Semiconductor device, current detecting method, and load drive system

A current detecting method comprising the steps of:

• passing current to a first driver transistor having, a first electrode coupled to an external output terminal to which a load is coupled, and a second electrode coupled to a first voltage terminal to which first voltage is supplied;
• passing sense current to a first sense transistor coupled between a first terminal of a differential amplifier amplifying a potential difference between voltage of the first terminal and voltage of a second terminal and the first electrode of the first drive transistor;
• supplying voltage higher than the first voltage to the second terminal;
• passing current from a first current source coupled to a third terminal outputting detection current to the first voltage terminal;
• and
• detecting value of current flowing in the first drive transistor obtaining the detection current by subtracting current of the first current source from the current based on the sense current.

A load drive system comprising:

• a load;
• a semiconductor device driving the load;
• and
• a semiconductor integrated circuit device controlling the semiconductor device,
• wherein the semiconductor device comprises:
• a drive circuit having an external output terminal to which the load is coupled, a first voltage terminal to which first voltage is supplied, an input voltage terminal to which input voltage is supplied, a first drive transistor having a first electrode coupled to the external output terminal and, a second electrode coupled to the first voltage terminal, and a second drive transistor coupled to the external output terminal and the input voltage terminal;
• and
• a current detection circuit having a power supply voltage terminal to which a power supply voltage is supplied, a differential amplifier amplifying a potential difference between voltage of a first terminal and voltage of a second terminal, a first sense transistor passing sense current between the first terminal and the first electrode of the first drive transistor, a voltage supply circuit supplying voltage to the second terminal higher than voltage supplied to the first voltage terminal,
• a third terminal outputting detection current, a first current source coupled between the third terminal and the first voltage terminal;
• and a control circuit controlling voltage of the voltage supply circuit and current of the first current source, and
• wherein the detection current detected by the current detection circuit is current obtained by subtracting the current of the first current source from the current based on the sense current.