SINGLE INDUCTOR POWER CONVERTER SYSTEM AND METHODS
Methods, systems, and devices are described for a non-isolated dc-dc power converter that uses a single magnetic element and provides both a positive and a negative voltage output. The magnetic element, such as an inductor, is coupled with two or more switching modules that electrically switch the inductor to and from a voltage source, an inductor terminal, and/or a load. By electrically connecting and electrically isolating different components at various times, separate positive and negative voltage outputs are provided using the single inductor element. Switching may be controlled by a controller module, and a magnitude of the dc output voltage may be selected based on two or more resistors coupled with the controller module.
1 . A power converter apparatus, comprising:
a power source;
a first switching module coupled with the power source;
an inductor having a first connection terminal and a second connection terminal, the first connection terminal coupled with the first switching module;
a first output terminal coupled with a first load;
a second switching module coupled with the first switching module and the first connection terminal of the inductor;
a second output terminal coupled with a second load; and
a control module coupled with the first and second switching modules and configured to:
switch the first switching module to electrically couple the first connection terminal of the inductor with the power source and supply a voltage of a first polarity at the first output terminal;
switch the first switching module to electrically isolate the power source from the first connection terminal of the inductor; and
switch, while the power source is electrically isolated from the first connection terminal, the second switching module so as to electrically couple the first connection terminal of the inductor with the second output terminal and thereby supply a voltage of a second polarity to the second output terminal.
2 . The apparatus of claim 1 , wherein the control module is further configured to switch the second switching module to electrically isolate the second output terminal from the first connection terminal of the inductor while the first connection terminal of the inductor is electrically coupled with the power source.
3 . The apparatus of claim 1 , further comprising:
a third switching module coupled between the first input terminal of the inductor and a ground connection, and
wherein the control module is further configured to switch the third switching module to electrically couple the first input terminal of the inductor with ground and switch the first and second switching modules to electrically isolate the first input terminal of the inductor from the power source and the second output terminal when the voltages at the first and second output terminals are at or near target values for the first and second output terminal voltages.
4 . The apparatus of claim 1 , further comprising:
a first output capacitor coupled between the second connection terminal of the inductor and a ground connection; and
a second output capacitor coupled between the second switching module and a ground connection.
5 . The apparatus of claim 1 , further comprising:
a third switching module coupled between the second connection terminal of the inductor and the first output terminal; and
wherein the control module is further configured to switch the third switching module to alternately electrically isolate or electrically couple the first output terminal and the second connection terminal of the inductor.
6 . The apparatus of claim 5 , wherein the control module is further configured to:
switch the third switching module to electrically isolate the first output terminal from the second connection terminal of the inductor;
switch the second switching module to electrically couple the first connection terminal of the inductor with the second output terminal while the first output terminal is electrically isolated from the second connection terminal of the inductor; and
switch the first switching module to electrically isolate the first connection terminal of the inductor from the power source while the power source is electrically isolated from the first connection terminal while the first output terminal is electrically isolated from the second connection terminal of the inductor and the first connection terminal of the inductor to the second output terminal.
7 . The apparatus of claim 1 , wherein the control module is coupled with two or more resistors, and the control module is configured to control the switching of the modules based on the value of the resistors.
8 . The apparatus of claim 3 , wherein the third switching module comprises a bi-directional voltage blocking switch.
9 . A method for providing power to a first and a second output load, comprising:
electrically coupling a first inductor connection terminal with a power source;
electrically coupling the first output load with a second inductor connection terminal;
electrically isolating the second output load from the first inductor connection terminal while the first inductor connection terminal is electrically coupled with the power source; and
after electrically coupling the first inductor connection terminal with the power source, electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load thereby providing power to the second output load.
10 . The method of claim 9 , further comprising:
after electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load, electrically isolating the second output load from the first inductor connection terminal and electrically coupling the first inductor connection terminal with the power source.
11 . The method of claim 9 , further comprising:
after coupling the first inductor connection terminal with the power source and before electrically coupling the first inductor connection terminal with the second output load, electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with a ground connection.
12 . The method of claim 11 , further comprising:
after ramping down current in the inductor, electrically isolating the first inductor connection terminal from the ground connection and electrically coupling the first inductor connection terminal with the second output load.
13 . The method of claim 9 , further comprising:
after electrically coupling the first inductor connection terminal with the power source:
electrically isolating the first inductor connection terminal from the power source,
electrically isolating the second inductor connection terminal from the first output load, and
electrically coupling the first inductor connection terminal with the second output load.
14 . The method of claim 9 , wherein timing of the electrically coupling and electrically isolating steps is determined based on input to a controller module.
15 . The method of claim 14 , wherein the timing is determined based on values of two or more resistors coupled with the controller module.
16 . An apparatus for providing power to a first and a second output load, comprising:
means for electrically coupling a first inductor connection terminal with a power source;
means for electrically coupling the first output load with a second inductor connection terminal;
means for electrically isolating the second output load from the first inductor connection terminal while the first inductor connection terminal is electrically coupled with the power source; and
means for electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load after electrically coupling the first inductor connection terminal with the power source.
17 . The apparatus of claim 16 , further comprising:
means for electrically isolating the second output load from the first inductor connection terminal and electrically coupling the first inductor connection terminal with the power source after electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load.
18 . The apparatus of claim 16 , further comprising:
means for electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with a ground connection to ramp down current in the inductor after coupling the first inductor connection terminal with the power source and before electrically coupling the first inductor connection terminal with the second output load.
19 . The apparatus of claim 18 , further comprising:
means for electrically isolating the first inductor connection terminal from the ground connection and electrically coupling the first inductor connection terminal with the second output load after ramping down current in the inductor.
20 . The apparatus of claim 16 , further comprising:
controller means for controlling the timing of the electrically coupling and electrically isolating steps.