Procedure for charging a portable device using a battery-operated computer

Abstract

A method of charging a battery of a device using a battery of a computer powered by the battery, in which the procedure is implemented by a circuit independent of the computer's processors. The method includes supplying a power supply voltage, insufficient to charge a battery, to a computer port, as long as a device is detected as connected to the port, controlling the supply of a charging voltage to the port, while supplying charging voltage to the port, detecting an end of charging condition of a battery of the device, and controlling the cutting off of the charging voltage to the port if the end of charging condition is detected, where this condition is determined according to the intensity of a charging current and according to a quantity of electrical charge supplied to the port and/or of a charging period.

1 .- 21 . (canceled) 
     
     
         22 . A device, comprising:
 an input configured to couple to a supply voltage line;   detection circuitry configured to couple to a port and to generate a detection signal indicating an external device is coupled to the port; and   sleep-mode charge-control circuitry configured to generate a sleep-mode charge-control signal based on an indication of an intensity of a charging current of a charging voltage line and a counting signal, wherein the sleep-mode charge-control circuitry is configured to detect an end of charging condition when a threshold quantity of electrical charge has been supplied to the port.   
     
     
         23 . The device according to  claim 22  wherein the sleep-mode charge-control circuitry comprises:
 a comparator configured to compare the intensity of the charging current to a current threshold value corresponding to an expected intensity of a charging current at an end of a charging cycle and to generate the indication of the intensity of the charging current; 
 a counter configured to generate an indication a charging time has elapsed; and 
 a logic circuit configured to generate the charge-control signal based on the detection signal, the indication of the intensity of the charging current and the indication the charging time has elapsed. 
 
     
     
         24 . The device according to  claim 22  wherein the counter is configured to indicate the charging time has elapsed when a threshold charging period has elapsed. 
     
     
         25 . The device according to  claim 22  wherein the detection circuitry comprises:
 a finite-state machine configured to supply the detection signal; 
 a bypass switch configured to couple the supply voltage line to the port; 
 a discharge switch configured to control discharging of capacitors coupled to the port; and 
 a current limiter inserted on a link coupling the supply voltage line to the port, wherein the state machine is configured to receive a signal representative of a voltage drop on the link coupling the supply voltage line to the port, a signal indicating a current limit of the current limiter has been exceeded, and a signal indicating a charging voltage is present. 
 
     
     
         26 . A method, comprising:
 putting a computer into a sleep mode, the computer having a battery, one or more processors, a port, and charge-control circuitry; and   in response to an indication of an external device being coupled to the port, controlling, by the charge-control circuitry, supply of a charging voltage to the port during the sleep mode, the controlling including detecting an end of charging condition of the external device based on an indication of an intensity of a charging current and a counting signal, wherein the end of charging condition is considered detected in response to an indication that an amount of electrical charge supplied to the port is higher than a threshold amount of charge.   
     
     
         27 . The method according to  claim 26  wherein the end of charging condition is considered detected in response an indication that the intensity of the charging current is lower than a threshold charging current. 
     
     
         28 . The method according to  claim 26  wherein the end of charging condition is considered detected in response to an indication that a charging period has exceeded a threshold charging period. 
     
     
         29 . The method according to  claim 26 , comprising generating the indication of a device connected to the port in response to detection of a current intensity drop on a line supplying power to the port. 
     
     
         30 . A system, comprising:
 a port;   power supply circuitry configured to generate a supply voltage and a charging voltage; and   a port-charging control device configured to control charging of external devices in a system sleep mode, the port-charging control device including:
 detection circuitry coupled to the port and configured to generate a detection signal indicating an external device is coupled to the port; and 
 charge-control circuitry configured to generate a charge-control signal based on an indication of an intensity of a charging current of a charging voltage line and a counting signal, wherein the charge-control circuitry is configured to detect an end of charging condition when a threshold quantity of electrical charge has been supplied to the port. 
   
     
     
         31 . The system of  claim 30  wherein the charge-control circuitry is configured to detect an end of charging condition when an intensity of the charging current is lower than a threshold charging current. 
     
     
         32 . The system of  claim 30  wherein the detection circuitry comprises:
 a finite-state machine configured to supply the detection signal; 
 a bypass switch configured to couple a supply voltage line to the port; 
 a discharge switch configured to control discharging of capacitors coupled to the port; and 
 a current limiter inserted on a link coupling the supply voltage line to the port, wherein the state machine is configured to receive a signal representative of a voltage drop on the link coupling the supply voltage line to the port, a signal indicating a current limit of the current limiter has been exceeded, and a signal indicating a charging voltage is present. 
 
     
     
         33 . The system of  claim 30  wherein the charge-control circuitry comprises:
 a comparator configured to compare the intensity of the charging current to a current threshold value corresponding to an expected intensity of a charging current at an end of a charging cycle and to generate the indication of the intensity of the charging current; 
 a counter configured to generate an indication a charging time has elapsed; and 
 a logic circuit configured to generate the charge-control signal based on the detection signal, the indication of the intensity of the charging current and the indication the charging time has elapsed.