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US4230958A Expired / Lapsed US ⏱️ 0.0 years remaining

Loss of clock detector circuit

Assignee: AT&T Inc
•
Filing: 1978-08-09
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Granted: 1980-10-28
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Expires: 1998-08-09
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Abstract

Abstract This invention involves a detector circuit in MOS technology for sensing "loss of clock"; that is, whenever a clock input voltage pulse source is interrupted or stops (becomes "stuck") at any level, the output voltage of the detector circuit is at a high level, but is at a low level when the clock is working properly. Such a circuit is achieved by means of a first MOS electrical inverter (I 1 ), connected for feeding its output to an MOS electrical differentiator (Δ), connector for feeding its output to a thresholding MOS amplifier (A), connected for feeding its output to a unidirectional MOS current inhibitor (D), connected for feeding its output to a second MOS electrical inverter (I 2 ), connected in parallel with a storage capacitor (C) in parallel with a leakage current source (J L ), whereby the output of the second inverter is a binary indication of the presence vs. absence of clock pulse input to the first inverter.

Inventors

  • 👤 Harry J. Boll
  • 👤 Michael K. Maul

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 14:26
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/19

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 161 words
Semiconductor apparatus comprising: (a) an MOS differentiator (Δ) having an input terminal; (b) an MOS thresholding amplifier (A) having an input terminal connected to an output terminal of the differentiator (Δ); (c) an MOS unidirectional current inhibitor (D) having an input terminal connected to an output terminal of the amplifier (A); (d) an MOS storage capacitor (C) having one terminal connected to an output terminal of the inhibitor (D); (e) a leakage current source (J L ) connected to said one terminal for providing a leakage current thereto if and only if the charge on said terminal is above a threshold, said inhibitor (D) directed for delivering charge in a direction tending to charge said one terminal and said leakage current being in a direction tending to discharge said one terminal; whereby the voltage level at said one terminal is a binary indication of whether or not clock pulse voltage is being applied to the input terminal of the differentiator (Δ).
Claim 2
Dependent Claim 161 words
Semiconductor apparatus comprising: (a) an MOS differentiator (Δ) having an input terminal; (b) an MOS thresholding amplifier (A) having an input terminal connected to an output terminal of the differentiator (Δ); (c) an MOS unidirectional current inhibitor (D) having an input terminal connected to an output terminal of the amplifier (A); (d) an MOS storage capacitor (C) having one terminal connected to an output terminal of the inhibitor (D); (e) a leakage current source (J L ) connected to said one terminal for providing a leakage current thereto if and only if the charge on said terminal is above a threshold, said inhibitor (D) directed for delivering charge in a direction tending to charge said one terminal and said leakage current being in a direction tending to discharge said one terminal; whereby the voltage level at said one terminal is a binary indication of whether or not clock pulse voltage is being applied to the input terminal of the differentiator (Δ).
Claim 3
Dependent Claim 188 words
Semiconductor apparatus which comprises: (a) a first MOS voltage shifting device (I 1 ) having an input terminal for the application thereto of a clock pulse voltage source; (b) an MOS differentiator (Δ) having an input terminal connected to an output terminal of the first device (I 1 ); (c) an MOS thresholding amplifier (A) having an input terminal connected to an output terminal of the differentiator (Δ); (d) an MOS unidirectional current inhibitor (D) having an input terminal connected to an output terminal of the differentiator (Δ); (e) an MOS storage capacitor (C) having one terminal connected to an output terminal of the inhibitor (D); (f) a leakage current source connected to said one terminal for providing a leakage current thereto if and only if the charge on said terminal is above a threshold, said inhibitor (D) directed for delivering charge in a direction tending to charge said one terminal and said leakage current being in a direction tending to discharge said one terminal; whereby the voltage level at said one terminal is a binary indication of whether or not the clock pulse voltage source is operative.
Claim 4
Dependent Claim 188 words
Semiconductor apparatus which comprises: (a) a first MOS voltage shifting device (I 1 ) having an input terminal for the application thereto of a clock pulse voltage source; (b) an MOS differentiator (Δ) having an input terminal connected to an output terminal of the first device (I 1 ); (c) an MOS thresholding amplifier (A) having an input terminal connected to an output terminal of the differentiator (Δ); (d) an MOS unidirectional current inhibitor (D) having an input terminal connected to an output terminal of the differentiator (Δ); (e) an MOS storage capacitor (C) having one terminal connected to an output terminal of the inhibitor (D); (f) a leakage current source connected to said one terminal for providing a leakage current thereto if and only if the charge on said terminal is above a threshold, said inhibitor (D) directed for delivering charge in a direction tending to charge said one terminal and said leakage current being in a direction tending to discharge said one terminal; whereby the voltage level at said one terminal is a binary indication of whether or not the clock pulse voltage source is operative.
Claim 5
Dependent Claim 51 words
Apparatus according to claim 2 which further comprises a second MOS voltage shifting device I 2 whose input terminal is connected to said one terminal, whereby the voltage level at an output terminal of said second device I 2 is a binary output indicative of interruption of said clock pulse input.
Claim 6
Dependent Claim 14 words
Apparatus according to claim 3 in which said second device is a voltage inverter.
Claim 7
Dependent Claim 17 words
Apparatus according to claim 2 in which said first device (I 1 ) is an MOS inverter.
Claim 8
Dependent Claim 24 words
Apparatus according to claim 2 in which said inhibitor (D) is an MOS field effect transistor whose gate electrode is connected to its drain.
Claim 9
Dependent Claim 377 words
Semiconductor apparatus comprising: (a) a first MS transistor (T 1 ) whose source is connected to a first node N 1 ; (b) a second MOS transistor (T 2 ), characterized by a high transconductance at least ten times that of the first transistor (T 1 ), the drain of T 2 being connected to said first node (N 1 ), and the gate electrode of T 2 being connected to an input node (N 2 ); (c) a third MOS transistor (T 3 ) whose source is connected to its drain and whose gate electrode is connected to the first node (N 1 ); (d) a fourth MOS transistor (T 4 ), characterized in its "on" state by a fourth impedance, whose drain is connected to the drain of the third transistor (T 3 ); (e) a fifth MOS transistor (T 5 ) whose gate electrode is connected to the drain of the fourth transistor (T 4 ); (f) a sixth MOS transistor (T 6 ) whose source is connected to the drain of the fifth transistor (T 5 ), the transconductance of T 5 being at least ten times that of T 6 ; (g) a seventh MOS transistor (T 7 ) whose source is connected to the drain of an eighth MOS transistor (T 8 ), the gate electrode of said eighth transistor being connected to the drain of the fifth transistor (T 5 ), the transconductance of T 8 being at least ten times that of T 7 ; (h) a ninth MOS transistor (T 9 ) whose gate electrode is connected to its drain and to the drain of the eighth transistor (T 8 ); (i) a tenth MOS transistor (T 10 ) whose drain is connected to the source of the ninth transistor (T 9 ) and whose gate electrode is connected to the drain of an eleventh MOS transistor (T 11 ) and to the source of a twelfth MOS transistor (T 12 ), the transconductance of T 11 being at least ten times that of T 12 ; (j) a thirteenth MOS transistor (T 13 ) whose source is connected to its drain and whose gate electrode is connected to the drain of the tenth transistor (T 10 ).
Claim 10
Dependent Claim 377 words
Semiconductor apparatus comprising: (a) a first MS transistor (T 1 ) whose source is connected to a first node N 1 ; (b) a second MOS transistor (T 2 ), characterized by a high transconductance at least ten times that of the first transistor (T 1 ), the drain of T 2 being connected to said first node (N 1 ), and the gate electrode of T 2 being connected to an input node (N 2 ); (c) a third MOS transistor (T 3 ) whose source is connected to its drain and whose gate electrode is connected to the first node (N 1 ); (d) a fourth MOS transistor (T 4 ), characterized in its "on" state by a fourth impedance, whose drain is connected to the drain of the third transistor (T 3 ); (e) a fifth MOS transistor (T 5 ) whose gate electrode is connected to the drain of the fourth transistor (T 4 ); (f) a sixth MOS transistor (T 6 ) whose source is connected to the drain of the fifth transistor (T 5 ), the transconductance of T 5 being at least ten times that of T 6 ; (g) a seventh MOS transistor (T 7 ) whose source is connected to the drain of an eighth MOS transistor (T 8 ), the gate electrode of said eighth transistor being connected to the drain of the fifth transistor (T 5 ), the transconductance of T 8 being at least ten times that of T 7 ; (h) a ninth MOS transistor (T 9 ) whose gate electrode is connected to its drain and to the drain of the eighth transistor (T 8 ); (i) a tenth MOS transistor (T 10 ) whose drain is connected to the source of the ninth transistor (T 9 ) and whose gate electrode is connected to the drain of an eleventh MOS transistor (T 11 ) and to the source of a twelfth MOS transistor (T 12 ), the transconductance of T 11 being at least ten times that of T 12 ; (j) a thirteenth MOS transistor (T 13 ) whose source is connected to its drain and whose gate electrode is connected to the drain of the tenth transistor (T 10 ).
Claim 11
Dependent Claim 28 words
Apparatus according to claim 7 which further includes means for producing an output voltage level corresponding to the voltage level on the gate electrode of T 13 .
Claim 12
Dependent Claim 143 words
Apparatus according to claim 8 in which said means comprises fourteenth and fifteenth MOS transistors (T 14 and T 15 ) the ratio of whose transconductance is less than 1/10, the source of the fourteenth transistor (T 14 ) being connected to the drain of the fifteenth transistor (T 15 ), the gate electrode of the fifteenth transistor (T 15 ) being connected to the gate electrode of the thirteenth transistor (T 13 ), and the drain of the fifteenth transistor (T 15 ) being connected to an output node (N 0 ), whereby in response to a clock pulse source applied to the gate electrode of the second transistor (T 2 ), the voltage level at the drain of the fifteenth transistor (T 15 ) is a binary indication of whether or not the clock pulse source is or is not interrupted.

References Cited (Backward Citations)

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US3153762A Cited
US3458822A Cited
US3903474A Cited
US4004162A Cited
US4004164A Cited
US4048518A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1983-10-28 1984-04-28 1984-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1987-10-28 1988-04-28 1988-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1991-10-28 1992-04-28 1992-10-28 $7700.00 Window Closed / Lapsed

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