Sensing current of a DC-DC converter

摘要

A DC-DC converter includes a directly coupled inductor with coil elements and power-switching phases. Each phase includes a high-side and low-side switch, where the high-side switch couples a voltage source to a coil element and the low-side switch couples the coil element to a ground voltage. Each switch is configured to be alternately activated and no two switches are activated at the same time. A current sensor for the DC-DC converter includes a single current amplifier having inputs and an output. The output provides a current sensing signal. The current sensor also includes a single RC network coupled to one of the power-switching phases and a first input of the current amplifier. The current sensor also includes a resistive ladder. The ladder includes, for each of the other power-switching phases, a resistor coupled in parallel to the RC network resistor and to a second input of the current amplifier.

主权项

1. A current sensor for a DC (‘Direct Current’)-DC converter, the DC-DC converter comprising:
a directly coupled inductor comprising a plurality of coil elements; and a plurality of power-switching phases, each power-switching phase coupled to a different one of the plurality of coil elements, each phase comprising: a high-side switch and a low-side switch, wherein the high-side switch is configured, when activated, to couple a voltage source to one of the coil elements and the low-side switch is configured, when activated, to couple the coil element to a ground voltage, wherein each switch of the DC-DC converter is configured to be alternately activated and no two switches are activated at the same time; the current sensor comprising:
a single current amplifier comprising a plurality of inputs and an output, wherein the output provides a current sensing signal;a single RC network (Resistor-Capacitor network') coupled to one of the power-switching phases and a first input of the current amplifier, the RC network comprising a resistor in series with a capacitor; anda resistive ladder comprising: for each of the other power-switching phases, a resistor coupled in parallel to the resistor of the RC network and coupled to a second input of the current amplifier.