit including the capacitor 7 shown in FIG.

Therefore, this allows counter 2 and decoder 3
will be reset.

As described above, the present invention does not include various functional circuits, and after applying DC power to the electric circuit system, the other electric circuits are reset after the predetermined electric circuit is activated. The electrical circuit is reliably reset.

In particular, if the configuration is such that the battery power supply voltage is boosted and used as the power supply voltage for the circuit system, generating a differential signal when the voltage is boosted and using it as a reset signal is an extremely simple and reliable circuit. It is possible to reset the electrical circuit.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, with FIG. 1 being a block diagram and FIG. 2 being a time chart for explaining its operation. 1...Integrated circuit, 2...Counter, 4
...... Boost circuit, 6... Pulse generation circuit, 7... Capacitor.

Claims (1)

[Scope of utility model registration request] A pulse generation circuit that generates a pulse after applying a DC power source is provided, a booster circuit that boosts the output of the DC power source in response to the pulse is provided, a differentiation circuit that differentiates the output of the booster circuit is provided, and the DC power source is A reset device for an electric circuit, comprising a circuit to be reset that is reset by the output of the differentiating circuit after a delay time after application of power.