Timer circuit for stretching the duration of an input pulse
AssigneeSharp Kabushiki Kaisha
InventorKenji Ishibashi
Life of this patent
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Abstract
A timer circuit is provided including a self-holding circuit that includes a reset delay circuit for delaying an input pulse by a prescribed time. The output of the self-holding circuit is caused to fall by the rising edge of the input pulse and to rise by the falling edge of the input pulse or the rising edge of a pulse fed back through the reset delay circuit whichever occurs last. Since the pulse duration can be stretched up to a length equal to the reset delay time by the action of the self-holding circuit, the possibility of the input pulse being split through a pulse stretching circuit is eliminated.
Claims14
A timer apparatus comprising:
- a self-holding means for receiving an input pulse and for outputting a first signal having a prescribed pulse duration to a first node;
- and
- a pulse stretching means for receiving said first signal and for stretching a pulse duration of said first signal by a prescribed time,
- said self-holding means comprising:
- a first inverting means coupled to said first node;
- an input amplifying means for receiving said input pulse and for generating a second signal in response to said input pulse, a level of said second signal representing an inverted level of said input pulse, and an output of said input amplifying means being connected to said first node;
- a second inverting means for receiving said first signal via said first node and for generating a third signal;
- and
- a reset delay means for receiving said third signal via a second node and for generating a reset signal delayed by a prescribed delay time, said reset signal resetting said self-holding means;
- wherein said first inverting means receives said third signal via said second node and said reset signal and generates a fourth signal, which is an output of the first inverting means, and
- wherein said second signal and said fourth signal are supplied to the first node to provide said first signal to said pulse stretching means.
A timer apparatus comprising:
- a self-holding means for providing an output pulse in response to an active transistion of an input pulse, said self-holding means including latching means for providing said output pulse with a predetermined fixed duration in the event said input pulse has a duration which does not exceed a predetermined minimum duration, and for providing said output pulse with a duration substantially equal to said input pulse duration in the event said input pulse duration exceeds said predetermined minimum duration;
- and
- pulse stretching means for stretching the duration of said output pulse provided by said self-holding means to a prescribed value, wherein an output state of self-holding means is inverted before an output state of said pulse stretching means.
Dependencies are inferred from the claim text.