摘要:
A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.
摘要:
A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.
摘要:
A class D amplifier includes: an amplifier that generates a digital signal for driving a load based on an input signal; an attenuator that attenuates the input signal according to an attenuation command signal; and a clip prevention controller that outputs the attenuation command signal to intermittently attenuate the input signal when the digital signal is brought into a clip state or a near-clip state.
摘要:
A delay circuit is provided, which is capable of eliminating the influence of noise of low frequency as disturbance. A plurality of memory cells including a plurality of capacitors store an analog signal as an input signal by storing charge of the input signal in the capacitors. A first inverting device inverts the input signal to generate an inverted signal. A control circuit generates and delivers control signals to the memory cells to select the input signal and the inverted signal alternately and sequentially write the selected signals into the memory cells in a predetermined writing sequence. The control circuit further generates and delivers to the memory cells to sequentially read out the input signal and the inverted signal from the memory cells in a sequence corresponding to the predetermined writing sequence. A second inverting device inverts the read-out inverted signal. An output signal is synthesized from the read-out input signal and an output signal of the second inverting device.
摘要:
An analog-digital converter includes a .DELTA..SIGMA. modulator, a digital filter, a high-pass filter and a multiplier which are connected in series. Analog input is converted into serial-bit strings by the .DELTA..SIGMA. modulator, for which gain `1/A` is set. The digital filter extracts low-frequency components, corresponding to the analog input, from the serial-bit strings, so the low-frequency components are converted into parallel-bit digital data. The high-pass filter removes DC offset component from output of the digital filter; and then, output thereof is multiplied by scaling gain `A` by the multiplier so that digital output is produced. The .DELTA..SIGMA. modulator includes at least three switched-capacitor integrators and a one-bit quantizer, which are connected in series, as well as a one-sample delay circuit. One-bit output, produced by the one-bit quantizer, is delayed by the one-sample delay circuit, whose output is delivered to each switched-capacitor integrator. Each switched-capacitor integrator is configured using a CMOS differential amplifier which is configured by a CMOS operational amplifier and at least one amplitude-limiting circuit. The amplitude-limiting circuit is configured by two PMOS transistors and two NMOS transistors which are connected in parallel in a diode-connection manner; and this circuit is provided to limit amplitude in output of the CMOS differential amplifier by stabilizing its operating point.
摘要:
An analog/digital converter where input analog signals are successively converted into digital signals under a time sharing control system; the analog/digital converter includes an integrating portion, a plurality of integrated calculus memory portions, a signal digitalizing portion, a feedback analog signal generating portion, and a switching portion. According to the disclosed analog/digital converter, input analog signals for a plurality of channels or input analog signals for highly-ordered integrating processes can be converted into digital signals without making the size of the circuit large.
摘要:
A D/A converter is formed of a combination of switches and capacitors. A voltage source supplies a plurality of different predetermined voltages corresponding, respectively, to different logical levels of bit data of input digital data. A first switch device is connected to the voltage source for selecting the different predetermined voltages. A first capacitor is connected to the voltage source by way of the first switch device, and charged by the different voltages selected by the first switch device. A second capacitor is connected to the first capacitor by way of a second switch device, for carrying out distribution of charge between the first and second capacitors. A charge-to-voltage converter circuit is associated with the second capacitor, for converting charge from the second capacitor to voltage. A clock signal generator circuit generates clock signals for selectively driving the first and second switch devices, in synchronism with the bit data of the input digital data.
摘要:
A DC/DC converter is constituted of a switching element (e.g., a MOS transistor), an LC low-pass filter constituted of an inductor and a capacitor, and a control circuit for controlling the on/off timing of the switching element such that the output voltage is set to a predetermined voltage value. A series circuit (serving as a snubber circuit) constituted of a resistor and a switch is further connected in parallel with the inductor. The control circuit closes the switch so that the resistor is connected in parallel with the inductor in a resonance mode of the LC low-pass filter. Thus, it is possible to dissipate energy accumulated in the inductor in a short time without using a relatively large circuit scale, thus avoiding the occurrence of ringing.
摘要:
A PWM modulator adds first and second input signals to each other, and performs PWM modulation processing for outputting a PWM-modulated pulse whose pulse width is modulated according to a result of addition. A shift register delays a bit stream acquired from a ΔΣ modulator, thereby generating two bit streams having a time difference which is one-half a period of PWM modulation processing, and the bit streams are supplied at first and second input signals to the PWM modulator.
摘要:
A class-D amplifier for pulse-width-modulating an analog input signal to output a pulse-width-modulated signal, includes: a differentiating circuit for differentiating the pulse-width-modulated signal of the class-D amplifier; and a negative feedback circuit for feeding back the differentiated signal of the differentiating circuit to an input side of the class-D amplifier in a negative feedback manner.