Wireless power receiving apparatus

1. A control circuit for a wireless power receiving apparatus, comprising:

a current detection unit that detects a current I that flows through a predetermined path;

a received power calculation unit that calculates an electric power consumption P D of the wireless power receiving apparatus based on a predetermined function f D (I) with the current I as an argument;

a parameter acquisition unit that acquires parameters α 1 through α N to be respectively set for N (N represents an integer of 2 or more) segments obtained by dividing a range of the current I into N segments; and

a correction unit that corrects the electric power consumption P D calculated by the received power calculation unit using the parameter α i when the current I is included in the i-th (1≤i≤N) segment.

2. The control circuit according to claim 1 , wherein the j-th (1≤j≤N) parameter α j is used to correct a slope of the received electric power P RPj for the current I for the j-th segment.

3. The control circuit according to claim 2 , wherein, with a threshold that determines a boundary between the i-th segment and the (i+1)-th segment as I i , the correction unit calculates the received electric power P RPi for the j-th segment according to correction expressions that include:

P RP1 =α 1 ×f D ( I );

P RP2 =α 2 ×f D ( I−I 1 )+α 1 ×f D ( I 1 );

P RP3 =α 3 ×f D ( I−I 2 )+α 2 ×f D ( I−I 1 )+α 1 ×f D ( I 1 );

and the like.

4. The control circuit according to claim 1 , wherein, in addition to the parameters α 1 through α N , the parameter acquisition unit is configured to acquire a parameter β via an external component,

and wherein the correction unit adds the parameter β to the received electric power P RP .

5. The control circuit according to claim 1 , wherein, with a threshold that determines a boundary between the i-th segment and the (i+1)-th segment as I i , the parameter acquisition unit is further configured to acquire, via an external component, parameters that indicate threshold values I 1 through I N-1 .

6. The control circuit according to claim 1 , wherein the parameter acquisition unit comprises:

an interface circuit that receives, via an external processor, serial data including an external parameter; and

a register that stores the parameter thus received.

7. The control circuit according to claim 1 , wherein the parameter acquisition unit is configured to be coupled to a plurality of resistors as external components,

and wherein the parameter acquisition unit is configured to acquire the parameters α 1 through α N according to resistance values of the plurality of respective resistors thus connected.

8. The control circuit according to claim 1 , wherein the current detection unit is configured to measure a current I LOAD that flows through a load of the wireless power receiving apparatus,

and wherein the function f D (I) is defined with the current I LOAD as an argument.

9. The control circuit according to claim 8 , wherein, in addition to the control circuit, the wireless power receiving apparatus further comprises:

a reception coil;

a rectifier circuit that rectifies a current that flows through the reception coil; and

a smoothing capacitor that is connected to an output of the rectifier circuit, so as to generate a rectified voltage V RECT ,

and wherein the function f D (I LOAD ) includes a term represented by (V RECT ×I LOAD ).

10. The control circuit according to claim 9 , wherein the function f D (I LOAD ) further includes a term (R ON ×I LOAD 2 ) with R ON as a predetermined constant.

11. The control circuit according to claim 9 , wherein the control circuit comprises:

a power supply current measurement unit that measures an operation current I DD that flows through the control circuit; and

a voltage measurement unit that measures a power supply voltage V DD supplied to the control circuit,

and wherein the function f D (I LOAD ) further includes a term (V DD ×I DD ).

12. The control circuit according to claim 11 , wherein the control circuit operates using the rectified voltage V RECT as the power supply voltage V DD .

13. The control circuit according to claim 1 , that conforms to the Qi standard.

14. The control circuit according to claim 1 , monolithically integrated on a single semiconductor substrate.

15. A wireless power receiving apparatus comprising:

a reception coil;

a rectifier circuit that rectifies a current that flows through the reception coil;

a smoothing capacitor that is connected to an output of the rectifier circuit, so as to generate a rectified voltage V RECT ; and

the control circuit according to claim 1 .

16. An electronic device comprising:

a reception coil;

a rectifier circuit that rectifies a current that flows through the reception coil;

a smoothing capacitor that is connected to an output of the rectifier circuit, so as to generate a rectified voltage V RECT ; and

the control circuit according to claim 1 .