Effective value voltage stabilizer for a display apparatus

• US 4,726,658 A
• Filed: 05/23/1984
• Issued: 02/23/1988
• Est. Priority Date: 05/31/1983
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Saka, Masakazu, Nishimura, Toshio
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Gallivan, Richard F.
• Application Number:
  US06/613,212
• Time in Patent Office: 1,371 Days
• Field of Search: 350/331 R, 350/332, 323/299, 323/906, 323/283
• US Class Current: 345/212
• CPC Class Codes: G09G 3/18 using liquid crystals
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

A voltage stabilizer receiver power from a power circuit for inputting a power source voltage. The voltage stabilizer changes the width of pulses in accordance with the changes in the effective value of the power source voltage and stabilizes the effective value of an applied voltage to a display regardless of the change in the effective value of the power source voltage by subtracting this pulse from pulses comprising the display drive waveforms.

Claims

1. In a display drive circuit including display drive means for driving a display with display drive waveforms formed of drive pulses, said drive waveforms being developed from voltage supplied from a power source, an effective drive voltage stabilizer comprising:

means for sensing said voltage developed from said power source and developing a binary representation of the relative value of said voltage;

means, responsive to said binary representation, for supplying a control signal representative of the period of each said drive pulse to said display drive means, said display drive means being responsive to said control signal to control the period of each said drive pulse.

2. The drive voltage stabilizer of claim 1 wherein said control signal has a pulse width which varies in proportion to said binary representation;

said display drive means reducing the pulse width of each said drive pulse by the width of said control signal to thereby produce drive pulses having a pulse width which decreases with increasing supply voltage developed by said voltage source.

3. The electronic apparatus of claim 1, wherein the display is a liquid crystal display.

4. The electronic apparatus of claim 1, wherein said power source is a solar battery.

5. The electronic apparatus of claim 1, wherein said stabilizing means is included within a large scale integrated circuit.