Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
195 words
A driver circuit for providing a test signal to a device under test, wherein said test signal is responsive to a combination of a predetermined logic signal and a control signal from a circuit board tester, said driver circuit comprising: a gain amplifier, having first and second input ports and at least one output port, for receiving said predetermined logic signal from said tester at said first input port and providing an output signal at said output port responsive to said predetermined logic signal and for receiving a feedback signal at said second input port; a first buffer, connected to receive said output signal, for generating a first feedback signal, said first buffer having a high output impedance; a second buffer, connected to receive said output signal and said control signal, for buffering said output signal and for providing said test signal, responsive to said output signal, to said device under test; and feedback means for providing a feedback signal to said second input port wherein said feedback signal comprises said first feedback signal when said test signal is representative of three-state and wherein said feedback signal comprises said test signal at all other times.
Claim 2
Dependent Claim
195 words
A driver circuit for providing a test signal to a device under test, wherein said test signal is responsive to a combination of a predetermined logic signal and a control signal from a circuit board tester, said driver circuit comprising: a gain amplifier, having first and second input ports and at least one output port, for receiving said predetermined logic signal from said tester at said first input port and providing an output signal at said output port responsive to said predetermined logic signal and for receiving a feedback signal at said second input port; a first buffer, connected to receive said output signal, for generating a first feedback signal, said first buffer having a high output impedance; a second buffer, connected to receive said output signal and said control signal, for buffering said output signal and for providing said test signal, responsive to said output signal, to said device under test; and feedback means for providing a feedback signal to said second input port wherein said feedback signal comprises said first feedback signal when said test signal is representative of three-state and wherein said feedback signal comprises said test signal at all other times.
Claim 3
Dependent Claim
32 words
The driver circuit of claim 1, wherein said feedback means comprises switch means for providing said test signal to said second input port when said driver circuit is not in said three-state.
Claim 4
Dependent Claim
42 words
The driver circuit of claim 2, wherein said switch means provides a low output impedance when said driver circuit is not in said tri-state and wherein said switch means provides a high output impedance when said driver circuit is in said three-state.
Claim 5
Dependent Claim
15 words
The driver circuit of claim 3, wherein said switch means comprises a field effect transistor.
Claim 6
Dependent Claim
25 words
The driver circuit of claim 1, wherein said first feedback signal prevents said gain amplifier from saturating when said driver circuit is in said three-state.