Power-up signal generating circuit and method for driving the same
First Claim
1. A power-up signal generating circuit, comprising:
- a level detector configured to deactivate a first level detection signal when a level of an external voltage increases above a first reference voltage;
a level comparator configured to deactivate a second level detection signal when the level of the external voltage increases above a second reference voltage; and
a reentry protector configured to activate a power-up signal in response to the second level detection signal and deactivate the power-up signal in response to a deactivation of the first level detection signal.
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Abstract
A power-up signal generating circuit that prevents repeatedly generating a power-up signal even when there is noise on an external voltage. The power-up signal generating circuit includes a level detector, a level comparator, and a reentry protector. The level detector is configured to deactivate a first level detection signal when a level of an external voltage increases above a upper limit reference voltage. The level comparator is configured to deactivate a second level detection signal when the level of the external voltage increases above a lower limit reference voltage. The reentry protector is configured to activate the power-up signal in response to the second level detection signal and deactivate the power-up signal in response to a deactivation of the first level detection signal.
19 Citations
19 Claims
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1. A power-up signal generating circuit, comprising:
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a level detector configured to deactivate a first level detection signal when a level of an external voltage increases above a first reference voltage; a level comparator configured to deactivate a second level detection signal when the level of the external voltage increases above a second reference voltage; and a reentry protector configured to activate a power-up signal in response to the second level detection signal and deactivate the power-up signal in response to a deactivation of the first level detection signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for driving a power-up signal generating circuit, the method comprising:
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detecting a level of an external voltage; deactivating a power-up signal, a level of which follows the level of the external voltage when activated, to a ground voltage level when the level of the external voltage increases above a first reference voltage; and reactivating the power-up signal when the level of the external voltage falls below a second reference voltage, wherein the second reference voltage has a level lower than the first reference voltage. - View Dependent Claims (11)
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12. A power-up signal generating circuit, comprising:
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a first pre-signal generating unit configured to deactivate a first level detection signal when a level of a signal corresponding to an external voltage increases above a first reference voltage; a second pre-signal generating unit configured to deactivate a second level detection signal when the level of the signal increases above a second reference voltage; and a main signal generating unit configured to activate a power-up signal in response to an activation of the second level detection signal, and deactivate the power-up signal in response to a deactivation of the first level detection signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification