Hi Team,
My customer designed TLC2272 on their board as current sensor as below circuit,and they found there is a 1.5V bump during power down(the power supply less than 4V)
Could you help check why there is a bump during the power supply power down? What's the output voltage when the device power supply less than 4V?
Schematic:
Blue is the power supply and red is the output.
..
Hello Nick,
The TLC2272IDR minimum supply voltage is 4.4 V. When the supply is below that level during either start-up, or power-down, the op amp's internal circuits are in transition and probably aren't at their normal operating levels. The result may be that a high output offset appears while the amplifier is moving towards the powered up state, or shutting down. We don't usually characterize how the amplifier behaves when it is powering through that region. A while back I wrote a blog about what might be observed when an op amp is powered just below its lowest supply rating. It might provide some useful information about the under-voltage region.
Also note that the circuit has many capacitors connected across various points in the circuit. One, or more, of these capacitors may be holding a charge that is transferred as the circuit powers down resulting in an output voltage level shift. You might try removing one capacitor at a time and see if any of them affect the hump behavior.
Regards, Thomas
PA - Linear Applications Engineering
