rampedcurrent

Ramped current refers to a controlled, time-dependent change in electrical current, typically designed to increase or decrease at a predetermined rate rather than abruptly. The current profile is often a linear ramp, I(t) = I0 + r t, where r is the ramp rate, though other shapes such as exponential ramps are common.

Ramped current is used to reduce inrush currents, mitigate electromagnetic interference, and lessen mechanical or electrical stress on components. It is common in soft-start circuits for power supplies and motor controllers, in programmable current sources, battery charging circuits, and LED drivers.

Implementation considerations include hardware approaches such as slew-rate limited regulators, current regulators, PWM schemes with ramped duty cycles, and dedicated control ICs that impose a ramp on the commanded current. Software-based ramping is also used in control loops by gradually adjusting the reference value over time while using feedback to track the target.

Key considerations include choosing an appropriate ramp rate to balance speed and stability. Too slow a ramp limits performance; too fast can cause overshoot, EMI, or excitation of resonances. System parasitics, temperature, and load dynamics influence ramp behavior and require proper sensing and compensation.

Related concepts include inrush current, soft start, slew rate control, and current-mode control.