VOLTAGE DROP MEASUREMENT CIRCUIT

• US 20070296421A1
• Filed: 06/07/2007
• Published: 12/27/2007
• Est. Priority Date: 06/07/2006
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Matsunaga, Toshiyuki
• Granted Patent: US 7,902,844 B2
• Time in Patent Office: Days
• US Class Current: 324/713
• CPC Class Codes: G01R 19/16528 using digital techniques or performing arithmetic operations using digital techniques to measure a voltage or a current, see G01R19/25
• CPC Class Codes: G01R 19/16552 in I.C. power supplies
• CPC Class Codes: G01R 31/3004 Current or voltage test
• CPC Class Codes: G01R 31/31701 Arrangements for setting the Unit Under Test [UUT] in a test mode
• CPC Class Codes: G01R 31/31721 Power aspects, e.g. power supplies for test circuits, power saving during test for scan test G01R31/318575

Abstract

A voltage drop measurement circuit includes a voltage drop circuit to generate an output voltage and fluctuate the output voltage according to a fluctuation in a power supply voltage, where the output voltage being the power supply voltage dropped by a predetermined amount and a flip-flop to retain a flag indicating a drop in the power supply voltage according to the output voltage.

Claims

1. A voltage drop measurement circuit comprising:

a voltage drop circuit to generate an output voltage and fluctuate the output voltage according to a fluctuation of a power supply voltage, the output voltage being the power supply voltage dropped by a predetermined amount; and

a flip-flop to retain a flag indicating a drop of the power supply voltage according to the output voltage.

2. The voltage drop measurement circuit according to claim 1, wherein the voltage drop circuit changes a value of the output voltage according to an external input signal.

3. The voltage drop measurement circuit according to claim 1, wherein the voltage drop circuit generates the output voltage, the output voltage being a voltage dividing the power supply voltage by a predetermined division ratio.

4. The voltage drop measurement circuit according to claim 3, wherein the voltage drop circuit changes the division ratio according to an external input signal.

5. The voltage drop measurement circuit according to claim 1, wherein the flip-flop includes an input voltage threshold to evaluate a level of an input signal and the input voltage threshold fluctuates according to the fluctuation in the power supply voltage.

6. The voltage drop measurement circuit according to claim 2, wherein the flip-flop includes an input voltage threshold to evaluate a level of an input signal and the input voltage threshold fluctuates according to the fluctuation in the power supply voltage.

7. The voltage drop measurement circuit according to claim 3, wherein the flip-flop includes an input voltage threshold to evaluate a level of an input signal and the input voltage threshold fluctuates according to the fluctuation in the power supply voltage.

8. The voltage drop measurement circuit according to claim 4, wherein the flip-flop includes an input voltage threshold to evaluate a level of an input signal and the input voltage threshold fluctuates according to the fluctuation in the power supply voltage.

9. The voltage drop measurement circuit according to claim 5, wherein the input voltage threshold and the output voltage fluctuate at different sensitivities for the fluctuation in the power supply voltage.

10. A semiconductor device comprising a plurality of voltage drop measurement circuits,

wherein the voltage drop circuit includes:

a voltage drop circuit to generate an output voltage and fluctuate the output voltage according to a fluctuation in a power supply voltage, the output voltage being the power supply voltage dropped by a predetermined amount; and

a flip-flop to retain a flag indicating a drop in the power supply voltage according to the output voltage.