Detecting and driving load using MOS transistor

1. A semiconductor high-side driver comprising:

a power supply terminal;

an input terminal;

an output terminal to be coupled to a load element;

an output MOS transistor having a drain coupled to the power supply terminal, a source coupled to the output terminal and a gate;

a sense MOS transistor having a drain coupled to the power supply terminal, a gate coupled to the gate of the output MOS transistor and a source;

a control circuit coupled to the input terminal and provides a control signal to the gate of the output MOS transistor; and

a voltage detection circuit which includes:

a threshold voltage generation circuit having a first terminal coupled to the power supply terminal and a second terminal which generates a voltage lower than a voltage of the power supply terminal by a threshold voltage; and

a comparator having:

a first input coupled to the second terminal of the threshold voltage generation circuit;

a second input coupled to the source of the sense MOS transistor; and

an output for providing a detection signal, wherein the detection signal is of a high level when a voltage at the first input thereof is higher than a voltage at the second input thereof, and wherein the detection signal is of a low level when a voltage at the first input thereof is lower than a voltage at the second input thereof.

2. A semiconductor high-side driver according to claim 1 , further comprising:

a semiconductor substrate having:

a main surface where a first source electrode serving as the source of the output MOS transistor, a second source electrode serving as the source of the sense MOS transistor and an electrode coupled to the first terminal of threshold voltage generation circuit are formed, and

a back surface where a drain electrode serving as the drain of the output MOS transistor and the drain of the sense MOS transistor is formed.

3. A semiconductor high-side driver according to claim 2 ,

wherein the second source electrode is surrounded by the first source electrode in a plan view.

4. A semiconductor high-side driver according to claim 2 ,

wherein the first source electrode has an opening where the second source electrode is formed in the plan view.

5. A semiconductor high-side driver according to claim 2 ,

wherein the semiconductor substrate comprises:

a first semiconductor region of a first conductive type;

the drain electrode electrically connected with the first semiconductor region;

a second semiconductor region joined with the first semiconductor region and being of a second conductive type which is different from the first conductive type;

a first layer of the first conductive type, formed in the second semiconductor region and served as the source of the output MOS transistor;

a third semiconductor region of the second conductive type joined with the first semiconductor region;

a second layer of the first conductive type, formed in the third semiconductor region and served as the source of the sense MOS transistor;

a gate insulating film;

a gate electrode disposed to oppose to the first semiconductor region, the second semiconductor region and the third semiconductor region through the gate insulating film; and

the electrode electrically connected with the first semiconductor region.