| 摘要 |
A pulse width modulation apparatus having a storage circuit for temporarily storing pulse width data inputted over a data bus and then inverting it, the pulse width data determining a pulse width, a counting circuit for counting a clock signal in response to an external pulse width modulation enable signal and an external reset signal, a comparison circuit for comparing the number of logical 0 bits of the inverted pulse width data from the storage circuit with the number of logical 1 bits of count data from the counting circuit and outputting a high signal when the number of the logical 0 bits of the inverted pulse width data is greater than or equal to the number of the logical 1 bits of the count data and a low signal when the number of the logical 0 bits of the inverted pulse width data is smaller than the number of the logical 1 bits of the count data, and an output circuit for latching an output signal from the comparison circuit to output a pulse width modulation signal. Therefore, since the comparison of the pulse width data and the count data are performed only with PMOS and NMOS transistors of different current gains in the comparison circuit, the processing time can be reduced and the integration can be enhanced in manufacturing a single chip.
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