Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Synchronizing
Reexamination Certificate
2003-05-15
2004-07-13
Lam, Tuan T. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Synchronizing
C327S143000, C327S198000
Reexamination Certificate
active
06762632
ABSTRACT:
TECHNICAL FIELD
The present invention relates to electronic circuits, and more particularly to electronic circuits for providing a reset signal to another electronic circuit.
BACKGROUND
Most programmed or programmable type logic circuits must be set in a zero state or reset state when powered on to assure that their constitutive elements do not present undetermined logic states. The power on reset (POR) circuits provided for this deliver a reset signal when the supply voltage rises and reaches a first switching threshold V
1
, and release the reset signal when the voltage reaches a second switching threshold V
2
. According to the chosen convention, the active value of the reset signal may be 1 or 0. The release of the reset signal corresponds to its setting to 0 in the first case and to its setting to 1 in the second case.
Electronic circuits may implement a reset signal with a positive polarity or a negative polarity. Existing reset signal generators lack the ability to detect whether the circuit to which the reset signal is directed requires a negative polarity active reset signal or a positive polarity active reset signal. As a result, both positive polarity and negative polarity reset signal generators must exist in the marketplace. Use of the wrong signal generator is a design flaw that requires redesign.
Therefore, there is a need in the art for a circuit that detects the required polarity of a circuit's reset signal and provides a reset signal of the appropriate polarity.
SUMMARY
In one aspect, a reset driver circuit for generating an input reset signal for a second circuit is provided. The reset driver circuit comprises means for generating a first signal indicative of a required characteristic of an input reset signal for a second circuit; means for comparing the first signal and a second signal indicative of a characteristic of a first input reset signal; and means for generating a second input reset signal that includes the required characteristic of an input reset signal for a second circuit.
In another aspect, a method of generating an input reset signal is provided. The method comprises generating a first signal indicative of a required characteristic of an input reset signal for a second circuit; comparing the first signal and a signal indicative of a characteristic of a first reset signal; and generating a second reset signal that includes the required characteristic of an input reset signal for a second circuit.
In another aspect, a reset driver circuit for generating an input reset signal for a second circuit is provided. The reset driver circuit comprises a flip-flop having an input connected to the reset input of a second circuit; a first comparator including a first input connected to a first output of the flip-flop and a second input that receives an external reset signal; a second comparator including a first input connected to a second output of the flip-flop and a second input that receives an external reset signal; a first switch connected to the output of the first comparator for selectively connecting the reset input of the second circuit to a first voltage; and a second switch connected to the output of the second comparator for selectively connecting the reset input of the second circuit to a second voltage.
In yet another aspect, a reset driver circuit for generating an input reset signal for a second circuit is provided. The reset driver circuit comprises a first flip-flop having a first input for receiving a reset input signal, and generating a first signal indicative of a characteristic of the reset input signal; a second flip-flop having an input connected to a reset input pin of a second circuit and generating second and third outputs indicative of a characteristic of the reset input pin; a digital logic circuit for comparing the first output with at least one of the second output and the third output; a first switch connected to the output of the digital logic circuit for selectively connecting the reset input of the second circuit to a first voltage; and a second switch connected to the output of the digital logic circuit for selectively connecting the reset input of the second circuit to a second voltage.
REFERENCES:
patent: 5345583 (1994-09-01), Davis
patent: 5644250 (1997-07-01), Ooishi
patent: 5880611 (1999-03-01), Danstrom
patent: 5959477 (1999-09-01), Chung
patent: 6069574 (2000-05-01), Eo et al.
patent: 6072732 (2000-06-01), McClure
patent: 6134686 (2000-10-01), Jha
patent: 6157579 (2000-12-01), Micheloni et al.
patent: 6236249 (2001-05-01), Choi et al.
patent: 6363025 (2002-03-01), McLaury
patent: 6377090 (2002-04-01), Bruno
patent: 2001/0054921 (2001-12-01), Akiyoshi
patent: 2002/0063589 (2002-05-01), Nguyen
patent: 2002/0075745 (2002-06-01), McLaury
patent: 2002/0089860 (2002-07-01), Kashima et al.
patent: 2002/0140439 (2002-10-01), Enam et al.
patent: 2002/0140689 (2002-10-01), Huang et al.
patent: 2002/0145454 (2002-10-01), Jensen
Himpe Vincent
Swanson Cal
Jorgenson Lisa K.
Kubida William J.
Lam Tuan T.
STMicroelectronics Inc.
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