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A Method for Improving Efficiency of DC/DC Converter

IP.com Disclosure Number: IPCOM000013362D
Original Publication Date: 2000-Feb-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Abstract

Disclosed is a DC/DC (DC-to-DC) converter that consists of two PWM (Power Width Modulation) regulators. Input line and output line of these regulators are common. These two regulators switch alternately. And, the two regulators produce same output voltage. Fig.1 shows circuit diagram of this invention. Assuming that this DC/DC converter supply maximum current Imax at voltage Vout, each regulator shall have an ability to provide current Imax/2 at voltage Vout. And, two regulators switch alternately so that the input current of the switching transistor does not duplicate.

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A Method for Improving Efficiency of DC/DC Converter

   Disclosed is a DC/DC (DC-to-DC) converter that consists of two PWM
(Power Width

Modulation) regulators. Input line and output line of these regulators
are common. These
two regulators switch alternately. And, the two regulators produce
same output voltage.

Fig.1 shows circuit diagram of this invention.

Assuming that this DC/DC converter supply maximum current Imax at
voltage Vout, each
regulator shall have an ability to provide current Imax/2 at voltage
Vout. And, two regulators
switch alternately so that the input current of the switching
transistor does not duplicate.

Fig.2 shows input current of each switching transistor. By this
alternate switching topology,
total RMS (Root Mean Square value) current flowing from the input
capacitor will be
decreased. It's because each switching phases are shifted and the peak
value of current
pulse flowing from the input capacitor turns to be approximate half of
one regulator circuit
and pulse width becomes double in total. In result, the efficiency of
DC/DC converter is
improved, since power losses created by ESR (Effective Series
Resistance) of the input
capacitor will be saved by reduction of total RMS input current. In
case of load current is
less than Imax/2 at voltage Vout, it's effective to save power losses
by turning off one
regulator while the other regulator is on to supply power to the load.
On the other hand,
there is another power losses produced inside battery pack since
battery impeda...