EP0097857A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Current switch emitter follower
Assignee: International Business Machines Corp
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Filing: 1983-06-10
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Granted: —
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Expires: 2003-06-10
Abstract
Abstract 57 Disclosed in a high performance current switch push-pull driver circuit. A first output of the current switch (T1, T2) is direct coupled to the push-pull driver (T5, T6) while the second output of the current switch is coupled to the push-pull driver by means of an emitter follower (T3) and current mirror (TM). Emitter followers (T3, T4) connected to the current switch (T1, T2) provide a first pair of true/ complement outputs (OUT1, OUT1) while push-pull drivers provide a second set of true/complementary outputs (OUT2, OUT2) having a higher drive capability. The current mirror (TM) is biased near its turn on potential providing current control switching of the current mode transistor and the push-pull driver transistor with which it is coupled. The circuit is greatly tolerant for varying load conditions, is protected against short circuit and power supply failures and has means for three state operation.
Inventors
- 👤 Leo Boyes Freeman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 05:19
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/02; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/603; H03K19/00; H03K19/02; H03K19/08; H03K19/082; H03K19/0823; H03K19/0826
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
86 words
Current switch emitter follower circuit comprising a current switch (Tl, T2) adapted to receive at least one input and providing true/complement first and second outputs, a push-pull circuit (T5, T6) having first and second inputs and an output, the first input being electrically connected to the first output of said current switch, characterized by circuit means including an emitter follower (T3) and current mirror (TM) electrically coupling the second output of said current switch (T1, T2) to the second input of said push-pull (T5, T6) circuit.
Claim 2
Dependent Claim
86 words
Current switch emitter follower circuit comprising a current switch (Tl, T2) adapted to receive at least one input and providing true/complement first and second outputs, a push-pull circuit (T5, T6) having first and second inputs and an output, the first input being electrically connected to the first output of said current switch, characterized by circuit means including an emitter follower (T3) and current mirror (TM) electrically coupling the second output of said current switch (T1, T2) to the second input of said push-pull (T5, T6) circuit.
Claim 3
Dependent Claim
115 words
The circuit as claimed in claim 1, characterized by the current switch circuit including at least first and second transistors (Tl, T2) having their emitters connected in common and to a substantially constant source of current (T10, R3); third and fourth transistors (T3, T4) each having their base electrode connected to the collector of said first and second transistors (Tl, T2), respectively and forming emitter follower circuits; a push-pull driver including fifth and sixth transistors (T5, T6), the base of the fifth transistor (T5) being coupled to the collector of said second transistor (T2); and a current mirror (TM) coupling the emitter of said third transistor (T3) to the base of said sixth transistor (T6).
Claim 4
Dependent Claim
53 words
The circuit as claimed in claim 2, characterized by another push-pull driver (T5', T6').having first and second inputs, the first input being coupled to the collector of said first transistor (Tl); and another current mirror (TM') coupling the emitter of said fourth transistor (T4) to a second input of said another push-pull driver.
Claim 5
Dependent Claim
46 words
The circuit as claimed in claims 1 to 3, characterized by a resistor network (R4', R6, R5) for setting a bias potential to said current mirror (TM), at least one resistor (R6) of said resistor network coupling the emitter follower (T4) to said current mirror (TM).
Claim 6
Dependent Claim
44 words
The circuit as claimed in claim 4, characterized in that said current mirror comprises: a transistor (TM) the collector and base regions of which being connected in common and to said resistor network, and the emitter region being connected to a voltage source (VT).
Claim 7
Dependent Claim
57 words
The circuit as claimed in claim 5, characterized by a conductive connection extending from the common base collector connection of said current mirror transistor (TM) to the second input of said push-pull circuit (T5, T6); and a unidirectionally conducting means (SBD4) coupling the second input of said push-pull circuit to the output (OUT2) of said push-pull circuit.
Claim 8
Dependent Claim
76 words
The circuit as claimed in claim 4, characterized in that said resistor network comprises first, second, and third resistors connected in a series electrical current path; said first resistor (R5) being connected between a first voltage source (VCC) and said current mirror (TM); said second resistor (R6) being connected between said current mirror (TM) and said emitter follower (T3); said mird resistor (R4') being connected between said second resistor (R6) and a second voltage source (VEE).
Claim 9
Dependent Claim
87 words
The circuit as in claims 1 to 7, characterized in that said push-pull circuit comprises firs: and second push-pull transistors (T5, T6) conrected in a series electrical path between first and second voltage sources (VCC, VT), the emitter of the first push-pull transistor (T5) being connected to the collector of the second push-pull transistor (T6) and forming the output (OUT2) for the push-pull circuit, the base of the first push-pull transistor (T5) forming the first input, the base of the second transistor (T6) forming the second input.
Claim 10
Dependent Claim
50 words
The circuit as claimed in claim 8, characterized by a unidirectionally conducting means (SBD3) coupling the base of the first push-pull transistor (T5) to the collector of the first push-pull transistor; and a resistance (R7) coupling the collector of the first push-pull transistor (T5) to said first voltage source (VCC).
Claim 11
Dependent Claim
30 words
The cicuit as claimed in claims 1 to 9, characterized by disabling means (T8) connected to both the first input and the second input of said push-pull circuit (T5, T6).
References Cited (Backward Citations)
No citation records indexed.
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