EP0344614A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
TTL totem pole anti-simultaneous conduction circuit
Assignee: National Semiconductor Corp
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Filing: 1989-05-25
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Granted: —
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Expires: 2009-05-25
Abstract
Abstract An anti-simultaneous conduction transistor is incorporated into the standard TTL circuit totem pole to reduce simultaneous conduction of the pullup and pulldown transistor elements of the totem pole. The collector of the active discharge anti-simultaneous conduction transistor element (Q5) is operatively coupled to a base of the pullup transistor element (Q2,Q3) through a diode (D5), the emitter is coupled to low potential, and the base is coupled to the base of the pulldown transistor element (Q4) through ballast resistance (R6,R7). The anti-simultaneous conduction transistor element (Q5) mirrors the conducting state of the pulldown transistor element (Q4) without current hogging substantially diverting or discharging base current from the base of the pullup transistor element (Q2,Q3) whenever the pulldown transistor element (Q4) is conducting. Undesirable current spikes in the sourcing current are avoided by preventing simultaneous conduction in the totem pole.
Inventors
- 👤 Julio Estrada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 14:28
CPC Classifications
H; H03; H03K; H03K19/00; H03K19/02; H03K19/08; H03K19/082; H03K19/088; H03K19/0008; H03K19/001
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
136 words
In a circuit having an output node, a (V₀) pullup element (Q₂,Q₃) for sourcing current from high potential to (V cc ) to the output node, and a pulldown (Q₄) for sinking current from the output node to low potential, the improvement for reducing simultaneous conduction of the pullup and pulldown elements comprising: an active anti-simultaneous element (Q₅) having a collector operatively coupled to a base of the pullup element and an emitter operatively coupled to low potential for diverting base drive current from the pullup element to low potential when the anti-simultaneous element is conducting, said anti-simultaneous element having a base operatively coupled to the base of the pulldown element to follow the conducting state of the pulldown element and substantially divert base drive current from the pullup element whenever the pulldown element is conducting.
Claim 2
Dependent Claim
136 words
In a circuit having an output node, a (V₀) pullup element (Q₂,Q₃) for sourcing current from high potential to (V cc ) to the output node, and a pulldown (Q₄) for sinking current from the output node to low potential, the improvement for reducing simultaneous conduction of the pullup and pulldown elements comprising: an active anti-simultaneous element (Q₅) having a collector operatively coupled to a base of the pullup element and an emitter operatively coupled to low potential for diverting base drive current from the pullup element to low potential when the anti-simultaneous element is conducting, said anti-simultaneous element having a base operatively coupled to the base of the pulldown element to follow the conducting state of the pulldown element and substantially divert base drive current from the pullup element whenever the pulldown element is conducting.
Claim 3
Dependent Claim
26 words
The circuit of claim 1 wherein the collector of the anti-simultaneous element is operatively coupled through a diode (D5) to the base of the pullup element.
Claim 4
Dependent Claim
41 words
The circuit of claim 1 wherein the base of the anti-simultaneous element is operatively coupled to the base of the pulldown element through resistor means (R6, R7) selected to substantially reduce current hogging between the anti-simultaneous element and the pulldown element.
Claim 5
Dependent Claim
45 words
The circuit of claim 3 wherein the resistor means comprises a first resistor (R7) coupled to the base of the pulldown element, a second resistor (R6) coupled to the base of the anti-simultaneous element, said first and second resistors being coupled at a common node.
Claim 6
Dependent Claim
41 words
The circuit of claim 4 further comprising a phase splitter element (Q1) for controlling the conducting states of the pullup and pulldown elements, the phase splitter element having an emitter coupled to the common node of said first and second resistors.
Claim 7
Dependent Claim
129 words
In a TTL circuit totem pole having a pullup transistor element for sourcing current from high potential to an output node and a pulldown transistor element for sinking current from the output node to low potential, the improvement for reducing simultaneous conduction of the pullup and pulldown transistor elements comprising: an active discharge transistor element having a collector operatively coupled to the base of the pullup transistor element, an emitter operatively coupled to low potential, and a base operatively coupled to the base of the pulldown transistor element so that the conducting state of the active discharge transistor element mirrors the conducting state of the pulldown transistor element for substantially diverting base drive current from the base of the pullup transistor element whenever the pulldown transistor element is conducting.
Claim 8
Dependent Claim
129 words
In a TTL circuit totem pole having a pullup transistor element for sourcing current from high potential to an output node and a pulldown transistor element for sinking current from the output node to low potential, the improvement for reducing simultaneous conduction of the pullup and pulldown transistor elements comprising: an active discharge transistor element having a collector operatively coupled to the base of the pullup transistor element, an emitter operatively coupled to low potential, and a base operatively coupled to the base of the pulldown transistor element so that the conducting state of the active discharge transistor element mirrors the conducting state of the pulldown transistor element for substantially diverting base drive current from the base of the pullup transistor element whenever the pulldown transistor element is conducting.
Claim 9
Dependent Claim
48 words
The TTL circuit totem pole of claim 6 wherein the base of the active discharge transistor element is operatively coupled to the base of the pulldown transistor element through resistor means selected to substantially avoid current hogging between the active discharge transistor element and the pulldown transistor element.
Claim 10
Dependent Claim
41 words
The TTL circuit totem pole of claim 7 wherein the resistor means comprises a first resistor operatively coupled to the base of the active discharge transistor element, and a second transistor operatively coupled at the base of the pulldown transistor element.
Claim 11
Dependent Claim
45 words
The TTL circuit totem pole of claim 8 wherein the collector of the active discharge transistor element is operatively coupled to the base of the pullup transistor element through a diode oriented to block current flow back to the base of the pullup transistor element.
Claim 12
Dependent Claim
62 words
The TTL circuit totem pole of claim 9 comprising a phase splitter transistor element operatively coupled to the totem pole for controlling the conducting states of the pullup and pulldown transistor elements, the emitter of said phase splitter transistor being coupled respectively to the bases of the active discharge transistor element and the pulldown transistor element through the first and second resistors.
Claim 13
Dependent Claim
21 words
The TTL circuit totem pole of claim 6 wherein the totem pole is incorporated in an ECL to TTL translator circuit.
Claim 14
Dependent Claim
114 words
A totem pole for TTL circuits having a pullup transistor element for sourcing current from high potential to an output node and a pulldown transistor element for sinking current from the output node to low potential, the improvement comprising: an anti-simultaneous conduction transistor element having a collector operatively coupled to a base of the pullup transistor element and an emitter coupled to low potential, the base of said anti-simultaneous conduction transistor element being operatively coupled to the base of the pulldown transistor element for mirroring the conducting state of the pulldown transistor element and substantially diverting base drive current from the base of the pullup transistor element whenever the pulldown transistor element is conducting.
Claim 15
Dependent Claim
114 words
A totem pole for TTL circuits having a pullup transistor element for sourcing current from high potential to an output node and a pulldown transistor element for sinking current from the output node to low potential, the improvement comprising: an anti-simultaneous conduction transistor element having a collector operatively coupled to a base of the pullup transistor element and an emitter coupled to low potential, the base of said anti-simultaneous conduction transistor element being operatively coupled to the base of the pulldown transistor element for mirroring the conducting state of the pulldown transistor element and substantially diverting base drive current from the base of the pullup transistor element whenever the pulldown transistor element is conducting.
References Cited (Backward Citations)
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