Semiconductor device and power feed system

Abstract

A semiconductor device includes a power supply circuit which generates an output voltage to be supplied to a USB device connected to a USB connector, a sensing circuit which senses an output voltage or an output state of the power supply circuit, a control circuit which controls the power supply circuit, and a register which stores an output set voltage value associated with the power supply circuit or various types of information. The control circuit outputs a notification signal based on a result of sensing by the sensing circuit to the outside.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 a power supply circuit which generates an output voltage to be supplied to a USB device connected to a USB connector;   a sensing circuit which senses the output voltage or an output state of the power supply circuit;   a control circuit which controls the power supply circuit; and   a register which stores an output set voltage value associated with the power supply circuit or various types of information,   the control circuit outputting a notification signal based on a result of sensing by the sensing circuit to outside.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein
 the control circuit has the register store the output set voltage value associated with the power supply circuit or information on a state of the power supply circuit based on the result of sensing by the sensing circuit.   
     
     
         3 . The semiconductor device according to  claim 2 , wherein
 the control circuit has the register store the output set voltage value based on a setting command from the outside.   
     
     
         4 . The semiconductor device according to  claim 2 , wherein
 the sensing circuit includes a temperature abnormal condition determination circuit which determines whether a temperature of the power supply circuit is normal, and   the control circuit has the register store information on the output state of the power supply circuit based on a result of determination by the temperature abnormal condition determination circuit.   
     
     
         5 . The semiconductor device according to  claim 2 , wherein
 the sensing circuit includes a voltage abnormal condition determination circuit which determines whether a voltage of the power supply circuit is normal, and   the control circuit has the register store information on the state of the power supply circuit based on a result of determination by the voltage abnormal condition determination circuit.   
     
     
         6 . A semiconductor device comprising:
 a power supply unit which generates an output voltage to be supplied to a USB device connected to a USB connector; and   a control unit which controls the power supply unit,   the power supply unit including
 a power supply circuit, 
 a sensing circuit which senses an output voltage or an output state of the power supply circuit, 
 a power supply control circuit which controls the power supply circuit, and 
 a register which stores an output set voltage value associated with the power supply circuit or various types of information, 
   the power supply control circuit having the register store the output set voltage value of the power supply circuit or information on a state of the power supply circuit based on a result of sensing by the sensing circuit, and   the control unit performing a prescribed operation based on the output set voltage value of the power supply circuit or the information on the state of the power supply circuit stored in the register.   
     
     
         7 . The semiconductor device according to  claim 6 , wherein
 the power supply control circuit outputs a notification signal to the control unit in response to the result of sensing by the sensing circuit, and   the control unit issues a request to the power supply control circuit for information on the state of the power supply circuit stored in the register based on the notification signal from the power supply control circuit.   
     
     
         8 . The semiconductor device according to  claim 6 , wherein
 the sensing circuit includes a temperature abnormal condition determination circuit which determines whether a temperature of the power supply circuit is normal, and   the power supply control circuit has the register store information indicating that the temperature of the power supply circuit is abnormal when the temperature of the power supply circuit is abnormal as a result of determination by the temperature abnormal condition determination circuit.   
     
     
         9 . The semiconductor device according to  claim 8 , wherein
 the power supply control circuit has the register store information indicating that the temperature of the power supply circuit is normal when the temperature of the power supply circuit is normal as a result of determination by the temperature abnormal condition determination circuit, and   the control unit performs a recovery operation based on information on a state of the temperature of the power supply circuit stored in the register.   
     
     
         10 . The semiconductor device according to  claim 6 , wherein
 the sensing circuit includes a voltage abnormal condition determination circuit which determines whether a voltage of the power supply circuit exceeds a reference value, and   the power supply control circuit has the register store information indicating that a voltage state of the power supply circuit is abnormal when a voltage of the power supply circuit is abnormal based on a result of determination by the voltage abnormal condition determination circuit.   
     
     
         11 . The semiconductor device according to  claim 10 , wherein
 the control unit instructs the power supply control circuit to perform a reset operation to initialize an operation of the power supply unit based on the information indicating that the voltage state of the power supply circuit is abnormal stored in the register.   
     
     
         12 . The semiconductor device according to  claim 11 , wherein
 the control unit counts the number of times of the reset operation performed, and   when the number of times of the reset operation performed is equal to or more than a prescribed number of times, the control unit stops an operation to reset the power supply unit.   
     
     
         13 . A power feed system which feeds power to a USB device connected to a USB connector, the power feed system comprising:
 a control unit which obtains information on an output voltage which can variably be set for driving the USB device by communicating with the USB device; and   a power supply unit which generates an output voltage to be supplied to the USB device based on the obtained information on the output voltage,   the power supply unit including
 a power supply circuit, 
 a sensing circuit which senses an output voltage or an output state of the power supply circuit, 
 a power supply control circuit which controls the power supply circuit, and 
 a register which stores information on the power supply circuit, 
   the power supply control circuit outputting a notification signal based on a result of sensing by the sensing circuit to outside.