Electronic device and method for testing a circuit board

• US 8,508,235 B2
• Filed: 12/02/2010
• Issued: 08/13/2013
• Est. Priority Date: 06/02/2008
• Status: Expired due to Fees

• Current Assignee: Sartorius Lab Instruments GmbH & Co. KG (Sartorius AG)
• Original Assignee: Sartorius Weighing Technology GmbH (Sartorius AG)
• Inventors: Weitemeier, Swen, Oldendorf, Christian
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): LE, THANG XUAN
• Application Number:
  US12/958,982
• Publication Number:
  US 20110133752A1
• Time in Patent Office: 985 Days
• Field of Search: 324/322, 324/537, 324/555, 324/750.01, 324/606, 324/763.01
• US Class Current: 324/555
• CPC Class Codes: G01R 31/2815 Functional tests, e.g. boundary scans, using the normal I/O contacts contacting devices G01R31/2808; testing digital circuits G01R31/317, G06F11/00
• 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: G06F 21/86 Secure or tamper-resistant housings
• CPC Class Codes: H05K 1/0275 Security details, e.g. tampering prevention or detection
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 2201/10204 Dummy component, dummy PCB or template, e.g. for monitoring, controlling of processes, comparing, scanning

Abstract

An electronic device, and associated method, provided with a circuit board (10), with a set of input contacts (IN/COM), a set of output contacts (OUT/COM) and an electrical circuit (18) connected between the input contacts (IN/COM) and the output contacts (OUT/COM) and a controller. The controller carries out a real-time test of the circuit board using a test signal introduced into the electrical circuit, the electrical circuit (18) being designed as a passive network having a characteristic transfer function and provided with at least one capacitive element, wherein the capacitive element is a conductor surface (221) forming a capacitor in the assembled state with a corresponding, device-side conductor surface (222″), which is connected to the electrical circuit (18) via a contact element in the assembled state, whereby the capacitive value of the capacitive element in the assembled state differs from the capacitive value of the capacitive element in the disassembled state.

Claims

1. An electronic device comprising

a circuit board having a set of input contacts, a set of output contacts and an electrical circuit connected between the input contacts and the output contacts, and

a controller,

wherein the controller is configured, at least once during operation of the device,

to apply a predetermined test signal, configured as at least one of a pulsed signal, an alternating current signal with a predetermined frequency and an alternating current signal with a sequence of predetermined frequencies, to the set of input contacts,

to tap off a response signal at the set of output contacts,

to carry out a signal analysis on the response signal,

to compare a result of the signal analysis with an expected value stored in a memory of the controller, and

if no match is determined between the signal analysis result and the expected value, to prevent, at least partially, further operation of at least part of the device,

wherein the electrical circuit is configured as a passive network having a characteristic transfer function and comprises at least one capacitive element comprising a conductor surface which, in the installed condition, forms a capacitor with a corresponding, device-side conductor surface which, in the installed condition, is connected via a contact element to the electrical circuit, whereby the capacitance of the capacitive element in the installed condition differs from the capacitance of the capacitive element in the uninstalled condition.

2. The electronic device as claimed in claim 1, wherein the passive network further comprises at least one inductive element comprising a conducting wire looped into a coil around a cut-out in the circuit board which, in an installed condition, is penetrated by a ferromagnetic rod or by a ferromagnetic fastening pin, whereby the inductance of the inductive element in the installed condition differs from the inductance of the inductive element in the uninstalled condition.

3. The electronic device as claimed in claim 1, wherein the electrical circuit comprises at least two separate partial circuits which, in the installed condition, are connected to electrically conduct by interaction with at least one of:

at least one device component and at least one installation component.

5. The electronic device as claimed in claim 1, wherein the characteristic transfer function is specific to a source of the electronic device.

6. The electronic device as claimed in claim 1, wherein the characteristic transfer function is unique to the circuit board.

7. The electronic device as claimed in claim 1, wherein the controller is configured to deactivate at least a predetermined operation of the electrical circuit.

8. The electronic device as claimed in claim 1, wherein the controller is configured to block activation of the electrical circuit.

4. A method for testing a circuit board which comprises a set of input contacts, a set of output contacts and an electrical circuit connected between the input contacts and the output contacts, comprising:

a) applying a predetermined test signal, configured as at least one of a pulsed signal, an alternating current signal with a predetermined frequency and an alternating current signal with a sequence of predetermined frequencies, to the set of input contacts,

b) tapping off a response signal at the set of output contacts,

c) analyzing the response signal,

wherein a controller performs said applying, said tapping and said analyzing at least once during operation of an electronic device which comprises the circuit board,

d) comparing a result of the signal analysis with an expected value, and

e) if said comparing produces no match between the signal analysis result and the expected value, preventing, at least partially, further operation of at least part of the electronic device,

wherein the electrical circuit is configured as a passive network having a characteristic transfer function and comprises at least one capacitive element comprising a conductor surface which, in the installed condition, forms a capacitor with a corresponding, device-side conductor surface which, in the installed condition, is connected via a contact element to the electrical circuit, whereby the capacitance of the capacitive element in the installed condition differs from the capacitance of the capacitive element in the uninstalled condition.