# US 6,295,621 B1 · Apparatus for detecting output bond integrity in a display driver circuit

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 6,295,621 B1
- Document ID: US6295621B1
- Status: Granted
- Kind: B1
- Application number: 08/052,494
- Filed: 1993-04-22
- Granted: 2001-09-25
- Earliest claimed: 1993-04-22
- Assignees: Medtronic, Inc.
- Inventors: Richard Alexander Erhart; Richard Brian Nelson
- Web page: https://patentgrep.com/patent/US6295621B1

## CPC

- G09G 3/006: {Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309)}
- G01R 31/50: Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections (testing of sparking plugs H01T13/58)
- G01R 31/54: Testing for continuity
- G01R 31/66: Testing of connections, e.g. of plugs or non-disconnectable joints (testing for incorrect line connections G01R31/55)
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A display driver circuit for driving a flat panel display including circuitry for detecting integrity of bonding of outputs of the driver circuit to the display. The bond integrity detecting circuitry includes a test mode current source which applies current to the output being tested to raise its voltage to a threshold level. At a defined sampling time following initiation of application of the test mode current, the voltage on the output being tested is compared to the threshold level, and the result of the comparison is stored and output from the driver circuit. If the voltage of the output has not reached the threshold level at the defined sampling time, the output connection is determined to be good.

## Claims

### Claim 1

A display driver circuit having an output for driving a display, comprising means for detecting integrity of bonding of said output to a display, said bond integrity detecting means in turn comprising:
means for driving said output to a first voltage level;
means for applying a test mode current to said output to change voltage on said output to a second voltage level;
means for defining a sampling time following initiation of application of said test mode current to said output; and
means for indicating whether voltage on said output has reached said second voltage level at said sampling time.

### Claim 2 (depends on 1)

An apparatus according to claim 1 wherein said indicating means comprises a circuit means for providing a first logic signal when voltage on said output has not reached said second voltage level and for providing a second logic signal when voltage on said output has reached said voltage level.

### Claim 3 (depends on 2)

Apparatus according to claim 2 wherein said indicating means further comprises means for storing whichever of said first and second logic signals is present at said sampling time and means for outputting said stored signal from said display driver circuit.

### Claim 4 (depends on 3)

An apparatus according to claim 3 wherein said logic signal providing means comprises a switch circuit and wherein said second voltage level is a switching threshold for said switching circuit.

### Claim 5 (depends on 4)

An apparatus according to claim 4 wherein said storing means comprises means for latching said first or second logic signals provided by said switching circuit.

### Claim 6 (depends on 1, 2, 3, 4, 5)

Apparatus according to claim 1 or claim 2 or claim 3 or claim 4 or claim 5 wherein said sampling time defining means comprises means for defining a sampling time intermediate a first time at which said voltage on said output typically would reach said second voltage level if said output was properly bonded to said display and a second time at which said voltage on said output typically would reach said second voltage level if said output was not properly bonded to said display.