Circuit for battery charging and system supply, combining capacitive and inductive charging
A power converter and methods with an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor are presented. A first terminal of the inductor is connected to the first output terminal. An input switch is connected between the input terminal and a first terminal of the capacitor. A first capacitive charging switch is connected between the first terminal of the capacitor and the second output terminal. A second capacitive charging switch is connected between the second output terminal and a second terminal of the capacitor. A ground switch is connected between the second terminal of the capacitor and a reference potential. The power converter can convert electrical power into electrical power for powering an external device d or into electrical power for charging an external energy storage device.
1 . A power converter with an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal, the power converter further comprising:
an input switch connected between the input terminal and a first terminal of the capacitor;
a first capacitive charging switch connected between the first terminal of the capacitor and the second output terminal;
a second capacitive charging switch connected between the second output terminal and a second terminal of the capacitor;
a ground switch connected between the second terminal of the capacitor and a reference potential; and
a series connection of a first inductive charging switch and a second inductive charging switch connected between the first terminal of the capacitor and the second terminal of the capacitor, wherein a second terminal of the inductor is connected to an Intermediate node between the first inductive charging switch and the second inductive charging switch,
wherein the first inductive charging switch is connected between the second terminal of the inductor and a first intermediate node between the input switch and the first capacitive switch, and wherein the second inductive charging switch is connected between the second terminal of the inductor and a second intermediate node between the ground switch and the second capacitive charging switch.
2 . The power converter of claim 1 , wherein the power converter is configured to convert electrical power at the Input terminal into
electrical power for powering an external electronic device at the first output terminal, or into
electrical power for charging an external energy storage device at the second output terminal.
3 . The power converter of claim 1 , wherein the power converter is configured, when in a capacitive charging mode,
to turn off the output switch, the first inductive charging switch and the second inductive charging switch, and
to control the remaining switches such that an external storage device connected to the second output terminal is charged with a constant charging current.
4 . The power converter of claim 1 , wherein the power converter is further configured to alternate between a first phase and a second phase, wherein the power converter is configured, during the first phase,
to turn on the input switch and the second capacitive charging switch, and
to turn off the first capacitive charging switch and the ground switch for generating an electrical path from the input terminal via the capacitor to the second output terminal;
and wherein the power converter is configured, during the second phase,
to turn on the ground switch and the first capacitive charging switch, and
to turn off the input switch and the second capacitive charging switch for generating an electrical path from the reference potential via the capacitor to the second output terminal.
5 . The power converter of claim 1 , wherein the power converter is configured, when in an inductive charging mode,
to turn off the first capacitive charging switch and the second capacitive charging switch, and
to control the remaining switches for regulating an output voltage at the first output terminal or at the second output terminal.
6 . The power converter of claim 5 , wherein the power converter is configured to alternate between a first time interval, a second time interval, and a third time interval, wherein the power converter is configured to, during the first time interval,
to turn on the ground switch and the first inductive charging switch, and
to turn off the input switch and the second inductive charging switch for generating an electrical path from the reference potential via the capacitor and via the inductor to the first output terminal,
wherein the power converter is configured, during the second time interval,
to turn on the input switch and the second inductive charging switch, and
to turn off the ground switch and the first inductive charging switch for generating an electrical path from the input terminal via the capacitor and via the inductor to the first output terminal,
and wherein the power converter is configured, during the third time interval,
to turn off the ground switch and the second inductive charging switch, and
to turn on the input switch and the first inductive charging switch for generating an electrical path from the input terminal via the inductor to the first output terminal.
7 . The power converter of claim 1 , wherein the power converter is configured, when in an inductive charging mode
to turn on the output switch,
to turn off the first capacitive charging switch and the second capacitive charging switch, and
to control the remaining switches such that an external storage device connected to the second output terminal is charged with a constant charging voltage or such that a constant charging voltage is provided at the first output terminal.
8 . The power converter of claim 6 , wherein the power converter is configured, during a third time interval,
to turn on the ground switch and the second inductive charging switch, and
to turn off the input switch and the first inductive charging switch for generating an electrical path from the reference potential via the inductor to the second output terminal.
9 . The power converter of claim 4 , wherein the power converter further comprises a second capacitor, a third capacitive charging switch, a fourth capacitive charging switch, a fifth capacitive charging switch, and a sixth capacitive charging switch, wherein
the third capacitive charging switch is connected between the input terminal and a first terminal of the second capacitor;
the fourth capacitive charging switch Is connected between the first terminal of the second capacitor and the second output terminal;
the fifth capacitive charging switch is connected between the second output terminal and a second terminal of the second capacitor; and
the sixth capacitive charging switch is connected between the second terminal of the second capacitor and the reference potential.
10 . The power converter of claim 9 , wherein the power converter is further configured to, during the second phase,
to turn on the third capacitive charging switch and the fifth capacitive charging switch, and
to turn off the fourth capacitive charging switch and the sixth capacitive charging switch for generating an electrical path from the input terminal via the inductor to the second output terminal,
and, during the first phase,
to turn off the third capacitive charging switch and the fifth capacitive charging switch, and
to turn on the fourth capacitive charging switch and the sixth capacitive charging switch for generating an electrical path from the reference potential via the inductor to the second output terminal.
11 . The power converter of claim 9 , wherein the third capacitive charging switch or the fourth capacitive charging switch is implemented as a transistor and the power converter is configured to turn off said transistor if a transistor current through said transistor falls below a threshold value.
12 . The power converter of claim 11 , wherein the power converter further comprises a comparator configured to compare the transistor current with the threshold value.
13 . The power converter of claim 1 , wherein the power converter is configured to, in a back-boost mode, to turn off the first and the second capacitive charging switches and to switch between
a magnetizing switching state in which the second inductive charging switch and the ground switch are turned on, and
a demagnetizing switching state in which the input switch and the first inductive charging switch are turned on.
14 . The power converter of claim 1 , wherein the power converter is configured to, in a back-boost mode, to turn off the first and the second capacitive charging switches and to switch between
a primary switching state in which the second inductive charging switch and the ground switch are turned on,
a secondary switching state in which the first inductive charging switch and the ground switch are turned on, and
a tertiary switching state in which the second inductive charging switch and the input switch are turned on.
15 . The power converter of claim 1 , wherein the power converter further comprises
a first reverse current protection switch configured to connect a body of the first capacitive charging switch to a first reference potential, and
a second reverse current protection switch configured to connect a body of the first inductive charging switch to a second reference potential.
16 . A method for operating a power converter with an input terminal, a capacitor, a first output terminal, a second output terminal, an output switch between the first output terminal and the second output terminal, and an inductor, wherein a first terminal of the inductor is connected to the first output terminal, the method comprising:
connecting an input switch between the input terminal and a first terminal of the capacitor;
connecting a first capacitive charging switch between the first terminal of the capacitor and the second output terminal;
connecting a second capacitive charging switch between the second output terminal and a second terminal of the capacitor;
connecting a ground switch between the second terminal of the capacitor and a reference potential;
connecting a series connection of a first inductive charging switch and a second inductive charging switch between the first terminal of the capacitor and the second terminal of the capacitor; and
connecting the second terminal of the inductor to an Intermediate node between the first inductive charging switch and the second inductive charging switch,
wherein the first inductive charging switch is connected between the second terminal of the inductor and a first intermediate node between the input switch and the first capacitive switch, and wherein the second inductive charging switch is connected between the second terminal of the inductor and a second intermediate node between the ground switch and the second capacitive charging switch.
17 . The method of claim 16 , further comprising converting electrical power at the input terminal into
electrical power for powering an external electronic device at the first output terminal, or into
electrical power for charging an external energy storage device at the second output terminal.
18 . The method of claim 16 , further comprising, in a capacitive charging mode,
turning off the output switch, the first inductive charging switch and the second inductive charging switch, and
controlling the remaining switches such that an external storage device connected to the second output terminal is charged with a constant charging current.
19 . The method of claim 16 , further comprising, in an inductive charging mode,
turning off the first capacitive charging switch and the second capacitive charging switch, and
controlling the remaining switches for regulating an output voltage at the first output terminal.
20 . The method of claim 16 , further comprising
turning on the output switch, and
controlling the remaining switches such that an external storage device connected to the second output terminal is charged with a constant charging voltage.