Test Power Supply Reference Voltage Stepping for Stable Load Emulation
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Solution Overview
Problem
Existing test apparatuses struggle to emulate the performance of a set power supply in a flexible and precise manner, often affecting the stability of the system and leading to unintended oscillations.
Innovation Solution
A power supply apparatus that includes a voltage source, a current detection circuit, and a reference voltage generating circuit capable of transitioning through multiple voltage levels in response to output current, allowing for the emulation of various set power supply characteristics by adjusting voltage steps and settling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the phase compensation circuit characteristics are changed to emulate set power supply performance, then the responsiveness to load fluctuation is improved, but the system stability deteriorates and oscillation may occur
Solution Approach 1:
The invention divides the emulation function into separate segments: the phase compensation circuit maintains its original stable characteristics, while a dedicated output resistance emulation circuit (using operational amplifier OpA2 and resistors R21-R24) handles the set power supply emulation. This segmentation allows independent optimization of stability and emulation accuracy without mutual interference.
Solution Approach 2:
The invention introduces an intermediary output resistance emulation circuit that acts as a buffer between the voltage source and the load. This intermediary circuit (comprising OpA2, R21-R24) provides the desired output resistance characteristics without directly modifying the phase compensation circuit, thereby maintaining system stability while achieving accurate set power supply emulation.
2Reliability
If existing power supply apparatus is used to supply power to DUT, then the power supply is stable, but it cannot accurately emulate the performance characteristics of the set power supply in actual products
Solution Approach 1:
The invention makes the power supply apparatus universally adaptable by adding an output resistance emulation circuit that can simulate different set power supply characteristics. The circuit can emulate various output resistance values (including zero ohms for ideal voltage source behavior) while maintaining the original power supply's stable operation, thus achieving both reliability and adaptability.
Solution Approach 2:
The invention enables dynamic parameter changes by allowing the output resistance to be adjusted through the emulation circuit. By changing the resistance values in the emulation circuit (R21-R24) or the feedback signal characteristics, the power supply can adapt to emulate different set power supply performance characteristics while maintaining stable operation.
3Manufacturing precision
If feedback operation is performed to stabilize output voltage, then the voltage level is maintained, but the ability to emulate varying output resistance characteristics is limited
Solution Approach 1:
The invention employs dual feedback mechanisms: the original feedback circuit (OpA1, R11-R14) maintains output voltage stability, while a second feedback path through the output resistance emulation circuit (OpA2, R21-R24) provides output resistance emulation. The emulation circuit receives feedback signals (Vout and/or Iout) and adjusts its output accordingly to simulate the desired set power supply characteristics without compromising voltage stability.
Data Source
AI summary
A voltage source generates a power supply voltage VOUT stabilized such that it matches the voltage level that corresponds to a reference voltage VREF, and supplies the power supply voltage to a DUT. A current detection circuit generates a detection voltage Vm that corresponds to an output current IOUT that flows through the DUT. In the initial state, the reference voltage VREF generated by a reference voltage generating circuit is set to an initial voltage level that corresponds to an input voltage VIN. After the output current IOUT flows, the reference voltage transits to a first voltage level VL1 obtained by shifting the initial voltage level by a first voltage step that corresponds to the detection voltage Vm. Subsequently, the reference voltage VREF transits to a second voltage level VL2 obtained by shifting the initial voltage level by a second voltage step that corresponds to the detection voltage Vm.