Infra-red data processing circuit

• US 6,175,601 B1
• Filed: 11/23/1998
• Issued: 01/16/2001
• Est. Priority Date: 03/20/1997
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: SigmaTel Incorporated (NXP Semiconductors NV)
• Inventors: Rybicki, Mathew A, Rokhsaz, Shahriar, Jackson, H. Spence
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US09/198,075
• Time in Patent Office: 785 Days
• Field of Search: 375/345, 375/316, 375/219, 375/377, 359/189, 359/190, 359/191, 359/194, 250/214.B
• US Class Current: 375/345
• CPC Class Codes: H04L 25/063 Setting decision thresholds using feedback techniques only
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation

Abstract

A pre-amplifier circuit, which may be used in a variety of data recovery circuits to accurately recover data transmissions, includes an input regulatory circuit, a feedback circuit, and an amplifier. The input regulatory circuit regulates the magnitude of the data signal provided to the amplifier based on feedback signals from a feedback circuit. For low level data signals, the input regulatory circuit provides a full, or almost full, representation of the data signal to the amplifier for amplification. But, when the data signal levels increase, the input regulatory circuit attenuates, based on the feedback signals, the data signals more and more before providing them to the amplifier, such that the output of the amplifier stays within a certain range.

Claims

1. An infra-red data processing circuit comprising:

a light sensing diode that receives light pulse information;

a pulse detection circuit operably coupled to the light sensing diode, the pulse detection circuit includes;

a comparison circuit;

a gain circuit operably coupled to the comparison circuit;

an offset circuit operably coupled to the comparison circuit and the gain circuit; and

a pre-amplifier circuit operably coupled to the gain circuit and the light sensing diode, the pre-amplifier circuit includes an input regulatory circuit inter-operably coupled with an amplifier and a feedback circuit.

2. The infra-red data processing circuit of claim 1 further comprises a digital circuitry operably coupled to the pulse detection circuit, wherein the digital circuitry interprets digital pulses detected by the pulse detection circuit.

3. The infra-red data processing circuit of claim 1 further comprises an ambient light cancellation circuit operably coupled to the pulse detection circuit.