Driving voltage detecting device

• US 20050179422A1
• Filed: 02/13/2004
• Published: 08/18/2005
• Est. Priority Date: 02/13/2004
• Status: Abandoned Application

• Current Assignee: Add Microtech Corp.
• Original Assignee: Worldwide International Patent & Trademark Office
• Inventors: Chiang, Johnson
• Application Number:
  US10/777,058
• Publication Number:
  US 20050179422A1
• Time in Patent Office: Days
• US Class Current: 323/281
• CPC Class Codes: G05F 1/40 using discharge tubes or semiconductor devices as final control devices

Abstract

A driving voltage detecting device comprises a current controlling circuit connected with a loading in series which supplies an adjustable current and a feedback controlling circuit that generates a controlled signal to said current controlling circuit for keeping the loading current constant by comparing the feedback signal with a reference signal. Two comparators are designed to connect to said controlled signal to determine precisely if the driving voltage being too high or too low when supply a loading with a predetermined current.

Claims

1. A driving voltage detecting device comprises:

A current controlling circuit connected with a loading in series supplies an adjustable current;

A feedback controlling circuit comparing the feedback signal with a reference signal that generates a controlled signal to said current controlling circuit for keeping the loading current constant; and

Two comparators connected to said controlled signal comparing with two reference signals separately determine the driving voltage being too high or too low to supply a loading with a predetermined current.

2. A driving voltage detecting device according to claim 1 wherein said two comparators can be reduced to one comparator to determine the driving voltage being too high to supply a loading with a predetermined current.

3. A driving voltage detecting device according to claim 1 wherein said two comparators can be reduced to one comparator to determine the driving voltage being too low to supply a loading with a predetermined current.

4. A driving voltage detecting device according to claim 1 wherein said current controlling circuit can be accomplished by transistor circuits.

5. A driving voltage detecting device according to claim 1 wherein said feedback controlling circuit can be accomplished by a resistor connected to said loading in series, and an amplifier comparing with a reference signal and the voltage across said resistor.