DUT Supply Voltage Compensation During Current Range Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for providing a supply voltage to a device under test often result in glitches when switching between current measurement ranges due to slow switch resistance changes, which can damage the device and are difficult to fully control.
Innovation Solution
An apparatus with a controlled source, a switchable resistor, and a regulator that injects a compensation signal into the control loop to quickly counteract voltage drops caused by resistance changes, maintaining a stable voltage at the device under test port by anticipating and compensating for resistance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switchable resistor is used to change current measurement ranges, then measurement versatility is improved, but voltage glitches occur during switching
Solution Approach 1:
The compensation signal is generated in advance based on the detected switch state change before the voltage glitch fully occurs. The control signal is adjusted preliminarily to counteract the expected voltage drop, preventing the glitch from affecting the device under test.
Solution Approach 2:
The system detects the switch state of the switchable resistor and uses this feedback information to generate an appropriate compensation signal. The feedback loop continuously monitors and adjusts the control signal to maintain stable output voltage despite resistance changes.
2Reliability
If conventional control loop is used, then voltage regulation is achieved, but response speed is too slow to compensate for fast resistance changes
Solution Approach 1:
Instead of waiting for the voltage glitch to occur and then responding, the system preliminarily adjusts the control signal based on detected switch state changes. This proactive adjustment happens before the full voltage drop occurs, significantly improving response effectiveness.
Solution Approach 2:
The system uses its own internal switch state detection capability to generate compensation signals without requiring external intervention or additional sensing components. The control loop serves itself by utilizing information already available within the system.
3Object-affected harmful factors
If full control over switch resistance is attempted, then complete glitch cancellation is achieved, but device complexity increases
Solution Approach 1:
The system applies partial compensation rather than attempting complete control over switch resistance. By generating a compensation signal that counteracts the majority of the voltage drop without requiring full resistance control, the system achieves effective glitch reduction with simpler circuitry.
Solution Approach 2:
The control signal acts as an intermediary between the switch state detection and the voltage output. Rather than directly controlling switch resistance, the system uses the control signal to mediate and compensate for resistance changes, simplifying the overall control mechanism.
Data Source
AI summary
An apparatus for providing a supply voltage to a device under test includes: a controlled source; a switchable resistor circuited between the output of the controlled source and a dut port, having a comparatively smaller first resistance in a first switch state and a second resistance in a second switch state; a regulator that provides a control signal to the controlled source, to regulate a voltage to be provided to the dut. The apparatus changes a switch state of the switchable resistor while a voltage is provided to the dut via the switchable resistor. The apparatus injects a compensation signal into a control loop including the regulator, the controlled source and the switchable resistor, to thereby cause a change of the voltage provided by the controlled source, to at least partially compensate a change of a voltage drop across the switchable resistor.