| 摘要 |
PURPOSE:To reduce power consumption by filtering inputted ON-OFF signals for reduction in accordance with a high speed clock to satisfy a sampling theorem and by turning ON and OFF switching elements with a PWM signal converted in code with a SIGMA modulation. CONSTITUTION:By sampling 11 an input signal on a high speed in accordance with a high speed clock generated by a clock generator 12, a pulse train of 0 or 1 is outputted. Noise components are removed by a digital LPF 13 and it is outputted as n bits, which are quantized into 1 bits once again by a SIGMAmodulator 14 and outputted as a PWM modulated wave to drive an inductive load through a switching transistor 15. In the SIGMA modulator 14 the value where the output of an adder 141 is quantized into a 1 bit by a quantizer 142 and the result is delayed 143, the value where the output of the adder 141 is delayed 144 and a filter output are added 141 and the operation to quantize again is repeated in accordance with the high speed clock. The switching transistor can thereby be used and the power consumption reduced. |
