EP0466238A2
Expired / Lapsed
EP
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Driver circuit
Assignee: Koninklijke Philips NV
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Filing: 1991-06-27
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Granted: —
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Expires: 2011-06-27
Abstract
Abstract In a driver circuit, high- and low-impedance drive means (26 and 28 respectively) operate in parallel to effect a desired output transition. Adaptive control means 32 respond to a threshold value of the output signal (VO) and turn off the low-impedance drive means in the course of the output transition. The low initial output impedance of the driver circuit effects rapid charging of a line capacitance CL, while toward the end of the output transition the higher output impedance of the driver circuit more closely matches the input impedance ZL of a load circuit. This higher impedance dampens ringing and thereby reduces induced suppy line noise which is conventionally associated with high-speed driver circuits.
Inventors
- 👤 Thomas Dale Fletcher
- 👤 Edward Allyn Burton
- 👤 Benny Tin-Hung Ma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:53
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/16; H03K17/161; H03K17/165; H03K17/166; H03K17/167; H03K17/51; H03K17/56; H03K17/687; H03K17/6871; H03K17/6872
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
54 words
A driver circuit for causing a desired output transition in an output signal in response to a corresponding input transition in an input signal, characterized in that the circuit comprises adaptive control means for varying an output impedance of the driver circuit adaptively in response to the output signal as the output transition progresses.
Claim 2
Dependent Claim
25 words
A driver circuit as claimed in Claim 1 wherein the adaptive control means are arranged to increase the output impedance as the output transition progresses.
Claim 3
Dependent Claim
53 words
A driver circuit as claimed in Claim 2 wherein the circuit comprises first and second drive means responsive to the input signal and wherein the adaptive control means comprise means for deactivating the second drive means in response to the output signal crossing a threshold value in the course of the output transition
Claim 4
Dependent Claim
23 words
A driver circuit as claimed in Claim 3 wherein the first and second drive means comprise high- and low-output impedance drive means respectively.
Claim 5
Dependent Claim
56 words
A driver circuit as claimed in Claim 3 wherein the adaptive control means comprise; - a transmission gate for coupling the input signal to the second drive means; and - adaptive delay means for coupling the input signal to a gating input of the transmission gate in response to the output signal crossing the threshold value.
Claim 6
Dependent Claim
19 words
A driver circuit as claimed in Claim 5 wherein the first drive means also form the adaptive delay means.
Claim 7
Dependent Claim
64 words
A driver circuit as claimed in Claim 3 wherein: - the second drive means comprise a transistor having its main current path connected between a supply terminal and an output terminal of the driver circuit, which output terminal carries the output signal; and - clamping means are arranged to turn off the transistor actively in response to the output signal crossing said threshold value.
Claim 8
Dependent Claim
57 words
A driver circuit as claimed in Claim 3 wherein at least one of the first and second drive means comprise distributed drive means whereby at least a part of the drive means is activated with a small delay so as to reduce the rate of change of an current flowing in the circuit during the output transition.
Claim 9
Dependent Claim
35 words
A driver circuit as claimed in Claim 1 further comprising complementary drive means for effecting a complementary output transition of the output signal in a direction opposite to that of the first mentioned output transition.
Claim 10
Dependent Claim
20 words
A driver circuit as claimed in Claim 9 when constructed using complementary insulated gate transistors in a CMOS circuit configuration.
Claim 11
Dependent Claim
19 words
A driver circuit as claimed in Claim 3 wherein the second drive means comprise an insulated gate field-effect transistor.
Claim 12
Dependent Claim
24 words
A driver circuit as claimed in Claim 4 wherein the first and second drive means comprise insulated gate field-effect transistors of different channel dimensions.
Claim 13
Dependent Claim
17 words
An integrated circuit comprising at least one driver circuit as claimed in any of the previous Claims.
References Cited (Backward Citations)
No citation records indexed.
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