Touch dimmer system

• US 5,485,058 A
• Filed: 08/05/1994
• Issued: 01/16/1996
• Est. Priority Date: 11/12/1992
• Status: Expired due to Term

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Neiger, Benjamin, Watson, Douglas R., Lombardi, Albert, Aluma, Zvi, Justiniano, Joseph G., Bogorad, Lev, Rivera, Lester
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): Philogene, Haissa
• Application Number:
  US08/286,613
• Time in Patent Office: 529 Days
• Field of Search: 315/362, 315/194, 315/291, 315/307, 315/DIG. 4, 315/208, 315/293, 315/297
• US Class Current: 315/194
• CPC Class Codes: H05B 39/086 with possibility of remote control
• CPC Class Codes: Y10S 315/04 Dimming circuit for fluorescent lamps

Abstract

A key touch dimmer includes a switching device through which AC line current is passed to brighten a lamp in response to a control signal generated by a microprocessor. The microprocessor receives an input indicative of the zero crossing points of the AC line current and synchronizes this input with its own internal clock circuitry to generate a firing signal for the switching device at the correct phase angle in the next half cycle of the AC line current. The dimmer has memory capability whereby the lamp, when turned back on, will brighten to a preset level. This brightening is accomplished in a gradual manner. Likewise, a turned off lamp will fade to zero brightness, with the dimmer retaining the preset brightness level. The microprocessor shuts down quickly in the event of a power outage to preserve memory. An optional display includes a plurality of LEDs for indicating light level. Other options include providing the dimmer with several keys, each of which can be adjusted to a respective preset level.

Claims

1. A touch dimmer system comprising:

latching switch means comprising an input terminal, an output terminal, and a central terminal said control terminal being adapted to have applied to it a switching signal for causing said switch means to permit current from an AC line voltage source to flow through said latching switch means during a sub-cycle of said AC line voltage, said current operating to brighten one or more lamps connected in series with said output terminal;

zero crossing circuit means for generating a zero crossing signal in response to zero crossing points of said AC line voltage source;

a microprocessor comprising a self-contained clock oscillator connected to said zero crossing circuit means to receive said signal therefrom, said micro-processor producing a triggering signal output based on its own operating clock oscillator frequency;

key switch circuit means connected to said microprocessor, and said zero crossing signal;

output circuit means connected to said microprocessor to receive said triggering output signal therefrom and to thereupon generate said switching signal which is applied to said control terminal of said switching means;

power supply circuit means connected to said AC line current source and to said zero crossing circuit means, said power supply circuit means functioning to interrupt current flow through said latching switching means when voltage from said AC line voltage source reaches a certain level or when a predetermined time has elapsed since the most recent of said zero crossing points of said AC line voltage source; and

one or more respective dimmer key switches for setting various lamp brightness levels and for turning said one or more lamps on or off; and

comprising

said key switch circuit means connected to said key switches and to said microprocessor for indicating the state of said respective dimmer key switches to said microprocessor

means connected to said power supply circuit means to monitor the value of said power supply voltage and provide a monitor signal to said microprocessor;

said microprocessor evaluates said monitor signal to determine whether the power supply voltage is going up above a predetermined value or going down below said predetermined value, and provides a signal to said microprocessor to reset it when the power supply voltage is at said predetermined value;

said microprocessor Upon determining that said power supply voltage is falling initiates a halt mode to save the contents of the memory of said microprocessor;

said microprocessor upon determining that the supply voltage is rising starts itself up and first checks the memory of said microprocessor to see if the memory contents was lost during its shut down.