System and method for coded communication signals regulating inductive power transmission

Abstract

An inductive power transfer system and method for transferring power to an electrical device wirelessly include an inductive power outlet and an inductive power receiver. During operation, instruction signals are sent from the inductive power outlet to the inductive power receiver. When no instruction signals are transferred, the system is configured to deactivate such that power is drawn by the system only during operation.

What is claimed is: 
     
         1 . A signal transmission circuit for a wireless power receiver, said wireless power receiver comprising: a secondary inductive coil; and at least one electrical element selectively connectable to the secondary inductive coil by a switching unit;
 wherein:   said signal transmission circuit is configured to generate at least one coded signal by connecting said electrical element to said secondary inductive coil in pulses having an identifiable characteristic frequency.   
     
     
         2 . The signal transmission circuit of  claim 1 , wherein said identifiable characteristic frequency is selected from at least one of a group consisting of: 250 hertz, 500 hertz, 1 kilohertz, 1.5 kilohertz, 5 kilohertz and 8 kilohertz. 
     
     
         3 . The signal transmission circuit of  claim 1 , wherein said coded signal comprises an identification signal, said identification signal transmitted in response to an initial power pulse received from a wireless power outlet. 
     
     
         4 . The signal transmission circuit of  claim 3 , wherein said identification signal is selected from at least:
 a first signal to instruct the wireless power outlet to drive at least one primary inductive coil at a first operating power; and   a second signal to instruct the wireless power outlet to drive said at least one primary inductive coil at a second operating power.   
     
     
         5 . The signal transmission circuit of  claim 1 , wherein said coded signal comprises a termination signal to instruct a wireless power outlet to cease driving an associated primary inductive coil when said coded signal is detected. 
     
     
         6 . The signal transmission circuit of  claim 1 , wherein said coded signal comprises a perpetuation signal, said perpetuation signal transmitted to a wireless power outlet when power received lies within a permissible range of values to instruct the wireless power outlet to continue driving an associated primary inductive coil at the same power level. 
     
     
         7 . The signal transmission circuit of  claim 1 , wherein said coded signal comprises a power increase signal, said power increase signal transmitted to a wireless power outlet when said power received lies below a threshold value. 
     
     
         8 . The signal transmission circuit of  claim 1 , wherein said coded signal comprises a power decrease signal, said power decrease signal transmitted to a wireless power outlet when said power received lies above a threshold value. 
     
     
         9 . A method for regulating wireless power transmission from a wireless power outlet to a wireless power receiver across an inductive coupling, said inductive coupling comprising at least one primary inductive coil associated with said wireless power outlet and a secondary inductive coil associated with said wireless power receiver, the method comprising:
 driving said primary inductive coil at an initial operating power;   monitoring induced voltage in said secondary inductive coil;   connecting, by a signal transmission circuit associated with said wireless power receiver, an electrical element to said secondary inductive coil in pulses having an identifiable characteristic frequency thereby transmitting at least one control signal; and   detecting, by a signal reception circuit associated with said wireless power outlet, said control signal as pulses in primary voltage or primary current with said identifiable characteristic frequency.   
     
     
         10 . The method of  claim 9  wherein said characteristic frequency is selected from at least one of a group consisting of: 250 hertz, 500 hertz, 1 kilohertz, 1.5 kilohertz, 5 kilohertz and 8 kilohertz. 
     
     
         11 . The method of  claim 9  further comprising at least one of:
 if said signal reception circuit detects pulses in primary voltage or primary current having a characteristic frequency associated with a power increase signal then increasing operating power by an increment; and 
 if said signal reception circuit detects pulses in primary voltage or primary current having a characteristic frequency associated with a power decrease signal then decreasing operating power by an increment. 
 
     
     
         12 . The method of  claim 9  further comprising:
 said signal reception circuit detecting pulses in primary voltage or primary current having a characteristic frequency associated with a perpetuation signal; and 
 driving said primary inductive coil at the same power. 
 
     
     
         13 . The method of  claim 9  further comprising:
 said signal reception circuit detecting pulses in primary voltage or primary current having a characteristic frequency associated with a termination signal, and 
 ceasing to drive said primary inductive coil. 
 
     
     
         14 . A signal reception circuit for a wireless power outlet, said wireless power outlet comprising at least one primary inductive coil,
 wherein:   said signal reception circuit is configured to detect at least one coded signal detectable as a pulse having an identifiable characteristic frequency.   
     
     
         15 . The signal reception circuit of  claim 14 , wherein said characteristic frequency is selected from at least one of a group consisting of: 250 hertz, 500 hertz, 1 kilohertz, from 1.5 kilohertz to 5 kilohertz and 8 kilohertz. 
     
     
         16 . The signal reception circuit of  claim 14 , wherein said coded signal comprises an identification signal selected from at least:
 a first signal instructing the wireless power outlet to operate at a first operating power; and   a second signal instructing the wireless power outlet to operate at a second operating power.   
     
     
         17 . The signal reception circuit of  claim 14 , wherein said coded signal comprises a termination signal instructing the wireless power outlet to cease operating. 
     
     
         18 . The signal reception circuit of  claim 14 , wherein said coded signal comprises a perpetuation signal, said perpetuation signal instructing the wireless power outlet to continue operating at the same power level. 
     
     
         19 . The signal reception circuit of  claim 14 , wherein said coded signal comprises a power increase signal instructing the wireless power outlet to increase operating power. 
     
     
         20 . The signal reception circuit of  claim 14 , wherein said coded signal comprises a power decrease signal instructing the wireless power outlet to decrease operating power.