TEST SYSTEM AND METHOD

• US 20120062247A1
• Filed: 09/14/2010
• Published: 03/15/2012
• Est. Priority Date: 09/14/2010
• Status: Active Grant

• Current Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Original Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Inventors: Chang, Yaw-Guang
• Granted Patent: US 8,493,080 B2
• Time in Patent Office: Days
• US Class Current: 324/679
• CPC Class Codes: G01D 2218/10 Testing of sensors or measuring arrangements
• CPC Class Codes: G01D 5/2405 by varying dielectric
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G01R 31/2839 using signal generators, power supplies or circuit analysers G01R31/2879 takes precedence; multimeters G01R15/12, network analysers G01R27/28
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

A test system for testing a capacitive touch sensor is provided. The test system includes a resistor, a signal generator and a micro controller. A first end of the resistor is electrically connected to a sensing port of the capacitive touch sensor. The signal generator provides a test voltage to a second end of the resistor according to control information. In this way, the resistor generates a test current according to the test voltage, and the capacitive touch sensor provides a voltage difference to the sensing port according to a plurality of switching signals, and converts the test current into test information. The micro controller generates the control information according to a test table, and compares the test information according to the test table, so as to determine whether an operation of the capacitive touch sensor is normal.

Claims

1. A test system, for testing a capacitive touch sensor, and the test system comprising:

a resistor, having a first end electrically connected to a sensing port of the capacitive touch sensor;

a signal generator, electrically connected to a second end of the resistor, and providing a test voltage to the resistor according to control information, wherein the resistor generates a test current according to the test voltage, and the capacitive touch sensor provides a voltage difference to the sensing port according to a plurality of switching signals, and converts the test current into test information; and

a micro controller, electrically connected to an output port of the capacitive touch sensor for receiving the test information, generating the control information according to a test table, and comparing the test information according to the test table, so as to determine whether an operation of the capacitive touch sensor is normal.

2. The test system as claimed in claim 1, wherein the signal generator is implemented by a digital-to-analog converter.

3. The test system as claimed in claim 1, wherein the micro controller establishes the test table according to the resistor, the voltage difference and a frequency and a duty cycle of the switching signals, wherein the test table records a plurality of voltage information and a plurality of capacitance information, and the micro controller selects one of the plurality of voltage information to regard as the control information.

4. The test system as claimed in claim 3, wherein the micro controller looks up the test table according to the selected voltage information, so as to select one of the plurality of capacitance information, and the micro controller compares the test information to the selected capacitance information, so as to determine whether the test information is correct, wherein if the test information is correct, the micro controller determines that the operation of the capacitive touch sensor is normal, and if the test information is incorrect, the micro controller determines that the operation of the capacitive touch sensor is abnormal.

5. A test method, for testing a capacitive touch sensor, and the test method comprising:

electrically connecting a first end of a resistor to a sensing port of the capacitive touch sensor;

generating control information according to a test table;

providing a test voltage to a second end of the resistor according to the control information, so that the resistor generates a test current according to the test voltage, and the capacitive touch sensor providing a voltage difference to the sensing port according to a plurality of switching signals, and converting the test current into test information; and

receiving the test information, and comparing the test information according to the test table, so as to determine whether an operation of the capacitive touch sensor is normal.

6. The test method as claimed in claim 5, wherein the step of generating the control information according to the test table comprises:

establishing the test table according to the resistor, the voltage difference and a frequency and a duty cycle of the switching signals, wherein the test table records a plurality of voltage information and a plurality of capacitance information; and

selecting one of the plurality of voltage information to regard as the control information.

7. The test method as claimed in claim 6, wherein the step of comparing the test information according to the test table, so as to determine whether the operation of the capacitive touch sensor is normal comprises:

looking up the test table according to the selected voltage information, so as to select one of the plurality of capacitance information;

comparing the test information to the selected capacitance information, so as to determine whether the test information is correct;

determining that the operation of the capacitive touch sensor is normal if the test information is correct; and

determining that the operation of the capacitive touch sensor is abnormal if the test information is incorrect.