| 主权项 |
1. A programmable resistance measurement system for generating a bi-polar current comprising:
a bridge having a controller, a digital to analog converter for generating a first signal having a defined bi-polar current, a first current tracking amplifier for generating a second signal having a defined bi-polar current, and for transmitting the generated second signal to a reference resistor, a first comparator for receiving the output of the first current tracking amplifier en route to the reference resistor and for controlling a switch to place the bridge into a first state and a second state, the first state connecting a secondary input of the bridge to ground and the second state connecting the output of the digital to analog converter to an output of the bridge;an extender having
a bi-polar amplifier for receiving in a first configuration an output of the digital to analog converter in the bridge and in a second configuration an output of a servo current tracking amplifier in a high current extender, for amplifying the received output, and for transmitting the amplified current signal as an output of the extender, and a second comparator for receiving the output of the bipolar amplifier, for controlling a second current tracking amplifier to generate and transmit a signal having a defined bi-polar current to the secondary input of the bridge, and for receiving the output of the second current tracking amplifier en route to the secondary input of the bridge; and a high current extender having a high current bi-polar amplifier for receiving as an input in the second configuration the output of the digital to analog converter, for amplifying the received input, and for transmitting the amplified signal as an output; and a high current comparator for receiving the outputs of the high current bi-polar amplifier and the bi-polar amplifier in the second configuration for controlling the servo current tracking amplifier to generate and transmit a signal having defined bi-polar current to the input of the bi-polar amplifier in the extender; and a switching matrix having; a first switch circuit for in the first configuration coupling the output of the digital to analog converter in the bridge to the bi-polar amplifier in the extender and in the second configuration coupling the output of the digital to analog converter in the bridge to high current bi-polar amplifier in the high current extender and the output of the servo current tracking amplifier in the high current extender to the input of the bi-polar amplifier in the extender; a second switch circuit for in the first configuration coupling the output of the bi-polar amplifier in the extender to an output of the programmable resistance measurement system, in the second configuration coupling the output of the bi-polar amplifier in the extender to the high current comparator in the high current extender and the output of the high current extender to the output of the programmable resistance measurement system, in a third configuration coupling the output of the bridge to the output of the programmable resistance measurement system. |
