Alarm driving signal generator
AssigneeYazaki Corporation
InventorYoshiaki Matsumuro
Life of this patent
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Abstract
To activate a buzzer of voltage driven type in response to an alarm signal, the alarm driving signal generator comprises a capacitor connected between a supply voltage and the buzzer; a first transistor for intermittently discharging the capacitor in response to the alarm signal; and a second transistor for intermittently charging the capacitor in accordance with a time constant in response to a clock signal higher than the alarm signal in frequency, after the capacitor has once been discharged. The alarm buzzer can be actuated on the basis of the intermittently charged capacitor voltage. The above generator is simple in circuit configuration as compared with the conventional circuit.
Claims5
An alarm driving signal generator for driving a voltage actuated buzzer in response to an alarm signal, which comprises:
- (a) a capacitor having a first terminal connected to a supply voltage via a resistor and a second terminal conected to the alarm buzzer;
- (b) a first switching element connected to the first terminal of said capacitor, for intermittently discharging said capacitor in response to the alarm signal;
- and
- (c) a second switching element connected to the second terminal of said capacitor, for intermittently charging said capacitor in accordance with a time constant in response to a clock signal having a frequency higher than that of the alarm signal, after said capacitor has been discharged by said first switching elements, to activate the alarm buzzer in response to voltage intermittently charged on the second terminal of said capacitor.
Dependencies are inferred from the claim text.