PWM (pulse width modulation) signal outputting circuit and method of controlling output of PMW signal

1. A PWM (Pulse Width Modulation) signal outputting circuit, comprising:

a counting unit for counting a number of clocks to output a counter value, and for resetting the counter value to resume counting when a reset signal is input to the counting unit;

a dead time value storage unit for storing a dead time value; and

a plurality of PWM signal outputting units for setting a start setting value and a termination setting value, each of the PWM signal outputting units being configured to generate a termination signal and a start signal, each of said PWM signal outputting units being configured to output a PWM signal, which is raised according to the start signal generated by itself and is decreased according to the termination signal generated by itself, each of said PWM signal outputting units being configured to generate the termination signal when the counter value matches to the termination setting value generated by itself,

wherein said PWM signal outputting units includes a front stage PWM signal outputting unit for generating the PWM signal that is raised first, and a later stage PWM signal outputting unit for generating the PWM signal that is raised next after the PWM signal that is raised first,

said later stage PWM signal outputting unit is configured to generate the start signal when a sum of the termination setting value generated by the front stage PWM signal outputting unit and the dead time value matches to the counter value, and when a difference between the start setting value generated by itself and the termination setting value generated by the front stage PWM signal outputting unit is smaller than the dead time value,

said later stage PWM signal outputting unit is configured to generate the start signal when the start setting value generated by itself matches to the counter value, and when the difference is greater than the dead time value,

said front stage PWM signal outputting unit is configured to generate the start signal when the dead time value matches to the counter value, and when the start setting value generated by itself is smaller than the dead time value, and

said front stage PWM signal outputting unit is configured to generate the start signal when the start setting value generated by itself matches to the counter value, and when the start setting value generated by itself is greater than the dead time value.

2. The PWM signal outputting circuit according to claim 1 , wherein each of said PWM signal outputting units includes,

a start setting value storage unit for storing the start setting value;

a termination setting value storage unit for storing the termination setting value;

a termination comparing unit for generating and outputting the termination signal;

a start comparing unit for generating and outputting the start signal; and

an output control unit for generating and outputting the PWM signal.

3. A PWM (Pulse Width Modulation) signal outputting circuit, comprising:

a counting unit for counting a number of clocks to output a counter value, and for resetting the counter value to resume counting when a reset signal is input to the counting unit;

a dead time value storage unit for storing a dead time value;

a first PWM signal outputting unit configured to set a first start setting value and a first termination setting value, said first PWM signal outputting unit being configured to generate a first termination signal and a first start signal, said first PWM signal outputting unit being configured to output a first PWM signal to be raised according to the first start signal and decreased according to the first termination signal; and

a second PWM signal outputting unit configured to set a second start setting value and a second termination setting value, said second PWM signal outputting unit being configured to generate a second termination signal and a second start signal, said second PWM signal outputting unit being configured to output a second PWM signal to be raised according to the second start signal and decreased according to the second termination signal, said second PWM signal outputting unit being configured to output the second PWM signal before the first PWM signal outputting unit outputs the first PWM signal,

wherein said first PWM signal outputting unit is configured to generate the first termination signal when the counter value matches to the first termination setting value,

said second PWM signal outputting unit is configured to generate the second termination signal when the counter value matches to the second termination setting value,

said first PWM signal outputting unit is configured to generate the first start signal when a sum of the second termination setting value and the dead time value matches to the counter value, and when a difference between the first start setting value and the second termination setting value is smaller than the dead time value,

said first PWM signal outputting unit is configured to generate the first start signal when the first start setting value matches to the counter value, and when the difference is greater than the dead time value,

said second PWM signal outputting unit is configured to generate the second start signal when the second start setting value is smaller than the dead time value, and when the dead time value matches to the counter value, and

said second PWM signal outputting unit is configured to generate the second start signal, and when the second start setting value is greater than the dead time value when the second start setting value matches to the counter value.

4. The PWM signal outputting circuit according to claim 3 , wherein said first PWM signal outputting unit includes,

a first start setting value storage unit for storing the first start setting value;

a first termination setting value storage unit for storing the first termination setting value;

a first termination comparing unit for generating and outputting the first termination signal;

a first start comparing unit for generating and outputting the first start signal; and

a first output control unit for generating and outputting the first PWM signal.

5. The PWM signal outputting circuit according to claim 3 , wherein said second PWM signal outputting unit includes,

a second start setting value storage unit for storing the second start setting value;

a second termination setting value storage unit for storing the second termination setting value;

a second termination comparing unit for generating and outputting the second termination signal;

a second start comparing unit for generating and outputting the second start signal; and

a second output control unit for generating and outputting the second PWM signal.

6. A method of controlling an output of a PMW (Pulse Width Modulation) signal output from a PWM signal outputting circuit, said PWM signal outputting circuit including:

a counting unit for counting a number of clocks to output a counter value, and for resetting the counter value to resume counting when a reset signal is input to the counting unit;

a dead time value storage unit for storing a dead time value;

a first PWM signal outputting unit configured to set a first start setting value and a first termination setting value, said first PWM signal outputting unit being configured to generate a first termination signal and a first start signal, said first PWM signal outputting unit being configured to output a first PWM signal to be raised according to the first start signal and decreased according to the first termination signal; and

a second PWM signal outputting unit configured to set a second start setting value and a second termination setting value, said second PWM signal outputting unit being configured to generate a second termination signal and a second start signal, said second PWM signal outputting unit being configured to output a second PWM signal to be raised according to the second start signal and decreased according to the second termination signal, said second PWM signal outputting unit being configured to output the second PWM signal before the first PWM signal outputting unit outputs the first PWM signal,

wherein the method comprises the steps of:

generating the first termination signal with the first PWM signal outputting unit when the counter value matches to the first termination setting value;

generating the second termination signal with the second PWM signal outputting unit when the counter value matches to the second termination setting value;

generating the first start signal with the first PWM signal outputting unit when a sum of the second termination setting value and the dead time value matches to the counter value, and when a difference between the first start setting value and the second termination setting value is smaller than the dead time value; and

generating the first start signal with the first PWM signal outputting unit when the first start setting value matches to the counter value, and when the difference is greater than the dead time value.