POWER RECEIVER, WIRELESS POWER SYSTEM AND RELATED METHOD OF TRANSMITTING INFORMATION WITH A POWER RECEIVER

• US 20150207336A1
• Filed: 01/12/2015
• Published: 07/23/2015
• Est. Priority Date: 01/20/2014
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Larosa, Roberto, Morreale, Danilo Antonio Claudio, Benenati, Giovanni
• Granted Patent: US 9,973,039 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

A power receiver includes a resonant circuit generating an internal supply voltage. A voltage rectification circuit receives the internal supply voltage and generate a corresponding rectified voltage. A voltage regulator receives the rectified voltage and a modulation signal and is configured to generate a corresponding regulated voltage. A controlled voltage-to-current converter receives the regulated voltage and the modulation signal. The converter operates to deliver, through an output line of the power receiver, an output current having a DC value corresponding to the DC value of said regulated voltage and having an AC value corresponding to said modulation signal.

Claims

1. A power receiver, comprising:

a resonant circuit having a pair of supply terminals between which an internal supply voltage of the power receiver is made available, comprising;

a secondary coil configured to be magnetically coupled with a primary coil of a power transmitter,

a first resonance capacitance coupled in series with said secondary coil (L_S), and

a second resonance capacitance coupled between said pair of supply terminals;

a voltage rectification circuit configured to receive said internal supply voltage and to generate a corresponding rectified voltage;

a voltage regulator configured to receive said rectified voltage and further receive a modulation signal and to generate a corresponding regulated voltage;

a controlled voltage-to-current converter configured to receive said regulated voltage and further receive said modulation signal and adapted to deliver through an output line of the power receiver an output current having a DC value corresponding to the DC value of said regulated voltage and having an AC value corresponding to said modulation signal.

2. The power receiver of claim 1, further comprising a control unit adapted to monitor a functioning state of a load powered by said power receiver, configured to be supplied with said regulated voltage generated by said voltage regulator and to generate said modulation signal carrying information about said functioning state of the powered load.

3. The power receiver of claim 1, wherein said voltage regulator is adapted to adjust its functioning point to generate said regulated voltage as the sum of a nominal constant voltage and of an AC voltage corresponding to said modulation signal;

said controlled voltage-to-current converter configured to receive said regulated voltage and to be controlled with a fixed voltage.

4. The power receiver of claim 3, wherein said voltage regulator is a feedback switching converter comprising:

a voltage divider having a center tap, configured to generate at said center tap a feedback voltage as a function of said regulated voltage;

an error amplifier configured to receive in input said feedback voltage and a fixed reference voltage; and

a switched circuit connected to said center tap and controlled by said modulation signal, to modulate the level of said feedback voltage synchronously with variations of said modulation signal.

5. The power receiver of claim 3, wherein said voltage regulator is a feedback switching converter comprising:

a voltage divider having a center tap, configured to generate at said center tap a feedback voltage as a scaled replica of said regulated voltage;

an error amplifier configured to receive at a first input said feedback voltage and at a second input a reference voltage; and

a switched circuit connected to said second input and controlled by said modulation signal, configured to connect said second input with either a first reference voltage or a second reference voltage synchronously with variations of said modulation signal.

6. The power receiver of claim 1, wherein said voltage regulator is adapted to adjust its functioning point to keep said regulated voltage at a nominal constant voltage, and said controlled voltage-to-current converter is configured to receive said regulated voltage and to be controlled with said modulation signal.

7. The power receiver of claim 1, further including a switched capacitance circuit coupled between said pair of supply terminals and comprising at least a modulation capacitor and a switch that is controlled with said modulation signal and configured to control connection and disconnection of said modulation capacitor to and from said secondary coil.

8. The power receiver of claim 1, further comprising a battery configured to be charged in operation with said output current.

9. A wireless power transfer system, comprising:

a power transmitter having a primary coil; and

a power receiver comprising;

a resonant circuit having a pair of supply terminals between which an internal supply voltage of the power receiver is made available, comprising;

a secondary coil configured to be magnetically coupled with a primary coil of a power transmitter,

a first resonance capacitance coupled in series with said secondary coil (LS), and

a second resonance capacitance coupled between said pair of supply terminals;

a voltage rectification circuit configured to receive said internal supply voltage and to generate a corresponding rectified voltage;

a voltage regulator configured to receive said rectified voltage and further receive a modulation signal and to generate a corresponding regulated voltage;

a controlled voltage-to-current converter configured to receive said regulated voltage and further receive said modulation signal and adapted to deliver through an output line of the power receiver an output current having a DC value corresponding to the DC value of said regulated voltage and having an AC value corresponding to said modulation signal;

wherein the secondary coil is magnetically coupled with said primary coil.

10. A method of transmitting information contained in a modulation signal about a functioning state of a powered load, comprising:

generating a regulated voltage with a voltage regulator; and

generating with a controlled voltage-to-current converter an output current having a DC value corresponding to the DC value of said regulated voltage and having an AC value corresponding to said modulation signal;

wherein generating the regulated voltage comprises adjusting a functioning point of the voltage regulator for generating said regulated voltage as the sum of a nominal constant voltage and of an AC voltage corresponding to said modulation signal;

wherein generating the output current comprises controlling said voltage-to-current converter with a fixed voltage for delivering through an output line the output current having an AC value corresponding to an AC value of said regulated voltage.

11. A method of transmitting information contained in a modulation signal about a functioning state of a powered load, comprising:

generating a regulated voltage with a voltage regulator; and

generating with a controlled voltage-to-current converter an output current having a DC value corresponding to the DC value of said regulated voltage and having an AC value corresponding to said modulation signal;

wherein generating the regulated voltage comprises adjusting the functioning point of the voltage regulator for keeping said regulated voltage at a nominal constant voltage;

wherein generating the output current comprises controlling said controlled voltage-to-current converter with said modulation signal for delivering through an output line the output current having an AC value corresponding to an AC value of said regulated voltage.