In-vehicle semiconductor device

An in-vehicle semiconductor device, comprising:

• a first regulator that converts a voltage level of a first voltage externally supplied, to generate a second voltage;
• a second regulator that converts a voltage level of the first voltage to generate a third voltage;
• an internal circuit to which each of the second voltage and the third voltage is provided;
• and
• a voltage monitoring unit that monitors the first, second, and third voltages,
• wherein the internal circuit includes:
• a processor that is operated by the second voltage provided from the first regulator;
• and
• an oscillator that is operated by the third voltage provided from the second regulator, the oscillator generating a clock signal serving as an operation clock for the processor,
• the voltage monitoring unit stops providing the clock signal to the processor when a voltage level of at least any one of the first, second and third voltages is below a set value, and provides the clock signal to the processor when voltage levels of all the first, second and third voltages exceed the set value,
• wherein the voltage monitoring unit includes:
• a voltage monitoring circuit that outputs a first control signal when a voltage level of at least one of the first, second and third voltages is below the set value, and outputs a second control signal when all the voltage levels of the first, second and third voltages exceed the set value;
• a switch unit that provides or stops providing the clock signal to the processor on the basis of the first control signal or the second control signal output from the voltage monitoring circuit,
• wherein the voltage monitoring circuit includes:
• a first voltage drop detecting circuit that outputs a first detection signal when the voltage level of the first voltage is below a first set value, and outputs a second detection signal when the voltage level of the first voltage exceeds the first set value;
• a second voltage drop detecting circuit that outputs a third detection signal when the voltage level of the second voltage is below a second set value, and outputs a fourth detection signal when the voltage level of the second voltage exceeds the second set value;
• a third voltage drop detecting circuit that outputs a fifth detection signal when the voltage level of the third voltage is below a third set value, and outputs a sixth detection signal when the voltage level of the third voltage exceeds the third set value;
• and
• a control-signal generator that outputs the first control signal to the switch unit when at least any one of the first, third and fifth detection signals is input, and outputs the second control signal to the switch unit when all the second, fourth and sixth detection signals are input.