PULSE DENSITY MODULATING AND DEMODULATING CIRCUIT AND INVERTER CONTROLLER USING THE MODULATING AND DEMODULATING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a pulse density modulating and demodulating circuit capable of demodulating a pulse density modulated signal with higher accuracy even when a photocoupler, etc., is used as an electrical insulating means of a transmission line, and an inverter controller that uses the pulse density modulating and demodulating circuit.;SOLUTION: Forward voltage VF of a temperature detecting diode 112 extracted as an analog signal is modulated into a pulse density modulated signal Vout. A stop bit is imparted to the pulse density modulated signal Vout modulated in this way, and the signal SVout imparted with the stop bit is transmitted from a high voltage circuit side to a low voltage circuit side. The transmitted signal SVout is received, the number nx of pulses for a fixed time Tc is counted, and the forward voltage VF of the temperature detecting diode 112 which is extracted as the ratio of the counted number nx of pulses to the maximum number n100 of pulses is demodulated with the maximum number n100 of pulses that can be received in the fixed time Tc as pulse density 100%.;COPYRIGHT: (C)2011,JPO&INPIT