ZERO CURRENT DETECTOR AND DC-DC CONVERTER USING SAME

摘要

A DC-DC converter includes a zero current detector. The DC-DC converter includes a high-side switch and a low-side switch. When the DC-DC converter works in a discontinuous conduction mode (DCM). The zero current detector detects a zero current a detection node which is arranged between the high-side switch and the low-side switch generates the zero current, the zero current detector outputs the control signal to a driver. The driver switches the high-side switch and the low-side switch off simultaneously according to the control signal. The zero current detector includes a temperature compensation unit to control a responsivity of the zero current detector which not influenced by temperature change.

主权项

1. A zero current detector comprising:
a bias current source; a current mirror comprising: an input terminal coupled to the bias current source, a first output terminal, and a second output terminal; a first transistor coupled to the first output terminal and grounded via a first resistor; a second transistor coupled to the second output terminal and a detection node via a second resistor; a first comparator comprising a non-inverting input terminal coupled to the second output terminal and an inverting input terminal coupled to the first output terminal; a temperature compensation unit configured to control a voltage of the non-inverting input terminal, so that the voltage is in a predetermined range as temperature changes; and when the voltage of the non-inverting input terminal is larger than a voltage of the inverting input terminal, the first comparator outputs an indication signal to denote that the detection node generates a zero current.