摘要:
PROBLEM TO BE SOLVED: To provide a class D amplifier that keeps from adding to a cost even if increasing an upper limit of a maximum frequency, and keeps an output from becoming unstable because of LC resonance.SOLUTION: The class D amplifier includes: a first output circuit having first and second switching devices connected in series between a first power line for feeding a first potential and a second power line for feeding a second potential lower than the first potential, and adapted to operate complementarily to each other; a first capacitor connected between the first power line and the second power line; a pulse width modulator for generating a pulse-width-modulated switching signal on the basis of a triangular wave and an audio signal to feed the first output circuit; and a slew rate limiting amplifier connected to an input section of the pulse width modulator fed with the audio signal, and limiting a slew rate of an output. A sounding device is connected in series with an inductor connected to a first output node of the first output circuit, and configures an LC filter together with the inductor.
摘要:
PROBLEM TO BE SOLVED: To provide a signal level conversion circuit, and a physical quantity detection device and an electronic apparatus therewith which can convert the signal level of a first input signal without amplifying noise superimposed on a second input signal.SOLUTION: A signal level conversion circuit 1 includes a first differential amplifier circuit 10 and a second differential amplifier circuit 20. The first differential amplifier circuit 10 outputs a potential difference between a first input signal and a second input signal multiplied by G1. The second differential amplifier circuit 20 outputs a potential difference between the output signal of the first differential amplifier circuit 10 and the second input signal multiplied by G2. The two gains G1, G2 satisfy relationships of G1×G2