Waveshaping circuit

• US 4,668,875 A
• Filed: 04/08/1986
• Issued: 05/26/1987
• Est. Priority Date: 04/09/1985
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Miyazaki, Masaaki, Ishii, Mitsuaki
• Primary Examiner(s): Miller, Charles D.
• Assistant Examiner(s): Ip, Shik Luen Paul
• Application Number:
  US06/849,440
• Time in Patent Office: 413 Days
• Field of Search: 307/31, 307/33, 307/10 R, 307/10 BP, 307/10 LS, 307/64, 307/105, 307/106, 307/107, 307/108, 307/109, 307/260, 307/265, 307/266, 307/267, 307/268, 307/310, 307/317 R , 307/296 R, 307/318, 307/362, 307/520, 307/542, 307/543, 307/592, 307/597, 307/608, 307/362, 307/360, 307/361, 307/363, 307/364, 307/110, 307/132 E, 307/141, 328/74, 333/214, 333/215, 333/165, 333/167, 333/172, 333/181
• US Class Current: 307/106
• CPC Class Codes: H03K 5/1254 specially adapted for pulses generated by closure of switches, i.e. anti-bouncing devices debouncing circuits for electronic time-pieces G04G5/00

Abstract

A waveshaping circuit for providing logic levels from a voltage source to a digital circuit comprising a pull-up (or pull-down) resistor for converting the voltage source into voltage signals of predetermined values, a low-pass filter connected to the resistor for eliminating noise components of the voltage signals, a voltage limiter for limiting the voltage signals to a predetermined voltage range, and a voltage divider for receiving and dividing the voltage signals to supply output voltages of high or low logic levels to the digital circuit.

Claims

1. A waveshaping circuit for providing high and low logic levels from a voltage source to a digital circuit comprising means for converting said voltage source into voltage signals of predetermined values, a low-pass filter connected to said converting means for eliminating noise components of said voltage signals, a voltage limiter for limiting said voltage signals to a predetermined voltage range covering both the high and low logic levels, and a voltage divider for receiving and dividing said voltage signals to supply output voltages corresponding to high or low logic levels to the digital circuit.

2. A waveshaping circuit according to claim 1, wherein said voltage limiter comprises a first diode for providing an upper limit of said predetermined voltage range and a second diode for providing a lower limit of said predetermined voltage range.

3. A waveshaping circuit according to claim 1 wherein said voltage limiter comprises a Zener diode.

4. A waveshaping circuit according to claim 1 wherein said converting means includes a resistor.