Integrated tri-state electromagnetic interference filter and line conditioning module

摘要

This disclosure describes systems, methods and articles of a passive EMI filter integrated with an active boost converter for low-side line transients and/or an active clipper for high-side line transients. During steady-state operation, the active circuitry is disabled so the circuit functions as a passive EMI filter. Inductive and capacitive components used in the passive EMI filter during steady-state operation may serve a dual role and become part of a boost converter when input voltage is below a low-line steady-state and, in some variations, the inductive and capacitive components may become part of a transient clipper when the input voltage is above a high-line steady-state level. The transient clipper may be implemented as a linear pass element or as a switch-mode converter (e.g., buck converter).

主权项

1. An electromagnetic interference (EMI) filter and line-conditioning (EMI-LC) circuit, the EMI-LC circuit having an input coupleable to an output of an input power source and an output coupleable to an input of a noise source, the EMI-LC circuit comprising:
a passive differential mode EMI filter circuit that includes a differential mode EMI inductor and a differential mode EMI capacitor; a boost converter circuit that includes a boost control switch controllable to be in an OFF state and an ON state, a boost output switch, the differential mode EMI inductor, and the differential mode EMI capacitor; a feedback circuit operably coupled to the input of the EMI-LC circuit to sense input characteristic information at the input of the EMI-LC circuit; and a control circuit operatively coupled to the feedback circuit to receive the input characteristic information from the feedback circuit and operatively coupled to the boost control switch, the control circuit:
during a first time in response to a first condition of the input characteristic information, controls the boost control switch to be continuously in the OFF state to disable the boost converter circuit; andduring a second time in response to a second condition of the input characteristic information, selectively controls the boost control switch to repeatedly switch between the OFF state and the ON state to enable the boost converter circuit which, when enabled, controllably increases an input voltage applied to the boost converter circuit.