Apparatus and method for charge control in wireless charging system
An apparatus and a method for charge control are provided. The apparatus for charge control may include an integrated direct current-to-direct current (DC/DC) converter configured to step up an output voltage level of a load to be greater than or equal to a supply voltage level set in a power amplifier, and the power amplifier configured to convert a direct current (DC) voltage stepped up by the integrated DC/DC converter into an alternating current (AC) voltage based on a resonant frequency, and to amplify the converted AC voltage. The apparatus for charge control may include a rectification unit configured to convert an AC power received wirelessly into a DC power; and a DC/DC converter configured to step down a voltage level of the DC power to a voltage level required by a load in the receiving mode.
1. An electronic device for charge control, the electronic device comprising:
a direct current-to-direct current (DC/DC) converter configured to step down a voltage level of a DC power outputted from a rectifier of the electronic device to a voltage level for a load of the electronic device and to step up an output voltage level of a DC power from the load to be greater than or equal to a supply voltage level for a power amplifier of the electronic device; and
the power amplifier configured to convert a DC voltage stepped up by the DC/DC converter into an alternating current (AC) voltage and to amplify the converted AC voltage,
wherein the DC/DC converter is further configured to step down the voltage level of the DC power outputted from the rectifier in a power receiving mode and to step up the output voltage level of the DC power from the load in a power transmitting mode,
wherein the DC/DC converter comprises:
a first capacitor connected to the power amplifier;
a second capacitor connected to the load; and
an output voltage determining unit configured to determine a voltage applied to the first capacitor to be an output voltage of the DC/DC converter in the transmitting mode, and to determine a voltage applied to the second capacitor to be an output voltage of the DC/DC converter in the receiving mode.
2. The electronic device of claim 1 , wherein
the rectifier is configured to convert an AC power received wirelessly into the DC power in the receiving mode.
3. The electronic device of claim 2 , wherein the first capacitor is connected in parallel to the power amplifier;
the second capacitor is connected in parallel to the load; and
the DC/DC converter further comprises;
a first transistor of a P-channel metal oxide semiconductor (PMOS) type, the first transistor connected in series to the first capacitor;
a second transistor of an N-channel metal oxide semiconductor (NMOS) type, the second transistor connected in parallel to the first transistor; and
an inductor connected in series to the second transistor.
4. The electronic device of claim 3 , wherein the DC/DC converter further comprises:
a driving voltage determining unit configured to compare the voltage applied to the second capacitor to the voltage applied to the first capacitor and determine a higher voltage to be a driving voltage of the output voltage determining unit.
5. The electronic device of claim 3 , further comprising:
a third switch unit configured to connect the rectifier to the DC/DC converter in the receiving mode to charge the load with a power, and connect the DC/DC converter to the power amplifier in the transmitting mode to transmit the power stored in the load.
6. The electronic device of claim 3 , further comprising:
a controller configured to control an operating time of the first transistor based on a difference between a voltage required by the load and the voltage applied to the second capacitor in the receiving mode.
7. The electronic device of claim 6 , wherein the controller is further configured to control the operating time of the first transistor based on a difference between a supply voltage set in the power amplifier and the voltage applied to the first capacitor.
8. The electronic device of claim 2 , wherein the load comprises:
a battery charger configured to charge a battery by storing the DC voltage stepped down by the DC/DC converter;
the battery configured to be charged by the battery charger in the receiving mode, and to transfer a DC voltage to the DC/DC converter in the transmitting mode; and
a first switch unit configured to connect the battery charger to the battery in the receiving mode, and to break the connection between the battery charger and the battery and connect the DC/DC converter to the battery in the transmitting mode.
9. The electronic device of claim 2 , further comprising:
a power transceiver configured to receive the AC power from a wireless power transmitting device in the receiving mode, and to transmit the AC power amplified by the power amplifier to a wireless power receiving device in the transmitting mode.
10. The electronic device of claim 9 , further comprising:
a second switch unit configured to connect the power transceiver to the rectifier in the receiving mode, and to break the connection between the power transceiver and the rectifier and connect the power transceiver to the power amplifier in the transmitting mode.
11. A method for charge control, the method comprising:
converting an alternating current (AC) power received wirelessly into a direct current (DC) power;
stepping down a voltage level of the DC power to a voltage level for a load, using a direct current-to-direct current (DC/DC) converter;
stepping up an output voltage level of a DC power from the load to be greater than or equal to a supply voltage level for a power amplifier using the DC/DC converter; and
converting the stepped up voltage level into an AC voltage and amplifying the converted AC voltage,
wherein the DC/DC converter is configured to step down a voltage level of a DC power in a power receiving mode and to step up the output voltage level of a DC power from the load in a power transmitting mode, and
wherein the DC/DC converter comprises;
a first capacitor connected to the power amplifier;
a second capacitor connected to the load; and
an output voltage determining unit configured to determine a voltage applied to the first capacitor to be an output voltage of the DC/DC converter in the transmitting mode, and to determine a voltage applied to the second capacitor to be an output voltage of the DC/DC converter in the receiving mode.
12. The method of claim 11 , further comprising:
determining one of the receiving mode and the transmitting mode for charge control in a wireless charging system.
13. The method of claim 11 , wherein the stepping down comprises determining a voltage applied to the load to be the output voltage of the DC/DC converter in the receiving mode.
14. The method of claim 13 , wherein the stepping up comprises determining a voltage applied to the power amplifier to be the output voltage of the DC/DC converter in the transmitting mode.
15. The method of claim 11 , further comprising:
receiving the AC power through a mutual resonance between a power transceiver and a wireless power transmitting device in the receiving mode; and
transmitting the AC power amplified by the power amplifier through a mutual resonance between the power transceiver and a wireless power receiving device in the transmitting mode.