Intelligent Multi-meter with Automatic function selection

• US 20100013511A1
• Filed: 09/24/2008
• Published: 01/21/2010
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Cyrustek Co.
• Original Assignee: Cyrustek Co.
• Inventors: LI, Chun-Liang
• Granted Patent: US 7,746,092 B2
• Time in Patent Office: Days
• US Class Current: 324/754.20
• CPC Class Codes: G01R 15/125 for digital multimeters

Abstract

Intelligent Multi-meter with Automatic function selection A measuring device with the function of automatically determining the type of device under test (DUT) and selecting measuring function, comprising: a controller for sequentially providing a plurality of checking phases; a protection circuit connecting to input end and protecting the measuring device; a switch composed of a plurality of test circuits, being connected to the controller and sequentially connecting the plurality of test circuits with the output end of the protection circuit; a plurality of DUT type detectors, connecting to the switch and comparing the voltage of input end sequentially through a plurality of comparison circuits, transmitting the result of comparison to the controller for determining the type of DUT; and a measurement unit connecting to the controller, measuring the DUT according to the result of determination of the controller and displaying the result of measurement on a display.

Claims

1. A measuring device with function of automatically selecting measuring function, comprising:

a controller for sequentially providing a plurality of checking phases;

a protection circuit with a first end connecting to an input end connected with DUT and a second end connecting to said controller, performing switching action according to signal of said controller;

a switch composed of a plurality of test circuits, with a first end connecting to third end of said protection circuit, a second end connecting to said controller and sequentially performing switching action according to said plurality of checking phases for sequentially connecting said plurality of test circuits with said protection circuit, and a third end connecting to a current input end; and

a DUT type detector with a first end connecting to a third end of said switch, sequentially comparing voltage of said input end with a comparison circuit and transmitting the result of comparison to said controller with a second end;

wherein said controller determines type of DUT according to result of comparison transmitted by said DUT type detector.

2. The measuring device according to claim 1, wherein said protection circuit includes a pair of electric switches and said pair of electric switches are under control of said controller.

3. The measuring device according to claim 1, further comprising a large voltage detector, with first end connecting to second end of said protection circuit, second end connecting to said controller, and third end connecting to third end of said protection circuit.

4. The measuring device according to claim 1, further comprising a current detector, with first end connecting to said current input end, and second end connecting to said controller.

5. The measuring device according to claim 1, further comprising a short detector, with first end connecting to third end of said switch, and second end connecting to said controller.

6. The measuring device according to claim 5, wherein said short detector is further connected to a buzzer.

7. The measuring device according to claim 1, wherein said plurality of scan modes provided by said controller are sequentially for:

voltage, diode, capacitor, open detection.

8. The measuring device according to claim 7, wherein said diode detection mode can be further divided into a positive bias voltage scan signal and a negative bias voltage scan signal.

9. The measuring device according to claim 1, wherein test circuit of said switch is selected from the group consisting of:

an input voltage test circuit configuration, a diode positive bias voltage test circuit configuration, a diode negative bias voltage test circuit configuration, a capacitor charging test circuit configuration, a capacitor dis-charging test circuit configuration, and an open test circuit configuration.

10. The measuring device according to claim 1, wherein said controller performs look-up table to compare result of comparison against a pre-set table for determining type of DUT.

11. The measuring device according to claim 9, wherein said input voltage test circuit configuration comprises:

an input end of voltage under test;

a first terminal, connecting to said input end of voltage under test through a first resistor;

a second terminal, connecting to said input end of voltage under test through a second resistor; and

a third terminal, connecting to said input end of voltage under test through a PTC resistor R_PTC;

wherein said second terminal and said third terminal are floating and said first terminal connects to ground.

12. The measuring device according to claim 9, wherein said diode positive bias voltage test circuit configuration in said switch comprises:

an input end of DUT;

a first terminal, connecting to said input end of DUT through a first resistor;

a second terminal, connecting to said input end of DUT through a second resistor; and

a third terminal, connecting to said input end of DUT through a PTC resistor R_PTC;

wherein said second terminal connects to comparator in said DUT type detector, said third terminal connects to a positive voltage, and said first terminal connects to ground.

13. The measuring device according to claim 9, wherein said diode negative bias voltage test circuit configuration in said switch comprises:

an input end of DUT;

a first terminal, connecting to said input end of DUT through a first resistor;

a second terminal, connecting to said input end of DUT through a second resistor; and

a third terminal, connecting to said input end of DUT through a PTC resistor R_PTC;

wherein said second terminal connects to comparator in said DUT type detector, said third terminal connects to a negative voltage, and said first terminal connects to ground.

14. The measuring device according to claim 9, wherein said capacitor charging test circuit configuration in said switch comprises:

an input end of DUT;

a first terminal, connecting to said input end of DUT through a first resistor;

a second terminal, connecting to said input end of DUT through a second resistor; and

a third terminal, connecting to said input end of DUT through a PTC resistor R_PTC;

wherein said second terminal connects to comparator in said DUT type detector, said third terminal connects to a negative voltage, and said first terminal is floating.

15. The measuring device according to claim 9, wherein said capacitor dis-charging test circuit configuration in said switch comprises:

an input end of DUT;

a first terminal, connecting to said input end of DUT through a first resistor;

a second terminal, connecting to said input end of DUT through a second resistor; and

a third terminal, connecting to said input end of DUT through a PTC resistor R_PTC;

wherein said second terminal connects to ground, said third terminal connects to comparator in said DUT type detector, and said first terminal is floating.

16. The measuring device according to claim 9, wherein said open test circuit configuration in said switch comprises:

an input end of DUT;

a first terminal, connecting to said input end of DUT through a first resistor;

a second terminal, connecting to said input end of DUT through a second resistor; and

a third terminal, connecting to said input end of DUT through a PTC resistor R_PTC;

wherein said third terminal connects to comparator in said DUT type detector, said second terminal is floating, and said first terminal connects to a negative voltage.

17. The measuring device according to claim 10, wherein said pre-set table is a pre-set logic table.

18. A measuring device with function of automatically selecting measuring function, comprising:

a controller for sequentially providing a plurality of checking signals;

a protection circuit with a first end connecting to an input end connected with DUT and a second end connecting to said controller, performing switching action according to signal of said controller;

a switch composed of a plurality of test circuits, with a first end connecting to third end of said protection circuit, a second end connecting to said controller and sequentially performing switching action according to said plurality of checking phases for sequentially connecting said plurality of test circuits with said protection circuit, and a third end connecting to a current input end;

a DUT type detector with a first end connecting to a third end of said switch, sequentially comparing voltage of said input end with a comparison circuit and transmitting the result of comparison to said controller with a second end; and

a measurement unit, connecting to said controller and selecting a corresponding measurement unit for performing measurement on said DUT according to result of determination of said controller, and displaying result of measurement on a display.

19. The measuring device according to claim 18, wherein said measurement unit is composed of a AD/DA converter, a data processing unit, and a range control circuit.

20. A measuring device with function of automatically selecting measuring function, disposed with a display for displaying values of a plurality of auto scan modes and measure modes, a controller connecting to a protection circuit and a switch for providing a plurality of circuits with switching and selection modes to perform measurement of particular signals, and a pair of inputs, the characteristic in that:

switching and selection modes of said plurality of circuits are selected according to auto scan mode provided by said controller to automatically determine type of said DUT connecting to said pair of inputs and to selectively perform automatic value measurement on said DUT.

21. The measuring device according to claim 20, further comprising a plurality of additional function keys, which can be pressed for directly activating additional measure functions and displaying measured result.

22. The measuring device according to claim 20, wherein said plurality of additional function keys is selected from the group consisting of:

SEL (measure mode function key), RANGE (specific measurement range function key), and VAHz (frequency measurement function key), HOLD (value kept on display key), MAX/MIN (maximum/minimum value key), and BLT (backlight activation key).

23. The measuring device according to claim 20, wherein said plurality of checking phases further include a MANU mode (manually operated measurement mode) for performing measurement on specific DUT.

24. The measuring device according to claim 20, wherein said switch is provided with at least measure modes for voltage, current and passive components for selection.