Power converter with negative current capability and low quiescent current consumption

摘要

DC-DC current mode switching power converters that have negative current capability are presented. The power converters comprise: an output node, a pass device connected to the output node of the power converter, the pass device being configured to operate in accordance with a PWM signal and to supply at least a portion of an output current of the power converter, a PWM comparator for generating the PWM signal for controlling operation of the pass device in accordance with a current conducted by the pass device and a difference between an output voltage of the power converter and a reference voltage. The converters have push pull class B (or AB) current sensing, dynamic biasing of a current sense amplifier using error information, and using operational transconductance amplifiers that are fed an error voltage. This results in a lower quiescent current at zero load.

主权项

1. A power converter for converting a DC input voltage to a DC output voltage, the power converter comprising:
an output node; a pass device connected to the output node of the power converter, the pass device being configured to operate in accordance with a PWM signal and to supply at least a portion of an output current of the power converter; a PWM comparator for generating the PWM signal for controlling operation of the pass device in accordance with a current conducted by the pass device and a difference between an output voltage of the power converter and a reference voltage, the PWM comparator having a first input terminal and a second input terminal; a first current sensing circuit for outputting a first sense current depending on the current conducted by the pass device, the first current sensing circuit being configured to sense the current conducted by the pass device if the current conducted by the pass device has a given polarity, the first current sensing circuit further being connected to the PWM comparator in such a manner that a voltage depending on the first sense current is supplied to the first input terminal of the PWM comparator; and a second current sensing circuit for outputting a second sense current depending on the current conducted by the pass device, the second current sensing circuit being configured to sense the current conducted by the pass device if the current conducted by the pass device has a polarity opposite to the given polarity, the second current sensing circuit further being connected to the PWM comparator in such a manner that a voltage depending on the second sense current is supplied to the second input terminal of the PWM comparator.